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Author Topic: Amps Generated by Solar Panels  (Read 1195 times)

Dreamsend

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Amps Generated by Solar Panels
« on: January 11, 2018, 11:04:29 AM »
I've received my estimate from AM Solar so just checking and rechecking the plan.  I see that theoretically, or that is to say, in good sunlight, one may be able to expect UP TO about 5.5 amps per 100 Watts per hour of solar installed.  Ignoring extraneous variables for this comparison, I was planning on having 720 Watts, with a charge controller and hybrid inverter/charger big enough to fit my power needs (like NO AC off-grid).  I'll be in the southwest in the winter, and western CO to maybe central ID in the summer.  So, without checking astronomical charts, I'm thinking maybe 8 hours decent charging on good summer day, and 6 hours charging (with southern tilt) in the winter.  I know the panels will generate some power in the presence of any sunlight, but I'm trying to capture the bulk with this example.

Based on this, I would therefore expect something in the range of up to 320 amps in the summer 6 mos. and 230 amps in the winter mos. per day -- again, ignoring hours on either side of optimum.

When I asked AM Solar just how many amps I could expect in the summer from 720 watts of panels, they responded "about 200A per day".  So this number would take into account loses due to wire runs and maybe?  inversion losses?, but I have to ask for clarification on that.  He may have responded with "usable amps per day" as opposed to just raw amps into the system.

Can those of you with ACTUAL EXPERIENCE using bigger solar systems comment?  What kind of average or summer vs. winter, tilt vs. non tilt do you actually see?

I'd like to determine if I do/do not need/want another panel.

Thanks in advance
Linda
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

Paul & Ann

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Re: Amps Generated by Solar Panels
« Reply #1 on: January 11, 2018, 11:27:57 AM »
I agree with AM Solar's estimate.  A rough formula I use is [(watts/13.5volts)x.8]x5= average daily amp hours.  Where 13.5 volts is about minimum voltage necessary to charge a battery bank, .8 is 80% max efficiency of the solar panels, and  5 is hours of max output.  So 720watts/13.5 volts is  53.3 amp hours x 80% efficiency is 42.6 amps, x 5 hours at max efficiency per day is 213.3 amp hours.   Tilting panels to the proper angle will probably improve these numbers.
Paul & Ann  Iowa
2005 Winnebago Voyage 38J
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Gary RV_Wizard

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Re: Amps Generated by Solar Panels
« Reply #2 on: January 11, 2018, 01:33:04 PM »
Also remember that any estimate they give you is likley to be very conservative, since they don't want you coming back and claiming they promised large number of amps/day the system doesn't always deliver.  5.5 amps/day sounds like the raw output from the panel, and that gets reduced to some number of amps @ 12.6v actually placed in the batteries.  When talking per day or hour or any time period, you need to talk amp-hours delivered, not just amps.

Think of your system as a water tank, where the batteries are the tank. Your solar panel pours water (amps) in the top of the tank (battery bank) while you draw water (amps) out the bottom via a faucet. In incoming amps may be greater or lesser than the outflow and the tank (battery bank) stores any excess amps-hours.  It gives the stored excess out later when there is no incoming to replace it.  You size the battery bank to meet your daily power demands, with some excess for back-up on those days when you cannot replenish it. You size the solar array to be able to replace the amps you use from the battery bank each day, not for the peak DC power demand. The battery bank acts as a storage buffer to handle peak loads beyond what the panels can provide. If you are always in regions where plenty of sun is available, you may not need a large solar array because it refills the battery bank over a long period almost every day, but you may need a large battery bank (amp-hours stored) to meet peak demands and night time usage.
Gary
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Gary Brinck
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John From Detroit

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Re: Amps Generated by Solar Panels
« Reply #3 on: January 11, 2018, 05:27:52 PM »
Interesting they said 200 anps per day
AMPS is a flow rate (kind of like Gallons per minute)
AMP HOURS is a quantity  (GPM times Minutes)
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Dreamsend

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Re: Amps Generated by Solar Panels
« Reply #4 on: January 12, 2018, 02:26:14 AM »
Thanks all for your replies.  Yah, the amp vs. amp-hr term usage is my doing.  In my head I know what I was saying/intended, which is amp-hrs, but I think only quickly as amps, so I didn't catch it when I typed.  I'm certain AMS intended amp-hrs. 

Thank you Gary for the nice explanation as it did help me see things better. Today I'm going to try to estimate daily hours of usage to fill in my energy chart and see where I end up in comparison to the anticipated approx. 200 amphrs/day from the panels.

Paul -- I'm installing lithium so is the 13.8 still the charge voltage to use in your formula?  This  is the piece I don't fully understand yet i.e panel and  batt voltages in this system setup.  The specs for the sugessted battery says adsorption 14 to 14.6V and float 13.6 to 13.8V -- I know what those terms mean.  Specs state a charge efficiency of 99%.

L
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

VallAndMo

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Re: Amps Generated by Solar Panels
« Reply #5 on: January 12, 2018, 05:06:54 AM »
Hello Linda,

I'll be in the southwest in the winter, and western CO to maybe central ID in the summer.  So, without checking astronomical charts, I'm thinking maybe 8 hours decent charging on good summer day, and 6 hours charging (with southern tilt) in the winter.

Well, as someone who occasionally dabbles in astronomy, I think I can give you some info on that. Using the planetarium app I have installed on my phone, here's what I get:

Tucson, AZ Dec 21 2018 (Winter Solstice, aka shortest day of the year, ie your worst winter charging day): Sun climbs over 15 degrees above horizon[1] at 08:51, and goes back down below that same line at 15:53, so you have exactly 07h02m of presumably-good-for-charging sunlight.

Salmon, ID Sep 21 2018 (Eve of Fall Equinox aka last day of Summer, again your worst charging day): Sun will stay above 15 degrees over horizon [1] from 08:53 to 18:04, so 9h11m of good sun on your panels.

Therefore I think (unless some of my premises are wrong) that you could safely consider at least 1 hour more of charging time per day.

[1] 15 degrees is my *guess* (from somewhat unrelated astronomical information) for the minimum height above the horizon where decent solar charging (with tilted panels on winter) is possible; someone please correct me if I'm wrong.

Cheers,
--
   Vall.

« Last Edit: January 12, 2018, 05:10:20 AM by VallAndMo »

Dreamsend

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Re: Amps Generated by Solar Panels
« Reply #6 on: January 12, 2018, 05:12:16 AM »
Very cool Vall.!   The sun beaming down is about the only thing I really understand about the system I'm looking at.   :D

L
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

VallAndMo

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Re: Amps Generated by Solar Panels
« Reply #7 on: January 12, 2018, 05:22:12 AM »
Hi Linda,

Glad you liked it. These numbers don't change much from city to city in about a 300mi range, but if you want numbers for different locations, just send me a holler.

Cheers,
--
   Vall.

AStravelers

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Re: Amps Generated by Solar Panels
« Reply #8 on: January 12, 2018, 07:50:53 AM »
Thanks all for your replies.  Yah, the amp vs. amp-hr term usage is my doing.  In my head I know what I was saying/intended, which is amp-hrs, but I think only quickly as amps, so I didn't catch it when I typed.  I'm certain AMS intended amp-hrs. 

Thank you Gary for the nice explanation as it did help me see things better. Today I'm going to try to estimate daily hours of usage to fill in my energy chart and see where I end up in comparison to the anticipated approx. 200 amphrs/day from the panels.

Paul -- I'm installing lithium so is the 13.8 still the charge voltage to use in your formula?  This  is the piece I don't fully understand yet i.e panel and  batt voltages in this system setup.  The specs for the sugessted battery says adsorption 14 to 14.6V and float 13.6 to 13.8V -- I know what those terms mean.  Specs state a charge efficiency of 99%.

L
How many AH's of lithium battery are you installing & which manufacture of the battery is AMS providing?  With 720watts of solar, 400-500AH would be a good number, although more AH wouldn't be bad.

Will your lithium battery have a BMS (Battery Management System) to protect it from over charging or over discharging?  Does the BMS also display the individual battery cell voltage, & temperature?  Some people consider the BMS critical, others don't even bother with installing a BMS.  I have a BMS on my lithium that does the above, and consider it something I would not be without.  I always like to "know" what any of my systems are doing.  Not just my batteries and charging systems, but vehicle engines, etc.

Did you do an energy usage assessment for what you expect to be using on a daily basis?  What did you come up with?

Are you installing a battery monitor, such as a Trimetric?  For anyone doing extensive dry camping or boondocking a good monitor is something I would not be without. 

Is your charge controller and inverter/charger programmable so you can set/change the charging parameters?   

13.8 to 14.0 is about right for the charge voltage.  14.2-14.4 would be on the high side.  AMS should be very knowledgeable about the charge parameters for the batteries they are installing.

About the exact amount of amps and/or amp hours you get from your solar panels, that is extremely variable, based on time of year, how far N or S you are, how much haze/dust/clouds are in the sky.   You will start getting 1-3 amps from the panels, shortly after daylight.  However with heavy cloud cover you will get very little, but still some amps from the panels.  Think in the range of 3-10amps from 720watts depending on just how thick the clouds are.  Consider being very conservative with power usage on very cloudy days.

What size wire is being used from the combiner box on the roof to the charge controller?  Did you use a wire size calculator to check the percentage of voltage drop based on the wire size and length of the wire.  Note, that the length is not just for a one way trip but the round trip, i.e. double the length from the combiner box to the controller.  Increasing the wire size so that you have a 1% voltage drop instead of a 3-5% drop does not cost much more but helps in how may usable amps you get to the batteries. 

A better consideration than know precisely how many amps you will get from 720watts, is to size your system so you have at least as many watts as you have AH's of battery.  Having more watts of solar than AH of battery is better.  So if you have 400AH-500AH of lithium and 720watts of solar that is a very good system.

Is your controller a MPPT?  Are your solar panels all in series or a series/parallel configuration.  You probably already know that shading one cell of one panel pretty much kills all the panels in that series of panels.  So something like a TV antenna, or air conditioner shroud, or tree branch, shading part of one panel really affects your system.  This is more important than knowing the precise number of amps coming from the panels. 

About tilting the panels.  How do you feel about getting up on the roof and putting the panels down in a 25mph wind with gusts to 40mph?  No one belongs on the roof in that kind of wind.  Also consider how often you will be moving.  If you are going to boondock in one spot for a week or month or two, tilting panels is one thing, but putting them up and down every 2-3 days gets old pretty quick.  Also consider, all the panels in a series configuration must be tilted or there is no benefit from titling.  The affect is the same as shading part of one panel.
Al & Sharon
2006 Winnebago Sightseer 29R
2009 Chevy Colorado 4X4

http://downtheroadaroundthebend.blogspot.com/

Sun2Retire

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Re: Amps Generated by Solar Panels
« Reply #9 on: January 12, 2018, 08:56:44 AM »
When I installed solar on the last sticks and bricks, I was referred to this site which allows you to calculate production based on panel tilt, azimuth, and system size, along with location. You start with your address and then enter the other parameters. The site presumes an 86% efficiency but you can adjust it. Pretty useful. Note that because the site is designed for residential PV systems which are much larger, system size is in kW, so in the OP's case his system would be 0.72 kW. Also note the site shows monthly production.

Where I'm sitting now (south of Tucson) according to this site and assuming 20% loss with my 800W system I'm only going to produce 63 kWH/month (2.03 kWH/day or 161 Ah @ 12.6v) with the panels flat. If I orient them south and tilt to 31 degrees that increases to 261 Ah. In theory this means I can start the day with my four 6V batteries at min voltage (50%) and with no power usage all day and the panels tilted, just get a full charge by the end of the day.
Scott
Fulltiming in a 2005 Newmar Dutch Star 3810, Spartan, Cat C7 350
Eezrv TPMS, VMSpc, 800W Solar
2002 Dodge RAM 1500 Quad Cab toad
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Dreamsend

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Re: Amps Generated by Solar Panels
« Reply #10 on: January 12, 2018, 09:20:45 AM »
How many AH's of lithium battery are you installing & which manufacture of the battery is AMS providing?  With 720watts of solar, 400-500AH would be a good number, although more AH wouldn't be bad.

The estimate currently is for 600 Ahrs of battery.  2 x 300 Ahr.  LifeBlue Lithium Ion Battery.  These are drop-in replacement batteries that AM Solar is using pretty extensively as opposed to the Victron series. They are not applying any mark-up to them, but selling them at their retail price. 10 year limited warranty. Advantage is cheaper and being "drop-in" don't require the extensive, specialized labor as Victrons where each one has to be wired separately.  Yah, I'm sorta a guinea here, but AM says they have had no complaints and systems are operating as designed.  Just like lead acid batts, the lower you draw down the lithiums with each cycle, the more you contribute to a shortened life span, so you really don't want to go all the way to 20-50% on a regular basis.

http://www.lifebluebattery.com/order-lifeblue-lithium-rv-battery/300ah-lifeblue-lithium-rv-battery.html

Will your lithium battery have a BMS (Battery Management System) to protect it from over charging or over discharging?  Does the BMS also display the individual battery cell voltage, & temperature?  Some people consider the BMS critical, others don't even bother with installing a BMS.  I have a BMS on my lithium that does the above, and consider it something I would not be without.  I always like to "know" what any of my systems are doing.  Not just my batteries and charging systems, but vehicle engines, etc.

Yes, there is an EMS system build into the batteries for controlling under/over charging and for preventing charging when out of temperature (range is 32 degrees to 114 degrees charging).  The batteries are self balancing as well. The batteries will be inside the trailer. These batteries are slightly different than the "blue" stacking ones we've all seen.  They are drop-ins that look pretty much like a flooded cell or AGM case, so I think the monitoring is for an entire battery and not each cell inside.  Monitoring of batts can also be done via provided software and bluetooth.

Did you do an energy usage assessment for what you expect to be using on a daily basis?  What did you come up with?

Yes, I just finished it last night.  I came up with 180 Ahrs/day for just the bare, basic minimums, so I have some concern.  This number does not include any furnace ops,
LED lights, portable fan, let alone using a rice cooker, or hand mixer, or ninja on occasion and maybe on the same day I relocate and need to use the slide, steps, and tongue jack.  I have just emailed the complete table to AM Solar -- first, to check if my numbers are reasonable, and second, to express concern that I think I need to add another panel, and maybe go with 800Ahs of lithium.  cough!  cough!! cough!!!  Hey, it's only $$$.


Are you installing a battery monitor, such as a Trimetric?  For anyone doing extensive dry camping or boondocking a good monitor is something I would not be without. 

Yes, it's a Victron Color Control Monitoring Kit, which is an option that I am choosing.  Shows me watts, and amps in and out, and some other stuff I don't remember just now.

Is your charge controller and inverter/charger programmable so you can set/change the charging parameters?

Didn't ask that question, but I could look up the equipment and check.  Once the system is operational, would I really need to change the charging parameters?  I guess if in the future I changed batteries that required something else I would need that feature. The charge controller is a SunRunner Victron MPPT 85A.  The inverter/charger is a hybrid unit, Victron MultiPlus 12/3000/120-50 120V that will integrate all charging sources - solar, generator, shore, portable panel, also alternator, although I'm aware the wire from the alternator is very limiting for charging.    

What size wire is being used from the combiner box on the roof to the charge controller?

I don't see a gauge specified on the estimate for the wire from the combiner box to the charge controller.  THe inverter/charger section specifies Cable 4/0 so I'm guessing that's a 4 gauge. I don't think AM will use anything less than a 4 for the run from the panels to the inverter.

Is your controller a MPPT?

Yes, MPPT

Are your solar panels all in series or a series/parallel configuration. Parellel - voltage will remain the same across the panels

About tilting the panels.  How do you feel about getting up on the roof and putting the panels down in a 25mph wind with gusts to 40mph?  I'd feel like a lunatic if I did that!  Hopefully I can plan ahead better than that.  But, tilting in the winter is I think important.  I'll be doing a mix of boondocking, and RV parks, but I don't want to have to go to a park every 3 days in order to use my ninja for 5 minutes, or instant pot for an hour, or furnace blower.

Truly appreciate all your thoughts, and my having to try to answer the questions.  I spent an hour going over all my questions with AM Solar - is there enough ump to charge quickly, can I see amps going in and out on a monitor, what does the BMS actually do, what is my max Watts through the inverter (2400W right now), self-balancing, switching to shore/generator, etc. etc. and I got positive answers to all the questions. 

There is still something nagging at me however that hasn't been addressed by all the technical stuff, and I think it is concern about the solar and battery capacity, so I need to keep chasing info until I'm comfortable.  I've heard so many differing things about how many solar watts people live on, and of course, one can't really compare because no one really knows just how they are actually managing their energy usage.  My generator will only be an emergency 1000W and I don't plan to use an AC off-grid.

Cheers, Linda
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

Gary RV_Wizard

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Re: Amps Generated by Solar Panels
« Reply #11 on: January 12, 2018, 10:02:01 AM »
Quote
[1] 15 degrees is my *guess* (from somewhat unrelated astronomical information) for the minimum height above the horizon where decent solar charging (with tilted panels on winter) is possible; someone please correct me if I'm wrong.

I'm no solar expert, but I think that a sun angle of only 15 degrees is going to be marginal at best on a horizontal panel.  That is not very far above the horizon, especially in areas that have hills or trees to interfere.   Tilting the panel itself another 15 degrees, so that the angle of incidence is 30 total, probably gets into the range for decent power generation. In any case, the ratings are for a 90 degree incidence and anything less reduces the output. From what I read, both voltage and amps fall as the angle reduces, so net power output can take a substantial hit.  And some panel designs do better than others at off-angles or partial sun.
Gary
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Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Gary RV_Wizard

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Re: Amps Generated by Solar Panels
« Reply #12 on: January 12, 2018, 10:20:06 AM »
Quote
I came up with 180 Ahrs/day for just the bare, basic minimums, so I have some concern.  This number does not include any furnace ops,
LED lights, portable fan, let alone using a rice cooker, or hand mixer, or ninja on occasion and maybe on the same day I relocate and need to use the slide, steps, and tongue jack.  I have just emailed the complete table to AM Solar -- first, to check if my numbers are reasonable, and second, to express concern that I think I need to add another panel, and maybe go with 800Ahs of lithium.  cough!  cough!! cough!!!  Hey, it's only $$$.

Yeah, the first reality check is always a shocker.  I doubt if it's practical to operate exclusively from a portable solar system without employing some energy conservation measures. You won't be able to simply turn on electric appliances willy-nilly as most do at home. That doesn't mean you have to live sub-standard, but you will have to develop more efficient habits.

180AH doesn't sound like it's beyond your panel capacity. That's about 2200 watt-hours per day so your 750 watt panels should easily replace that on any sunny day.  And 600 AH of battery, assuming you can utilize up to 80% of that, yields plenty of power for one day and adequate for 2-3 days if needed.  About the only significant add-on to the 180 AH would be furnace use. Most everything else you cited is small change in the total picture.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Frank B

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Re: Amps Generated by Solar Panels
« Reply #13 on: January 12, 2018, 05:20:35 PM »
Some good answers here already, and AM Solar is respected.  If they are doing the install for you, then you will get a system that works.


However, as to your question about adding a panel -- I would.  But then, I just installed a very 'solar heavy' system on our travel trailer, but I don't regret it.  My batteries charge even on cloudy days.


The cost of panels alone is generally not huge compared to the overall system cost.  I've never heard anyone complain that they had too much solar.  I don't need a number, but ask yourself how much more it would cost to add another panel or two, and compare that to the overall cost at the moment, and what your budget will tolerate.


Remember too that there will be cloudy days, and our electrical usage always tends to increase over time.


Finally, ask AM Solar.  I am sure that they will give you a fair answer.


Frank.
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AStravelers

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Re: Amps Generated by Solar Panels
« Reply #14 on: January 13, 2018, 09:20:38 AM »
Quote
Quote from: AStravelers on January 12, 2018, 07:50:53 AM

    How many AH's of lithium battery are you installing & which manufacture of the battery is AMS providing?  With 720watts of solar, 400-500AH would be a good number, although more AH wouldn't be bad.

    The estimate currently is for 600 Ahrs of battery.  2 x 300 Ahr.  LifeBlue Lithium Ion Battery.  These are drop-in replacement batteries that AM Solar is using pretty extensively as opposed to the Victron series. They are not applying any mark-up to them, but selling them at their retail price. 10 year limited warranty. Advantage is cheaper and being "drop-in" don't require the extensive, specialized labor as Victrons where each one has to be wired separately.  Yah, I'm sorta a guinea here, but AM says they have had no complaints and systems are operating as designed.  Just like lead acid batts, the lower you draw down the lithiums with each cycle, the more you contribute to a shortened life span, so you really don't want to go all the way to 20-50% on a regular basis.

    http://www.lifebluebattery.com/order-lifeblue-lithium-rv-battery/300ah-lifeblue-lithium-rv-battery.html

    Will your lithium battery have a BMS (Battery Management System) to protect it from over charging or over discharging?  Does the BMS also display the individual battery cell voltage, & temperature?  Some people consider the BMS critical, others don't even bother with installing a BMS.  I have a BMS on my lithium that does the above, and consider it something I would not be without.  I always like to "know" what any of my systems are doing.  Not just my batteries and charging systems, but vehicle engines, etc.

    Yes, there is an EMS system build into the batteries for controlling under/over charging and for preventing charging when out of temperature (range is 32 degrees to 114 degrees charging).  The batteries are self balancing as well. The batteries will be inside the trailer. These batteries are slightly different than the "blue" stacking ones we've all seen.  They are drop-ins that look pretty much like a flooded cell or AGM case, so I think the monitoring is for an entire battery and not each cell inside.  Monitoring of batts can also be done via provided software and bluetooth.

    Did you do an energy usage assessment for what you expect to be using on a daily basis?  What did you come up with?

    Yes, I just finished it last night.  I came up with 180 Ahrs/day for just the bare, basic minimums, so I have some concern.  This number does not include any furnace ops,
    LED lights, portable fan, let alone using a rice cooker, or hand mixer, or ninja on occasion and maybe on the same day I relocate and need to use the slide, steps, and tongue jack.  I have just emailed the complete table to AM Solar -- first, to check if my numbers are reasonable, and second, to express concern that I think I need to add another panel, and maybe go with 800Ahs of lithium.  cough!  cough!! cough!!!  Hey, it's only $$$.

    Are you installing a battery monitor, such as a Trimetric?  For anyone doing extensive dry camping or boondocking a good monitor is something I would not be without.

    Yes, it's a Victron Color Control Monitoring Kit, which is an option that I am choosing.  Shows me watts, and amps in and out, and some other stuff I don't remember just now.

    Is your charge controller and inverter/charger programmable so you can set/change the charging parameters?

    Didn't ask that question, but I could look up the equipment and check.  Once the system is operational, would I really need to change the charging parameters?  I guess if in the future I changed batteries that required something else I would need that feature. The charge controller is a SunRunner Victron MPPT 85A.  The inverter/charger is a hybrid unit, Victron MultiPlus 12/3000/120-50 120V that will integrate all charging sources - solar, generator, shore, portable panel, also alternator, although I'm aware the wire from the alternator is very limiting for charging.   

    What size wire is being used from the combiner box on the roof to the charge controller?

    I don't see a gauge specified on the estimate for the wire from the combiner box to the charge controller.  THe inverter/charger section specifies Cable 4/0 so I'm guessing that's a 4 gauge. I don't think AM will use anything less than a 4 for the run from the panels to the inverter.

    Is your controller a MPPT?

    Yes, MPPT

    Are your solar panels all in series or a series/parallel configuration. Parellel - voltage will remain the same across the panels

    About tilting the panels.  How do you feel about getting up on the roof and putting the panels down in a 25mph wind with gusts to 40mph?  I'd feel like a lunatic if I did that!  Hopefully I can plan ahead better than that.  But, tilting in the winter is I think important.  I'll be doing a mix of boondocking, and RV parks, but I don't want to have to go to a park every 3 days in order to use my ninja for 5 minutes, or instant pot for an hour, or furnace blower.
You have done an excellent job of designing your system.

However you are way, way over concerned about your usage. 

To use 180AH in a day you are going to have to use lots of things for long duration each day.  Microwave for cooking, not just heating things up; TV & satellite receiver for 6-10 hours; lots of hair drier use; cook with crock pot or instapot.  Just using a computer for 4-6 hours in a day, TV for 2-4 hours, microwave for a max of 10-20 total minutes on high each day; maybe the furnace occasionally, such as to take the chill off in the morning.  At that your usage will be in the 100-140AH in a day. 

600Ah of lithium and 720AH of solar is a very large system and will more than satisfy what you are likely to use.  In fact I believe the system you are planning on installing would more than satisfy your needs to go for weeks or months w/o ever using a generator or shore power. 

As I stated in another reply, buy a 1000watt or better yet 2000watt Honda or similar inverter type generator.  Run that for 2 hours and pump in a constant 60-100 amps from your charger and you will have put 120AH to 200AH back in your battery to get you over a very cloudy couple of days.

Quote
Yes, it's a Victron Color Control Monitoring Kit, which is an option that I am choosing.  Shows me watts, and amps in and out, and some other stuff I don't remember just now.
While the instantaneous readouts of amps and voltage is important to show you what you are using at any point in time, the most important item you want is the total number of AH's used.  You want to know if you have used 300-400AH's from your battery and equally as important how much your solar panels have put back in.  For example if in the morning you see your AH usage from the cloudy day yesterday & the day before and your nighttime usage has put you at 350AH's used, and now you have a sunny but hazy day, and by 5pm your AH reading is 200AH (the solar panels put 150AH back in) your batteries are now at 66% full. You are good to go for the night.  Lithium works very, very well for days and weeks at a time swinging from 40% full to 60-80% full.  That is why you go with lithium.  With any lead acid, AGM included you want to get that battery back to 100% as often as you can.  Also for longest life with lead acid you don't want to go much below 75% full.  Going to 50% full cuts your battery life by about 50% (3000 cycles at 75% full to around 1500 cycles at 50% full)  In fact for longest life with lithium you don't want to consistently go to 100%.  Going to about 90-93% full is better.

 
Quote
Is your controller a MPPT?

    Yes, MPPT

    Are your solar panels all in series or a series/parallel configuration. Parellel - voltage will remain the same across the panels

AMS installs 100-160watt panels, which typically are 12V nominal voltage panels.  That is the max voltage is about 18V.  IF all your panels are installed in parallel, you don't have enough voltage at the MPPT controller to make use of it.  You need 36V to 40 something volts for the MPPT controller to be useful.  I really suspect AMS will be wiring your panels in some combination of series/parallel.  Two to three panel in series then those are in parallel with the other series wired panels.  If all panels are in parallel you don't need the more expensive MPPT controller.

Quote
What size wire is being used from the combiner box on the roof to the charge controller?

    I don't see a gauge specified on the estimate for the wire from the combiner box to the charge controller.  THe inverter/charger section specifies Cable 4/0 so I'm guessing that's a 4 gauge. I don't think AM will use anything less than a 4 for the run from the panels to the inverter.
No 4 gauge is not 4/0.  The 4/0 cable is excellent for the inverter to battery, or controller to battery.  Wire size is 4 gauge, 2 gauge, 1/0, 2/0, etc.  Each number meaning larger size wire.  If you are truly going to have all panels in parallel you probably should have 2 gauge or larger wire depending on the length of wire from the combiner box to the solar contorller.  HOWEVER you really need to use a wire size calculator to be sure your voltage loss will be 3% or lower.  1% loss is best.
 
As an example, we went to Alaska on a 4 1/2 month trip (139 days) in 2016.  Our 400AH lithium and 650watts of solar allowed us to boondock/dry camp for 137 of the 139 days.  We only ran the generator for charging for about 2 hours one time on that trip because of a string of days very cloudy weather.  Note, our house batteries don't charge from the engine while we are driving.   We use the TV and satellite receiver for 3-5 hours a day.  Two laptops for 4-6 hours a day, some microwave usage to heat things up, a toaster some mornings.  We do use a catalytic heater instead of the furnace for heat.  At night we have lots of blankets/quilts on the bed and leave the heater off.  My wife uses a power wheel chair and also a 4 wheel power scooter when we are out and about.  We charge both of them through the inverter as well.  The two days we had elect hookups was because we stayed in an RV park and because we could we plugged into shore power. 

We also consistently travel and dry camp.  Currently we are 7 days into a 7-8 week trip though southern NM, AZ, & CA.  We have no plans on staying at a place with elect hookups or using our generator. 
« Last Edit: January 13, 2018, 09:24:25 AM by AStravelers »
Al & Sharon
2006 Winnebago Sightseer 29R
2009 Chevy Colorado 4X4

http://downtheroadaroundthebend.blogspot.com/

Heli_av8tor

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Re: Amps Generated by Solar Panels
« Reply #15 on: January 13, 2018, 10:30:01 AM »
  Note, our house batteries don't charge from the engine while we are driving. 

VERY informative post.

Is there a reason for not charging the Lithium batteries from the engine alternator?

Tom
Tom & Theresa
2004 Pace Arrow 37C, Workhorse W22, 8.1 Vortec
2014 Honda CR-V Toad, Roadmaster -5 Base and tow bar
SMI Stay and Play Duo Brake system

JakeR

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Re: Amps Generated by Solar Panels
« Reply #16 on: January 13, 2018, 11:00:09 AM »
Linda, I am not even close to being as technically smart as most members here but I wanted to tell you that I have been extremely pleased with the solar install on our 2017 Winnebago Navion that AM Solar did.  I explained what we planned on doing while camping and originally was going with just 2 panels but based on my usage they recommended 3.  I had them install a surge suppressor while at it (rv parks nice for hot showers and laundry after boon docking), 2 6V Lifeline AGM Batteries,  and modify an outlet that was not designed to run off the inverter (good thing to identify on yours - which outlets use the inverter).  The internal monitor shows input/output, the controller includes a temp gauge for the batteries, and I had them install a Trik L Charge for the chassis battery.  I can share pics of the install if you are at all interested but I wanted to say I would not hesitate to trust their knowledge.

You can stay in their parking lot and walk to some fast food restaurants.  Not much for entertainment immediately nearby.  We were with them for 2.5 days. 
Jake
Northern CO
2017 Winnebago Navion 24J
2010 Toyota Corolla (manual) toad

Dreamsend

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Re: Amps Generated by Solar Panels
« Reply #17 on: January 13, 2018, 09:19:23 PM »
However, as to your question about adding a panel -- I would.   . . The cost of panels alone is generally not huge compared to the overall system cost.  I've never heard anyone complain that they had too much solar.

Hi Frank - This is my thinking also.  Another 180W panel and the labor are relatively inexpensive - compared to the overall investment.  There is plenty of room on the roof so might as well do it up-front. That would give me a whopping 900 W of panels.  Just have to make sure everything else in the system can handle the extra power without upgrading some component.  A talk with AM Solar (hopefully next week) will clarify this.

Linda
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

Dreamsend

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Re: Amps Generated by Solar Panels
« Reply #18 on: January 13, 2018, 10:56:55 PM »

As an example, we went to Alaska on a 4 1/2 month trip (139 days) in 2016.  Our 400AH lithium and 650watts of solar allowed us to boondock/dry camp for 137 of the 139 days.  We only ran the generator for charging for about 2 hours one time on that trip because of a string of days very cloudy weather.  Note, our house batteries don't charge from the engine while we are driving.   We use the TV and satellite receiver for 3-5 hours a day.  Two laptops for 4-6 hours a day, some microwave usage to heat things up, a toaster some mornings.  We do use a catalytic heater instead of the furnace for heat.  At night we have lots of blankets/quilts on the bed and leave the heater off.  My wife uses a power wheel chair and also a 4 wheel power scooter when we are out and about.  We charge both of them through the inverter as well.  The two days we had elect hookups was because we stayed in an RV park and because we could we plugged into shore power. 

We also consistently travel and dry camp.  Currently we are 7 days into a 7-8 week trip though southern NM, AZ, & CA.  We have no plans on staying at a place with elect hookups or using our generator.

Hi Al  - Wow, thank you for the time and effort for your posts.  I know how much of an investment such detailed posts require.  My overall reaction was "Hey this is WONDERFUL, really GREAT"!  Real life experience indicating that I'll have enough power to live as I envision, which of course means conservation and keeping track of where my batteries are at. My estimates are just that - because you have to start somewhere, so I may be guilty of being overly concerned at this point, but this derives from the fact that the final decisions about the system are imminent and is due to not having experience living the RV lifestyle . . yet! 

Except for info from my 120V appliance baseplates and a couple of wattage numbers from the TT manufacturer, all my other watt/amp/amp-hr information has had to come from web resources.  I've been collecting info on electrical requirements (off & on) since Sep 2016, so the time had come to compile it into something I could see, on paper, and study.  What I've determined is that information out there about electric usage for specific items varies WIDELY - for the same item.  And, I need to try and get usages that match the equipment I have.  For example, televisions - the amp draw varies widely depending on the size TV and whether 120 vs 12V.  LED lights are another example, but they don't contribute much to the overall total so I'm not concerned about the range reported, but still. . . .  I have seen published info that a 12W LED bulb draws anywhere from 0.12 to 0.2 amps.  That's kinda a large INDIVIDUAL difference -- and can lead me to wonder about the published accuracy of other bigger ticket items -- like the furnace fan.  Due to these vagaries, differences, and my lack of trusting the numbers, I may be over-estimating, "just to be on the safe-side" as they say.

But, for whatever reason, my barebones usage still comes to around 180 Ahrs per day.  No microwave cooking -- only heating water for my Melita pour-over coffee filter, reheating coffee and food, no hair dryers, no furnace fan, no satellite, no excessive computer or TV use, no slow cooker or instant pot use. 

To make it easier maybe, if anyone is interested, I've attached a revised, mostly completed ESTIMATE TABLE that lays it all out.  I've separated the "occasional use" items, and included a column for their daily usage, so I can see their impact IF and WHEN they are used.  I've listed the furnace fan as SEASONAL, and not for example, included any furnace usage in my "normal" expected daily routine.   All this is simply an attempt to capture the "most likely scenario" for daily usage and see how much excess capacity I may have for cloudy-days, or needing the furnace, etc.  I am not trying to size the system to use high-draw non-essential items (like iron, vacuum, toaster, etc.) on a daily basis. 

As Gary the Emeritus has so aptly pointed-out "Propane is my friend while boondocking"   Heck yes, I can boil water for coffee on the stove, my Coleman stovetop/grill, or even my ole MSR camping stove.  I don't NEED to use a microwave for example.  But is it more convenient all around to do so on a regular basis?. . . yes. 

Any system design kudos go to AM Solar.  I simply sent them info on the TT layout, where I wanted to system to go, and how I planned to use the TT.  They did in fact come up with the 720 W of solar panels and the 600 Ahrs of battery.  By some magic, this is the same size system I had envisioned based on my earliest estimates (now refined somewhat).

Yes, I'll have a 1000 watt genny (biggest I can lift, and no, I don't want to connect 2 of them) but I don't want to have to use it on a regular basis.  It's for emergency power (slide, steps, tongue jack etc. use) in case of system failure, or to add necessary battery amps IF I should get stuck in sunless conditions that threaten my essential daily needs, in spite of conservation. 

I see what you are saying about monitoring for the total amps in/out of the battery.  I'll have to clarify this with AMS - they will likely call on Monday I think.  We have only had a one hour discussion so far, and while a lot was covered, there are still some details to pin down, so I'll add this to the list.  I do think I remember being told there is a direct read-out on the monitor for the percentage of battery charge remaining however.  It's not something that has to be calculated from amps out and in as I recall.  Will address this however.

AMS is currently using 100 and 180 W panels. Mine will all be 180 W.   And you are correct, I don't know if they will do a combination of series and parallel for the solar panels or not.  Can't really tell from the estimate they have provided.  This is an area I trust their expertise.  Same thing for the wiring, I trust their judgement.

The charge controller is a SunRunner Victron MPPT 85A.  According to the specs, this controller can handle solar inputs of up to 1150 W.  It is rated at 85 amps.  This is getting into the details with which I am the still the least knowledgeable, so here is a link to access the Datasheet on the controller if you'd like to check it out.  Mine is the 150/85.

https://www.victronenergy.com/solar-charge-controllers/mppt-150-70

With the input from the good folks here, and AM Solar's expertise, I think I'm getting excited again about how great this is gonna be.  Al, your solar system sounds awesome, and works exactly like I would like mine to operate.  I will be in RV parks now and then, -- laundry, longer showers, other amenities, change of pace, using those cooking appliances and freezing soups, chili, pot roast and stew meals (not all on the same day obviously), but I would like to NOT have to stay at one simply to charge batteries, although if such an occasion should arise, that's okay to and I'll deal with it.

Thank you again,
Linda

 
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

Dreamsend

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Re: Amps Generated by Solar Panels
« Reply #19 on: January 13, 2018, 11:13:24 PM »
. . . I have been extremely pleased with the solar install on our 2017 Winnebago Navion that AM Solar did.  I explained what we planned on doing while camping and originally was going with just 2 panels but based on my usage they recommended 3.  We were with them for 2.5 days.

Hello JakeR

Thank you for the feedback about AM Solar, it is so good to hear that kind of endorsement.  I had planned on using a portable surge suppressor, but the idea of having one installed by AMS is a good one and I'm going to further consider this.  I didn't realize they could do this, so thanks for the heads-up.  I think we'll have discussions about which outlets, including a port from the manufacturer to use a portable solar array will be wired into the inverter/charger system when I actually go to their shop in May.  Some time ago, I read about their set-up for guests quarters (parking lot?) and need to refresh myself on the details.  I hope my stay is as short as yours!  I'm thinking it could be up to 4 days.  But, I'll have my truck to tool around in so can site-see, go to restaurants, etc. and if there is someplace to stay, may take my tent and sleeping bag.  Gosh I'm getting excited again about this whole adventure.  Thank you.  L
« Last Edit: January 14, 2018, 05:42:58 AM by Dreamsend »
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

AStravelers

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Re: Amps Generated by Solar Panels
« Reply #20 on: January 15, 2018, 09:35:46 AM »
VERY informative post.

Is there a reason for not charging the Lithium batteries from the engine alternator?

Tom
The Winnebago we have wasn't wired to charge from the engine and I never wanted to bother installing the solenoid and wiring to do that.  Other than that I don't know of a reason not to.   
Al & Sharon
2006 Winnebago Sightseer 29R
2009 Chevy Colorado 4X4

http://downtheroadaroundthebend.blogspot.com/

AStravelers

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Re: Amps Generated by Solar Panels
« Reply #21 on: January 15, 2018, 09:59:31 AM »
..............  LED lights are another example, but they don't contribute much to the overall total so I'm not concerned about the range reported, but still. . . .  I have seen published info that a 12W LED bulb draws anywhere from 0.12 to 0.2 amps.  That's kinda a large INDIVIDUAL difference -- and can lead me to wonder about the published accuracy of other bigger ticket items -- like the furnace fan.  Due to these vagaries, differences, and my lack of trusting the numbers, I may be over-estimating, "just to be on the safe-side" as they say.

You are right on about LED's, about 0.2 amps.  Furnace fan does pull about 6-8 amps while running.  Plus it is noisy.  That is why we use a catalytic heater for 98% of our heating needs. Some times we run the furnace in early morning to take the chill off. 

...........But, for whatever reason, my barebones usage still comes to around 180 Ahrs per day.  No microwave cooking -- only heating water for my Melita pour-over coffee filter, reheating coffee and food, no hair dryers, no furnace fan, no satellite, no excessive computer or TV use, no slow cooker or instant pot use. 

Your estimate is good.  It is good to estimate on the higher side of usage.  Once you get the system installed and using it you will truly know what your usage is.  Please come back in a couple of months after you have used your system for a while and give us your "real world" experience.
 
..............AMS is currently using 100 and 180 W panels. Mine will all be 180 W.   And you are correct, I don't know if they will do a combination of series and parallel for the solar panels or not.  Can't really tell from the estimate they have provided.  This is an area I trust their expertise.  Same thing for the wiring, I trust their judgement.
About wire size from the combiner box to the controller. Consider asking them to size the wire for a 1% voltage drop and see if they will and/or see what the cost would be.  While I have not personally evaluated other peoples solar installs, what I have read from other people I consider experts is a frequent short coming of many installers is too small a wire size from the combiner box to the controller.  Not sure if AMS is one of them or not.  The cost of a little larger wire size is minimal compared the cost of the rest of the system.

.............With the input from the good folks here, and AM Solar's expertise, I think I'm getting excited again about how great this is gonna be.  Al, your solar system sounds awesome, and works exactly like I would like mine to operate.  I will be in RV parks now and then, -- laundry, longer showers, other amenities, change of pace, using those cooking appliances and freezing soups, chili, pot roast and stew meals (not all on the same day obviously), but I would like to NOT have to stay at one simply to charge batteries, although if such an occasion should arise, that's okay to and I'll deal with it.

From what I have read from others, AMS is a reliable, quality installer.

Thank you again,
Linda

 
Al & Sharon
2006 Winnebago Sightseer 29R
2009 Chevy Colorado 4X4

http://downtheroadaroundthebend.blogspot.com/

ChasA

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Re: Amps Generated by Solar Panels
« Reply #22 on: January 15, 2018, 10:28:26 AM »
Al, I had an '06 Sightseer 29R. It did charge the house batteries from the alternator.  The solenoid that does it is in the small compartment in front of the door, inside a black enclosure. Occasionally the solenoid failed to make contact.  I was usually able to get in working by repeatedly operating the Mom switch on the dash. The contacts get oxidized and exercising the solenoid "wipes" the contacts. I was going to replace the solenoid with one that has silver contacts but never got around to it because it is really hard to get to.
Apex, NC
2010 Winnebago journey Express 34Y (pre DEF)
2007 Saturn Vue

AStravelers

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Re: Amps Generated by Solar Panels
« Reply #23 on: January 15, 2018, 12:10:15 PM »
Al, I had an '06 Sightseer 29R. It did charge the house batteries from the alternator.  The solenoid that does it is in the small compartment in front of the door, inside a black enclosure. Occasionally the solenoid failed to make contact.  I was usually able to get in working by repeatedly operating the Mom switch on the dash. The contacts get oxidized and exercising the solenoid "wipes" the contacts. I was going to replace the solenoid with one that has silver contacts but never got around to it because it is really hard to get to.
Thanks.  I give it a try.  I also have a couple of days w/o much to do.  We are sitting in a boondocking spot near Yuma waiting on Service Pro Awning schedule to come and replace awning fabric on 2 slide toppers and the main awning. 
Al & Sharon
2006 Winnebago Sightseer 29R
2009 Chevy Colorado 4X4

http://downtheroadaroundthebend.blogspot.com/

ALLOY

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Re: Amps Generated by Solar Panels
« Reply #24 on: January 15, 2018, 08:21:43 PM »
VERY informative post.

Is there a reason for not charging the Lithium batteries from the engine alternator?

Tom

Continually charging any battery is not ideal.  Flooded lead acid will tolerate it but Lipo will not.

Lipo is best charge to 98% SOC.  The idea Lipo charger has 3 cycles bulk, float, and standby/storage.
 
FLA does best when charged to 100% SOC.  The ideal FLA charger has 5 cycles  bulk, absorption,  float,  equalization on occasion, and  standby/storage.

 
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Frank B

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Re: Amps Generated by Solar Panels
« Reply #25 on: January 16, 2018, 03:28:11 PM »
ALLOY:


Quote
The idea Lipo charger has 3 cycles bulk, float, and standby/storage.


Interesting. I always understood that Lithium-ion batteries charged only in bulk stage, and they required no float.

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

Quote
The ideal FLA charger has 5 cycles  bulk, absorption,  float,  equalization on occasion, and  standby/storage.

That is a new thought for me as well. What is the difference between float and standby / storage?

[/size][size=0px]Frank.[/size]
Linux:  Free, open, elegant.
06 GMC 3500 Duramax crew/long pulling 2010 Arctic Fox 30U with 1700 lb Reese Titan Class 5.
1.2 kw solar

ALLOY

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Re: Amps Generated by Solar Panels
« Reply #26 on: January 17, 2018, 10:57:58 AM »
ALLOY:




Interesting. I always understood that Lithium-ion batteries charged only in bulk stage, and they required no float.

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

That is a new thought for me as well. What is the difference between float and standby / storage?

[/size][size=0px]Frank.[/size]

My apologies I made quick comment without details.

Yes, no float for all types of Lipo except LifePo4.  When bulk charging cut off will be 90-95%SOC which is OK if it is a large bank that was design for 50%-60% capacity use. 
For smaller banks in RVs designed for 80% capacity use a float charge will top up to 98% SOC.  Float for LifePo4 is different in that it is set below 100%SOC.

This is a link to the Victron LifePo4 batteries that AM Solar sells. Charge voltage is 14.2V and float at 13.5V
 https://www.victronenergy.com/upload/documents/Datasheet-12,8-Volt-lithium-iron-phosphate-batteries-Smart-EN.pdf

Below is the explanation of standby/storage for the ProNautic charger I use.  I'm adding a Victon Multiplus that can be programmed to do the same.

During extended periods of non-use, Battery Health Mode will initiate every 21 days ensuring fully conditioned batteries which will be ready to go.






 
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Frank B

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Re: Amps Generated by Solar Panels
« Reply #27 on: January 17, 2018, 11:05:16 AM »
ALLOY:

Quote
During extended periods of non-use, Battery Health Mode will initiate every 21 days ensuring fully conditioned batteries which will be ready to go.

Got it.  Sounds like a 'marketing gimmick', but I can see why it might be useful.

Thanks!


Frank.

Linux:  Free, open, elegant.
06 GMC 3500 Duramax crew/long pulling 2010 Arctic Fox 30U with 1700 lb Reese Titan Class 5.
1.2 kw solar

Dreamsend

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Re: Amps Generated by Solar Panels
« Reply #28 on: January 17, 2018, 11:07:43 AM »
ALLOY

One small item.  "LIpo" is shorthand for lithium ion polymer batteries, which are vastly different than Lithium Iron Phosphate --LiFePo, which are of course what we're using in RVs.  You'll totally fry a LiFePo if one treats it like a Lipo.

L
Linda with kitty Sarah
2017 Ford F250 Lariat aka Gypsy Rose

ALLOY

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Re: Amps Generated by Solar Panels
« Reply #29 on: January 17, 2018, 09:17:56 PM »
ALLOY

One small item.  "LIpo" is shorthand for lithium ion polymer batteries, which are vastly different than Lithium Iron Phosphate --LiFePo, which are of course what we're using in RVs.  You'll totally fry a LiFePo if one treats it like a Lipo.

L

Geeez :)  more details ...my mistake I've a bad habit of throwing all lithium under the same "Lipo" tag.   

When you refer to "totally fry" are you referring to the lower cell voltage LiFePo4 has vs other lithium?



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