I want solar!

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Ex-Calif

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May 15, 2020
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3,799
Location
NorthCentral Florida
That makes sense. I have a Bluetti Portable EB150 with two 100W hard frame panels with LONG cables but being able to use short cables would be a real benefit. I keep the Bluetti inside when I put the panels out. Maybe put those two hard frame panels on the roof and get the more portable panels to put in the sun. Thanks for your help!

So you have portable solar and you want more solar?

The first step is as Mark said a while ago and that is to monitor your amperage consumption over 24 hours and get a power budget.

Alternatively you can make some educated guesses by building a power chart like this.

1660234312151.png

Another way for you might be to turn off all charging systems and monitor battery voltage until you get to about 10.5V. Charge everything up and do it again. If you have 200 a/h of battery and the batteries go dead in 48 hours, you are consuming something in the neighborhood of 80-100 amps a day.

Once you have figured out your consumption there are only 2 questions.

1/ How do I replenish 24 hours of consumption in a reasonable amount of time while still supplying the daily load - This equals how much shore power, generator run time or solar you must have. Anything less you run at a power deficit until the batteries are dead.

2/ How many days do I want to survive without solar, understanding that in a pinch I can run the generator (if I have one) - Generally I like about 1/2 the calculated solar wattage.

Let's say I need 60amps a day. 60 X 12 = 720W. So on the surface 800W will do it.

Coupled with 800W of solar I might have 400 amp hours of battery. On this hypothetical day there was no sun so my fully charged battery bank is now at 340 amp/hrs.

I still need 800W to run the day so will need more than 800W to also fill up the batteries so I might be needing 1200W of solar or 6 X 200W panels. There are also efficiency losses but being in the southwest the extra margins are probably not so important.

I get the idea of using portable panels but that would be a serious PITA to set up all the time and the fact you have to have storage for those 200W panels.
 

Lou Schneider

Site Team
Joined
Mar 14, 2005
Posts
12,022
Excellent information...thank you so much!
You're welcome! A bit late and off-topic, but take a look at the WINs (Wandering Individuals Network). They organize groups who travel the country, finding free and inexpensive places to stay for a few days to a week at a time. They find interesting things to do at each location, then travel an hour or two down the road to their next stop. You can enter or leave a group at any time. They have a group that will be staying on the beach at Puerto Penasco (Rocky Point) in December, a circuit wandering through Arizona for the winter and another one touring Florida before resuming their full activities in the spring. An interesting alternative to sitting in one or more LTVAs for the winter.

Click on the Events tab on their website to see what they're currently doing and their future plans. Long term planning usually happens at their January Quartzsite meetup.

WIN RV Singles Travel Club
 

paulieboi1

Member
Joined
Aug 11, 2022
Posts
17
Location
Albuquerque
Where? Or where would you be willing to go? Do you know what you need it to do?

Mark B.
Albuquerque, NM
Hi Mark, is there anyone here in Albuquerque you would recommend? I’m looking to buy a solar kit online, and would like to find someone to help install it. Thanks!
 

Mark_K5LXP

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Joined
Nov 17, 2018
Posts
2,986
Location
Albuquerque, NM
I've never had anyone in ABQ work on my RV so have no direct references. The PO of my RV had a solar panel installed at some shop in CA, found the receipt for it in the documentation binder. She paid $1300 for a 120W panel and a $30 10A controller. Criminal.

Mark B.
Albuquerque, NM
 

theLegionWithin

Active member
Joined
May 6, 2022
Posts
27
Location
Seattle, WA
i've been researching this as well as I intend to be boondocking a fair amount.

my plan is to get a multimeter w/ a clamp so I can measure the energy usage of the AC appliances I plan on keeping (electronics mostly) - that will give me a baseline for AC usage per hour, relatively easy to calculate the hours of expected use, conversion from DC and loss of the cables & inverter/charger (probably a few Ah/day). Then add that value + whatever the expected DC load is for 12v appliances (fridge, water pump, lights, USB ports, etc), as those are all well documented. the end result is amp hours for a day. multiply by 3 or 4 days to have a good leeway if the panels get damaged or something and I need to bug out and go find shore power...

so, once I know the estimated amp hours needed per day, then I can size the solar panel array to provide that much power generation to make up for what I "spend" each day. Once that's been done, then I need to see what solar panels I can get that will either meet/exceed that variable AND can fit on the vehicle's roof. If the panels needed exceeds the size available on the roof then I need to reduce my AC load (AC is not as efficient as DC power). so maybe rinse/repeat that process a few times.
- currently, I'm thinking 5x panels x whatever Amphours x up to 5 hours of direct sunlight per day.

once that has been figured out, then I need to buy the rest of the equipment. All equipment needs to be fused - either in-line fuses or fuses at the battery and at the breaker/fuse box. electricity can be dangerous - possibly life threatening if you dont treat it with respect. other equipment needed (not an exhaustive list, I'm still researching this myself):
- fuses
- solar charge controller than can handle the maximum VoC produced by the solar panel array (with a 15% error margin)
- battery bank w/ bms & whatever other safety features I need
- shunt on the negative terminal of the battery for monitoring
- inverter charger (pure sine wave inverter converts DC to AC / charger for shore power)
- fuses (reiterating, they're important)
- stepdown/buck converter to reduce the battery voltage to the appliance voltage (as I will be using a 48v system)
- bus bars, fuse blocks (AC circuits and DC circuits)
- marine grade stranded wire/cabling, lugs/mc4 connectors, etc (stranded wire is more resistant to shocks, solid core wire will eventually short out and cause a fire in the walls). you can make your own cabling but I will be buying mine pre-made because I have enough tools.

here's my tentative calculations:
- I estimate that I will expect to use around 8 kWh per 24 hour timespan at 12v. I need, at minimum, a 2100 Ah @ 12v battery bank (3 days storage to be safe)... this is why I intend to use a 48v system - that's a 550 Ah @ 48v battery bank (rounding up to account for conversion loss and loss due to cabling length as this is still a rough estimate).
- 8 kWh/day = 5 hours direct sunlight x 5 panels x 320watts per panel... and 320 isnt very big. more is better in this situation as long as the solar charge controller can handle the total voltage (VoC). I think I can fit 5x 375w panels - that's 9.37 kWh, or around 110 extra Ah generated every 5 hour day.


complicated? yeah, it is. look at the math, do the calculations that are going to work for your use case - and good luck!
 

Ex-Calif

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Joined
May 15, 2020
Posts
3,799
Location
NorthCentral Florida
>>- I estimate that I will expect to use around 8 kWh per 24 hour timespan at 12v. I need, at minimum, a 2100 Ah @ 12v battery bank (3 days storage to be safe)... this is why I intend to use a 48v system - that's a 550 Ah @ 48v battery bank (rounding up to account for conversion loss and loss due to cabling length as this is still a rough estimate).<<

Wow! That's a lot of battery. Have you sourced brands? Where will they be stored?
 

theLegionWithin

Active member
Joined
May 6, 2022
Posts
27
Location
Seattle, WA
>>- I estimate that I will expect to use around 8 kWh per 24 hour timespan at 12v. I need, at minimum, a 2100 Ah @ 12v battery bank (3 days storage to be safe)... this is why I intend to use a 48v system - that's a 550 Ah @ 48v battery bank (rounding up to account for conversion loss and loss due to cabling length as this is still a rough estimate).<<

Wow! That's a lot of battery. Have you sourced brands? Where will they be stored?

yep - the absolute minimum I can get away with day to day is either 2x of SignatureSolar's EG4-LifePower4 100ah/48v or 1x Trophy Battery's 48V220C-1 - leaning towards the Trophy at the moment as it uses CATL cells, but the EG4's have a nice battery racking system... so I dunno. it'll come down to who can offer the best shipping price probably, the cost will be about the same for the hardware itself.

going to store the batteries over the wheel well area in my Stepvan - the wheel well on the other side of the vehicle will be balanced with my fresh water storage (40 gallons or so).

 

solarman

Well-known member
Joined
Feb 8, 2018
Posts
669
Location
Texas
i've been researching this as well as I intend to be boondocking a fair amount.

my plan is to get a multimeter w/ a clamp so I can measure the energy usage of the AC appliances I plan on keeping (electronics mostly) - that will give me a baseline for AC usage per hour, relatively easy to calculate the hours of expected use, conversion from DC and loss of the cables & inverter/charger (probably a few Ah/day). Then add that value + whatever the expected DC load is for 12v appliances (fridge, water pump, lights, USB ports, etc), as those are all well documented. the end result is amp hours for a day. multiply by 3 or 4 days to have a good leeway if the panels get damaged or something and I need to bug out and go find shore power...

so, once I know the estimated amp hours needed per day, then I can size the solar panel array to provide that much power generation to make up for what I "spend" each day. Once that's been done, then I need to see what solar panels I can get that will either meet/exceed that variable AND can fit on the vehicle's roof. If the panels needed exceeds the size available on the roof then I need to reduce my AC load (AC is not as efficient as DC power). so maybe rinse/repeat that process a few times.
- currently, I'm thinking 5x panels x whatever Amphours x up to 5 hours of direct sunlight per day.

once that has been figured out, then I need to buy the rest of the equipment. All equipment needs to be fused - either in-line fuses or fuses at the battery and at the breaker/fuse box. electricity can be dangerous - possibly life threatening if you dont treat it with respect. other equipment needed (not an exhaustive list, I'm still researching this myself):
- fuses
- solar charge controller than can handle the maximum VoC produced by the solar panel array (with a 15% error margin)
- battery bank w/ bms & whatever other safety features I need
- shunt on the negative terminal of the battery for monitoring
- inverter charger (pure sine wave inverter converts DC to AC / charger for shore power)
- fuses (reiterating, they're important)
- stepdown/buck converter to reduce the battery voltage to the appliance voltage (as I will be using a 48v system)
- bus bars, fuse blocks (AC circuits and DC circuits)
- marine grade stranded wire/cabling, lugs/mc4 connectors, etc (stranded wire is more resistant to shocks, solid core wire will eventually short out and cause a fire in the walls). you can make your own cabling but I will be buying mine pre-made because I have enough tools.

here's my tentative calculations:
- I estimate that I will expect to use around 8 kWh per 24 hour timespan at 12v. I need, at minimum, a 2100 Ah @ 12v battery bank (3 days storage to be safe)... this is why I intend to use a 48v system - that's a 550 Ah @ 48v battery bank (rounding up to account for conversion loss and loss due to cabling length as this is still a rough estimate).
- 8 kWh/day = 5 hours direct sunlight x 5 panels x 320watts per panel... and 320 isnt very big. more is better in this situation as long as the solar charge controller can handle the total voltage (VoC). I think I can fit 5x 375w panels - that's 9.37 kWh, or around 110 extra Ah generated every 5 hour day.


complicated? yeah, it is. look at the math, do the calculations that are going to work for your use case - and good luck!

you seem to be a little confused with "8KW/hr at 12V then state you are using a 48V system..
your talking about Watts per hour, the battery voltage isn't important in this context.

take a look at my post from a few years back, it's biased for lead acid but you can multiply the battery requirement by 0.75 for lithium..

ballpark for 8000 W/hr is around 2400 PV Watts.. for 5 Days autonomy approx 38 KW/hrs that's a lot for an RV
are you sure about 8000W/hr.. ?


SEE HERE
 

theLegionWithin

Active member
Joined
May 6, 2022
Posts
27
Location
Seattle, WA
you seem to be a little confused with "8KW/hr at 12V then state you are using a 48V system..
your talking about Watts per hour, the battery voltage isn't important in this context.

take a look at my post from a few years back, it's biased for lead acid but you can multiply the battery requirement by 0.75 for lithium..

ballpark for 8000 W/hr is around 2400 PV Watts.. for 5 Days autonomy approx 38 KW/hrs that's a lot for an RV
are you sure about 8000W/hr.. ?


SEE HERE

its ~8 kWh/day not 8kW/hour. that'd be like... a mobile power plant! lol

the main reason to go 48v is 12v is just too bulky, too many interconnect cables between batteries when there's no real point.
 

solarman

Well-known member
Joined
Feb 8, 2018
Posts
669
Location
Texas
typo.. it should have read 8000 Watt/hrs.. even so that's a lot of power for a typical rv, my boondocking average is around 1200 to 1500 W/hrs.. including a DC fridge..what are you using that draws so much power ? or are you just stating that so many panels can generate xxx amount of energy ?.. ether way, you will need to have a good estimate of your daily consumption to calculate the PV watts and battery capacity without overspending unless you are not concerned financially..
 
Last edited:

carolyncaro

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Joined
Jul 24, 2022
Posts
87
Location
nova scotia, 1997, Class B
Here in New Mexico there is ample dirt and wind, but I'm in a city with electricity and running water. Out there you'd better like solitude because it's dirt as far as they eye can see. I can understand how some folks would like it depending what you're into, but it needs to be more than just cheap rent.

Mark B.
Albuquerque, NM
For this Canadian, it would be no snow, I suspect I could tolerate quite a bit to have zero snow - probably wont get there but who knows- I might! -smile
 

Pedro Dog

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Joined
Jul 9, 2022
Posts
544
Location
South Shores, CA
I have a small trailer with limited roof space due to 2 skylights, AC, bathroom fan and TV antenna. So when solar went on, I didn't want to cover all of the available area and sacrifice maintenance access.

I decided on less solar and more access for me to get on the roof for maintenance. If you put solar on, make sure you can get up there to inspect and seal.
 

Cameodon

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Joined
Jul 2, 2021
Posts
357
Location
Edgewater, fl
I find it humorous when someone wants to live in an RV to save money.
If someone has say a $2000 a month house pint, add maintenance, upkeep then it does save money. I’d sell my p,ace, use equity to buy deeded rv lot in the Ga. Mtns. Especially one with a full carport type cover with a nice deck the length of the 5th wheel under cover. Most for under a grand a yr pays for sewer and water, you only pay electric.
 

Ex-Calif

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Joined
May 15, 2020
Posts
3,799
Location
NorthCentral Florida
If someone has say a $2000 a month house pint, add maintenance, upkeep then it does save money. I’d sell my p,ace, use equity to buy deeded rv lot in the Ga. Mtns. Especially one with a full carport type cover with a nice deck the length of the 5th wheel under cover. Most for under a grand a yr pays for sewer and water, you only pay electric.

It's rarer to find property that allows a full time RV as the only residence where there is city water and sewer unless it is in an RV type park. City dwellers tend to not want living next to a full time RVer.

Most states also limit how long you can full time in an RV without moving it.

Not saying they don't exist but the choices are narrower.
 

Cameodon

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Joined
Jul 2, 2021
Posts
357
Location
Edgewater, fl
Most deeded rv lots allow 6 month usage. Several in GA do, one is under $700 per yr for septic, water and grounds maint. You pay your own electric. 2 of the many that do this allow a nicecar port type aluminum..or wood cover over the entire r/v with room for a deck 8-10’ over the deck, entire length. I have no desire to spend winters in the GA Mtns. The other 6 months would be in Florida, my current home state. No more house payment, ridiculous insurance, upkeep (new roof every 10 yrs required by insurance at approx $15,000 min! Yeah, I can save big money!
Some do allow permanent residence.
 

SeilerBird

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Joined
Feb 25, 2012
Posts
17,135
Location
St Cloud Florida USA
If someone has say a $2000 a month house pint, add maintenance, upkeep then it does save money. I’d sell my p,ace, use equity to buy deeded rv lot in the Ga. Mtns. Especially one with a full carport type cover with a nice deck the length of the 5th wheel under cover. Most for under a grand a yr pays for sewer and water, you only pay electric.
I have never heard of anyone doing that. It is the people that come here looking to buy a dirt cheap RV and go live in desert that think they will be saving money. People who own a very expensive house don't buy a dirt cheap RV. If someone sells their expensive California house can pay the mortgage off, pay the capitol gains tax, pay the realtor, and pay to have a mover move all their stuff can come to Florida and buy a really large beautiful house and still put a few thousand into the bank.
 
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