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Author Topic: How to determine how many amps my residential fridge takes?  (Read 19583 times)

doubravsky

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So... I'm looking at solar installations and trying to determine how much I need. My rig is a new class c with an 18 cu ft residential fridge being the big electrical consumer. 2 12 volt batteries and an inverter that runs fridge/ tvs/ plugs/ etc.

I looked at the fridge and it says 378 kw per year. I'm sure that's an average consumption in a house... how do I determine how many amps it will pull for me in a motorhome?

thanks!
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #1 on: July 05, 2014, 02:16:27 PM »
Ok I found another sticker on the fridge and it says "full load amps 6.5"......
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #2 on: July 05, 2014, 02:27:52 PM »
so how do I figure out how many watts of solar I need to run the fridge?
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

Carl L

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Re: How to determine how many amps my residential fridge takes?
« Reply #3 on: July 05, 2014, 03:02:49 PM »
so how do I figure out how many watts of solar I need to run the fridge?

6.5amps AC x 120VAC = 780 watts.
That is a fair number of solar panels.

You also need the battery pack capacity to run overnight.
780 12VDC = 65 amps DC.    12 hours of night x 65 amps = 780 amp-hours.   

780 amp hours is a real battery draw.  Hope your battery pack capacity is big ... really big


By the way, are you planning to run any other electrical loads  -- they will add to the requirements for panels and batteries.
« Last Edit: July 05, 2014, 03:04:27 PM by Carl L »
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Re: How to determine how many amps my residential fridge takes?
« Reply #4 on: July 05, 2014, 03:08:34 PM »
Carl's calculations are fine for sizing your system for average power usage, but be careful with respect to sizing for peak instantaneous current draw.  I don't know what fridge you are using but the Samsung's are popular among RVers so I'll use those for my example.  Samsung makes it very clear on their FAQ pages that inverters need to be sized to accommodate ~11 amps peak load. 

A couple of years ago the FAQs were more "welcoming" of the use of Samsung fridges in RVs, but it seems as if there may have been issues with people undersizing the inverters they were using because they were just looking at continuous current draw, not peak instantaneous.
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Cant Wait

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Re: How to determine how many amps my residential fridge takes?
« Reply #5 on: July 05, 2014, 05:01:29 PM »
Your full amp load of 6.5 is when the unit first starts up and the compressor draws more when starting, once running it'll pull a lot less. Our Maytag French Door unit pulls only 1 amp after the compressor gets going. Just like an A/C there's a much bigger draw until the unit gets up to speed so to speak.
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Lou Schneider

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Re: How to determine how many amps my residential fridge takes?
« Reply #6 on: July 05, 2014, 05:13:36 PM »
So... I'm looking at solar installations and trying to determine how much I need. My rig is a new class c with an 18 cu ft residential fridge being the big electrical consumer. 2 12 volt batteries and an inverter that runs fridge/ tvs/ plugs/ etc.

I looked at the fridge and it says 378 kw per year. I'm sure that's an average consumption in a house... how do I determine how many amps it will pull for me in a motorhome?

thanks!

The peak power the refrigerator draws vs. the average power used over the course of 24 hours are two different things.  The size of the inverter and it's wiring have to be large enough to handle the starting surge and the power usage of the refrigerator when it's running, but the average amount of power it uses over the course of a day will be less than that, because the compressor doesn't run 100% of the time.

The power the refrigerator draws will be roughly the same whether it's in an RV or in a house, so you're looking at an average consumption of 378 Kwh (kilowatt-hours) per year.  Since there's 365 days in a year, that's a little over 1 Kwh per day.

Power = Voltage x Current, so 1 Kilowatt-hour at 12 volts is 83 amp-hours.  A good rule of thumb is to round up the 12 volt draw to 100 amp-hours per Kwh to allow a margin of error for inverter loss, etc.

100 amp-hours is the amount of energy you can store in a pair of 200 amp-hour 6 volt golf cart batteries, discharged to the 50% level.

You'll have to generate a like amount of power (100 amp-hours) to recharge the batteries each day.  An average day has about 6 hours of full sunshine, so your solar system will have to generate at least 16 amps of current to replace 100 amp-hours over a 6 hour solar day. 
« Last Edit: July 05, 2014, 05:27:35 PM by Lou Schneider »

John From Detroit

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Re: How to determine how many amps my residential fridge takes?
« Reply #7 on: July 05, 2014, 05:26:42 PM »
When it comes to any appliance that has a 15 amp plug (2 flat parallel blades and an optional round pin) there is a super easy way to find out how much power it uses both at any given point in time (Such as when just plugged in) and over a period of time.

YOu buy about a thousand dollars worth of meters and plug them in.. Thankfully.. This does not cost quite a thousand dollars.. In fact it costs more like 20 bucks and sometimes you can pick them up for half that.

A Kill-a-Watt p3. 

Yup,  The very popular among many of us Kill-A-Watt is an amazing device.

It will show current amps draw
Current watts draw
Current POWER FACTOR (can be important)
and it will show KWH  Which is what you need to find out for your fridge,, Total power used in a 24 hour (OR better yet 240) Hour period, OH, and it shows hours since it was plugged in too..  That way you know what you need to budget for.
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doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #8 on: July 05, 2014, 05:33:02 PM »
Thanks for all of the information! My fridge is a Whirlpool. I have noticed that it cycles off and on every once in a while after it's all cooled down... and the inverter is an 1800 watt inverter that came OEM installed in the rig.

Adding to that... We realized after a couple of nights of draining the battery to an inverter warning beep at 3:30 am, that once we added 4-5 Walmart plastic ice thingees, froze them and put them in the fridge at bedtime, we could turn off the fridge and by 10:00 am, it was still around 40 degrees and freezer stuff was still frozen. So we plan to run the fridge probably 14 ~ hours per day. But I'd like to get to the point where I don't have to run the generator multiple times during the day when boondocking.

When I look at solar stuff... they talk about wattage and not amp hours.... what amount of solar panel wattage would I need to generate 100 amp hours?

Dave
2015 Thor Four Winds 31W Class C
Riverside, California

Kevin Means

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Re: How to determine how many amps my residential fridge takes?
« Reply #9 on: July 05, 2014, 06:55:28 PM »
Installing solar panels to overcome the draw of appliances in an RV is a balancing act - I know, because I'm right in the middle of it. It's easy to put too big or too small of a solar array on an RV. Too small and you'll be disappointed, because you're still drawing your batteries down - too big and you'll be unable to store all the power that your panels are capable of producing (That's the situation I'm in right now). Carl's math and the info about additional loads are important considerations.

Our coach has a lot of appliances, including a 20 square-foot Maytag residential fridge that's rated at 653 KWh per year. We have six 160 watt panels on the roof (960 watts), an Outback FM-80 MPPT solar controller and six AGM house-batteries that are rated at 400 amp hours. Even with all those batteries, we still don't have enough battery capacity to store all the power that's being generated by the panels. In direct sunlght, the panels are putting about 45 amps back into the battery-bank each hour, but when the solar controller detects that the batteries have reached 14.4 volts, it throttles back and goes from bulk-charging to absorbsion-charging. That happens even though there is plenty of daylight left for additional bulk-charging.

Basically, I'm wasting some of the charging capacity of the solar panels but the fix is pretty easy - install additional house-batteries, which I'm about to do. Then, of course, you need to know if your RV's battery charger is capable of putting out enough amperage to charge a substantially larger battery-bank in a reasonable amount of time. Some are, some aren't. Like I said, it's a balancing act.

Kev
« Last Edit: July 05, 2014, 07:05:23 PM by Kevin Means »
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RVI Brake 2, TST 507 TPMS, 960 watts of solar, SolaRVector tilt
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Re: How to determine how many amps my residential fridge takes?
« Reply #10 on: July 05, 2014, 07:38:14 PM »
After my last post I saw that you had just posted again, and you asked a question about how many panels you'd need to generate 100 amp hours in a day. On paper, it's going to seem better than in reality. I say that, because I know what the performance specs for my panels say, but I also know what I'm really getting out of them.

The specs for my 160 watt panels say that each panel's output is rated at 8.65 amps per hour. But remember, that's on a clear sunny day in direct sunlight with an ambient temperature of 75 degrees. Solar panels become less efficient as they get warmer. In reality, after running my panels' output through about 20 feet of 8 and 4 gauge wire, on a 92 degree day (today), my six panels are averaging 7.5 amps (each), each hour. If you factor in six hours of daily sunlight (I think five is more realistic but it's pretty subjective), that means three of my panels would generate 135 amps each day - under good conditions.

If you really wanted to get 100 amps each day out of a solar array, I wouldn't get anything less than that. By the time you factor in partial cloud-cover, parasitic loads, partial shading and other "real life" factors, that's what you're going to need to see 100 amps - and that might not even happen.

Kev
« Last Edit: July 05, 2014, 07:43:22 PM by Kevin Means »
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RVI Brake 2, TST 507 TPMS, 960 watts of solar, SolaRVector tilt
Lakeside, California

doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #11 on: July 05, 2014, 08:12:05 PM »
Kevin- thanks for the info. How do I determine whether my battery charger can put out the amps to charge additional batteries, and is that the inverter or the converter?

My inverter says it is a Xantrex Pro XM1800....and it says "MSW, WXFER 1800 watt" on a little page they gave me with serial numbers.

the converter says "converter, power, 55 AMP, 30 AMP AC, 11 DC Circuits"   

I don't know what those descriptors mean yet though :(

I was thinking in the 400-500 watt range would meet my needs.... which sounds like you described a 480 watt set up......

With the inverter I have already, I'd only need the battery and a charge controller I think?
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

Gary RV_Wizard

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Re: How to determine how many amps my residential fridge takes?
« Reply #12 on: July 05, 2014, 09:02:25 PM »
Watts (and amps too) are instantaneous measures of consumption.  You need to factor in time (hours) to determine how much power has to be stored, so the units you need are watt-hours or amp-hours.   Battery amp-hours are assumed to be at 12v, so an amp-hour on a 12v battery is one amp usage for one hour @ 12v.  Watts are equal to volts x amps, so that same one amp @ 12v represents 12 watts. That means that one 12v battery amp hour is 12 watts x 1 hour or 12 watt-hours.

So, if you need 60 watts for 8 hours, that is 480 watt-hours. Divide by 12 to get battery amp-hours for a 12v battery: 40 amp-hours

Just remember that the usable amp hours in a battery is only about 50% of the rated amp-hour capacity.
Gary
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doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #13 on: July 06, 2014, 11:23:32 AM »
Thanks Gary- its starting to make better sense now....
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

wackymac

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Re: How to determine how many amps my residential fridge takes?
« Reply #14 on: July 06, 2014, 11:43:29 AM »
including a 20 square-foot Maytag residential fridge   Kevin... don't you mean 20 cubic foot?
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doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #15 on: July 06, 2014, 11:44:28 AM »
I was able to look up the inverter and determined it is an inverter and not inverter/charger....

Can anyone tell me what these numbers mean - for the converter? Will it be able to handle supplying power to charge an extra two batteries?

the converter says "converter, power, 55 AMP, 30 AMP AC, 11 DC Circuits"   


thanks!
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

Kevin Means

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Re: How to determine how many amps my residential fridge takes?
« Reply #16 on: July 06, 2014, 12:26:31 PM »
including a 20 square-foot Maytag residential fridge   Kevin... don't you mean 20 cubic foot?

Yup. That's exactly what I meant. Typing faster than I'm thinking.  ;D

Kev
2011 Winnebago Tour 42QD
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RVI Brake 2, TST 507 TPMS, 960 watts of solar, SolaRVector tilt
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Gary RV_Wizard

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Re: How to determine how many amps my residential fridge takes?
« Reply #17 on: July 06, 2014, 12:41:41 PM »
That sounds like a combination converter/charger and AC/DC load center. The converter/charger portion produces a max of 55 amps, with the first priority going to any DC loads and the balance available for battery charging.

Any charger will handle multiple batteries - it's just a matter of how much time to replace the amount of amp-hours that were lost through discharge. It's tempting to think that a 55 amp charger will replace 110 amp-hours in just two hours, but batteries don't work that way. As the state-of-charge  builds up, the rate at which charging occurs slows down, so you only get the full 55 amps for a short time while the battery is severely discharged. Then the rate falls off and finishes at something less than 6-8 amp. So your 55 amp (max) charger may come up a little short of ideal at first, but after an hour it probably makes no difference. And if the batteries were only partially discharged to begin with, it makes no difference at all.
Gary
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Kevin Means

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Re: How to determine how many amps my residential fridge takes?
« Reply #18 on: July 06, 2014, 01:56:57 PM »
Dave, before I bought and installed my system, I did a fair amount of research and I picked the brains of a lot of folks on this forum. When it comes to inverters/converters/chargers, however, I only know specifics about my system, because I read the manuals, but others here will be able to answer specific questions about your system better than I.

From what I understand, chargers are part of the converter and they're sized for the battery-bank that comes with the RV. If someone were to significantly increase the size of their battery-bank, the charger would still charge the batteries but it would take proportionately longer. And from what I've read, some factory-installed chargers might never be able to fully charge a battery-bank if it's too big. I'm quite sure there's a simple mathematic formula that would tell you how big your charger would need to be to charge whatever size battery-bank you have, but I don't know it.

I think your envisioned 400-500 watt solar array (with controller), would serve your needs well. And yes, other than wiring and a fuse, that's all you'd "need." I would recommend, however, that you also purchase a good battery monitor (not a simple volt-meter). A good battery monitor will let you monitor your battery-bank's condition easily and accurately (I like the Trimetric 2030 for RVs). Pay close attention to wire-size, wire-run length and where your panels are mounted. There are some seemingly small details about solar installations that can have a significant impact on the overall efficiency of the system. When you start shopping for controllers, I highly recommend buying a good quality MPPT controller. They're more expensive but they get more energy from an array that size than a PWM controller.

I'm certainly not the only person here who's done what you're doing, and I'm sure others will give you good advice. Keep asking questions so we can, hopefully, help you avoid some problems and save you some money.
 
Kev
« Last Edit: July 07, 2014, 01:49:11 AM by Kevin Means »
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Lakeside, California

doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #19 on: July 07, 2014, 07:52:39 PM »
Thanks Kevin! I'll keep researching once I get home. What does "MPPT" stand for when looking for a good controller?
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

Wavery

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Re: How to determine how many amps my residential fridge takes?
« Reply #20 on: July 07, 2014, 08:37:27 PM »
Basic rule of thumb for ANY solar array......... you should have 1AH of battery storage for every watt of solar output for a good balance......... yes.... that means 1000ah of storage for a 1000W array for "optimum" benefit.

One og the hardest issues to deal with on an RV solar system is "Sun angle". On a large system, like you are talking about, not much can be done about that unless you have adjustable racks and are willing to climb on the roof to adjust the panels for the best Sun angle for the place that you are parked on that day. That is why the "6hr a day" rule is used..... it is often less. This can be compensated for by having 150% of the solar array that you calculate that you "need".
« Last Edit: July 07, 2014, 08:39:21 PM by Wavery »
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Re: How to determine how many amps my residential fridge takes?
« Reply #21 on: July 07, 2014, 08:50:31 PM »
I sold a spare Motosat dish that I had a few years ago to someone who mounted two of them on his roof and then mounted two 100 watt panels to each base. They stored on cradles he built when the MotoSats were lowered but with them he was able to remotely track the sun depending on where he was parked. The last time I talked to him he thought he matched the output of six panels with his four.


With the current decline of Motosat I'll bet the a couple of working F2s could be had for a little over the cost of retrieving them.


Before anyone asks his name was John and I have lost all contact with him.

Kevin Means

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Re: How to determine how many amps my residential fridge takes?
« Reply #22 on: July 08, 2014, 11:39:48 AM »
MPPT stands for Maximum Power Point Tracking and PWM stands for Pulse Width Modulation. There are oodles of information online about the advantages and disadvantages of each but, basically, MPPT controllers are able to harvest more energy from a solar array, in typical RVing environments, than are PWM controllers but the array must be of a sufficient size and wired differently.

For example, a fully charged 12 volt battery-bank (after resting with no loads) will indicate a charge of 12.7 volts, so it follows that you'd need more than 12.7 volts to force electricity into the batteries to charge them. Most people say 14.8 volts works best but if you've got AGM batteries (like me), some say 14.4 volts is best. A PWM controller takes the 16 to 18 volts of, say, a 100 watt panel and sends it directly to the battery-bank, regulating it and charging the batteries at a predictable and constant degree of efficiency. If you had two 100 watt panels, you'd wire them in parallel, because that would give you more amps to force-feed the batteries. Wiring panels in series with a PWM controller would be wasteful, because PWM controllers cannot convert the extra voltage into amps.

MPPT controllers are more sophisticated and more efficient for many, but not all, solar applications. They're also more expensive. They can take higher output voltages from solar arrays and convert the extra voltage into amps. They can also take lower voltages from multiple panels and combine them to extract more energy (Like when the sun is rising or setting). This is why you'd wire your two 100 watt panels in series if you had an MPPT controller. Most MPPT controllers are "happiest" (most efficient) with an input voltage of between 36 - 42 volts.

In reality, if you were only going to use two 100 watt panels, it wouldn't make sense to use an MPPT controller. Two 100 watt panels just aren't going to generate enough power in the "real world" to make an MPPT controller cost effective. People, who know a lot more about this solar stuff than I do, generally say that a solar array with an output of 400 - 500 watts is where you should start thinking about MPPT controllers. RV'rs often run their batteries down but if you knew that your battery-bank was never going to be run down very low, a PWM controller would still be the way to go, even with a very large solar array. MPPT controllers are better than PWM controllers at harvesting energy from solar panels in different conditions, but that isn't necessary if your batteries don't need much charging.

Wayne and Jeff are correct about panels that are tilted toward the sun being more efficient than panels that are lying flat on an RV's roof - especially during winter when the sun is low in the sky. (Some say as much as 30% more efficient.) They make inexpensive tilt-kits for roof tops but you have to ask yourself if you're going to climb up on your roof and adjust each panel every time you pull into a campsite. I'm in pretty good shape and I climb around on my RV's roof all the time, but I have no desire to do that every time we pull into a campsite (Cuts into my time visiting Sam Adams  ;)). Now, if we were going to be somewhere off-grid for an extended period of time, maybe, but then you've got other off-grid isues to deal with (dumping, fresh water etc.) My solution was to over-build my system to compensate for less efficient angles.

You're getting a ton of info here, and I know it's a lot to take in. Tom (the forum Administrator), has agreed to let me write an article about installing a solar system in/on an RV, and I'm right in the middle of doing so. There will be a link in the article to a video that highlights many of the things we're talking about. Meanwhile, keep asking those questions.

Kev
« Last Edit: July 08, 2014, 11:47:38 AM by Kevin Means »
2011 Winnebago Tour 42QD
Towing a Jeep Rubicon Unlimited LJ
RVI Brake 2, TST 507 TPMS, 960 watts of solar, SolaRVector tilt
Lakeside, California

doubravsky

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Re: How to determine how many amps my residential fridge takes?
« Reply #23 on: July 09, 2014, 11:39:26 AM »
Kevin,

thanks- you're right it is a ton of info! I'm thinking that with the residential fridge - there is the probability of running down the batteries so the MPPT sounds like a god option. I agree about getting up on the roof- not sure I'd do that very often.

Didi you have your system installed? If so, what did you look for in a good rv solar company?

dave
Dave
2015 Thor Four Winds 31W Class C
Riverside, California

John From Detroit

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Re: How to determine how many amps my residential fridge takes?
« Reply #24 on: July 09, 2014, 01:28:39 PM »
I will tell you another difference between PWM and other Solor controllers.

PWM's generate square waves.. Square waves consist of the fundemental frequency and all the ODD harmonics (The fundemental is the 1st harmonic (Frequency times 1) Odds, would be Fundemental frequency times all of the following 3,5,7,9,~~~99999)

So, if the PWM controller is operating at, say 100 or even 1000 HZ (not out of range) that is going to blow away any chance I have of using my Ham radios, it may interfere with television, and everything else audio/video in your RV.   IT will not bother clocks or electric blankets (Both of which are bothered by MSW inverters) since it will pass through (one hopes a true sine wave) inverter before it gets there and is well filtered,  but anything supject to RFI (Radio Frequency Interference) will very likely have issues.
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Re: How to determine how many amps my residential fridge takes?
« Reply #25 on: July 09, 2014, 04:21:09 PM »
Dave, I installed my system myself - from top to bottom - and I'd never installed or helped install one before. The more I read/learned about RV solar, and the more I talked with, so-called, professional installers, the more I realized that most didn't understand some of the install-issues that can cause a perfectly good system to not function well. Even the place I've been taking our motorhomes to for years (who's been installing RV solar systems for years), demonstrated a clear lack of knowledge. To them, it's just another install job. 

During my research, I came across, and tracked down, a guy named Bob Shearer, who writes an online blog uinder the name, "HandyBob." He's a retired electrical engineer who now lives in Montana. He and his wife lived in their 5th wheel with only solar panels and batteries for years (no generator). I highly recommend Googling "HandyBob" and reading it. He worked with me for about a month, helping me select which components to buy (and which ones not to buy), how to choose the best locations to mount things etc. He's a little... eccentric, but was very helpful.

Between Bob and several other knowledgeable folks on this forum, I was able to do the install mself and avoid many common install problems. If you have any "Do-it-yourself" ability, you can save yourself a lot of money by doing so. It was time-consuming but not difficult. My system works very well.

Kev
2011 Winnebago Tour 42QD
Towing a Jeep Rubicon Unlimited LJ
RVI Brake 2, TST 507 TPMS, 960 watts of solar, SolaRVector tilt
Lakeside, California

Wavery

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Re: How to determine how many amps my residential fridge takes?
« Reply #26 on: July 09, 2014, 04:24:14 PM »
Kevin,

thanks- you're right it is a ton of info! I'm thinking that with the residential fridge - there is the probability of running down the batteries so the MPPT sounds like a god option. I agree about getting up on the roof- not sure I'd do that very often.

Didi you have your system installed? If so, what did you look for in a good rv solar company?

dave
An MPPT controller will (on average) increase the output of your 200W array by ~10% to approx 220W.

I decent MPPT controller for your array will cost ~$250
http://www.amazon.com/MorningStar-SunSaver-SS-MPPT-15L-Charge-Controller/dp/B008H64TBU/ref=sr_1_sc_1?ie=UTF8&qid=1404940325&sr=8-1-spell&keywords=morningstarr+mppt+charge+controller

An additional 100W solar panel will cost ~ $150 and give you a total array of 300W with your current controller.......That is approx 50% more power for $100 less...put another way, for about the same $, you can double the output of your current array....... as I stated before, unless you are talking a fairly large array, the MPPT controller may not be your most cost effective solution. IF YOU HAVE THE ROOM.....another panel (or 2) has a far greater benefit.
http://www.amazon.com/RENOGY-Monocrystalline-Photovoltaic-Battery-Charging/dp/B009Z6CW7O/ref=sr_1_1?ie=UTF8&qid=1404940517&sr=8-1&keywords=100w+solar+panel
Wayne
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Retired our '98 Winnebago Adventurer Nov 2018

Wife, Carolyn...... 5 kids.... 14 grandkids.... 12 greats. Christmas has become a real burden :-)


Retired GM Service Manager driving a Ford....What's the world coming too??

Kevin Means

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Re: How to determine how many amps my residential fridge takes?
« Reply #27 on: July 09, 2014, 04:52:55 PM »
Just to be cliear, I am not recommending buying an MPPT controller for an array with an output of 200 or even 300 watts (unless you were going to buy more panels later). A PWM controller would work just fine for a system that size. In fact, some recommend not using a contoller at all until you hit the 300 watt mark, because contollers themselves draw power (MPPT more than PWM). Between normal appliance use, parasitic loads and the actual output of panel(s) rated at 200 watts, overcharging a battery-bank is unlikely.

Kev
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Powerstroke2000

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Re: How to determine how many amps my residential fridge takes?
« Reply #28 on: July 07, 2018, 07:29:16 PM »
Kevin- thanks for the info. How do I determine whether my battery charger can put out the amps to charge additional batteries, and is that the inverter or the converter?

My inverter says it is a Xantrex Pro XM1800....and it says "MSW, WXFER 1800 watt" on a little page they gave me with serial numbers.

the converter says "converter, power, 55 AMP, 30 AMP AC, 11 DC Circuits"   

I don't know what those descriptors mean yet though :(

I was thinking in the 400-500 watt range would meet my needs.... which sounds like you described a 480 watt set up......

With the inverter I have already, I'd only need the battery and a charge controller I think?

Wow, this is an old post, but pertains to me here in July of 2018....or 4 years after the post....so I'll assume Solar has even gotten better over that time?   I too am wanting to add a solar array, and it looks like I'll also want 100 Amps.   I would like to also change batteries (4 - six volt lead/acid at the moment) so we'll see.   I too have a residential fridge, a coffee pot for our morning coffee, and a little tv at night sometimes.   I do believe I'd rather have 'too much' rather than too little, since I live in the Pacific Northwest with a ton of cloudy days.   We're not full timers, but will go for long trips coming up, as well as lots of boon docking.   Lithium batteries would be nice, but they're so very pricy these days!    So much yet to learn...
2008 Tiffin Phaeton Motorhome
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