DIY for Rv only

[Vallka1]

Ok I am the new guy with all the stupid new guy questions......
First I can build build one, I have the skills, just not the knowledge.....yet, that's where you all step in.

I want to build a panel to charge my single (double if it all works out) 12V deep cycle RV battery at a decent rate of speed. We don't use a fridge, we are on LED lights, the bigest draw is the water pump for the shower.
I have watched a few videos on soldering the cells and don't see an issue getting that done or building an enclosure for my needs.

So, is there a list?
What type of cells?
What is the difference in the cells?
Will a cheap charge converter work well enough?

Thanks for your time and effort to help me out, (as well as all the others that have been helped)
Troy

[Amy@altE]

Don't bother building your own panel. These days the factory built panels will cost less than you will spend on components to build your own, and will last many times longer than homemade.

Use your money to by a nice 12V panel and PWM charge controller, you'll save yourself a lot of wasted time and money.

[Vallka1]

Ok thanks for the info, so for what I am looking for what watt output panel should I be lookig for?

[SunEagle]

I agree with Amy.

The cost of manufactured panels have come way down in price. What you think you will save on a DIY you will find that you will spend a lot more due to cell breakage and low performing panels. Also the panel will have a very short life due to moisture intrusion. In the long run purchasing a completed panel is the lowest cost.

What is your RV battery Ah rating and where do you want to use your solar panel to charge it. From that info we can help you size the solar panel wattage and charge controller.

[Vallka1]

No Ah rating on the battery but these are the spec's I found online.
G24RV
PART NO. (CE):
G24RV
PART NO. (BCI):
24 RV

PERSONAL WARRANTY:
18 MONTHS

COMMERCIAL WARRANTY:
3 MONTHS

VOLTS:
12V

COLD CRANKING AMPS:
450

CRANKING AMPS:
550

RESERVE CAPACITY MINUTES:
130

[Amy@altE]

Group 24, so probably about 79Ah hybrid battery.

[Wy_White_Wolf]

Ok thanks for the info, so for what I am looking for what watt output panel should I be lookig for?

How big is the battery bank and/or how much power will you be using in a day?

In an RV it would be advisable to still have a battery isolator so you can charge the batteries off the engine alternator.

WWW

[Sunking]

How big is the battery bank and/or how much power will you be using in a day?

In an RV it would be advisable to still have a battery isolator so you can charge the batteries off the engine alternator.

WWW

Ditto for a BCI 24 battery the alternator can fully charge on in half an hour. No need for solar.

[Vallka1]

This single battery is in a ent Trailer (Pop Up) so it's a bit tough to always hookup and charge. Battery does charge while I am pulling it. If we are careful I can make it last 3+ days but we are out for up to 2 weeks at a time. Would a 50W system work to keep the battery topped up?

[Amy@altE]

A 50W would work, an 80W might do better. Make sure you also use a charge controller sized correctly for the panel. Take the panels Isc x 1.25, that's the smallest size charge controller to use. For example, a 50W has an Isc of 3.03A, so you should get a 4A or bigger charge controller (like a Morningstar SunGuard-4).

[Sunking]

80 watt panel is a bit on the lite side if using a PWM charge controller as that would only generate up to 4 amps or C/20 on a 80 AH battery. You need to get up to at least C/10 to do any good or a 160 watt panel.

[Amy@altE]

The Kyocera 140 is wildly popular for RVs. And a decent compromise between my 80W and SunKing's 160W.

[Sunking]

If we are careful I can make it last 3+ days but we are out for up to 2 weeks at a time. Would a 50W system work to keep the battery topped up?

OK assuming it is an 80 AH battery tells us you are using about 300 to 400 watt hours per day. Assuming you are going to use a PWM controller, mounted flat on top of the RV, and have and have direct Sun from Dawn to Dusk with no shade is going to take 150 to 200 watts of a panel to replace that energy every day. If shaded no amount of power will work.

[Amy@altE]

But he says he can make it last 3 days. I suppose the big question is, what does "lasts 3 days" mean? Use it all the way down to dead, or to 50%?

The problem with going bigger than 140 or 145W, is there aren't a lot of 12V panels any bigger than that. Then you'd have to jump up to 20V and MPPT charge controller.

I still vote Kyo140 (or similar) with PWM charge controller, and if they need to, they can hook up and charge from the truck every now and then. Or a compromise of a Genasun GV-10-Pb-12V for $145.

[Vallka1]

Wow this is great info!!
Ok so I search eBay for a 140w solar kit and find a pile of them in china for a good price. Why should I NOT buy these?