Solar Help

[Pete's Pop-up]

I just purchased a new Rockwood 2514F. My wife and i are "off-gridders" and this is our 1st..RV.
In researching solar needs, the suggestions are all over the place. Can someone with experience set us in the right direction? We are considering 2- AGM, 200 Watt set up. Any advice would be appreciated.

 

[Rich W.]

200 watts of solar is about a 10amp battery charger during full sunlight, and two AGMs (around 200ah) is a about 100ah of usable power at best. You might get by with a small system like that, but only if you have very low power consumption needs.

Have you analyzed your daily power consumption needs? You need to do that, including after sundown power consumption, to determine your needed battery bank ah, and then you need to figure out the daily charging needs of the chosen battery bank size. You’ll also have days of insufficient sunlight and you’ll never get 100% out of your solar, so while the system has to be big enough, you also need a back-up charging source.

And not to be pessimistic, but for solar to be effective you need to park in full sun, causing a significant cooling need, which can not be practically addressed with solar, and requires a very large battery bank after sundown. I‘ve done it with 1975w of solar and a large Li-ion battery bank, but it was very technical, expensive, and still only gave me about 7-8 hours of cooling time running one AC after sundown.

So it all just depends on power needs, budget, and practicality. What do you need in terms of power production for your plan? Also if you are planning portable “ ground mount” panels you can easily have a larger array and by tending it during the day get more out of it.

My SWAG system design would be around 400w of portable solar (so you can park in the shade) and four 100ah agms, obviously with no consideration for cooling, but you may have lower power consumption needs.

I’m not surprised suggestions are “all over the place” for a variety of reasons, but there is only one right answer and that is the system that meets your needs and fits your budget, or as close to both as possible.

 

[Kevin D Pem]

200 watts of solar is about a 10amp battery charger during full sunlight, and two AGMs (around 200ah) is a about 100ah of usable power at best. You might get by with a small system like that, but only if you have very low power consumption needs.

Have you analyzed your daily power consumption needs? You need to do that, including after sundown power consumption, to determine your needed battery bank ah, and then you need to figure out the daily charging needs of the chosen battery bank size. You’ll also have days of insufficient sunlight and you’ll never get 100% out of your solar, so while the system has to be big enough, you also need a back-up charging source.

And not to be pessimistic, but for solar to be effective you need to park in full sun, causing a significant cooling need, which can not be practically addressed with solar, and requires a very large battery bank after sundown. I‘ve done it with 1975w of solar and a large Li-ion battery bank, but it was very technical, expensive, and still only gave me about 7-8 hours of cooling time running one AC after sundown.

So it all just depends on power needs, budget, and practicality. What do you need in terms of power production for your plan? Also if you are planning portable “ ground mount” panels you can easily have a larger array and by tending it during the day get more out of it.

My SWAG system design would be around 400w of solar and four 100ah agms, obviously with no consideration for cooling, but you may have lower power consumption needs.

I agree with this. I will only say the following to add to it. First a picture.

This is a 400ah thin plate lead Carbon AGM battery bank.

I feed it with 2000w of solar, and it will not run a window shaker all night. For the record a lower state of charge can be achieved without harm than a standard AGM. the life cycle at 50% far exceeds lithium unless we talk LTO.

I can run a small portable swamp cooler all night with the system.

Only real-estate and funds can limit what solar can do, both limited in the RV world. However energy saving (LED lights, lower energy fridge (not an RV item), swamp cooling, etc. ) can be the answer for full off grid system. However I am not fully off grid, as I still use propane to cook half of my food, and heat my water and house. However I feel I have done well.