RC Airplane Battery, 12 volt Solar Charging Station

[CHELLIE]

Hi Everyone I am trying to help a friend design a solar battery charging Station, for a RC Electric Flying Club, the flying field does not have any power going to it, and a 12v solar system is needed to plug in the lipo chargers to, here is what I have come up with. there are not a lot of people at this flying field

1. 80 Watt Solar Panel for a 12v system
2. 10 amp 12v solar panel Regulator
3. (4) group 27 Deep Cycle Marine Batteries, i think they are 80 to 90 AH each, the 6v ,GC-2 golf cart Batteries would be better, but they are much more money.

They were thinking of using the Harbor frieght 45 watt 12 volt, 3 panel solar system, that cost about $199.00, i found a 80 Watt solar panel on EBay for a 12 volt system for $170.00 almost twice the Wattage and a 12 volt 10 amp solar regulator for $22.00, the (4) group 27 Marine Deep Cycle Batteries from Pep Boys are about $75.00 each, i think they are about 80 to 90 Ah. do you think this will work OK, Thank you in Advance, Chellie

PS. the average lipo battery that will be charged is a 2250mah, 3 cell lipo 20C, 11.1 volts

 

[crutschow]

80W @ 12V is 6.6A in direct sunlight. In an hour you would get 6.6AH of charge, in an average day perhaps 40-50AH.

Do you plan on leaving the system at the flying field when you are not there?

How may lipo batteries do you need to charge and how often?

 

[nickelflippr]

I would go for the 80W panel, seems like a good price if a quality manufacturer. Wouldn't hurt to add insurance against shipping damage. I've had a couple dinged panels during shipping, that were eventually handled alright, but kind of frustrating.

Depending on how many packs a day are charged, two T-105 (6V, 225ah, $115?) batteries could be the best investment. Rule of thumb is no more than 50% depth of discharge, or 110ah/2.5ah = 44 packs a day. Adding more panel could be the better tradeoff? On a typical RV setup, you expect to see 120-130W of panel with the two T-105's.

 

[CHELLIE]

Thank you Carl and Kent for the Feed back yes using a 120 to 130 Watt panel would be better, just trying to keep cost down, and give them a little better system than the Harbor freight 45 watt 3 panel system for their charging station, I belive the charging station will be there all the time, I will look into the T-105 Batteries too, I belive about 30 lipos Max would be charged per day, I will have to double check with that number, Thanks Again for the Information, Chellie

 

[HarveyH42]

The larger panel is a much better choice, as you will never actually see maximum output as advertised. You probably won't always get clear sunny days either. Think starting with 2 batteries would also be a good idea, to save a little money, and see how it works out. You can add more later, if you find your panel can handle it, and really need them. I don't think you are going to drain the batteries as quickly as you think, how many airplanes are going to be charging off it at the same time, or continuously? The deep cycle batteries will likely continue to charge, if not to heavily loaded down with plane chargers, which would taking up an surplus from the solar panel anyway. The solar panel doesn't care what kind of battery it's charging anyway...