Community Forums

Tagalong · 01-02-2007, 01:27 PM

I don't have electricity where we store our MH and I'd like to hear some suggestions about solar charging the three house and two engine batteries. Presently, I place a 5watt panel on the roof ladder hooked up to the two engine batteries. Even though we're in New England, it seems to be holding the batteries around 12.6v even with the "memory" draw on them. Obviously, after a few days of clouds I notice more drop in voltage, but overall it seems to help keep them from dropping too far. I do start the GenSet bi-weekly to charge all of the batteries as well as exercise the generator.
It's the three house batteries that could use some help. (I do kill the draw at the dash.) The Journey has a solar panel on the roof for them however it's not mounted in a manner that will not allow me to get it facing the sun. Can anyone tell me how large a panel(s) or watts I'd need to charge all five batteries?
Thanks in advance for your help,
Dave
P.S. I'll be posting this on the MH Mag forums.

Tagalong · 01-02-2007, 01:27 PM

I don't have electricity where we store our MH and I'd like to hear some suggestions about solar charging the three house and two engine batteries. Presently, I place a 5watt panel on the roof ladder hooked up to the two engine batteries. Even though we're in New England, it seems to be holding the batteries around 12.6v even with the "memory" draw on them. Obviously, after a few days of clouds I notice more drop in voltage, but overall it seems to help keep them from dropping too far. I do start the GenSet bi-weekly to charge all of the batteries as well as exercise the generator.
It's the three house batteries that could use some help. (I do kill the draw at the dash.) The Journey has a solar panel on the roof for them however it's not mounted in a manner that will not allow me to get it facing the sun. Can anyone tell me how large a panel(s) or watts I'd need to charge all five batteries?
Thanks in advance for your help,
Dave
P.S. I'll be posting this on the MH Mag forums.

Gary the Wombat · 01-02-2007, 03:26 PM

Try this website--it may answer your questions.

http://www.windsun.com/Small_Systems/rv_solar_faq.htm

Gary RVRoamer · 01-02-2007, 05:07 PM

A 5 watt panel isn't much for 5 batteries, even if only replacing parasitic draw and self discharge. That's one watt per battery or a max of 0.08 amps/hour each. And you don't get much direct sun in winter New England, or for very long either. I'd increase the panel size to at least a 20 watt or better yet a 50-80 watt panel (if the budget permits). A large panel, e.g. 50 watts, might actually deliver 20-25 watts, whereas a small one is delivering almost nothing in the winter.

Cruzer · 01-02-2007, 05:12 PM

I had 10 watts on my house batteries (two twelves) on my Suncruiser and it did nothing. Later I put it on my chassis battery (single 12 volt) when I installed two 110 watt panels on the house side. The 10 watts on the chassis battery helped but it still went down I'd guess that you'd need at least 20 watts, if not more, per battery. Naturally, this will depend upon the amount of sunlight available. Unfortunately for solar to work you need lots of it or else you really have to manage your power consumption. I now have 480 watts on the roof and it does what I want it too (extends my boondocking time between generator charge cycles) but it's not a very cost effective method.

Tagalong · 01-02-2007, 05:14 PM

Thanks for the website Wombat.

Gary, I realized the 5 watt really wasn't going to help very much. I was more concerned with the cost of the panel and my better half really didn't understand how much we really need to go "solar" here in New England. After a year with the 5 watt both of us are realizing that we need more and larger panels. Thanks for the info.
Yikes! that's a lot of panel wattage!!! Thanks Cruzer. It seems, somewhere about 20 watts a battery is what I'm leaning toward. Remember, I really want battery charging rather than powering the accessories.
Thanks all,
Dave