A Battery Where No Battery Has Gone Before

[Denece]

Good figuring, I did notice there were only a few B/W wires running around. We'll figure out which ones those are and which are 120 V (hopefully another color/s)

I'm glad you like the title. I hoped if it was clever more people would read it.

And it worked 8-)

[itlives]

If you have black and white in your plug harness, those are the beginning of the 12V system. You could follow the harness to where it goes into the camper and tie into it there. Then you could put the battery inside.

[Greg H]

I am late on this thread, but 10 watts is not enough. I have a 15 watt on mine sitting in the yard and a couple of cloudy days and the voltage guage in the trailer will start drawing down the battery.

[Denece]

Ah ha! That's what I was afraid of.

I was thinking we might need 20watts of panel for the lights and occasional (or near daily when used much) cellphone ipad charging. And probably need to keep an eye on voltage even then.

Thanks.

[mary and bob]

Looks like I put too much faith in believing the ad & reviews on the 10 watt panel. I'll just send it back and search for something better.

[Thomas G.]

Originally Posted by mary and bob

Looks like I put too much faith in believing the ad & reviews on the 10 watt panel. I'll just send it back and search for something better.

Bob, Have you looked at eBay? I see 50 watt panels for $100 with free shipping (just as an example).

[Larry,C]

Bob,
I am not familiar with the 10 watt panel you purchased but it may be all you need. The first question you need to ask yourself before you buy a "better" panel is "what do I reasonably want to power with the sun?" How long in terms of hours and minutes each day do you want to use the lights, TV, computer, water pump, refrigerator, etc.... and then based on the power consumption of those devices you can calculate the number of amp hours of battery reserve you need. This is usually the point where people start to think about conservation and "what do I really need?" Remember when sizing your battery needs you should only use about 70% 0f your battery's amp hour rating because repeated deep discharging of a lead acid battery will reduce it's usable life. By now I am sure you are thinking - but all I wanted was a solar panel! OK so now you should have a pretty good idea of how many amp hours of solar panels you need to purchase and that will dictate the size panels you need to purchase and whether you need a charge regulator to protect your battery/batteries. To have a properly designed system that you will be happy with there are other important variables you need to consider like distance between your panels and battery and wire size. Depending on your power requirements you may have to consider panel placement and angle with respect to the sun.
I hope I am not boring you with too much information but as I said in the beginning a 10 watt panel may be all you need if all you want to do is top off or maintain your battery during periods of storage.
If I can be of assistance and help you determine what you need feel free to contact me.

Larry Clift
Bluegrass Solar Solutions
larryclift@gmail.com

[mary and bob]

Tom & Larry: Thanks for the info. We have two different camping situations, sometimes we take our teardrop which has no electrical needs other than a few rare times when we use a 12 volt blanket, or other times we use the Uhaul camper which has four 12 volt lights and 12 volt operated furnace. I have several 1150 truck batteries [retired truck mechanic] so I take one or two with the teardrop if I think I may need that blanket. On our recent 3 week trip with the Uhaul we always had shore power but for some reason the battery went dead. I had load tested it before we went and it was good so I believe there is a problem with the power converter so that is going to be replaced. I just need a solar panel to keep a battery up for those few day trips where there is no 110 power available. When I was still working, it was not unusual for customers to walk away from a truck and leave the headlights on, the batteries would last a long time with that much load so I'm not too concerned with discharging a battery on a long weekend trip or even worried about battery life as I have several and they were free as they were good take outs because we always replaced all the batteries when one went bad. Larry you're certainly not boring me, just making me think too much, LOL!! The Uhaul has it's original equipment solar panel, but I don't know what it's rating is or if it even works, but the Uhaul repair manual says it is not capable of charging the battery. I suppose because it is 28 years old it may be outdated technology. Thanks everyone, lot of good info on this site. Bob

[Larry,C]

Bob,
You should be able to test your Uhaul panel with a multi meter (< $10. at Wallyworld) to see if it is providing current.

You are lucky to have a supply of batteries cause that can be a major cost factor in a solar electric generating system. Toms suggestion of 50 watt panels sounds good for your current needs - weekends lights and electric blanket (12 volt I hope) and furnace). The furnace concerns me a little depending on it's requirements - is it 12volt powered?, electronic ignition? thermostat? I have seen some that draw considerable amperage. Somewhere down the road if you plan to use your camper for longer periods you can always add another panel and charge controller if needed.

I would recommend LED lights if you don't already have them. They draw about 1/10th of the current of incandescent lamps. For what it is worth I prefer the mono-crystalline panels to poly-crystalline. When you are ready to buy your panels consider a reputable dealer. All solar panels are not created equal.

Larry Clift
Bluegrass Solar Solutions
larryclift@gmail.com

[mary and bob]

Larry: I have two multimeters already. The furnace operates off 12 volts, has a fan and thermostat and electronic ignition. I've found that the battery has to have a good charge in it to have power enough to open the electric gas valve. When we have 110 power available we use an electric heater instead of the furnace. I was thinking of the solar panel for use to help a battery that I am going to power a string of 12 volt awning/patio lights with. It's nothing that I really need to have, but the one I bought looked like a good deal, but that's based on me knowing nothing about solar. The Uhaul solar panel feeds into some little solid device next to the battery, like a rectifier or what??? I'll look in the repair manual and see if it says.

[Larry,C]

My guess is that the device you are looking at is a charge controller. If thats is what it is its purpose is to prevent overcharge of you battery and in some cases it isolates the solar panel from the rest of your 12 volt system. Check the battery side of the device and you should get a reading of 13.6 volts - 14.8 volts if the panel is in the sun.

It is amazing how once you are getting free electricity from the sun you will be able to figure out even more ways to use it. Given your furnace requirements and some nice accent lighting you might want to consider 80 or 100 watt panel especially since you have a supply of batteries. Hopefully your charge controller is in operating condition.

My problem has been limited suitable roof area on our Casita for the panels I would like. Currently I am using 2 - 50 watt panels. But as soon as I figure out the roof problem I will need more batteries. My wife owns the business and even she says I should think conservation instead. She is so smart!

[Greg H]

After living in the Texas desert off grid for a couple of years you begin to realize that solar power is a vicious circle. The more power you need the more panels you need and then you need more batteries to store that power, it may never end.

[honda03842]

Generally people basically use the same amount of power every night. It's nice to have a panel a little larger than your minimal needs because then they are still capable of charging on a partial sun day.

We have 80 watts.