Battery and Solar???

[Charlie33]

Hello All

My wife and I lost our battery on the last trip. We replaced it but our solar panel does not seem to be charging it as well. My questions are as follows.

A) Once we start boon docking how long should the battery last? We use it minimally.... but right now its a bit cooler out so we do run the heater, some lights at night and the radio.

B) If its clear and sunny how much power should be replaced by the solar panel during the day? I under stand the built in readouts " micro pluse system monitor" are not very accurate but it seems it use to jump up to a full charge on a sunny day.

[FLYNCLD]

Greetings!

How your solar system charges your battery is a somewhat complicated subject. First you need to make sure all the components of your system are matched. The size (wattage) of your panels, your controller, your batteries, and your power requirements. The first thing you need to do is asses your power requirements. Add up all the amperage of your electrical components, multiplied by the number of hours you use them. This will give you your total amp hour requirement. If your panel is generating less than this, or your battery is not large enough to recover, you will continue to either run out of juice, or kill your batteries. There are worksheets available from several of the solar panels suppliers websites that can help you do this. Remember, you are simply topping off your batteries with the solar, so chances are you just don't have enough input or storage capacity to keep up with your demand.

Hope this helps!!

FLYNCLD

[Charlie33]

Thanks for the reply.
We have had the trailer for 2 years ( 05 purchased used) and have dry camped for a week straight and not had any issues up until now. I'm assuming the solar and everything else was factory installed.
It was suggested by a friend when we got it to double up on the battery (either two 6 volts in line or two 12 volts) but like I said we just haven't had any issues until now.

[FLYNCLD]

You might just want to start by checking the output of the solar panel. It is possible it has dropped off for some reason.

[Charlie33]

Sorry to bother you again Flyncld. How do I do that?

[FLYNCLD]

No problem! However if you are either unfamiliar with electrical testing or do not have the tools, you might want to take it to your AS dealer, or a local auto electrical repair shop. You will first need a simple multimeter. You can pick one of these up at Home Depot for about $10. You will then need to make sure the solar panel is getting sunlight, and test its output where it enters the controller. If you are not getting around 14-17V, then your panel or its wiring is malfunctioning. If that test is good, then you will need to test the output from the controller before it enters the battery. If that test is good, then you are probably just using more juice then is coming in, but since you say you have used this setup for awhile without a problem, this shouldn't be the case. If the panel output is low, start with the simple things. It could just be dirty! If that is not the case, check the wiring for frays or shorts. If the panel output is good, but the output from the controller is low, you will probably need to seek assistance to replace or repair the controller. Once again check for loose, worn or shorted wires at the controller as that may solve the problem. HOWEVER...BE CAREFUL!! A solar panel that is exposed to light will be putting out current!! You should either isolate the panel from the controller before working on it, or cover the panel with a blanket or plastic to stop the flow of current. It is my experience, that unless you are comfortable with electricity, it is best left to professionals. A solar panel can give you one heck of a jolt and you should always treat any wire that is hooked to it as if it is HOT!! Hopefully this will at least give you an idea of what you are looking for.

Good Luck!

[Airstream25]

Charlie33,
To give you an actual scenario, I have a 120 watt solar panel and 2 group 27 batteries. When running the furnace on nights below freezing, the furnace fan will deplete the batteries (down to about 12.3 volts) in just one night but if the following day is sunny, the panel will fully restore the batteries.

[FLYNCLD]

It sounds like you are probably just exceeding your ability to recharge the batteries. If you frequently pull the battery down to less than 40% or more of its charge, you will kill the battery in pretty short order. You may want to look at adding an additional panel. I would go ahead and do the energy audit and see how it compares to your output and storage capacity.