Solar Panel Battery Charging And Problems 1998 v70 mostly

[MrAl]

Little Update...

Having some better luck with the solar charging. The battery voltage began to go too high so i had to connect a charge controller up to the panel. The controller is supposed to turn on at i think 13 volts and turn off at 14 volts, then wait till it gets back down to 13 volts before it turns on again. There is a chance that this one is charging up to 14 volts and then sort of holding it there, which means allowing less charge current at 14 volts.
I think the battery may have developed a problem because the voltage goes up with just a small amount of current, and that is why it does not charge well with the alternator. The alternator puts out a few amps and already the voltage goes up to 14 volts, so it doesnt charge the battery very well. It has to be run for a least 10 or 12 minutes i think.

Anyway, from what i have seen now over the past few weeks is that maybe a 10 watt panel would work ok if the battery was not too bad. It's going to depend on what your insolation levels are though, which means if you have any shading or other reason for lack of sunlight then you need a higher power panel.
One thing seems sure though, the 20 watt panel appears to be working in a way that keeps the battery charged. Right now it is around 6:30am here on the east coast and that means there was no charging for almost 12 hours, and yet the battery voltage is still up to 12.8 volts, which is the best i have ever seen the so-called "resting" voltage of this or any other battery i ever had out there. In an hour or two it will start charging again.

Another interesting thing is that we just had the driveway paved with asphalt and that meant that i had to park on the street for a few days. That in turn means that the panel was turned 90 degrees from the way i normally keep it for good energy capture. The panel still managed to pick up some sunlight though so over those days it still kept the battery voltage up. It could be that the battery is better now in some ways too though from all the constant charging over the past weeks. It seems that it just needs a higher voltage to get it to charge enough. That must mean the internal resistance went up. Maybe some sulfation. The car starts well though so the battery can still deliver plenty of energy to start the car.

All this means i have to recommend at least trying this if you have problems with dead battery from not using the car that much. It looks like it will keep it charged indefinitely without starting the engine. The requirement though is enough sunlight has to reach the panel for enough time to charge the battery each day. That means if you have any shading or whatever you will have to do some experimenting and possibly buy a second panel if you need it.

Good luck with your setup.

[MrAl]

Little update.

I took the solar panel off today for some minor maintenance. When i went out to the store the other day i went to put the panel in the back seat and found that the mounting bracket could bend too easy. It's not the brackets themselves though it is the crummy way the aluminum frame of the panel attaches to the panel. The metal should be a little thicker for that. If you grab one of the brackets and pull a little it bends the aluminum on the panel itself. I added a support brace across the two brackets connecting them together at the bottom so it makes the whole thing a lot stronger. Lucky i had a piece of angle aluminum around and some bolts and nuts.
If you ever decide to get one for the car you have to be able to mount it in a way that keeps it from blowing off the roof or whatever and you want it to be strong. Some of the mounting schemes are very poor when you buy a panel so you have to look into this as well as the panel itself. It's worth getting a good set of mounting brackets or make up something strong yourself using angle aluminum. 1/16 inch thick stuff might work, but the 1/8 inch stock is much stronger and does not bend as easy.

Hopefully tomorrow it goes back on the car, but i also wanted to see how the car battery would react to not being charged at all for a whole day since it has been charging on a very regular basis ever since the panel was first installed.