Question about solar battery maint.

[Curious Hound]

Weird question.....the little solar panel I had been using plugged into the power outlet was a 12V panel (about 6"x6") and since it was only putting out 5.5V could it have been drawing from the battery?

It should be designed not to do that. But only the designers of that product know for sure. If it was a really, really cheap unit, there may be some doubt.

 

[RonD]

Yes, Battery itself is OK, good news indeed

A solar panel "should" have at least 2 diodes that prevent current flow TO the panel, so current can only flow OUT of the panel
And most do because they only have voltage output for a few hours a day, when in direct sunlight

Electricity can only "flow" from a higher voltage to a lower voltage
Which is why solar panels for vehicles have 13+ volt output, voltage has to be higher than battery's voltage or no "flow" TO the battery

So the 6volt panel had no hope of sending voltage to the 12v battery, it may have been designed for use with re-chargeable batteries, which can be handy to have for Cell phones, flashlights, portable radios or ??

 

[Shadowranger]

Thanks, will charge it and see what happens.

 

[Shadowranger]

This morning's voltage reading was 12.46 (after reconnecting late yesterday) so it looks like a parasitic draw going on.

 

[RonD]

Yes, you will need an AMP meter which is part of most Volt meters, even the cheap ones

 

[Runnin'OnEmpty]

Battery voltage will change slightly according to temperature, but a
test for amp draw is a good idea to confirm what's going on.

I've found that most of my vehicles draw about 7-15 MA naturally,
with everything off.

 

[Eddo Rogue]

AGM batteries are a little better about not losing charge in vehicles that aren't driven much...

 

[lansdowner]

Have you thought about adding a charge controller to your setup?

 

[Shadowranger]

No, but shortly after this discussion I found a battery maintainer online called Battery + and it produces up to 18 volts so I put on the dash when not driving the truck. Plugs into power outlet and comes with two battery clips also and works perfectly. When I looked for another (ebay) it had disappeared...

 

[PrettyDoll]

I’ve been in a similar situation with my vehicle, leaving it parked for a while and using a small solar panel. Honestly, 6 volts might be a bit low for keeping a battery topped up over a couple of weeks, especially if the panel isn’t providing enough current. I had the same issue with an old setup, and after speaking with solarsmart.ie, they suggested a 12-volt system for better reliability. I swapped to a 10-watt panel, like the one you found, and it worked fine without any issues. The 18 volts should be fine too, as long as you’re using a proper charge controller to prevent overcharging and protect the wiring.

 

[Curious Hound]

I’ve been in a similar situation with my vehicle, leaving it parked for a while and using a small solar panel. Honestly, 6 volts might be a bit low for keeping a battery topped up over a couple of weeks, especially if the panel isn’t providing enough current.

Considering that our truck batteries are 12volts, yes, 6 volts is definitely low and will not charge a 12volt battery. The charging voltage must be higher than the battery voltage in order to charge. However, too high will cook and ruin the battery. That's why the regulators on our alternators maintain the voltage just under 14 when the engine is running. A trickle charger (maintainer) must provide around 13.5 - 14 volts and limit current to a very low level to prevent battery damage.