Renogy 10w Battery Charger / Maintainer for Starter Battery

[A_Bus_Called_Quest]

Skoolie Fam!
Just dropping a cool gadget I picked up recently - this Renogy 10w Solar Battery Charger & Maintainer.

After having to jump the bus once already this summer, I was worried about our starter batteries draining while not in-use - the Vegas summer heat is really harsh on batteries as-is, let alone a bus starters that sit for months on end, even when disconnected.

I came accross this Renogy gadget and picked it up on sale - so far it has really worked out.

Before using the solar charger, our dash voltmeter was in the low 12's, the VERY low end of the 12v zone. After having the charger on the battery it pops right up to the high end of te 14v zone, and I feel like she starts up quicker - less lag on the turn-over.

It could be all in my head, but for $50 and just bigger than a sheet of note book paper, I feel pretty happy about this addition to our setup.

Does anyone else use something like this on your starter batteries?

[Rucker]

Originally Posted by Bear Gerschafer

Skoolie Fam!
Just dropping a cool gadget I picked up recently - this Renogy 10w Solar Battery Charger & Maintainer.

After having to jump the bus once already this summer, I was worried about our starter batteries draining while not in-use - the Vegas summer heat is really harsh on batteries as-is, let alone a bus starters that sit for months on end, even when disconnected.

I came accross this Renogy gadget and picked it up on sale - so far it has really worked out.

Before using the solar charger, our dash voltmeter was in the low 12's, the VERY low end of the 12v zone. After having the charger on the battery it pops right up to the high end of te 14v zone, and I feel like she starts up quicker - less lag on the turn-over.

It could be all in my head, but for $50 and just bigger than a sheet of note book paper, I feel pretty happy about this addition to our setup.

Does anyone else use something like this on your starter batteries?

Where do you put the solar panel out of curiosity?

I have pretty good batteries and (knock on wood) no parasitic draws, so it's not been an issue with me. I also have two spare batteries in parallel and on the other side of an isolator so in the rare case I run out of juice I can leverage those. Happened earlier this year, worked as designed.

[john61ct]

Be sure to isolate a battery

disconnect from any loads and charge source for at least an hour

before measuring voltage to try to guesstimate SoC%.

[A_Bus_Called_Quest]

I just lean it against the body of the bus, resting on the fold-out step by the front driver's side wheel.

When you say isolate the battery, do you mean I should only connect this to one battery?

I had it connected to the full bank - 3 batteries in parallel. Connecting the charger to battery 1 positive and battery 3 negative, just like they are wired to the bus.

[flattracker]

I have used a 20 watt solar charger in the new Crown with success. I place the solar panel between the windshield and the dash. The bus is pointed in the right direction so I get good sunlight exposure. I recall seeing 13 volts + on the voltmeter. I plug it into the "cigarette lighter socket" since that is always hot. I have used a smaller one in one of my pickups to keep a little extra charge in the batteries.

[john61ct]

Originally Posted by Bear Gerschafer

When you say isolate the battery, do you mean I should only connect this to one battery?

No, your bank is really one big battery.

What I mean is, voltage does not correspond to SoC% in any reliable or accurate way.

So to get even a rough guesstimate, the bank must be "at rest" isolated (disconnected) from any charge sources or loads, for at least an hour

more like 24+hrs but...

[Rwnielsen]

Originally Posted by flattracker

I have used a 20 watt solar charger in the new Crown with success. I place the solar panel between the windshield and the dash. The bus is pointed in the right direction so I get good sunlight exposure. I recall seeing 13 volts + on the voltmeter. I plug it into the "cigarette lighter socket" since that is always hot. I have used a smaller one in one of my pickups to keep a little extra charge in the batteries.

I have a little 20 watt setup too. I used the suction cups and stuck it to the side window right behind the driver's seat. I ran the output into a cigarette socket as well. The window is facing somewhat southwest and it shows that it's charging in the sun. When I'm at the bus I generally have a generator running and a small, 35 amp, converter plugged in. I think it would keep the start batteries topped up if I weren't around for a while. I'm not aware of any parasitic draws in my system. Ideally, if I really depended on it, I'd mount the panel on the roof, tilted up and pointed in a southerly direction.