Maintaining small starter battery

[Lt.Dan]

Hey all, I keep my Polaris RZR stored in my DIY Solar Trailer (link in sig), and I'm trying to think of a good way to keep the battery in the RZR topped off, because after a few weeks of it sitting, it will start to dip below 12v, and I've had to jump it/slow charge it several times now.

First instinct is to just get a simple Battery Tender/ Noco 2a charger, plug it into the trailer and forget it. But I like to turn off the Deye inverter thats in there, when its not in use, because it draws a lot of idle power when all it is doing is maintaining a small battery. Now my 48v to 13.8v converter is always powered, and I have THIS Cigarette/Socket outlet less than 5 feet from the RZR.

Would it be viable to just run a simple Cig/Socket plug to an SAE connector, that then plugged directly to the RZR battery? It would obviously maintain the battery at 13.8v, which might be a little high for a FLA battery? My other concern would be if the battery is low, and I plugged it in, then it would draw more than 10a from the Cig Lighter and pop the fuse.

Is there a better way to do this without involving more electronics? Or is this simpler than I'm making it out to be?

 

[sunshine_eggo]

8-40V to 13.8V converter:

https://www.amazon.com/Stayhome-Voltage-Regulator-Stabilizer-Automatic/dp/B07SRTVR9C

Shouldn't overload. It will simply run at a under 13.8V @ 5A until voltage gets to 13.8V. There's probably a lower limit that it won't work below, but I would expect that in most cases, it should be no problem.

Since it can't draw more than about 70W, it shouldn't pop the 10A fuse.

 

[Lt.Dan]

8-40V to 13.8V converter:

https://www.amazon.com/Stayhome-Voltage-Regulator-Stabilizer-Automatic/dp/B07SRTVR9C

Shouldn't overload. It will simply run at a under 13.8V @ 5A until voltage gets to 13.8V. There's probably a lower limit that it won't work below, but I would expect that in most cases, it should be no problem.

Since it can't draw more than about 70W, it shouldn't pop the 10A fuse.

I'm already using this one: https://www.amazon.com/gp/product/B01MYMVGSU/ref=ppx_yo_dt_b_search_asin_title

I was just hoping to not have to buy more equipment.

 

[sunshine_eggo]

I'm already using this one: https://www.amazon.com/gp/product/B01MYMVGSU/ref=ppx_yo_dt_b_search_asin_title

I was just hoping to not have to buy more equipment.

@ 30A output, there's nothing preventing it from pulling 10A on the plug.

 

[Lt.Dan]

@ 30A output, there's nothing preventing it from pulling 10A on the plug.

Ok, say I get the 5a model and wire it just for the RZR. Is 13.8v too high to maintain? Shouldn't storage voltage be 13.4v for a FLA?

 

[sunshine_eggo]

Ok, say I get the 5a model and wire it just for the RZR. Is 13.8v too high to maintain? Shouldn't storage voltage be 13.4v for a FLA?

It varies. 13.2-13.8V are common numbers, and 13.8V is a little high for FLA. I've never seen any in a more moderate range. You'll need to top off the electrolyte periodically.

The 5A I found is 8-40V input. I didn't see one for a 48V range.

 

[Lt.Dan]

It varies. 13.2-13.8V are common numbers, and 13.8V is a little high for FLA. I've never seen any in a more moderate range. You'll need to top off the electrolyte periodically.

The 5A I found is 8-40V input. I didn't see one for a 48V range.

https://www.amazon.com/13-8V-Transformer-Non-Isolated-40-90V-10A/dp/B07DH31MT3/ref=sr_1_5

Found a 10a one atleast. I can just set it up independently, and then run a powerpole connector to hookup the RZR battery to it. Shouldn't be very bad at all.