Battery Inquiry-Questions

[Capebuild]

After getting (somewhat) educated on AGM batteries VS Lithium, I had settled on a lithium (battleborn) 100Ah 12 volt.

However now I'm questioning this choice and I need to bounce some thoughts off of other members.

I liked the fact that with the lithium battery, I could draw power from it far below the 50% limit of an AGM, they are smaller and lighter, and seem to be more efficient.
I've learned recently if using a lithium battery you need to also have a "battery management system". I'm still trying to learn about that, so that adds a little twist to the mix.

The downside of the lithium is it seems problematic to have battery to battery charging off my tow vehicle (Subaru Outback) and can't go below the 50% capacity. Yes they are less
expensive, but I'm not considering that as an issue for now.

I thought maybe of getting 2 100 Ah AGM batteries, so with that set up I could go back to considering battery to battery charging, wouldn't need to figure a BMS into the mix, I'd have the equivalent power of 1 100Ah lithium,
but the footprint and weight is now much greater than the single lithium battery. The weight thing is really a big difference.

If anyone had any overall thoughts I'd love to hear what you may have to say.

Thanks very much.

John

[saltydawg]

After getting (somewhat) educated on AGM batteries VS Lithium, I had settled on a lithium (battleborn) 100Ah 12 volt.

They are good batteries, but pricey for what they are. The good thing, and it adds price, is they make a self heating one if your going to be using the camper in the winter

However now I'm questioning this choice and I need to bounce some thoughts off of other members.

I liked the fact that with the lithium battery, I could draw power from it far below the 50% limit of an AGM, they are smaller and lighter, and seem to be more efficient.
I've learned recently if using a lithium battery you need to also have a "battery management system". I'm still trying to learn about that, so that adds a little twist to the mix.

The bms is internal in the battery, no need to think about it all, its already done and figured out

The downside of the lithium is it seems problematic to have battery to battery charging off my tow vehicle (Subaru Outback) and can't go below the 50% capacity. Yes they are less
expensive, but I'm not considering that as an issue for now.

I think you missed typed here i think you meant agm. But I will answer the lithium parts, yes the lithium can go down to 0% with out an issue, not going below 10% adds even more life to the battery. The issue with charging from a vehicle is the lithium will happily draw so much power you could hurt the alt in the car. There are a few ways to handle this, dc to dc charger is one and mppt solar charges will work fine like this too. Get a 10 or 20 amp mppt charger and hook it to the 7 pin from the car ( or a separate anderson plug if you dont have a 7 pin ). The dc to dc or mppt will limit it self to 10 or 20 amps ( what ever it is rated for ). the good thing about using a mppt for this is you can parallels the car and solar panel thru the one charger, when your plugged in it would use both, when unplugged it would use the solar.

I thought maybe of getting 2 100 Ah AGM batteries, so with that set up I could go back to considering battery to battery charging, wouldn't need to figure a BMS into the mix, I'd have the equivalent power of 1 100Ah lithium,
but the footprint and weight is now much greater than the single lithium battery. The weight thing is really a big difference.

Again I think you miss typing. see above about bms

battle born heated battery
https://www.amazon.com/100Ah-12V-LiFePO ... 164&sr=1-4

[Capebuild]

Thanks for the reply, SaltyDawg.

Yes... I meant the AGM's are less expensive. Probably not so concerned about keeping the battery warm, no winter camping planned.

Regarding the battery management system, I had no idea what that is. A rep from NOCO I was communicating with via email mentioned I'd need a BMS with charging a lithium battery with one of their Genius chargers.
After a little research it seems some batteries (at least the Battleborn batteries) have, as you mentioned, a BMS built into their chemistry.

The one thing I'm concerned about Batt to batt charging is, as you mention, the potential to mess up the tow vehicles alternator. I am planning on using an MPPT controller for 2 solar panels (Victron 100/20 or 100/30).
I wasn't aware that controller could be used to charge the battery from tow vehicle. I was looking at a Sterling charger, yet still concerned about alternator issues.

Thank you for your comments.....still a bit perplexed by it all but still figuring it all out.

John

[saltydawg]

if your worried just get this one. its designed exactly for what you want. 2 inputs.

https://www.renogy.com/dcc50s-12v-50a-d ... with-mppt/