I have 4 lithium Epoch batteries. I use three of the 12v to make up 36v for my Minn Kota Ultrex trolling motor. The other one is used just for my Hummingbird graphs.
Here is my dilemma or problem.
I went fishing today and I had my chargers plugged in for a few days and when i got on the water, after an hour I noticed my trolling motor on 10 was moving me at 0.8 mph speed, usually I am well over 3 mph.
I lifted my trolling motor and sure enough the prop was spinning slow...real slow.
I loaded up the boat came home and started checking as to the percentage these batteries were charged to. Just on the series of 12volt to my 36-volt trolling motor my batteries ranged from 9%, 50% and 17% charged. I thought these were supposed to drain in power equally across each battery.
The battery that is just running my graphs was at 38% charged.
I checked my on-board chargers, and they seem to be working just fine. I do have one 31 AGM battery for cranking power, and it was fully charged.
My three batteries are on a separate charger, a 3-bank charger. The other battery is on a 2-bank charger that includes the AGM 31 series battery.
These Lithium batteries are 1 month old and they have an 11-year warranty. I think I am covered for warranty on these things if it is the batteries.
The question here is this. Do you have to have some special on-board battery charger for Lithium batteries? I do not think you do but I'm asking those that know more about this than I do, which is properly 99% of you all.

what charger do you have now?

it takes a certain type to charge them.

I have the XPS Pro series 15.3, that is my 3-bank charger. 15 amp, so 5amp per bank
I have a NOCO genius, two bank charger 8 amp so 4 per bank.

Yeah, I don’t think that charger will pump enough voltage into the batteries. If it has an AGM setting, it might work, but might not either. Minnkota PCL or Noco Gen Pro are 2 good lithium chargers.


Edit: I looked at the BPS website and it says it “not for lithium batteries”. But try it on AGM and see where it puts the battery in % status.

I just went ahead and purchased the Noco chargers. I would always be wondering if my batteries were fully charged every time on the water. Better safe than sorry kind of deal.

Thanks for the help.

Invest in a good, real-time battery monitor system and keep an eye on SOC while on the water.