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Charging Lithium Batteries in Series

Posted By: T Bird

Charging Lithium Batteries in Series - 04/21/24 06:14 PM

If I have two 12V 50 AH Lithium batteries connected in series to power a 24 V trolling motor, how would I connect the 12V on- board charger connections to charge both batteries simultaneously?
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/21/24 07:41 PM

As long as you have a lithium charger , nothing changes as you hook up the batteries .
Posted By: tmd11111

Re: Charging Lithium Batteries in Series - 04/21/24 07:52 PM

Have at least a two bank charger and connect a bank to each battery, same as any other batteries.
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/21/24 07:58 PM

Some chargers will charge lithium and wet cells , AGM at the same time .
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/22/24 10:23 AM

Ebay has some ionic battery chargers , 3 bank is $50.00 , 4 bank is $75.00
Posted By: T Bird

Re: Charging Lithium Batteries in Series - 04/22/24 11:58 AM

Thanks y'all. thumb
Posted By: hopalong

Re: Charging Lithium Batteries in Series - 04/22/24 03:16 PM

noco genius and minnkota pc chargers will do lithium, my pc does it in agm mode
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/24/24 02:48 PM

Well my cheaper Ionic Lithium refub trolling battery took a dump , gamble is i think i lost . Was down to 49 % and about 10min it shut down , no bluetooth . No nothing.
Short story when i got it was reading 12 v 48 ah , so i called cust service , they said to drop it down to 20% , and it would fix it . So it on the charger and it was reading 1% 46 ah , 13 cycles , 4 hrs to charge
Had to come in after a hour
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/25/24 08:32 AM

Checked Refub Ionic battery this morning and it read 100% 12 v 46 ah , so i loss 2 more ah . So that was a waste of $ 175 .00 ,
only used it twice , 30 day warranty , now i don't have any warranty they should have junked this one ,
Posted By: goodman_fishing

Re: Charging Lithium Batteries in Series - 04/25/24 10:32 AM

I'd do a capacity test on it. The apps aren't always the most accurate and have been an on-going challenge across most brands.
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/25/24 10:49 AM

4 hours of use and it quit's completely , dead as a dumb bell .
Posted By: Allison1

Re: Charging Lithium Batteries in Series - 04/25/24 04:14 PM

Sounds like you have a bad cell in there or the bms is not working.
Posted By: grout-scout

Re: Charging Lithium Batteries in Series - 04/25/24 07:04 PM

Originally Posted by Bandit 200 XP
4 hours of use and it quit's completely , dead as a dumb bell .




Running what device?
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/25/24 09:51 PM

Trolling motor
Posted By: T Bird

Re: Charging Lithium Batteries in Series - 04/25/24 10:14 PM

Easy equation.

Amp hour capacity of battery divided by max amp draw of the unit your powering = Run time.

Example

Two 100 AH 12V batteries in series = 200 AH divided by (say a trolling motor with 50 AH max draw) = a run time of 4 hours.

If you're running the trolling at half speed setting then that would be a 25 AH draw and you'd get 8 hours run time.
Posted By: Stump jumper

Re: Charging Lithium Batteries in Series - 04/26/24 01:38 AM

Originally Posted by Bandit 200 XP
Some chargers will charge lithium and wet cells , AGM at the same time .

Switched to lithiums this month. Bought a MinnKota Precision charger and it charges all three. I plugged it in before installing in the boat and set the battery types. The lights on the MinnKota can be a little confusing when the batterry is hooked up and charging. When you push the battery type button it will only indicate the battery type for 2 seconds before changing back to % of charge.
Posted By: Bandit 200 XP

Re: Charging Lithium Batteries in Series - 04/26/24 10:50 AM

Originally Posted by Allison1
Sounds like you have a bad cell in there or the bms is not working.


This morning the battery showed 4 cell was bad and it had a error , minutes later it showed ever thing ok , but still reading 12 v 46 ah
It does have some problems , other batteries read fine . They knew when they sold it , it had problems because it had a sticker on it saying 12v 48 ah
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