Trolling motor/Lithium battery question

[Bass in the grass]

I would think “REPAIR” mode is a problem! Usually it is only something used on lead acid batteries. (15+ volts!) Drew can address that particular charger as I am not a user of Noco.

I thought the same thing when I read it, it’s typically for SLA.

[DREWTICK]

On another note. I have a 24V MK Fortrex trolling motor. Does anyone know if I can use a Lithium 12v 50ah battery and a 12v 100ah battery connected in series. And if so what type of charger.

you can but it will be the same as running 2 12v50ah

charger NOCO 10x2, Minnkota 212pcl or 220pcl

[bobcoy]

https://no.co/support/genius10-repair-mode

[Tarheel14]

Update. They instructed me to connect it to a 12v source to see if it could discharge. Then connect it to the charger to see if it would charge. I connected it to my Helix 7 and it did drain the battery. It's now reading 1.2volts. I connected it to my Noco charger and the charger was flashing and would not charge the battery. I emailed them back and will wait to see what they advise. It is still reading 1.2volts.

[yupitsme]

The Helix 7 is not a 12v source. Another battery is a 12v source. Put your 1.2v reading battery and a known good 12v battery in parallel, +2+. -2-. then attempt to charge the problem battery. I'm a bit surprised the BMS did not kick in and disconnect. Sounds like the BMS isn't doing it's job either.

[Tarheel14]

I switched the leads on my charger and currently the bad battery is charging. I will be ordering the better noco charger. My 5x3 charger, I'm gonna have to sell.

[CJ1]

The Helix 7 is not a 12v source. Another battery is a 12v source. Put your 1.2v reading battery and a known good 12v battery in parallel, +2+. -2-. then attempt to charge the problem battery. I'm a bit surprised the BMS did not kick in and disconnect. Sounds like the BMS isn't doing it's job either.

I am guessing the BMS is activated and that reading is just residual voltage. Sounds like to me the charger was the problem all along and I hope the o/p would at least verify that and say so before you try to sell it. Alot of the new style chargers will not wake up a BMS to charge. CJ

[Tarheel14]

I did switch the leads on the charger and it charged the battery fine. I initially had problems with that particular lead from the beginning. I just installed the new Noco 10x3 today and it is working fine.
The problem is I can't get warranty through noco on the other charger. It will charge all 3 leads but that 1 bank has been problematic. Since I cut off the 110v plug to install it initially it voids the warranty. I did not make that mistake with the new charger.

[Tarheel14]

Redodo is still telling me my setup is not recommended.

I'm running 2 50 AH batteries in series 24 volts. My MK TM pulls 58AH at max draw.
They recommended I get 100 AH batteries.

[Bass in the grass]

Redodo is still telling me my setup is not recommended.

I'm running 2 50 AH batteries in series 24 volts. My MK TM pulls 58AH at max draw.
They recommended I get 100 AH batteries.

yeah, you are able to pull more than they can give. Unless you’re going to run on less than half power all the time, you need a bigger BMS amp draw capacity.

For example, the ionic 50’s can handle 150amp draw for 3 seconds. Your batteries can only handle 50amps maximum. They are cheap for a reason.

edit: i looked at the wrong spec, still not gonna work though.

[JK9027]

If the mode button is depressed for 5 seconds it will start charging a battery that is too low for it to recognize the battery....on that charger. Then choose the mode you want. I unplugged mine and restarted after 30 seconds because that restart mode stays on for 5 minutes....just saying. I charged 2 100ah lithium batteries from 35% yesterday with that charger. Took maybe 12 hours though. I think your issue has to do with the bms set at 50ah, but what do I know?

[bobcoy]

Most LiFeP04 batteries are Max Draw rated at 1C(equal to amp hr capacity) 50 AH = 50 amps. I have seen some with lower max ratings, but that usually means internal wire and or construction at low standards. JMO Bob

[Tarheel14]

So basically I should get better batteries??

[Bass in the grass]

So basically I should get better batteries??

You need to read the specs. LiTime says you can use their 50ah batteries to pull 100amps for 3 seconds. You have 3 options:

1. Never run at full speed with your current TM.

2. Buy a more efficient TM.

3. Buy bigger/better batteries.

Option 1 is the cheapest.

[goodman_fishing]

yeah, you are able to pull more than they can give. Unless you’re going to run on less than half power all the time, you need a bigger BMS amp draw capacity.

For example, the ionic 50’s can handle 150amp draw for 3 seconds. Your batteries can only handle 50amps maximum. They are cheap for a reason.

Seems like the Ionics will still drop out as well after 3 seconds with his setup. The Redodo's are rated at a 2C (100a) discharge rate for 5 seconds. Under "parameters" on the page, https://www.redodopower.com/products...ery-640wh-640w

If we're comparing continuous discharge rates...Monster Marine has a 2C continuous discharge rate on their 50Ah battery.

[Bass in the grass]

Seems like the Ionics will still drop out as well after 3 seconds with his setup. The Redodo's are rated at a 2C (100a) discharge rate for 5 seconds. Under "parameters" on the page, https://www.redodopower.com/products...ery-640wh-640w




If we're comparing continuous discharge rates...Monster Marine has a 2C continuous discharge rate on their 50Ah battery.

yeah, his setup is a problem for all of the 50’s that I’ve looked at so far.

[Tarheel14]

Thanks again for the info..I appreciate it

[goodman_fishing]

yeah, his setup is a problem for all of the 50’s that I’ve looked at so far.

Not quite, some 50Ahs have 1.2C (60a) and 2C (100a) continuous discharge rates, like the Monster Marine battery that I mentioned. The common issue is certainly with the 1C batteries, it gets overlooked pretty often. No doubt.

[Tarheel14]

I guess I'm kinda up a,creek.

What would you do??

[Bill Reynolds]

I have the same setup and so far it is ok (about 3 yrs).
However I did rebalance them once because after a full charge and 30 minute rest, there was about .3 volts difference in the two batteries. The instructions say to check them every 6 months but I don’t do it that often.



ReDoDo also pitched a fit when they learned I was using the batteries on an 80# 24 volt trolling motor. They offered to trade out the 50AH for 100 AH but I couldn’t afford the cost difference.
My position was that the max amperage shown on the MK website is locked rotor condition rather than normal use and I emailed the amperage readings I took in normal use. I have been in current so strong I was slipping back and the motor never drew over 38 amps.
I was not trying to be argumentative with them but 50AH was all I could afford. I would love to have 100 AH batteries. The same is true for the 5X3 charger, I bought it new open box on eBay for $125.
In the end they were still not happy with me and I doubt if they would honor a warranty for me. Just keeping my fingers crossed.



It does sound like you had a bad charger, if the battery is taking a full charge now I would add a Bluetooth monitor to the circuit and try them for a while. Hopefully the problem is behind you.