Charging 2 lithiums in parallel

[Aj14]

This topic was discussed sometime ago with different opinions.
Here goes..
Noco 4 bank 10 amp charger installed. 3 banks are charging 3 lead acids for a 36 volt trolling motor.
I just installed 2 new lithiums of the same capacity in parallel for my 12 volt loads.
I bought a separate Noco 1 bank 10 amp charger to charge one of the parallel lithiums and I was going to use the other bank from the existing charger to charge the other parallel battery.
Or.. should I not install the single bank and just utilize the remaining lead of the 4 bank crisscrossing the leads and be done with it just understanding it will take a longer charge?
What would be the best for the longevity of the two lithiums?
Thank you

[DREWTICK]

use both chargers one on each battery

[Aj14]

use both chargers one on each battery

Wow. Obviously you're working past your normal hours.
Thank you

[WarEagleChatt]

Lithiumhub tech told me to parallel charge my Ionics with pos lead on batt 1 and negative lead on battery 2. Yes, it does take a longer to charge.

[Aj14]

Lithiumhub tech told me to parallel charge my Ionics with pos lead on batt 1 and negative lead on battery 2. Yes, it does take a longer to charge.

This is what happened last time.
Varying opinions.

[yam911]

For many tasks there are no single definitive answers. No right or wrong. Just different means to achieve the same end.

Personal preferences are then espoused as the only way, or the best way, to get from here to there.

[z520brewer]

What is the best way? I too have been told one way but read where the other way was recommended

[DBolton]

Why wouldn't you use the extra charger if you already have it? That will be faster and more efficient.

[Aj14]

Why wouldn't you use the extra charger if you already have it? That will be faster and more efficient.

Other than the pain in the neck adding it, I honestly didn't know if it was really needed.
My other concern / question is the best practice for longevity of these two expensive batteries.
More than likely I will add the extra charger if there are still different opinions of what to do.

[DREWTICK]

if you use one charger YES cross the leads pos to one battery and neg to the other, works great but very slow unless you have a 15amp charger, 5 amps on a 100 or 125ah battery will sometimes result in other issues, chargers will struggle after 10 to 12 hours overheating and quite often burning out that bank, more amps the better, 5 amps each will still get them charged but also sometimes not quite as high of volts, after 13.4v the NOCO will drop back to about 3 amps splitting 1.5 amps to each battery and usually cut off soon after that, nothing wrong with that but a charger putting 10 to 15 amps constant current into the battery will push them to 14.1 to 14.2 volts, cells will better balance and you will get more run time
if they are parallel for cranking that part don't really matter as much because 2 100ah or 125ah will be more then enough anyway you will get charge from the outboard also
should you decide to use one, definitely run it in the AGM setting , that will help with the top off voltage

I run 2 125ah Parallel with 10amps per battery when im at home, when I travel I also clip on a 20amp charger on top of that putting 20amps per battery total

[yam911]

What is the best way? I too have been told one way but read where the other way was recommended

The best way for one won't always be the best way for the other.

For example, when doing wiring connections, the best way for me, based on my personal experience, is to use a dab of solder together with a butt connector and heat shrink tubing. To others, solder is the kiss of death.

[Aj14]

Thanks guys. I installed the single bank charger and used the remaining bank on the 4 bank Noco to charge the other parallel battery.
Maybe I was overthinking it as both ways would be fine. But for two $700 batteries I was just being safe. This was my battery only boat that I just finished.
Thanks again.

[Aj14]

One other thing before this is finished...
I purposely did not state what type of batteries I was using as I was hoping that some other companies who sell us lithium batteries would chime in. As this was only related to a customer service question and not a sales question, only one dealer responded.
Thank you Andy!!
This is the reason I own 6 Ionics in two different boats. Also proving to me customer service is more important to me than a hard sell from other dealers.
Thanks Andy for proving to me I made the right decision buying your Ionics.