I'm late to the game on the Lithium batteries but I've got a basic question a lot of you probably know...First of all I have a 24V, 72# trolling motor currently and was wondering if I can replace both my 12v lead acid batteries with just 1-24v:60Ah Lithium battery? I plan on upgrading my trolling motor to a 36V 112lb soon so I'm assuming the 36v would work the same and I can buy just 1, 36V 120Ah Lithium to instead of 3 lead acid batteries? Saving a ton of room and weight?

Also, do they require a special charger or can I keep using my Minn Kota lead acid charger on a lithium battery?

Thanks for any info.

in theory you should be able to parallel the batteries for 36v.

when you hook 3 lead acid together the third battery gets 24v passed thru it, lithium do take special chargers most of the time. if you have one of the mk precision chargers I believe they will work on a lot of the lithium.

can't afford them so barely read up on them, some of the guys with them will have better info on chargers.

I'm talking about just 1 36Volt Lithium battery though, not 3 separate 12Volt lithium's. On the 36v battery there's only 2 posts sticking out of it so I don't think you have a choice to run them in series or parallel. Even though the way I read about it, it seems like its basically 3 12V Lithium batteries in 1 big case basically.

You will need a dedicated 36v charger for one 36v battery. This will cover the 36v battery and a cranking battery.
Ionic 2 Bank Charger 36V10A, 12V10A ( https://lithiumhub.com/product/ionic-2-bank-battery-charger/ )

Edit: well never mind, lol; but 3 batteries is better than 1 in this case. I just know the pros that are running the 24v or 36v lithiums, are running multiples of them in parallel.

when you go series for more voltage you keep the same ah, when you go parallel you keep the same voltage but increase ah.


How to connect a battery in Series?
The positive terminal of the first battery is connected to the negative terminal of the second battery, the positive terminal of the second is connected to the negative of the third, etc. The voltage of the assembled battery is the sum of the battery voltages of the individual batteries. So the batteries are connected: + to - to + to - to + to -, etc. The capacity of the battery is unchanged.

How to connect a battery in Parallel?
The positive terminal of the first battery is connected to the positive terminal of the second battery, the positive terminal of the second is connected to the positive of the third, etc. and The negative terminal of the first battery is connected to the negative terminal of the second battery, the negative terminal of the second is connected to the negative of the third, etc. So the batteries are connected: + to + to + and - to - to -. In this configuration, the capacity is the sum of the capacities of the individual batteries and voltage is unchanged. For example, if you take 5 6V 10AH batteries and connect the batteries in series, you would end up with a battery array that is 30 Volts and 10AH. If you connect the batteries in parallel, you would end up with a battery array that is 6 Volts and 50AH. By the way, this is how ordinary auto batteries are made. 6 2volt cells are put in series to give 12v battery and the 6 cells are just enclosed in one case. Many ni-cad batteries are done the same way.


https://www.batteryweb.com/faq#q2

in your first post I thought you were going from 24 to 36 by adding a 12v to the 24.

if I could afford lithiums I would not rely on a single battery, would go 3 12v. should something happen to the single you are done, whole lot cheaper to buy a 12v than a 36v lithium and if you lose a single 12v the newer brushless motors will keep on goin on 24v.

Ok, I believe you’re correct, I just know that for some reason they recommend using multiple 12’s vs a single 24v or 36v.

Yes, they are running multiples of the "36V-in-one" battery module. The popular name 36V model is rated at a total energy supply of 2496 Watts. You can only get so much energy stored inside one box, and that's it. Compare that with a good 100AH 12V Li Iron Phosphate battery, and you see each carries around 1280 Watts. That's per battery, so 3X is 3,840 Watts, or 54% MORE stored energy than the single 36V energy cell provides. This is why pros run 2 of those 36V units in their boat.

One advantage of 12V batteries is that if one battery fails, you still have 2, and if you happen to run a Lowrance Ghost, you can reconfigure the wiring in a couple of minutes, then reprogram the Ghost to 24V, and save the day. If anything at all happens to the 36V model, you're done; there is no regroup beyond replacement.
If your special 36V charger dies, you're done. If you have 12V batteries, there are inexpensive chargers that will charge Li available as a backup. Or, if you have a 3 bank Li charger, you can swap leads after the first battery charges to get all 3 charged.

I could go on with arguments against 36V battery configurations, not to mention the inflated cost for that big-brand-name. I got 3 good batteries with more stored energy for a lot less than a single 36V unit would cost. I'll never own one as my choice.

BTW, hopalong is correct that Amp-Hours are not cumulative. Three 12V batteries rated at 60AH put into series makes a 36V 60AH system.

The pros using three 12V batteries are using 100AH batteries, not 60AH batteries. Likewise, those with 36V that I have seen are all using two of them - for the same reason other pros don't use the 12V 60AH.

I admit I don't do a weekly search on what's available as I already have something I'm happy with. Who has a 36V 120AH battery?