charging DC batteries, 2 battery chargers & 3 batteries?

My problem is I have 2 battery chargers and 3 batteries to charge. I would perfer to keep them on 'trickle charge' for the winter.
is there a way to charge all 3 with only 2 chargers?
Could I hook up 2 batteries together (as 12V x 2)? If so, how do I connect them?
Would this hurt the batteries?

thanks in advance,

Cheers

As long as 2 of the 3 batteries are of the same type and capacity it can be done. If they are both lead acid or both agm, parallel them together with a piece of 8 ga wire, positives together and negatives together and apply the charging clips per normal. The other battery gets its own charger. If they are lead acid, charge first, then check the fluid level and only use distilled water to top them above the plates.

Good advise how to charge two batteries with one charger but just want to add that I do not put them constantly on trickle charger - top up the charge once a month or so. Store them in the indoor garage in the boat.

Make sure the batteries are all in the same condition and the same type of battery (gel/AGM/etc.) Also, make sure each is individually fully charged.

Next, contact the manufacturer of the charger and ask them the same question. Typically, it'll be fine 99 out of 100 times, but you don't know what type of internal resistance sensing circuits are in those chargers. Most chargers will be dumb and won't even test for this, but some may operate differently.

If the manufacturer gives you the thumbs up, you SHOULD be able to use one charger to connect all three in parallel, but only if they are all the same type and condition. All the charger will do is supply a float charge to keep them fully charged through the winter, so you aren't taxing it at all if they are fully charged.

There’s no need to trickle charge your batteries all winter. Fully charge them when you put them away, store them indoors and over the winter throw a trickle charger on them once a month to ensure they are fully charged.

That's how i do mine, once a month top-up is more than enough.

Well another point on "once a month", batteries that are not active, ie, being charged start to sulfate as soon as the charger is removed. I've had batteries last up to 12 years, and I keep mine on the garage floor hooked up to the smart float chargers from when they come out of the boat and RV until spring when they go back to work.

Fisherman: What brand of "smart float chargers" have you used here?

I like the idea of a shot of juice once a month. Certainly will check the fluid level after charging too.

Thanks guys,

I have a Battery Minder charger probably 15+ years old on one gp 24 battery and a couple of CTEK 3amp max smart chargers for the larger gp 27 and one for my ATV.

CTEK

Battery Minder

NOCO sold at CTC also has a variety of small intelligent chargers that come on sale every so often.

I have 3 Noco 340'''s and keep my 8 batteries on charge all winter long.......been doing it for years and zero issues

the noco is also great for reconditioning and does some lipo batts as well

Bingo X2

New battery chargers are so simple.
Disconnect negative cable, connect charger to battery and forget about it.
3 amp is plenty for most applications,
Come spring, you'll be ready

This post has been edited by JerryK on Oct 26, 2021 - 10:34 pm

Computer engineer here. Yes, you need to keep your batteries hooked up at all times to a charger. Once a month will be fine, but the colder they are, the quicker they will discharge. If they are in your unheated garage over the winter, and you are only charging once a month, you are doing damage to your batteries that could be avoided.

If your garage is heated at 20c all winter, then you can charge once a month and be ok.

But if you can, just leave them hooked up and charging year-round. This is why I tell people to get a charger and put it permanently in their boat. When you are done for the day, hook the charger up to shore power or at home when you get there. The alternator does NOT fully charge your batteries, period. Unless you have an alternator charging unit like this: https://volts.ca/collections/alternator-to-...battery-charger, but I can guarantee you probably don't! Lithium batteries are much more tolerant to discharge profiles than AGM or flooded batteries. If you have lithium you won't have to worry at all really, as long as they are inside and not in the cold.

Noco for charging batteries? That's an interesting idea. Are you keeping them connected all the time or just for the moment when batteries need a charge?