on board charger connections

[bucketmouth64]

I have a 24 volt trolling motor and a two bank on board charger. My question is do I hook up the charger any differently? I hook up the charger leads to each battery separately, not like I do with the trolling motor to create 24 volts. The reason I ask is when I charged the batteries this winter one needed a long charge and the other one a pretty short charge. That made me think that one was being fully charged by the onboard charger and the other wasn't getting charged fully? What do you think?

[Hoey]

Yes there are separate connections for the onboard charger to each battery. With one battery charging quicker than the other, by a large margin - I am thinking that is an indication that the slow one is nearing replacement.

[EBass]

I noticed the same with my batteries this year to bucketmouth. They are from 2008 - Optima Blue Tops. I hope to get another season out of them, but we'll see.

You can bring the batteries and dual bank charger into Batteries Plus and they will test them for free. I just called.

[bucketmouth64]

Both batteries are brand new bought in July. I usually unplug the charger once indicator shows full charge, should I just leave it plugged in so other battery gets "full charge"? How long will it take to fully charge second battery, and how would I know when it's fully charged? I thought the indicator light comes on when both are fully charged.

[Whoaru99]

I am of the opinion to leave the charger plugged in as much as possible. If it's a true multi-stage charger then it should go to the correct float mode when charging is complete. In that mode it continually monitors the batteries and bumps them with a bit of charge if/as necessary to keep them fully topped up, which is the best way a battery can be.

In your original post you said one battery took a long time to charge and the other a short time. How do you know that if the charger has only one charge indicator light as it sounds is the case in a later post?

[h8go4s]

1. Clean all the connections and battery posts.

2. If they are lead-acid batteries, check the water level.

3. If 1 & 2 don't help, get the batteries tested.

[bucketmouth64]

In your original post you said one battery took a long time to charge and the other a short time. How do you know that if the charger has only one charge indicator light as it sounds is the case in a later post?

[h8go4s]

"I have the batteries out of the boat. They're in my house and charged separately with a conventional charger."

Well, you did a good job of confusing me. Now it seems your original post apparently was referring to the batteries being out of the boat, charging on a conventional charger, not a "smart" charger which is what typical onboard chargers are. If that's what you're doing, once the batteries are charged, they should be disconnected from the charger and then connected to a battery maintainer. The cheapest one below works fine. You can run jumper wires to the second battery, or just alternate hooking it to each battery every couple of weeks. That will keep your batteries charged and desulfated through the winter.

http://www.northerntool.com/shop/tools/category_batteries-chargers-

jump-starters+battery-maintainers

If one battery took longer to charge on your conventional charger after you pulled them from the boat, you need to find out if that battery is bad, if the connections to that battery were bad, or if your onboard charger has a bad bank. First, get the suspect battery tested. If that's ok, clean all the terminals and posts and then swap leads on the onboard charger between batteries to see if the problem switches to the other battery. Then you'll know it's the charger.

[bucketmouth64]

Thanks, I'll have to look into a battery maintainer.

[gunner55]

We just use cheap little 2amp trickle chargers on our boats batteries in the winter,after they have been fully charged.I think we got ours from Harbor Freight on sale for less than $5.Just plugged into a powerstrip which is on a timer.

[gunner55]

Just an update as we just returned from the lake.Didn't do any fishing but no snow either. Discovered the chargers we have on our batteries during the winter are .5 amp float chargers(~ $5) or what others call maintainers & want $25-$30 for.Got ours at Harbor Freight on sale a couple times a year.I was told that a 2amp can boil your batteries dry if you're not careful.

[muskie-mike]

So it would be ok to put the cheap HF battery maintainers on my 3 batteries in my boat for 5 months and stored in a garage at my cabin up north? I have been pulling them and bringing home and charging every couple of months. would be much easier to just leave them in the boat but don't know if I can trust the chargers all winter...

[harvey lee]

I have used a 2 bank charger/maintainer for my 2 trolling motor batteries for the last 8 years or so, never an issue other than I do clean my connections every spring and also check the fluid level as they can get low, I just add distilled water. The maintainer I have now shows when the thing is charging or not or in maitain mode.

Last week I ordered a new 2 bank smart charger that will show when each one is charging as it shows lights for each bank. Then you know which one is full and if the other is still charging.

I do have them tested each spring also to just make sure I have 2 good batteries in the boat for trolling.

[gunner55]

We pull ours & put them in the basement at the cabin but that's because our boat is stored in a pole shed with no electricity.But the main reason we started doing this is that we got tired of hauling them all home.With 2 boats,2 lawntractors for mowers that meant we were hauling 7 batteries back & forth.That meant using a trailer in the spring & fall & have ran into some nasty weather coming home in Oct.But to answer your question I think you would be fine leaving them in your boat & charging as I have read of others on this site doing that.As far as trusting the chargers we have ours plugged into a fused powerstrip so if there is a power surge it will not burn up the chargers,although we always have a couple extra laying around(they seem to get dropped now & then),or blow up your batteries.We just pull them after we winterize the Yammie,check the water level,charge back to full charge using regular charger,then hook up .5 amp charger & leave on for winter.In the spring we just make sure of the water,never found 1 cell boiled dry,hook back up to regular charger to be sure they are fully charged(which they are)& back in the boat they go.Been doing this for 10-15 seasons without problems.The garage will probably get colder than our basement(cabin) but as long as the water levels are good,they are fully charged before you leave,& the .5amp chargers are working(no trouble with ours) your batteries freezing shouldn't be an issue.Sure beats hauling them back & forth.Sorry for the book