Fishing Forum

I have a 24-volt trolling motor, that I have only used a few times, and at the end of January I purchased two of the best ( 50 mos pro-rated/18 months free) deep cycle batteries that I could find locally. I also had installed a used on-board charger. I have always immediately plugged in the charger when I have gotten home from fishing. Even after charging the batteries for about 24 hours recently the tester built into the trolling motor registered that the power was low. I removed the batteries and attached my portable charger to them and the arrow pointed to "Check battery" on both batteries. I was wondering if the on-board charger was over charging them, but all cells are still full of water, and I would think that if they were being over charged that at least some of the water would have boiled off. I tried to test the on-board charger with out having batteries installed, but apparently it senses that batteries are not attached and shuts itself off. Any ideas, or did I just get two bad batteries?
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Sounds like a tough issue. I know if you charge them seperately, and then take them down to the parts store, they can test them out for you. I'm not very familiar with the onboard charging systems, so I don't think I would know how to test one out. I guess you could hook them back up and plug it in, and try to see how much voltage it is putting out. This may sound like a stupid question, but is the charger built for charging a 24 volt system? There is a difference in wiring for getting 24 volts, IE: pos on one battery gets hooked to negative on the other battery....just a thought. Hope you can get it figured out.
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All I know about any battery is you do not want them directly on the cement. For some weired reason it drains batteries.

Not sure if you had them on the cement but if you did, that could be an issue.
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Kent do you have a volt/ohm meter? I would charge the batteries separately and check there volt reading. Wait 24 hours and check it again. I suspect you have no way of load checking them. Of course me being a bit lazy, I would just take them back to where I bought them. Complain that they will not hold a charge and have them replace them. Also where they hooked up in series or parallel?
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Yes both will go at the same time if you don't use a battery isolator... What happens alot of the time a cell goes bad and drains both battiers down till they can not charge anymore. 99% of lead acid battiers can not be drained all the way down and still work right(hold amps aka an charge) 2nd if your battiers are not sealed you have to make sure you keep distilled water in them otherwise if the water falls below the plates the battery is toast.... just so everyone knows again this is what I do for a living, day in day out. I used to rebuild alternators and starters and deal with battery problems all day long. Now I sale the parts.....
The only marina battery I would use is the trogan.
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[size 1]"Yes both will go at the same time if you don't use a battery isolator..."[/size]
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[size 1]Where does one get an isolator and how does one install it? [/size]
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[size 1]BTW they are both Trojan Deep Cycle SCS 225 130 Amp batteries. I haven't had to add any water, distilled or otherwise, because the cells are all still full of the water that came in the battery. [/size]
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[size 1]"This may sound like a stupid question, but is the charger built for charging a 24 volt system?"[/size]
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[size 1]Yes it is.[/size]
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Kent,
I agree with mikecromaine that it is possible that both batteries could go bad in a close interval to each other, but I think it is more likely that you have an underlying problem. First thing I would do is check for a voltage draw. Simply remove your negative cable from the batteries, and connect a test light between the cables and the battery post. If the test light glows, you have a voltage draw. If the source is discharging the batteries faster than the onboard charger can charge them, they won't get to full capacity. If you have a draw start dis-connecting your electrical equipment one at a time until you find the one drawing the current.
Another thing I would check is the battery date code. you may have purchased the batteries recently, but it is not unusual ( especially for rv / marine batteries ) to sit on a shelf 6 months or more before they are sold. There should be a sticker or marking somewhere on the battery that will read something like C/5. That would have been produced 3/2005. Just something to check. Good luck, and feel free to pm me if you need help diagnosing the problem. I might be able to help.
Clint.
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you can get a battery isolater from any rebuilder of alternetors or starters or a battery shop. I would not trust a part store in anyway for these things. Going to a part store is like going to proctologist for a heart problem if you get my point. Kent in your are you have action alternator in bountiful and chic armature in ogden they both will treat you right for you r alternator starter wireing and battery needs.
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On a 24 volt system, the neg post on one battery hooks to the pos post on the other. That leaves you the other neg and pos posts to hook to the trolling motor. A long time ago Fords and Chevy's used to be different. They had different polarity to them. Fords always hooked with the positive post going to the starter but some of the Chevy's you had to hook the positive post to the frame ground and the neg to the starter. They were reverse polarity on some of them older vehicles. If you somehow hooked the batteries up wrong, then they will try to catch backwards. They'll hold a charge until they run down to zero again and then you can't charge them back the other way. The batteries will be shot and never will hold a charge after that. I had both my batteries go dead on me about 6 months ago. One was hooked to my 12volt trolling motor and the other to my lights. They just got old and the winter cold got to them. I bought a couple of the best marine batteries that Sears had for sale. Both of them are their largest Diehards and I am really impressed with both of them. I run the trolling motor off of one and a voltage converter on that same battery for a 110 volt spotlight. Haven't run it down yet and always have enough power to get back to the dock if the outboard should fail to start. On the other I run my regular lights on it and have kept the lights on all night for quite a few nights and haven't run it down yet. They hold a good charge to them and recharge pretty quick when I need to hook them up to the charger at the house. If they're both fairly new batteries, I'd take them back where you got them and have them check them. They have that warrantee on them and should replace both if they're bad. Good luck.
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Hey Kent,

Before you get too carried away with everything else, I would check out the simple stuff. Clean all the connections real good. Sitting through winter will corrode connections.All marine wiring should be soldered, not crimped. Any crimped connectors can oxidize inside and not carry voltage.
Then hook up the batteries to the charger and test voltage. Check it before hooking up the charger and again an hour after hooking up charger. That will tell you if your charger is working.
If it's all working good, then start looking for a power drain.
I would seriously doubt the batteries are that bad.

Take care,

WB
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I dropped off the batteries this morning to Batteries Plus. They tested the batteries and said that they were both fine, just needed to be charged. I have a Dual Pro (20 Amp 10 amps per bank) battery charger that I purchased used off of eBay.

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Can anyone recommend where I should take my boat to have the system tested, so that I can resolve why my batteries are not being charged, or to determine if I have a short somewhere?
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I thought that these on board chargers could only do a 12v. system. For 24v. you gotta run an isolator (perko) switch. Any marine store will be happy to sell you one. I'm not sure but I think you need to disconnect the jumper between the positive (on one battery) and the negative (on the other) for the on board charger to work. Call Josh at National Battery in Ogden. He is one smart sucker when it comes to charging systems. (801-621-0010).

Good Luck.
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