Battery & charger question

[majflyboy]

Just went out to install the new timer switches but noticed that one of the green (charged) lights was amber (charging) instead. It had been green all week. Opened battery compartment and one of the gp31 trolling batteries was boiling over. My guess is that it's the onboard charger not working properly and not a bad battery. What do ya'll think.

["G"]

Are you sure it is wired properly Maj.....reason I ask is because I think its different with one 12 volt cranking battery and two TM batteries wired ( in series) for 24 volts.....that it is with one cranking battery and then two 12's wired in paralel. Maybe WB knows.

[majflyboy]

I think that's the way I've got it wired. Hasen't been a problem until now.

["G"]

Maj..... what I mean is, I think the onboard charger wires up differently according to whether you have two batts in series or two batts in paralel.....so are you sure the charger is wired up properly. Its also possible that the battery that is boiling over has a bad cell and therefore your charger will not cut off.

[Wannabe...]

If it's been working and not giving you trouble up till now, I'm betting it's wired correctly. It's show up the first time if not. But, you can meter the posts that you've got the bank wired to and it should read 12V. If 24V, then it's wired improperly.

Now, when a charger kicks on and puts amperage to the battery, the water starts to "boil", so the fact that it was "boiling" may not necessarily mean anything. You may have just happened by when the charger was topping the battery off. Left sitting, it will discharge slowly and at some point, the charger will have to top it back off. Different chargers test for this at different intervals and kick on more or less often. That said, I suspect you may have a bad bank on your charger. No real way to check it other than to test the voltage when it's charging. Should be around 14V, but if it's not sensing the battery is full, and that is the problem, it's going to just keep charging and charging until it "boils" out the water and eventually will cause an explosion...not a pretty site. I can show you my T-shirt if you like....it's pretty and has lots of acid holes.

Anyway, here's what I'd do. 1) Check water levels in all batteries. 2) Plug charger up and check it's status every 30 minutes and see if it goes back to green. If after 3 hours (assuming the batts are already charged - not just having come back from the lake), they charger is still charging, call the mfg and get an RMA opened for warranty repair. Stinks, but there's not good way to test one with the tools you and I have. 4) If it kicks over green in that 3 hour span, disconnect, go fishing and make sure you're getting good power and longevity from it - fish, but run the TM on high and get some capacity off of it. 5) Come home and plug in and monitor it's status for the next 4 or 5 hours noting when the 1st battery kicks over green (assuming you've got 1 bank to each of the 2 trollers here, if 1 bank to two, this is moot). Do not leave it unattended for days on end though - kablooie alert here.

One other test you can run is repeat the above steps, but reverse the bank leads on your charger and see what it tries to do to the other battery.

Wannabe...

[majflyboy]

Thanks guys, just got back from Interstate store & they said "see the water in that cell jumping? I said yes. He said that's a bad cell". Is that a legitimate test? Oh yes, he had some sort of machine hooked to it when it started jumping.

[Wannabe...]

Well...I wouldn't qualify that as scientific...but if he's willing to replace under warranty..go for it. At the very least, you've just eliminated one of the variables. Still, I'd keep an eye on that bank and wouldn't leave it unattended for days on end.

Wannabe...

[majflyboy]

It's not an Interstate.

[Wannabe...]

If ya got a "bad cell", it probably won't output a full 12V. Ya got a meter you can read it with?

Wannabe...

[majflyboy]

Think so. Looking.