12 volt battery overcharged to 24 volts

[ryanmohr]

I bought a new battery and on-board charger yesterday from West Marine. The charger is the ProSport 12 (http://www.westmarine.com/webapp/wc...=true&storeNum=5002&subdeptNum=9&classNum=683). Currently I'm just trying to get the engine working so I went for a single battery even though the charger can handle two. The salesman that helped me at West Marine told me to just double up the leads on the single battery and everything would be fine.

However, after installing the battery and charger last night I arrived at the boat this afternoon to find my 12 volt battery carrying a 24+ volt charge. My guess is that doubling up the leads caused the battery to be overcharged, so I've disconnected the second set (and I've actually turned the charger off for the time being until the excess charge dissipates).

I now have a battery sitting at 24 volts though, and if I try to start the engine I'm pretty sure it'll do some heavy damage to the electronic components. So my questions are:

What's the best / quickest way to drain the excess charge from the battery?

What kind of damage might this overcharging have done to the battery?

 

[RAD]

Sounds like you need to bring the battery to West Marine and demand a new battery and tell the manager (this is the person you should be talking to) and also indicate he's lucky that your not bringing in a starter,gps,radar.radio's,bilge pumps,etc...... because his salesman is giving out false installation instructions.
Now if you read the instructions you will see that by taking BOTH output leads and joining them together you get 24 volts (see fig 4 on page 10)
good luck

 

[Roger Long]

What's the best / quickest way to drain the excess charge from the battery?

Take it back to WM as RAD suggests. This is the only way to deal with it if you want to depend on that battery long term.

Next time, read the instructions regardless of what a salesman tells you.

 

[BenDi]

Ahoy All,
I called Professional Mariner(manufacturer of the ProSport, www.pmariner.com ) at 1-603-433-4440 and according to them, the salesman at WM gave the right instructions. They said their charger will not overcharge the battery. When I first read this post I had some concern because I have the ProSport 20 plus on my fishing boat and it has three leads. I have only 2 batteries and the spare lead is connected to a battery also and I've not had any problems.
Fair Winds,
Ben

 

[Roger Long]

I have only 2 batteries and the spare lead is connected to a battery also and I've not had any problems.

Maybe but, if his 12 volt batteries read 24 bolts when a meter is connected, he has a problem.

 

[Lee Coller]

How did you "double up" the leads? The only way that you could get 24 volts that way is if you connected one positive and negative lead together, connected the other positive lead to the positive post and the other negative lead to the negative post. What you should have done is connected the two positive leads to the positive post and the two negative leads to the negative post.

 

[Ross]

It is chemically imposible to get 24 volts from a six cell battery. He needs to check his meter.

 

[BenDi]

Maybe but, if his 12 volt batteries read 24 bolts when a meter is connected, he has a problem.

Please don't shoot the messenger Roger. I'm not saying that he doesn't have problem. I'm just saying that WM salesman told him correctly and ProMariner says the same. And furthermore, ProMariner says that particular charger will not charge at more than 14.6 volts and thats all leads: meaning that the output from each lead isn't combined, if you follow the drift. Perhaps Ryan is to be reading his meter incorrectly or the meter is faulty. At any rate, WM has satisfaction guaranteed so if in doubt, return it all and get it anew.

 

[Texas Lake Sailor]

Hey Guys, Ross is correct. You cannot get 24 volts out of a 6 cell chem battery. Even if you applied a 24 volt charger once the charger is turned off or remove voltage will drop to max of 14.6 volts. Something is not right with meter. As for the battery if it isn't maintenance free check water level, most likely effect of chaging at too high a voltage if in fact it happened is you would deplete the water due to excess gassing. But my guess is there is something going on with your meter.

 

[Roger Long]

Please don't shoot the messenger Roger.

Sorry, I didn't mean to do that.

Although a battery can have a surface charge above it's nominal output, I can't believe after thinking about it a bit that it could be as high as 24 volts. Does this charger have separate control circuits for each set of leads? I have a similar charger and each battery is charged as if it were on a separate charger, basically two chargers in one case. However, if the batteries are connected as when the master switch is on both and you are drawing power for lights while the charger is operating, it charges according to the average of the two. The instructions warn that, if there is a significant difference between the batteries, one could be over or under charged.

If the Proline is similar to my charger, he shouldn't have a problem. I'm now suspecting that we are misunderstanding something he said or he is misreading his meter and the batteries could be fine.

 

[TimCup]

oh, he could read 24 volts correctly-

of course, not from the battery, but from the charger. unplug first, let sit shortly, then read. I think you'll find everything is fine.....


cup

 

[Tom Spohn]

How about checking with another meter first?

 

[ryanmohr]

Thanks for all the replies guys. There is a chance that the meter is busted, but it gives me the correct ~ 12 volt reading when I use it on my car battery.

As for how the charger was hooked up, I put both negative leads on the negative post and both positive leads on the positive post (those were the instructions given to me by the salesman, even though the manual says never to connect more than one set of leads to one battery).

I got to the boat around noon and checked the voltage. When I saw it was reading 24 volts I immediately disconnected the second set of leads and unplugged the charger, expecting the voltage to drop now that the charger was off. However when I left the boat around 6 that evening the battery was still reading 24 volts.

There must be something that I've done wrong because this shouldn't be happening. I double checked that the battery was indeed a 12 volt and not a 24 volt battery, and as Ross suggested it should be chemically impossible to get 24 volts off of it (actually the reading was closer to the 27 range).

I'll be back at the boat later today. Hopefully it's reading 12 volts by now. If not, I'm taking it back into WM. If it is indeed down to 12 and the fault wasn't an improper reading, is it safe to continue using it and expect a full battery life or must it be returned?

 

[Tim R.]

It sounds more like maybe you connected your batteries in series when you connected the charger. Check your wiring.

 

[ryanmohr]

I was careful about not doing that because the WM salesman emphasized not to. It was yellow with yellow (negative) and red with red (positive).

 

[Ross]

My first move would be to use a different meter. You have only one battery therefore you can't be connecting anything in series. If you so overcharged a battery you would have cooked it dry. The combination of metals and electrolite limits the lead/acid cells to 2.1 volts.
Try your meter on a different range or scale. Try it on 115 volts AC. Suspect the meter.

 

[Lee Coller]

The way you hooked it up there is no way you're going to get 24 volts out of a properly working charger (unless it happened to be a 24 volt charger).Even if you had hooked up one set of leads backwards you simply would have shorted the charger.

I agree with the others, try a different meter.

 

[ryanmohr]

Thanks again guys. Hopefully it is just the meter.

The ProSport12 charger is a dual bank 12/24 volt charger, so it's possible (but slim) that there's a problem with it and it's charging at 24 volts. Fingers crossed it's just the meter!

 

[RAD]

OK, it was early this morning when I posted and I was wrong .... I agree with Ross if you have only ONE battery than it cannot be 24 volts and the instructions are for two battery's wired in series and thats the only way you can get 24 volts out of a battery. check the meter and I might add that years ago I had a faulty 3 stage charger that would stay in the bulk charge mode at 16+ volts and never cycle, I called the mfg. and they replaced it and all is well now so don't rule out a bad charger

 

[ryanmohr]

Just got off the phone with Pro Mariner and I can confirm what BenDi said. Doubling them up is supposedly fine and recommended. Must be the meter.