Battery or Charger

[Kyhl]

Hooked up the trolling motor batteries and the charger erred. Checked the water and they were dry. Added half gallon-ish distilled water to each battery.

Now the charger attempts to charge them without erroring out.

Two fold question, I think the batteries are probably bad now with scale on the plates from running dry. Are they worth salvaging?

Why were they dry? Is the charger cooking them? I tried charging them for six hours yesterday afternoon using the onboard charger, after adding water, and they boiled the entire time without the charger signalling they had a full charge.

I am afraid that everything is toast, charger and batteries. How do I test if the charger is over charging?

[Surface Tension]

How does a battery get 1/2 gallon low before you notice something is wrong. It had to have had terrible reserve to almost nothing.

When you charge and discharge the battery you get a little gassing.

It isn't getting to and can't get to the voltage and it is boiling.

Could be the battery was on its way out and was boiling last season and reason why it is so low. Or it could be the level was never checked and topped off. So yes the battery is shot.

What brand and model charger do you have?

Amp meter? Have you checked the voltage while its charging?

Do this with a volt meter or if you don't have one maybe your sounder does.

[Kyhl]

Thanks for the response.

I think this is the start of third season on these batteries and the first time I've checked the fluid. I can verify the age tonight.

As far as usage goes, I guess this goes to show how little I use the trolling motor later in the year. The last trip was crappie fishing on a calm day and it was mainly on spot lock for a couple hours, maybe some small moves.

I will also check the brand and model of charger. I think it is 10 amps total that is distributable to either battery.

I can check the voltage. What should it read while charging? Guessing 15-ish volts.

I guess I'm going battery shopping this evening. Dang it.

[BobT]

Thanks for the response.

I think this is the start of third season on these batteries and the first time I've checked the fluid. I can verify the age tonight.

As far as usage goes, I guess this goes to show how little I use the trolling motor later in the year. The last trip was crappie fishing on a calm day and it was mainly on spot lock for a couple hours, maybe some small moves.

I will also check the brand and model of charger. I think it is 10 amps total that is distributable to either battery.

I can check the voltage. What should it read while charging? Guessing 15-ish volts.

I guess I'm going battery shopping this evening. Dang it.

Output voltage will depend on the type of charger. My on-board charger varies the applied voltage depending on the stage in the recharge sequence. I don't recall the exact voltages used though. I know the voltage is lower at first until the battery is up to about 90% recharged and then it increases the voltage and controls current to finish it out. With this in mind, if the battery is internally shorted enough that the charger is unable to detect when it is up to 90% charge, it may output a lower voltage indefinitely. If it is completely shorted, my charger will shut down and indicate a bad battery.

[leech~~]

Thanks for the response.

I think this is the start of third season on these batteries and the first time I've checked the fluid. I can verify the age tonight.

As far as usage goes, I guess this goes to show how little I use the trolling motor later in the year. The last trip was crappie fishing on a calm day and it was mainly on spot lock for a couple hours, maybe some small moves.

I will also check the brand and model of charger. I think it is 10 amps total that is distributable to either battery.

I can check the voltage. What should it read while charging? Guessing 15-ish volts.

I guess I'm going battery shopping this evening. Dang it.

I think people forget how hot batteries can get sitting in a boat all summer. Sitting under a cover in the sun can be twice as bad even if used or not they are going to dry out and need to be checked a few times a year if not sealed batteries.

[Kyhl]

Leave a boat outside? Sacrilege!

It is interesting that this problem only happened to my trolling motor batteries and not the starting battery. The fluid level is fine on the starting battery. All three are not sealed. Only the trolling motor batteries are charged by the onboard charger.

[delcecchi]

is it possible the on board charger is set for the wrong type of battery? AGM/gel cell/flooded cell?

[leech~~]

Leave a boat outside? Sacrilege!

Ok smart guy!

That's the point they are for the most part always out side. I don't think some people really know how hot a battery can get under a boat deck and with a cover on it can get even hotter. I fried a locator one time and when I brought it in to get looked at the guy asked if I had it under a boat cover on a lift. Yep, he said the Lq crystal in the screen can dry out if it gets to hot. So I'm sure water in a battery can dry out as well in that kind of heat!

[Kyhl]

The charger is set to flooded. I am beginning to think it is the charger. Ran the charger for 6 hours on Sunday boiling the pew out of the batteries before unplugging in.

Measured the batteries yesterday and they read almost 13 volts. I think the charger is over charging them and cooking the fluid out.

The charger is a ProMariner ProSport 12, 12 amps distributed.

Also the batteries were less than a year old. Purchase date scratched in, 4/12/2014.

[CaptainMusky]

Good news is the batteries should still be on warranty.