On Board Charger / Added Water to Batterys

Before putting my two trolling motor batterys back in the boat this spring, I made sure that the water level was good. Had to add about 2 oz. to each cell. I used distilled water. When I pluged in the on board charger, it was on for 8 hrs. and still did not show that the batterys were fully charged. I used them for 5 hrs. with no problem and plugged the charger in when I returned home. Same thing, charger still does not show a full charge. Last year I had the same problem but only the first time that I hooked up the charger. Is it possible that the water and battery acid is not mixed? Just wonder if anyone else has had this happen.

Hi Keith, I’m kinda shooting in the dark here, but I’ll give you some thoughts.

You said you added about 2 oz of water…were the plates showing?

I’m going to assume you are using a 10 amp charger/maintainer. Does your charger have a desulfiefire (I know I butcher the spelling!). If your plates have been exposed for any period of time this would bring your batteries back to life.

I recommend checking the water levels at least once a month, depending on the frequecy that you use them…more in the warmer months.

If you have an older charger that stays charging until you take it off, I would sell it at a garage sale, take that money and buy a charger/maintainer. The old style, if left on will “cook” the water out of your battery…more so in the warmer months. The charger/maintainers can be left on all winter to maintain a good charge. Batteries last longer will a constant full charge.

I doubt the the mixing of the water/acid is your problem. For about $3 you can get an acid tester and any auto parts store. Some convieniance stores handle them too. This will tell you where your cells are REALLY at as far as holding a charge.

I’m not an expert on batteries by any means (that’s my disclaimer) Hope this helps.

Check out Wade’s reply and links to battery care Link to Battery Care

How old are the batteries?
The specific gravity tester is a good idea.
They are very cheap.
They look like an antifreeze tester
with the floating balls
but are calibrated in % charge
instead of temp.
They are great to ensure that all battery cells are good.
Sometimes an individual battery cell will go bad
and won’t charge up hardly at all.
I’ve even seen individual cells short out so bad
that they acted as if the polarity had reversed
on that cell, and the battery would suck up any and all
charges you put on it.
When that happens like to a car battery,
the only way to start the car is to tottaly disconnect the
the old battery.

Don’t know if I need to say this…so I will…

When testing the cells, don’t get the acid/water on your carpet!

The batteries are two year old Interstates. I had a cell tester and checked each cell. Some cells tested great. Some tested fair but the more I kept mixing the water/acid, the higher they would test. My charger is a Dual Pro XL 5 amp charger. I am going to be using it allot this weekend with the Wisconsin opener so will soon find out if the problem is going to be fixed by mixing the fluid in the cells.

If the cells are not all about the same specific gravity
they need an equalize charge,
which is a little higher voltage/amp charge for a longer soak time.
Do you have access to a higher amp charger?

Yes………I have a 10amp charger. It is a 12/24 volt one so can either hook up and charge each one or charge back through the trolling motor plug. I used to charge my batteries that way before I got the on board charger. If they don’t come around, I will try that next. Thanks

Wallmart?

Again…I’m no expert…but once you’ve used your batteries, charge them up again (when you get home Sat) using you 10 amp charger using 12 v.

I’m interested in knowing how this turn out, so please let us know…

Thanks!

I wouldn’t blast a 12v battery with 24v, just stay with the 12v.
10 amps is better, but someone you know probably has at least a 15 amp car battery charger that you could borrow.
Use the bigger charger all weekend for several discharge/charge cycles. Then after the final charge, recheck individual cell SG.
Then switch back to the onboard charger to maintain them charged.

jwellsy, he has two 12’s together. But I still think you’re right…High amps low voltage…to get them back.

An equalize charge on industrial standby battery banks
is typicaly about 25% higher voltage than the normal float charge voltage.
Typical consumer automatic chargers with higher amperage ratings will output slightly higher voltages to achieve higher amps.
But, as soon as the normal charge is achieved the output voltage is stepped down to barely maintain 12v.

Well……..fished Friday afternoon and all day Sat. Plugged in the charger and when I checked it this AM., still 4 of the 5 lights were red. I’m almost sure that when I plugged the charger in, all 5 lights did not come on, just 4. I found the email address to the factory and told them the problem. Will see what they have to say. I brought both batteries home with me and am going to take them and have them checked out. Don’t think the problem is with the batteries because what is the chance both batteries would go bad and read the same?

Well, I think I figured out my problem. Cleaned all the charger connecters and battery terminals. Looks like that took care of the problem. They didn’t look dirty but just didn’t have good enough contact. Took a file and shined them all up and now everything is working. Since it is only a 5 amp charger, it must need a really good conection.

Hmmm…Glad it’s working for you! I’m a little surprised that when you have the charger on it, all lights don’t light up. But if it’s working after cleaning the connections…then it’s time to start thinking about fishing and not batteries!

Good Luck!