Here we go again Battery/charger issue

Last year I had an issue with a pair of Interstate series 27 deep cycle batteries. They would fully charge according to my on-board or my Schumacher digital charger. When on the water they were giving up the ghost in 1/2 the time they had brand new a few months earlier. I took them to an Interstate battery service center. The guy said they were 1/2 charged by hydrometer when my charger was saying 100%. He blamed it on the chargers but traded me a pair of series 29s for $20 each. The new 29s gave me 4+ hours of trolling power at 1.5 to 1.8 mph trolling Bandits. Fast forward to Sunday: both batteries were 100% full charged according to my MinnKota 2 bank on board. They had been charging all week. On the water they died in 1.5 hours! I went home, added distilled water to the cells that were the least bit low(none were as low as I would expect them to be before I normally add water) and charged them until today. My on-board said they were 100% as did my Schumacher. The Schumacher said they had over 13 volts each. I took them to said Interstate center and they checked them with a hydrometer and load test. The cells were all showing no more than 50% charge and the load test was fine. The service tech says it is a charger issue. I'm pulling what little hair I have left out. I have my doubts that 2 chargers have failed to fully charge them. Could the chargers be kicking out on voltage but not putting out enough amps to fully charge them? I can select the type of battery (small5A,med10A,large15A), standard, AGM, or gell cell. Any advice on setting the chargers up?

Any ideas?

15 amp and standard should do it. I might also get a meter and check line voltage your chargers are plugged into. I have seen long extension cords and low line voltage cause charging problems.

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Originally Posted by cray

15 amp and standard should do it. I might also get a meter and check line voltage your chargers are plugged into. I have seen long extension cords and low line voltage cause charging problems.

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I do have a 25 foot extension cord from the outlet to the chargers. I will definitely check that voltage. Thanks.

I have a 25 ft extension on my 2 bank BPS charger with no problem. I have Interstates as well. I would get a hydrometer and test the specific gravity in each cell. That will tell you for sure if it is charged and if a cell is weak or bad. They are cheap and easy to use. Then you will know if it is the battery or if something is killing them on the water.
SeaRay

IMHO linear's stink!!!!! I had the same problem with my Schumacher, when I switched to the old standard manual charger I found what I had been missing. In your manual for the Schu it says to charge deep cycles in the gel mode. I did gel/10a and when charged I went gel/2a. Something I've been told- in batteries and chargers, the heavier the better. I also believe that Schu linear also about killed my cranking battery, there's s difference between a processor and copper wound charger I'll promise. I bought a new charger from Harbor Freight for $50, I now feel I'm money ahead. I've had 2 Schu's and neither one of them lasted very long. In a price comparison I paid about a dollar/charge before they smoked. So, if it cost $45 dollars I got 45 charges,if lucky it could be even worse. I'll never own another, promise.

Silly question but you do have your charger hooked up with a 12v pair across each battery right? When I buy new batteries, I normally charge them the first time in the garage with a 15A charger. After that I put them in the boat and keep them charged with my BPS three bank.

I have came to the same conclusion. I do not use my BP 2 bank any longer and use my old trickle type. I have been much happier.
DP

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I have came to the same conclusion. I do not use my BP 2 bank any longer and use my old trickle type. I have been much happier.

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x2. I'll just stick with my trickle charger as well.

I've had pretty good luck with Dual Pro chargers. My son and I both use the Sportsmans Edition 3 bank charger. Plug it up and walk away. You might call them and ask them this question as not all chargers are meant to charge all types of batteries.

+1 for Dual Pro chargers.