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?