Battery/Charger help

[Little Scrooge]

Went out for the first time this past weekend. A week ago I "un-winterized" her and made sure everything worked, electronics, trolling motor, big engine cranked, etc. On Thursday we unplugged the onboard-charger and made the 4 hour drive to the lake. I dropped the old girl in the water only to have a dead cranking battery. Deep cycle batteries were fully charged and worked fine, the cranking battery was new last year?  Any thoughts? THANKS!    

[Scott F]

Either the battery is no good, or, one bank on the charger is bad. You need a volt meter to find out which one is bad. 

[Little Scrooge]

Thanks Scott F gonna tackle it this weekend- 

[Fairtax4me]

 What charger are you using and is it programmable so you can set the proper charge and float voltages for your specific batteries? 

Deep cycle and starting batteries have a different lead plate structure inside which gives them different discharge different capacaity characteristics, and as such they require different charging methods in order to be properly charged and maintained. 

If using the same charger you need to make sure the charge settings for each bank can be set for that specific type of battery, and that it is delivering the proper voltage and amperage as recommended by the battery manufacturer during each phase of the charge cycle. 

Different charge profiles are required for deep cycle vs starting, as well as for FLA, AGM, Gel type, or “dry” type cell batteries. Using a flooded profile on an AGM or Gel battery will overcharge it and create air pockets in the electrolyte which will damage the battery and it will not recover. A brand new AGM battery can be useless in just one charge cycle. 

 

Conversely, if charging a flooded battery with an AGM profile, the FLA battery will be chronically undercharged, which will cause sulfation of the plates. This will lead to a slow death over the course of a few months to maybe a year, depending on the battery size and charge setting. 

 

If your charger is not programmable, buy one that is. It will pay for itself the next time you Don’t have to replace dead batteries because of improper charging. 

[Little Scrooge]

Fairtax it's a ProMariner ProSport 20 plus. The charger has designated banks for cranking and deep cycle batteries which I had hooked up correctly. also it "reads" the battery type you are using, flooded, in this case and charges accordingly. I feel confident I had a bad battery. I will find out this weekend for sure but have an extra battery on standby just in case. - thanks for the response