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  1. 11-16-2017, 04:20 PM #1
    Tfall
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    Cranking Battery not holding charge?

    My 2016 Eyra has 4 Northstar AGM31 battery's and the cranking battery seems to lose some of its charge after a week. The trollers hold just fine. I always top them off after getting back from a day on the lake and check them before I go back out. After a week the cranking battery is sitting at 12.5v with a 75% charge. I checked all connections and switches to make sure everything is powered down. After a day of use its at 60% charge. I top it off and it's at 13.3v at 100%. Is it time to replace or is there a vampire that's draining my cranking battery? Any ideas?
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  2. J Risco
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    #2 11-16-2017, 04:23 PM
    Disconnect it after it's charged and retest in a week. If its still goes down it's the battery, if not then you probably have a draw on it somewhere when connected. You can do a draw test if you have a multimeter also.
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  3. CatFan
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    #3 11-16-2017, 04:25 PM
    Just leave the charger on. Your outboard will drain your battery.
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  4. catdude28
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    #4 11-16-2017, 05:49 PM
    Sometimes with the high quality AGM's like that Northstar, or the Odyssey, "topping" them off is really not bringing them up to full charge. Like Catfan suggested, leaving the intelligent charger on full time is a good call, or, for at least 1-2 full days after use to be sure they are fully charged. The installation of a battery cut off switch would also help to eliminate any parasitic draw. You could put the outboard on it as well, which is always a good idea.

    At full charge, AGM's should have around 12.8 volts after surface charge has dissipated. 13.3 is probably surface charge after coming off the charger.

    If you want to test it like J Risco suggested, then you need to be sure that the battery really is fully charged by leaving it on the charger for 2 days, and then disconnecting everything. Take a reading each day for a week.

    Do you have the Noco or the MK charger?
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  5. Tfall
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    #5 11-17-2017, 02:38 PM
    Thanks for all the info and suggestions.

    I use a Lester charger for the 3 trollers and a Schumacher charger for the cranking battery. When it shows 100% I take it off. I have the battery disconnect switch which I trip off every time I'm not using. I will leave the charger on longer to see if that helps. If not I will borrow a meter from my neighbor to see if I can find a draw somewhere.

    What do you mean by intelligent charger and what is a good one to buy? The Schumacher one I have is this one:

    https://www.amazon.com/Schumacher-XC...attery+charger
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