[dpfleghaar]

Storing outside cold, is it necessary to disconnect the batteries? Group 31 AGM's

[drifter]

 I'm on lake Ontario.  I always took mine out, but on the new boat this is not practical.  I asked the mechanic in the marina, they just disconnect the ground cable, this prevents any forgotten/unknown draw from draining the batts.  This boat sat outside last winter with no problem.

[dpfleghaar]

 I'm on lake Ontario.  I always took mine out, but on the new boat this is not practical.  I asked the mechanic in the marina, they just disconnect the ground cable, this prevents any forgotten/unknown draw from draining the batts.  This boat sat outside last winter with no problem.

[ReelMagic]

I winter my 38 Open in the water and leave the charger on. Have 2 banks of 3 Gel batteries each. Been doing this for 9 years with no adverse results.......

[sluggo]

Storing outside cold, is it necessary to disconnect the batteries? Group 31 AGM's

Necessary? I don't know, that said, I have stored mine in the boat, outside, and in the water for the last 10 years.  FWIW I leave the charger on, and I never had a problem.  To that end I think I get pretty good battery life as well.  It got down to -13 f last winter, fwi.  

[Uhehner]

Keep in mind that something like a CO Detector, Smoke Alarm, Stereo Clock, Bilge Pump etc. will always be connected to your batteries causing a drain, even with the battery switched off. Therefore the easy thing to do is like the mechanic said, "Disconnect the ground cable" but do it after the batteries are fully charged.
I always left the shore power cable dangling over the side of the boat and the 120 volt main breaker and battery charger breakers ON. Then a quick trip to the yard to check on the boat, plug in the power cable and give the batteries a short charge. No ladder required. Capt. George

[jhhall]

I have a 2006 36 Sovran.  The batteries are difficult to get to.  They were new when I bought the boat 7 years ago.  All I do is turn the battery switches and all the 12v breakers off.  On my boat with the switches and breakers off all 12v is disconnected including the CO Detector, smoke alarm and electronics. I have not had to replace the batteries. I store heated.  Other Tiara owners in the building do the same thing with similar battery life results.

[DavidB]

Actually the heat is worse on batteries.  In Florida they just die in 3 to 4 years with absolutely no warning.