Draining batteries

bshock · Feb 19, 2015

I had my batteries topped off last winter and didn't disconnect them. They were dead when I checked on them later that winter. An expensive lesson. This year I topped them off and disconnected them from everything. now I check them monthly and they're still reading full. So in short, probably. But I'm no expert. Just learning as I'm going.

Don S/V ILLusion · Feb 19, 2015

caprice said:
Hi all,

While laid up for the winter I leave my batteries connected onboard. I run an extension cord to an outlet in the marina to charge the batteries.

However someone has unplugged my cord from the outlet and my "shore power" and "battery charger" switches are on inside the boat.Can this drain my batteries ?

No.

Leaving a laid up boat connected to shore power is dangerous, not only for you but the boats stored near yours. I don't blame the marina or anyone else for unplugging it.

Davidasailor26 · Feb 20, 2015

Disconnect the batteries if you can. We left ours connected but with the main switches off at the start of this winter, but after only a few weeks they had discharged a fair amount. It turns out the way ours is wired there are a couple of small loads (bilge pump sensor for example) that are connected even with all switches off, and they add up over time. Don's right that having the boat connected to AC while on land can be dangerous to passers by.

Claude L.-Auger · Feb 20, 2015

Because of the danger possibility, with over 200 boats left unattended in the yard over the winter, our club forbids leaving them plugged up. Hope you'll be able to bring yours back to life. Easiest way is to charge them up to full, check each cell and equalize if you can, then disconnect and leave in the boat. If the batteries are in good condition, they'll still be almost fully charged up in the Spring and should not need more than a slight charge. Suggest you read Maine Sail's excellent article: http://forums.hunter.sailboatowners.com/showthread.php?p=1057483&highlight=Battery.

DougM · Feb 21, 2015

I have never left batteries connected during winter layup. I completely disconnect both terminals although probably not all that important to disconnect the ground side.
The batteries are fully charged, and water levels topped off.

After launching in the spring, there has always been sufficient starting power for the engine and to run the electronics. Voltage readings in both batteries have remained close to 13 volts.

I would be surprised if there were marinas around my location that would allow owners to string electrical cords to their boats in storage because of the potential for circuit overloads or fire not to mention the hit on their power bill. Anyway, most of the owners' boats would be stored so far away from a power source that they couldn't afford the cost of the cable required to reach their boats. If the boats had solar panels, they wouldn't function because they would be buried under a couple of feet of snow.

Ron20324 · Feb 21, 2015

DougM said:
...I would be surprised if there were marinas around my location that would allow owners to string electrical cords to their boats in storage... If the boats had solar panels, they wouldn't function because they would be buried under a couple of feet of snow.

Doug, I'm on the dock committee at my condo developement. We have rules that everyone should have a copy of, but there are so many renters, who knows if the slip-owners have forwarded the rules to the boat owners/renters.

We have rules about cords: A) They have to be rated for AT LEAST the amperage rating of the circuit breaker. B) For the 15/20 amp outlets, you must be AT THE BOAT to have anything plugged in (does not apply to 30-amps). No excuses like "I just went over to West, or got some lunch". If you are not on the boat, we disconnect the 15/20 cord. Obviously, the concern is people use wimpy cords to power higher-amperage loads. Fire does not wait for us to mail a violation to the owner, so we pull the plug with no notice given, but we leave a notice as to"why".

We had snow last Monday, but several days later I got on the boat and was getting 14 volts from the solars though the snow.

DougM · Feb 21, 2015

Ron20324 said:
We had snow last Monday, but several days later I got on the boat and was getting 14 volts from the solars though the snow.

Ron, what we get in this part of Virginia/Maryland hardly qualifies as snow... It's fairy dust. Where my boat is in the winter, a person could go for months without being able to get to a boat on the hard. Being able to keep a boat in the water is enviable in the bay area, but would result in a crushed hull up north or a sinking due to snow accumulation.