Batteries fully drained how big is the damage?

[Volkhard]

When I came to my (new to me) boat today, I found out that the marina started some work and have unplugged my boat about 10 days ago. They didn't notify me or did anything preventive, just unplugged. The housebank is ~ 44OAmp and the starting ~100AMP all brandnew Lifeline AGM's. Batterie switch was on ALL and the fridge was running on low.

Coming back to my boat from a charter trip to the BVI I have found it with all batteries drained .... How big is the possible damage to the batteries being drained by the fridge all the way .... What can I expect?

I will try tomorrow to start the engine with a back-up power unit and have the engine run for charging.

Any suggestions and recommendations (besides not trusting the dockmaster) ?[/SIZE]
Powerless in Florida

Volkhard

[sailingdog]

The batteries may be fine. Since the main load on the batteries was the refrigerator, not a load like an incandescent lamp, it is likely that the refrigerator didn't drain the batteries completely flat, since the electronics in the refrigerator will stop working once the voltage drops below a certain level.

Charging the batteries as soon as possible is probably a very good idea. From the LifeLine battery website:

Full recharge after 30 days storage in a full discharge condition 77°F (25°C).

Finally, you might want to add an automatic disconnect that will break the connection if the voltage drops below a certain point. Like this.

[Volkhard]

Sailingdog:

Thanks for your reply! Besides the fridge there was only the bilgepump on auto ... I hope that was not too bad either! The automatic disconnect you mentioned makes a lot of sense! Would it interfere in any way with any of the systems or my charging (Freedom 2500 and Heart 2000R). I am just starting to get serious about all this and have read Nigel Calders book twice but there are still so many questions ....

At least I hope I get the engine started tomorrow and re-charge during a day motor sail ....

Again, Thank's a lot!

Volkhard

[sailingdog]

The bilge pump might be a bigger problem... since most are relatively simple beasts and would trigger even at very low voltages, unless the switch is an electronic, rather than a float switch.

Don't believe that the automatic disconnect will interfere with any of the systems or charging, with the exception that it may mess up clocks or the memory function on some electronics if it is tripped... but that would also occur if the batteries go flat.

[camaraderie]

It is unliikely that a single discharge of new batteries to near flat has done any severe damage. Take a reading at the battery terminals to determine true voltage with everything turned off for a while for your records and go in writing to your marina that you hold them responsible for any damage done to the system.
Charge 'em up all the way with everything off. Let 'em stand a few hours and take another terminal reading. You should be in the 12.7-8V range. If lower...you have damage. Good luck.

[sailingdog]

It would have been worse if they were wet-cells, but I think AGMs will be okay. Just try not to have it happen again... And get something in writing from the marina about the problems as a CYA move.