Battery Bank Dry after Solar and Wind Gen Installation

[SV Sailfish]

An easy mistake to make...

It's a French boat so you have to use red wine in the batteries.

[hzcruiser]

Originally Posted by P3sailor

... What he did find, though, were some loose connections at a few battery posts. Now, I may be wrong, but if these connections were very loose, I believe that could have been the problem or at least part of the issue. ...

Well, loose battery (or other) connections only differ in the resistance they add to the current flow. Hence they get warmer the higher the current being pushed through but not causing any off-gassing per se. Still, clean and snug connections are important.

As mentioned before, the issue could be a lack of maintenance over such an extended period.

If you can't run a discharge test on a large battery bank, you could instead disconnect some batteries and run the daily loads from the others while counting the Ah coming out of them.

[john61ct]

I suspect new equipment installed continuously pumping out over voltage

[ramblinrod]

Originally Posted by P3sailor

While on the hard and owner away, contractors installed solar panels and a wind generator on the boat (Amel Super Maramu). Upon returning, after several months away, all cells on all 12 batteries were dry. Never had this issue before and guess that overcharging is the culprit.
Is anyone aware of any circuitry that should be installed that would have prevented this?
The boat isn't mine, but one I've sailed on, so I'm couldn't tell you the manufacturer or make of any of the installed units (solar/wind).
My only thought on this is overcharging causing excessive gassing of the cells.
I've suggested to the owner that after topping off the cells, fully charge the battery bank and have someone do a capacity check on the system. I doubt very much that the battery's will pass but it's worth a shot. Never did a cap check on a battery bank but have done it on individual batteries. Any help or advise would be appreciated.

If the batteries were OK to begin with, on the hard with nobody aboard, there should be no significant load and the controllers should keep the batteries on float. On proper float voltage, they should sit there for months without significant water loss.

So the suspicion is that the controllers aren't going into float properly.

As far as the batteries go, you can try adding water and charging but if they are deader than dead many Smart chargers will consider thm faulty and disconnect. It may be necessary to start charging with an old tech ferro-resonant charger until the are brought up a bit. It's certainly possible that they have been toasted irreparable.

But let this be a lesson. Never leave a boat unattended with a significant charge system connected. A 1000 Ahr bank only needs a 5A shore Smart charger or single 50 W panel with smart controller to keep it on float. If something goes wrong while absent, the risk is minimal.