all batteries dead

[mjk1040]

BOAT!
B=Break
O=Out
A=Another
T=Thousand
Mike!LOL

[km1125]

You really need to know what the age of those batteries are. You might be able to recover one or more, but if they are dated your time might be better spent just replacing them, especially the engine start batteries. You NEED at least one of those to be good, but if they are wired in parallel then you need to replace both at the same time. If your house batteries don't recover fully it would be more of an inconvenience, as you'd have to limit your usage or recharge more often but it's something you can work around till you replace.

If they are fairly new, then I'd give it a good try at recovery. I'd probably bring at least some of them home.

What type of charger is in the boat? It might take a LONG time to get all six batteries charged up if it's charging them all at the same time. It would be better to charge them individually.

[Lyndon670]

You must thaw them to charge them - do not try to charge them frozen. Besides, no rush - let them warm up and then check the specific gravity of each cell, top up with demineralized water and put them on a trickle charge.

I never remove my batteries - simply check the state of charge, top up if necessary and disconnect all cable ends as you never know what parasitic load exists on your boat.

As Mike said, might be at the end of their service life.

[Viper]

For what it's worth, if they were discharged and froze, they're toast. Don't trust them even if they seem to take a charge. In a discharged state, some of the electrolyte reverts to H2O which will freeze in the winter. When this happens, it'll distort plates, weaken the case, weaken the post connection points to the plates, etc. Under the right conditions, these can be dangerous when put back into service. Also, If this battery is in parallel with a good battery, it'll likely toast the good battery after a few charge cycles.

If the case hasn't swollen which usually happens after it has frozen, you might get lucky. Personally, I don't like to rely on luck when it comes to boating enjoyment and safety. I prefer to be proactive. It's too short a season for me!

PS; during the nice weather last week, I boarded the boat and tested the batteries. Still have a 90% charge. I'm good to go Like I said before, if you put a good battery to bed properly for the winter, it stands a better chance of making it. If it doesn't make it, it's likely to have had a problem to begin with and would likely let you down during the season anyway. No need to remove batteries for the winter if you do it right.