Trojan T105 3v x 4

[Steven UK]

backstory: - i outfitted my new to me boat in January with 4 x Trojan T105 batteries, 200w solar panel, and a victron MPPT. everything was going dandy until i parked the boat in Abaco and Dorian whisked my panel off to places unknown. when i finally stepped foot on the boat again (last month) the batteries were at 3v, house and start were combined. i traded for a working temporary panel and started charging them up. i will be heading out to Abaco again shortly to try and bring the boat back to Florida. does anyone have experience with batteries this deeply discharged and what my chances likely are to resurrect them? they were $600 plus for the four of them and i dont want to spend that again.

the batteries are series - parallel so should be 12v

Best Regards Steven

p.s. i'm planning an Atlantic crossing on this boat in the not too distant future.

[Dockhead]

Those are pretty tough batteries, but 3 months at 3v may have destroyed them. Charge them up, give them a good equalization charge, then do a capacity test. Some people say running them right down to zero and charging them up will help revive a battery which has been through that.

[john61ct]

I would just buy new.

If not, invest some serious time & energy into doing your best to "resurrect" them, full equalize cycle if possible,

then do as good a CC-load capacity discharge test as you can mange.

Usual go/no-go cutoff would be 80-90% SoH on cells that new.

Accepting 70% or lower would IMO be foolish before a long offshore trip.

[Steven UK]

I do believe that the Victron MPPT charger does an equalization charge every so often so by the time i get back it may have done it a couple of times. Fingers crossed. if not they will be trade ins. My power usage is minimal apart from the tiller pilot. Which Needs to go all night generally. Thanks for the response.

[john61ct]

Do not allow such automated equalizing, should be done manually following mfg specs as precisely as possible, ideally each unit in the bank separately isolated from any loads.

Best off shore power with an accurate ammeter and an adjustable charger or power supply.

[Steven UK]

Originally Posted by john61ct

Do not allow such automated equalizing, should be done manually following mfg specs as precisely as possible, ideally each unit in the bank separately isolated from any loads.

Best off shore power with an accurate ammeter and an adjustable charger or power supply.

bugger, its had several months of automated equalization's

[john61ct]

Don't stress about it, not usually talking about immediately noticeable "damage".

As we learn more about best practices for optimal longevity, we are better equipped to continuously improve, small benefits accumulate for a positive impact long term.

Or at least to compromise between the various trade-offs from a position of better information, not just continuing to make mistakes out of ignorance.

Many owners are happy to just replace their banks a bit more frequently and not worry about the details.

Which is also a perfectly valid POV, your rig your choice.

[Steven UK]

Just closing the loop, I visited my boat last week in Abaco. The batteries came back to (I’m guessing) need new condition. Running 110v power tools and refrigeration all day. Still got to fix the mast though.