Winter Battery Storage / Care

[sailorboy1]

I know the real right answer is to remove the batteries, take home, put them in my best easy chair by the glow of the fireplace, feed and water them regular, play soft music for them, read them nice novels etc...............But this is a lot of work for a large battery bank and there's the damage danger to both the batteries and myself to consider with doing this.

So I'm leaving them on the boat like I did for years with my last boat!!!

But the house bank is new this year and I feel I should really do something to take better care of them (if just so I feel proactive and feel all good wth myself).

The house batteries are 6V wet cells and the start is a sealed wet cell 12V.

So:
1 - is it worth getting one of those $60 trickle chargers

2 - don't need solar yet but could get a real panel, if it is only say a 65watt would it need a charge controller to not cook the battery

3 - I could go to the boat once in a while and run an extension cord to it (assuming I can find power at the marinia) and run the charger a while

4 - I could do nothing, like I've done in the past

PS - taking the batteries off the boat is not going to be a choice regardless

[redcobra]

Originally Posted by Don Lucas

I know the real right answer is to remove the batteries, take home, put them in my best easy chair by the glow of the fireplace, feed and water them regular, play soft music for them, read them nice novels etc...............But this is a lot of work for a large battery bank and there's the damage danger to both the batteries and myself to consider with doing this.

So I'm leaving them on the boat like I did for years with my last boat!!!

But the house bank is new this year and I feel I should really do something to take better care of them (if just so I feel proactive and feel all good wth myself).

The house batteries are 6V wet cells and the start is a sealed wet cell 12V.

So:
1 - is it worth getting one of those $60 trickle chargers

2 - don't need solar yet but could get a real panel, if it is only say a 65watt would it need a charge controller to not cook the battery

3 - I could go to the boat once in a while and run an extension cord to it (assuming I can find power at the marinia) and run the charger a while

4 - I could do nothing, like I've done in the past

PS - taking the batteries off the boat is not going to be a choice regardless

I'm with you on this, although I may need a new start battery anyway. My back won't handle moving the batteries. When I put the new house batts in, I hired a kid to do the lifting. Afterward I paid him he said, "Don't call me. I won't do it again."
I am going to try a trickle charger if the Marina puts the boat near enough an outlet.

[DeepFrz]

A 65 watt solar panel will put out max. 5 amps for a few hrs a day and even less for a few more hrs so it wont harm your bank. Just check the water level once in a while.

[mbianka]

I've got a 48 volt electric propulsion bank consisting of 4 8A4D's weighing 120 lbs each and a house bank of two 12 volt Gels about 80 lbs each. You know I'm not real keen on moving those every couple of months. So I don't. Solar panels have kept them topped up over the winter. I also power up the battery chargers when I come down to check on the boat. But, the solar pretty much do all the charging for the past four years in the off season.

[marshmat]

Check the water level in each cell, and top up any that are low.
Then charge the batteries fully.

Now turn off the main switches and make sure that nothing is drawing power from the bank.

Finally, hook up some small charging gadget- a little float charger that only puts out a couple of amps, or a small solar panel left in a window, to compensate for the slow self-discharge over time. (Note that some of the cheapest "trickle chargers" can still slowly boil off the electrolyte, as they won't shut down when 100% charge is reached.)

That's about all they should need..... a fully charged Pb-acid battery is not vulnerable to cold weather damage. They're only at risk if they're deeply discharged.

[barnakiel]

Charge them full up before leaving.

Leave them on trickle-charger, or.

Re-charge them periodically.

Depending on temperatures and battery types they lose charge at various rates.

b.

[Dockhead]

I have read something here or there that makes me wonder whether a "trickle" charger might damage batteries if left on over a period of months. Perhaps it can't if the current capacity of the charger is small enough in relation to the total battery bank size -- maybe someone who understands batteries better than I do could comment. But I read something that the voltage can cause corrosion of the cathode (?) plates.

My new Victron charger has a fourth charging phase -- "storage". The voltage is lower than float. Once a week, the charger will put a shot of absorption voltage through the batteries for a couple of hours, then go back to "storage mode". Maybe a more sophisticated main battery charger is a better answer, than a cheap trickle charger?

[marshmat]

Cheap trickle chargers don't know when to stop. If there is zero load being drawn from the bank, but you keep cranking 5 A into it, you will (very slowly) overcharge it. That's not a problem if you're there to keep an eye on it now and then, but if it's on its own for six months it could lose enough electrolyte to expose the plates.

4-stage chargers with a "storage" mode are much more sophisticated; if I had to leave a big bank unattended for months, I'd prefer one of these.

[sailorboy1]

Surprised I guess that more people haven't tried the trickle charger approach. My boat came stock with 1 for the start battery, but that will be covered so useless.

I can not see a few milli-amps a couple of hours a day doing any damage. The question is whether this is better/worst/the same as leaving the batteries slowing self discharging for months.

They're cheap, but if they really are just useless the money is just wasted.

[noelex 77]

Trickle charging is better than allowing the self discharge to drop the SOC significantly.
The correct size is not too critical, but it does vary with battery type, size and temperature. It is also worth checking there are no parasitic loads such as battery monitors and stereo memory , but something around 0.75A is usually needed for the house bank. These are very cheap.
A proper smart battery charger is better however. The other advantage of the larger charger , if the boat is in the water, it will keep the bilge pumps going in the case of a leaking stern gland or skin fitting.
The biggest problem is that its not unusual for someone to unplug you shore power and not plug it back in. A small solar panel is more foolproof.

[redcobra]

Originally Posted by noelex 77

Trickle charging is better than allowing the self discharge to drop the SOC significantly.
The correct size is not too critical, but it does vary with battery type, size and temperature. It is also worth checking there are no parasitic loads such as battery monitors and stereo memory , but something around 0.75A is usually needed for the house bank. These are very cheap.
A proper smart battery charger is better however. The other advantage of the larger charger , if the boat is in the water, it will keep the bilge pumps going in the case of a leaking stern gland or skin fitting.
The biggest problem is that its not unusual for someone to unplug you shore power and not plug it back in. A small solar panel is more foolproof.

Additionally, at least at my Marina, if I leave a feed to the boat all winter (electrical) while it is on the hard, there is a fee for that.

[noelex 77]

Yes good point about the cost. There are also some potential corrosion problems connected to shore power. I have also seen the boat end of the shore power plug develop some corrosion (or maybe broken strands) and melt. No fires, but close.
Solar solves all these problems and I think it is the better solution

[sailorboy1]

Originally Posted by redcobra

Additionally, at least at my Marina, if I leave a feed to the boat all winter (electrical) while it is on the hard, there is a fee for that.

Unless you leave your boat in the water; at my marina you can not leave an extension cord plugged in to you boat. All suggestions about using a smart charger don't apply.

[SailFastTri]

Originally Posted by redcobra

Additionally, at least at my Marina, if I leave a feed to the boat all winter (electrical) while it is on the hard, there is a fee for that.

If the boat is in water, it's worth it to pay for power. If on the hard, just top off the batteries every 60 days and no problem (if you have any small loads maybe more often). So long as they're at or near full charge they won't freeze.

[Maine Sail]

Originally Posted by Don Lucas

Surprised I guess that more people haven't tried the trickle charger approach. My boat came stock with 1 for the start battery, but that will be covered so useless.

I can not see a few milli-amps a couple of hours a day doing any damage. The question is whether this is better/worst/the same as leaving the batteries slowing self discharging for months.

They're cheap, but if they really are just useless the money is just wasted.

Don,

The colder the temps the lower the self discharge, and sulfation also drastically slows if not pretty much stops. I have been leaving batts on boats, as many do up here, for over 20 years. I occasionally visit the yard to do some work on the boat and turn on the charger while there. Never a single issue. Even my shop batteries and batteries removed from boats during upgrades, that are too good to turn in for cores, are stored in my un-heated shed not in my heated garage..

I am not a believer on long term unattended charging via solar or AC chargers as I have just seen to many problems/failures.

I simply 100% charge the batts then top up with water and charge for another day, then run multiple tests before disconnecting.

I then 100% disconnect the bats from the vessel to prevent phantom/parasitic loads from draining the batteries.

Occasionally top up on boat visits throughout the winter


Most yards up here mandate that batts be disconnected and not left on charge..

Last winter I purposely did not touch the bank from early Nov to April and it was still at an OCV & SG suggesting approx 95% SOC.. I charged them to full in early November and did not put a charge on them again until early April. The batteries were still at a resting open circuit voltage of 12.68 volts and ths was confirmed with an SG test. Full on this bank is about 12.73V. If they had been in my basement I would have needed to top them up every three to four weeks due to the much higher temps.



EDIT: Just read your boat is in the water so you'll want to visit and charge them more often because you'll not want to disconnect the bilge pumps...