Best Practice for Batteries for Winter

[CourageousME]

It's my first winter with my boat and recently lost my job. Finances are tight so I'm trying to learn what I can do myself.

I've got 4 sealed batteries (interstate brand I think) under my chart table bench. They somehow charge a 5th starting battery and a 6th windlass battery.

What's best practice for them? I'm reading some people simply disconnect them, others leave them as is- others use a tender (not something I can do).

In in Maine and it's cold. She just got pulled yesterday and will sit until May 1.

Thanks


Sent from someplace

[boatbod]

There are three things you can do with batteries over the winter, and each has its pros and cons.

1. If the batteries are small enough (e.g. Group 31 or smaller) you can take them off the boat and store them somewhere. Throw a charger on them occasionally to make sure they stay topped off. Downside is that you have no bilge pump in case water gets inside your boat.

2. If the batteries are larger and you can't physically lift them off the boat without major hassle, you can charge them and then disconnect them in-place. Again you run the risk of having no bilge pumping capability in case your bilge fills up.

3. If you have electricity available nearby, you can leave the batteries aboard and connected and charge them overnight about once a month. This works well provided there are no parasitic/hidden loads that will draw the batteries down in between charges. It also keeps your pumps operable to keep the bilges dry.

Personally I prefer option #3 for my boat.

[Mike OReilly]

Probably the best option is to remove the batteries and store them in a warm, dry place where they can be periodically charged. This is usually easier said than done...

If I can’t get to my boat for the winter I ensure my batteries are fully charged, and then disconnect the batteries by removing the cables from the posts.

When I can access my boat with shore power I have left the batteries in place, and just come down and charged the batteries every couple of months.

A couple of years I left the shore power charger working all winter. This was with a proper 3-stage charger. This approach runs the risk of electrical fires, so I’d be cautious about this approach.

[antoha]

if the boat is on the hard and you have a garplug, not having a bilge pump is probably not a problem (I know yards that make you sign a special waiver if your bilge doesn't gravity drain that you will come and check on your boat in the winter or they are not responsible).

as to maintaining batteries, an inexpensive solar panel + controller will probably keep you topped off?

[UNCIVILIZED]

Remove from boat, store someplace warm, charge periodically.

[SteveInMD]

You don't say what type of batteries they are. Flooded wet cell? AGM?

The best scenario is to keep the batteries at float voltage permanently, winter and summer. This prevents the opportunity for the batteries to sulfonate. If the batteries are wet cell you may need to check the electrolyte level every other month or so. Using a temperature compensating charge is good to, but it's not necessary if you don't have one. If the batteries are on a charger they will not freeze.

[boatbod]

Originally Posted by SteveInMD

You don't say what type of batteries they are. Flooded wet cell? AGM?

The best scenario is to keep the batteries at float voltage permanently, winter and summer. This prevents the opportunity for the batteries to sulfonate. If the batteries are wet cell you may need to check the electrolyte level every other month or so. Using a temperature compensating charge is good to, but it's not necessary if you don't have one. If the batteries are on a charger they will not freeze.

Most boatyards aren't going to want you to be plugged in all winter. First off it's a potential fire risk (some idiot always leaves a heater turned on) and secondly, there are usually only a few outlets to share amongst numerous boats.

[SteveInMD]

So the thread should be called a Best Practices for Batteries for Winter When No Power is Available? The answer is the same. Keep the batteries at float voltage as much as possible. Move the batteries to someplace where there is power, or add solar chargers, or recharge whenever possible. There is no magic solution. If you can't keep the batteries topped up, and can't move them, then just hope for the best I guess.

[Brob2]

Originally Posted by UNCIVILIZED

Remove from boat, store someplace warm, charge periodically.

...but don't leave them on the concrete floor in the basement

Good luck with with job hunt.

[SteveInMD]

Originally Posted by Brob2

...but don't leave them on the concrete floor in the basement

This was certainly true in the past, but with modern plastics it is no longer the case.

[CourageousME]

Great info thx. Yeah so I can't keep it plugged in. No power in the yard. I could bring my genny over and charge a few times over the winter. That seems to be best. I do have a 300 watt solar panel that's maybe 3x5 I got for free- if doing a solar charger is easy maybe that's the best way to do it. Start another thread about that ? LOL


Sent from someplace

[Brob2]

Originally Posted by SteveInMD

This was certainly true in the past, but with modern plastics it is no longer the case.

I had no idea!

[SteveInMD]

Originally Posted by CourageousME

Great info thx. Yeah so I can't keep it plugged in. No power in the yard. I could bring my genny over and charge a few times over the winter. That seems to be best. I do have a 300 watt solar panel that's maybe 3x5 I got for free- if doing a solar charger is easy maybe that's the best way to do it. Start another thread about that ? LOL


Sent from someplace

Solar would definitely be the best practice for the batteries, provided you use a decent controller. Many people get by with charging a few times over the winter.

[astokel]

Canada here!

I have AGM batteries. I give them a full charge. I disconnect and turn off everything. There is very little drain from AGMs. At some point on a mild day during the winter, I charge them. This takes most of the day so bring food and beverage.

I've been doing the above for five years. No problems.

[zstine]

My yard doesn't allow you to keep the boat plugged in, but if you have some projects to do, I found that plugging in and turning the charger on for a half day, twice a month, is plenty to keep them topped up. (i turn battery switch off when I leave the boat) The other option I find acceptable is to buy 30W solar panel and cheap pwm controller (~$75 amazon) and that will keep the batteries topped up. Removing them is fine, but a PITA. Plus you don't have power if you ever want to do some work on the boat and need to turn the lights on or some other 12V system while working.