Winter maintenance battery charging

Posts regarding the electrical systems and electronics on a Telstar.
seicam
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Winter maintenance battery charging

Post by seicam »

I was wondering how people keep their boat's batteries charged during the winter, assuming you keep the boat outside of a marina. Do you take the batteries home and have them periodically re-charged? Are there some "trickle" chargers available? Solar panels? Any other ideas?

Right now my stock 2 ACM batteries are on the boat, but I think I should take them home and keep them charged somehow. Looking for suggestions.

Thanks,
Maciek
Ron
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Winter maintenance battery charging

Post by Ron »

Maciek -

Regardless of where the batteries are stored (boat vs house), I'd want to keep a multi-stage battery maintainer on them. That means something like a "Battery Tender", and not a trickle charger. You want to "float" (final stage of a multi-stage charger) them. There's one reservation - based on the nominal winter temperature of the area. If it gets REALLY cold (below zero - Minnesota, Canada, Alaska ?), I'd probably take them off of the boat in favor of a heated building.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
Dan

Winter maintenance battery charging

Post by Dan »

I've been using a 25 watt solar panel with an MPPT charge controller to keep the batteries on my boat topped off over the winter. This is simpler than removing the batteries, since the boat is setup for solar panels to begin with. :D I wrote about the setup on my blog. You can read the article at http://tinyurl.com/yb4g2w8

Ron's point about the ambient winter temps is a good one, but doesn't really apply to the PNW.
Ron
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Winter maintenance battery charging

Post by Ron »

Dan wrote:Ron's point about the ambient winter temps is a good one, but doesn't really apply to the PNW.
Dan -

That was a general statement regarding sub-zero battery storage. They could freeze. I've been trying to contact you for awhile - could you send me a PM or email. Thanks.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
seicam
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Winter maintenance battery charging

Post by seicam »

Thanks for the replies. Dan, I've read your blog entries and also posts on this forum, which I missed earlier. Quite informative. I also studied a few chapters from Nigel Calder "Boatowner's Manual". All in all, I agree that solar panels would be a good solution, but it is a project that I need to put off for probably another season.

Here is what I think I am after:
- right now the boat is in a storage with no access to electricity
- right now the batteries need recharging and need to be kept recharged over the winter. The voltage on both batteries now is 11.86V, which I think is quite low.
- in the spring I will have the boat either in dry or wet moorage with electricity for sure.

I think I would like to purchase a regulated, three-phase charger that I can use now at home to recharge and float the batteries and during the season I could use in the marina to recharge the batteries after a sail, or use in marinas during longer trips (following the model of using the batteries for 2 days at most).
Therefore the specific questions I have:
- recommendation on the charger (I found a thread in members-only forum on that and I am re-searching some recommendations from both Ron and Dan).
- how to plug the charger when batteries are on the boat - directly to the batteries, or is it somehow possible to plug it into the BEP Marine Relay that I have installed along with the battery switch?
- will removing the batteries from the boat impact any onboard electronics (need to re-calibrate, etc)?

As for the ambient temperatures, they hover now around 40F, but we had dips to 15F for a few days a few weeks back. That would be probably the coldest it gets here.

Thanks,
Maciek
Ron
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Winter maintenance battery charging

Post by Ron »

Maciek -

I'm using a 1.25 amp "Deltran Battery Tender" which is hard-wired to the two small AGM's, and is plugged into the AC socket at the nav station. It's a tiny multi-stage charger that winds up in "float" mode when the batteries are almost fully charged. This works well for me, but I'd go higher (maybe 10 to 20 amps) if I normally depleted the batteries and had to recharge quickly or the boat had much larger batteries. As a safety feature, the Deltran will shut-down after 72 hours if it can't get the batteries up to 12.8 volts (or so) anyway, and it will definitely not be able to get something like Dan's golf cart batteries back up if they are run half-way down.

I've used these chargers (must have 10 of them) on a bunch of restored cars and they really do a good job of keeping the batteries alive. Some of the battteries are about 15 years old and they have yet to fail. Note that a 3/4 amp version is available as a waterproof charger as well (roughly half of mine are this waterproof unit).

I've had much larger chargers on other boats - up to around 80 amps as I recall. With a bank of several 8D's (200+ pounds apiece) you need this kind of power to bring them back after several days. I remember putting a 150 amp Balmor alternator with 4 stage regulator on the boat as well. It all depends on what kind of boat, the way you use it, and the capacity of the batteries.

Solar would work too, but you need a decent amount of sunlight all year long and may not be able to cover the boat depending on where the panel(s) are. Great for a mooring or anchorage. Not much else will work there.
Ron Marcuse
Telstar 28 #359 "Tri-Power"
seicam
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Winter maintenance battery charging

Post by seicam »

Thanks Ron.
Sorry for my ignorance in that subject, but when you say:
Ron wrote:"Deltran Battery Tender" which is hard-wired to the two small AGM's
could you explain what do you mean by "hard-wired". Is the charger wired to one battery and charges both because they are connected, or you need to have one charger wired to both batteries at the same time and charge both? If I take the betteries home, I'd need to charge them separately I guess.

Thanks,
Maciek
Ron
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Winter maintenance battery charging

Post by Ron »

Maciek -

The Deltran Battery Tender comes with 2 styles of wire attachment - alligator clips for a non-permanant installation and eye rings to screw down to the terminals. Each has a polarized plug at the other end which mates to a plug on the charger itself. You can't really jump the two batteries without permanently connecting them together, so I attached the eyes to one of the batteries and leave the A-B-BOTH-OFF switch on BOTH when I want to charge them. I could have used two tenders to take care of each individually, but I did not think that was necessary for these rather small AGM batteries. Note Photo below. This is the 1.25 "Plus" unit.

This setup works very well on my current 2 boats (Telstar and 20 ft SeaDoo jet boat) and a half dozen sports cars because of the kind of usage they all get. If I had to bring back two large deep cycles every other day it would not do it. Last boat was a big Catalina with over 600 amp hours of batteries. It would take the 1.25 amp Battery Tender at least 10 days to bring everything back to 100 percent (from half discharge), and it would shut-down after 72 hours at bulk mode anyway (safety feature).

If this setup works for you - make sure it's a real multi-stage charger that winds up in a "float" stage. A "trickle" charger wlll eventually hurt the batteries. The current may be a "trickle", but it's running at about 14.5 volts or greater. The Deltran units are probably the best around. They're used by millions of people with antique cars, motorcycles, boats, planes, etc. Jay Leno supposedly has 600 of them.

One other thing comes to mind - at 1.25 amps (bulk rate) it would be nearly impossible for one of these chargers to damage either the battery or boat if something goes wrong. They're perfect for floating most battery banks once they are charged. A friend with a 40 foot Catalina had his boat totalled because his fancy 80 amp multi-stage charger/inverter cooked all three 4d batteries (must have stayed in bulk mode) and the boiled acid condensed on everything inside the boat. Virtually destroyed it. Could of killed them if they were on-board and asleep. Almost happened to me as well about 15 years ago when 2 Promariner 50 amp chargers failed -(over 3 years), but it just cooked the batteries (twice) in my case.
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Ron Marcuse
Telstar 28 #359 "Tri-Power"
seicam
Posts: 94
Joined: Sun Feb 01, 2009 9:58 pm
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Winter maintenance battery charging

Post by seicam »

Thanks Ron - that helps. It's a good point on the safety as well.

I am assuming that removing the batteries will have no effect on the electronics, since they are diconnected already through the battery switch.

Regards,
Maciek
seicam
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Joined: Sun Feb 01, 2009 9:58 pm
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Winter maintenance battery charging

Post by seicam »

I have downloaded the technical brochure for AGM 35Ah Interstate Batteries that are on my boat. I wanted to post it in the Member's section, but it requires uploading the file to the website /info folder. Could someone help me with that?

Thanks,
Maciek
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