Battery tender

[Jotun]

Anyone have any suggestions for a battery tender/charger for 2 group 24 12v, wet cell batteries? I'm looking for something small and inexpensive to keep them topped off while at the dock and connected to shore power.

[Jotun]

Can I use something as simple as this:
http://www.defender.com/product.jsp?path=-1|328|51495|985|316472&id=186048

It mentions, though, a max output of 250 amp hours, which is pretty low. Also, I wonder if this would be enough for two batteries that are wired parallel.

Maybe this would be better:
http://www.defender.com/product.jsp?path=-1|328|51495|985|316472&id=724506

[sailingdog]

I'd go with the second one...the promite.. rather than the first and properly hard wire it in... the clips on the first and the design of it speak volumes about it being a very short-term and really not designed for marine use type item.

[Jotun]

I think my biggest concern is can these maintainers be used on batteries that are wired in parallel? Most only mention single battery applications or say nothing at all.

[CapnHand]

I wouldn't go with either of those. The minimum charger size usually recommended is 10% of the total Ah of all batteries on board. You likely have about 150 Ah in those batteries so the minimum charger size would be 15 A. If you go smaller on the charger it will mean that it will take longer to recharge the batteries after use and the batteries may never reach full charge. This causes sulfation and shortens battery life. The one you get should have a float charge function to ensure that your batteries are not damaged from over charging regardless of how long they are left on the charger. There are many posts in here regarding good chargers if you search for them. A recent post here: http://www.sailnet.com/forums/gear-m...s-battery.html is an example.

Having the batteries in parallel is not a problem as long as they were bought at the same time and maintained. If one battery is weaker, it will always pull the other one down.

Also the batteries and shore power should be wired into a disconnect switch with fuses / breakers on every circuit, use tinned wire, don't put the charger in the battery compartment and all that jazz.

Search and ye will find.

[TrueBlue]

Xantrex Truecharge 20+ is a unit I would highly recommend, due to it's smart, three-stage microprocessor. I installed the Truecharge 40+ model three years ago for my three 4D banks and have never even had to think about it since.

[cardiacpaul]

folks, this is EXACTLY what I was talking about in one of my pet peeves... look at his application and his stated needs.

he has 2 group 24 wet cells
he states...
"I'm looking for something small and inexpensive to keep them topped off while at the dock and connected to shore power"

he does NOT need a 250.00 battery charger for batteries that cost 39.99 EACH.
go to walmart, buy a 2 amp trickle charger for 25.00. clip it on, plug it in, all will be just fine.

[sailortjk1]

Paul,
Does he have to take the aligator clips off and unplug the charger before he goes sailing? (I hope your laughing right now)

[cardiacpaul]

just from his nippies... unless he's into that kinda thing

[TrueBlue]

Don't get your BP up paul . . . . I suggested a multi-level unit he would never have to worry about. A trickle charger will cook his cells if unattended.