I'm like you Ross, the original 29 yr old Newmar is still charging away (though I did have to replace the burned out indicator light and ammeter).
A fancy Xantrex (or whatever) is not in my initial restoration budget at the moment.

I have an IOTA DLS55 with IQ4 module. Has been completely rock solid. It does exactly what it is supposed to do every time with no flakiness at all. If it ever dies I will buy another for sure, for the price it's hard to beat.

If I was in salt water I might buy a charger that is a marine unit with a lot of settings you can adjust on it. Mostly because I don't have much else to waste money on these days. But after 4 years this unit still looks like the day I put it in, not a hint of corrosion anywhere.

I had a ProMariner Protech 4 30 amp before the IOTA and it was totally flaky, it never did the same thing twice. You could never tell what the hell it was up to. But it did say "marine" on it.

Pronautic 40amp into 6 series parallel GC2's - very happy. It takes very good care of my batteries.

I think there are lots of boats running new AGM batteries with an older charger that is not designed for AGM.

Another factor is that few of the chargers run independent profiles for battery banks. They may have independent battery bank outputs, but those are only independent via a diode to prevent cross charging on batteries. On most, all output lines run the same voltage profile. If I go out every weekend and reserve my engine start battery but cycle the house bank by 50%, then when I plug in the boat the engine start battery is subject to the same high voltage bulk charge cycle that is required by the state of house bank.

I don't know it that really causes much damage on the battery bank, but it certainly cannot do it any good. A few of the newer more expensive chargers run independent profiles, but it's almost equivalent to multiple independent charger for each bank, so they are quite a bit more expensive.

[quote=Wavelength;21426]Yes I bring home 4 G27s. Our club does not allow you to leave your boat plugged in while on the hard unless you are there to supervise.
My garage is a lot easier to get to these days than my boat with 3 feet of snow around it.[/quote]

Our place is the same, if the owner sees a power cord plugged in and you're not on the boat he'll cut it, seems simpler to me to just pull the thing out but not quite so dramatic I guess. You'd not likely do it twice after that though.

I used to leave a solar panel on all winter but I didn't like that idea at all. Based on what I've read here and elsewhere, batteries do not self discharge much at all in cold weather. So this year I've just made sure there's no parasitic loads on them, topped them up and left them alone.

Have been to the boat once a month or so to clean snow of the winter cover and the batteries are sitting at 12.6 for the house bank and 12.8 for the AGM starter which is essentially fully charged. I've plugged in the charger and it goes through the 3 stages and into float in about 2 minutes, which also indicates the batteries are not discharged to any degree.

This flew against everything I had ever heard about batteries, that they'd go dead in the cold, don't put them on concrete, yada yada yada. But so far it seems to be a simple and effective way of dealing with this issue. I do believe it is critical to ensure there are no loads, if you're not sure take the grounds off. If they do discharge to flat due to a hidden load it will not be good for them at all.

Greg, if you use an echo charger to charge your start battery it will limit the voltage to 14.2 volts regardless of what your big charger is putting out and limits the current as well. Much healthier for your starting battery since it needs so little charge.