Suggestions for LARGE battery charger?

[davejq]

I have 400AH of AGM batteries in my house bank, a 75A output alternator on the main engine plus a 4.4kW genset, and I'm looking to find the most efficient way to charge the batteries using diesel! (solar panels are planned but are not yet there). My thought is to get a 110V charger with a single output 100A or greater - the genset can feed it and the batteries can take it, giving lower fuel consumption and shorter running hours than using the main engine. But is there a marine quality, intelligent (ie voltage outputs suitable for AGMs), and 'cost effective' (ie within my budget!) charger out there. Any suggestions?

[sailingdog]

Try Iota. They make a 90 Amp charger that is less than $300 IIRC.

The only thing that has higher charging capacity that I know of are the Xantrex Freedom series of inverters, which have 100 amp charging for the Freedom 20 inverter/charger.

[btrayfors]

The Iota is an excellent choice. Also, they come in various sizes, and you can put any two identical sizes together to double capacity. However, with your 400AH battery bank the 90A Iota would be more than sufficient.

Also, the Iota's put out a lot more average amperage than do other chargers of the same rating. They're terrific. Be sure to get the IQ-4 smart charge option, either built in or plug-in.

Victron and others make high amperage chargers, but they're a lot more expensive. I have a Victron MultiPlus inverter/charger which puts out 120A, but you really don't need this for a 400AH bank.

Bill

[sailingdog]

Welcome back Bill... hope you've been out sailing.

Cam and I have become Iota converts... I recommended one to a friend of mine and have been pretty impressed by the beastie.

[xort]

My boat came with a Xantrex 40 amp charger. Xantrex says I can add another one in series and double the charge. But what they won't tell me is how!

[btrayfors]

You can't add another one "in series"...that would double the voltage! Whether you can put two in parallel or not is debatable; not strange that Xantrex is mute on this point.

However, for the price of another Xantrex you can buy a larger Iota to do the whole job by itself, and do it better.

That way, you'll have a good charger (the Iota) and a backup charger (the Xantrex) for that unlikely time when the Iota fails :-)

By the way, you CAN connect two identical Iota chargers together to get double the capacity. But, for most of us with house battery banks less than, say 800AH or so, there's no need. A 75A or 90A Iota is all you need.

Bill

[camaraderie]

Ed...I find no reference in the manual to anything like that and it is counter intuitive to me that it would work. Where did you see this was possible or was it a phone conversation?

[sailingdog]

Do this any you'll either fry the batteries or not charge them at all..depending on how the Xantrex reacts. Putting two chargers in SERIES would double the voltage, as pointed out by Bill and Cam, pretty much ensuring that you boil the batteries.

Originally Posted by xort

My boat came with a Xantrex 40 amp charger. Xantrex says I can add another one in series and double the charge. But what they won't tell me is how!

[xort]

OK, I got the terminology wrong. I meant parellel, not series.
I got this info from an independant consultant on boat electrics and then e-mailed Xantrex and they told me directly that I could wire a second to double the capacity. I asked for a wiring diagram and have not received a reply.

[dshafer45]

I have a 450AH house bank, charged either by dual 80amp alternators on engine (need special engine bracket and dual belt pully for second alternator); or by Heart (now Xantrex) 2500 inverter/charger powered by a 5kw gen set. the Heart starts at 130 amps and ratchets down through a 3 stage charge process. has worked fine for 14 years.