What Charger?

[Charlie]

Hi All:

I'm looking for a battery charger for my boat. It will be run off of a 3.5 KW generator and/or off of shore power. It will be charging a bank of 4 6v batteries. It is possible that I might add another 2 batteries in the future. I would like the charger to have temperature sensors. I plan on using the alternator to charge the starting battery and the generator battery. I'm thinking that one of these chargers that will allow multiple moduls to increase the charging capacity would be a good idea. My theory is to use the generator as the main charging system for the boat and the engine alternator as a back up. Can any of you guys let me know what brand works for you and why.

[ssullivan]

Charlie,

I'm doing as you say right now. I have a 5KW genset and 4 Trojan T-105's (420AH) charging off it. I use twin (2 at once) Iota brand 90 Amp smart chargers with great results. The max to charge (with my usage) is always less than an hour. Usually closer to 40 mins. You'll find these chargers are far less expensive than most, but work very well. I got mine at Jackrabbit Marine in CT.

[btrayfors]

Charlie,

Here's another vote for the Iota chargers. They are very well built, relatively inexpensive, and incorporate some interesting features to keep your batteries healthy (like pulse charging, which they don't advertise).

They come in different sizes from 90A down to about 15A I believe. Two identical ones (i.e., same capacity) can be paralleled, like ssullivan is doing.

Be sure you get the IQ-4 regulator: it's a $35 option which turns these into multistage smart chargers.

Bill

[Charlie]

Sean and Bill:

Thanks for the recomendations on the Iota. I've looked at them and find them regularly on E-Bay. Do they have temperature sensor devices available? I'll keep my eyes open for them.

[knottybuoyz]

Originally Posted by Charlie

Sean and Bill:

Thanks for the recomendations on the Iota. I've looked at them and find them regularly on E-Bay. Do they have temperature sensor devices available? I'll keep my eyes open for them.

IOTA Engineering Emergency Fluorescent Ballasts and AC/DC Power Converters

I have the DLS55 that I bought off of MarkPJ and it doesn't have battery temp sensing capability. I don't know about the other models.

[btrayfors]

Charlie,

I don't know about the temp sensors, but I don't think so. And, I don't think they're required, if what I've been told by an engineer selling them is right.

I bought a 45A model a couple of years ago from Associated1 on eBay. Found them to be reliable. I also managed to have a long chat with the seller about six months ago when I was researching various charge methods.

He told me that the reason the Iota doesn't have settings for flooded/gel/AGM or a temp sensor is that it's mode of operation works with any battery without danger to the battery. Apparently, they use a fairly high voltage for a fairly short period of time -- a kind of pulsing -- which cannot overcharge or cook the batteries.

And, these chargers are underrated compared to others. They will put out full rated power continuously, if the batteries can take it.

While I haven't yet verified this either by testing with an oscilliscope or by chatting with the factory engineers, I can tell you that mine has been perfectly reliable in keeping my bank of two T-105s well charged (I use these for my ham radios), without overcharging. And, very important to me: they put out very little RFI, so don't destroy your radio signals like many chargers do.

Because I'm in the midst of some battery pulsator tests, I happen to have eight different smart marine chargers in my shop. This includes those made by ProMariner (2 models), Heart, West Marine, Iota, and Guest, and 2 lesser known brands. If I had to toss them all out and keep just one, it would be the Iota....hands down.

Now, none of these can compare with my Victron 120A charger/2500 watt pure sine wave inverter on the boat, but that's another story altogether :-))

Bill

[Charlie]

Thanks Rick:

I guess that Is a luxury I can do w/o. Did you see that joike that I left on the Christmas Wish list.

A friend uses it in jest on the job site whenever there is a "tough" task that someone needs to accomplish. "If you were half the man that your mother is I could lift that lumber up no problem."

[ssullivan]

Charlie, I have no temp sensor either, and I can say that in close to a year of operation, with 1 full drain/charge cycle per day for 6 months, I've only had to add about a teaspoon of distilled water to my batts. The Iota 90's running into the Trojan T-105's definitely don't cook the batteries, but they do charge them very quickly.

I chose the DLS-90's (90 AMP) because my theory was that it is more expensive to run a genset longer than it is to really beef up your charging capacity. If I had to, I could blast 180A/H into the Trojans. I've never had to, except once when a charter guest used their hairdryer off the inverter.

The IOTA is good because it's a "set and forget" type of operation. No thinking. Just check the fluid level in the battery once in a while. Also, I have no sulphation from those little blasts the charger does from time to time.

I could go on for hours. They are one of my favorite purchases.

[Pblais]

My theory is to use the generator as the main charging system for the boat and the engine alternator as a back up.

The only issue you run into is the square waves coming off the generator. Square wave tend to have spikes on the edges and it's the spikes that will eventually trash the charger little by little. The better the charger and the better the generator the longer all this holds up.

Since I don't charge with a genset I can't give you anything specific about makes and designs. I do know the Xantrex shore cxharger I have will accept square wave input so it does both shore charging and geneset charging and has temp sensors. You could then just have one charger.

In that unit no temp sensor defaults to a hot setting of 104 F so it does not put out more when it's cool and the batteries would accept more. That would be the plus of the sensors. Other units may have a jumper setting you can set.

[btrayfors]

Paul,

Most marine generators have a sine wave (not square wave) output. This includes Northern Lights, NextGen, Panda, etc. It also includes the little gasoline-driven Honda gensets.

Bill

[Latitude9.5]

Yea i just got an Iota 55 amp, it rocks

[Pblais]

There is sine wave and there is modified square wave (the most common). Often they state it as modified sine wave to make is sound better. Most marine generators do not generate a pure sine wave output. It's really hard to make pure sine wave power. None of those you list are perfect or even great at it and some are far worse than others. Some have other qualities to make them very desirable however beyond just the quality of the power..

Generated AC power has it's problems and I wouldn't say it's bad because it is a way to make large amounts of power quickly to the extent nothing else comes close. Shore power isn't the greatest in all places in the world either. It does however exploit the devices connected and it is important to be mindful of it. Square waves alone wouldn't be so bad were it not for the implicit spikes that come with it.

[btrayfors]

Actually, it is my understanding that the output of marine diesel generators and modern industrial generators pretty closely approximates a good sine wave, not a "modified sine wave" and certainly not a "square wave".

See, e.g., http://www.pwmall.com/InverterGenerators.aspx

Look particularly at the oscilliscope shots in the middle of the page.

It's not difficult at all to create good sine wave output, witness the virtual explosion of inverter products on the market with "pure" sine wave output.

The real problem with generators has more to do with voltage regulation. You can buy special versions which greatly improve voltage stability, and virtually eliminate the high voltage spikes and surges which can be damaging to some equipment (like many battery chargers).

BTW, the Iota chargers have a very wide tolerance for input voltage fluctuation, and are therefore much better able to mate with onboard generators for efficient battery charging.

[Charlie]

Thanks for all the input fellas,

I think that the Next Gen and the Iota is a good match. I'm trying to decide what size Iota will be right. Using Caldwell's rule of thumb of 1/4 of the amp hours I should be fine with a pair of 55 amps and if I want to step up a little a pair of 75 amps should be fine.

Sean
Thanks for the first hand info. Appreciate it.

Bill:
Your Testimony to the Iota speaks wonders I looked at the Victron and thought about it for a minute but realized that it was overkill for my purposes.

Paul:
Thanks for the questions that I probably would not even have thought of.

I've decided on the Iota's and now need to decide what size. 2- 55 amps
or 2 - 75 amps

I'll see what the price does.

[ssullivan]

Charlie,

As for sizing, if you call up JackRabbit Marine in Stamford, CT, they will get all sorts of info from you and help you select the appropraite size charger(s). They'll need to know your battery bank capacity and the generator's *continuous* rated output. They'll help you get the right size.

Also, their prices were the lowest I found onilne, so I went with them. Great customer service and they went the extra mile by doing free "consulting" work in heping choose the right equipment for my setup.