Good charger for gro 27 1000 cold crank Amps

[fkittson]

I'm replacing my start batteries this spring with two new group 27 lead acid bats. I want a steperate charger for them for redundancy. I would like a 30-40 amp three stage charger for them. Can someone recommend a good reliable unit to use. We are away from the boat a lot and want piece of mind.. It is a 31' power boat with twin merc 454's.

[fkittson]

No one has any suggestions.

[hellosailor]

Anything that is designed for marine use and ignition protected (since you have gasoline engines) should do. I think there are UL standards for both ratings. There should be plenty of brands in the power range you are looking for, so price, warranty, and size probably will be the deciding points. Do check the installation specs and make sure it has adequate room around it for proper ventilation and mounting, and adequate cabling.

And if you're ordering from a US source, check the delivery and customs brokerage situation before you place any order.

[skipmac]

Since these are starting batteries you will usually not need to add much charge so any good quality marine charger should work. I like the Victrons but a good deal can be had on an Iota. Although not a "marine" charger they work fine on a boat. You might want to get a model with the IQ4 option which adds an equalization mode.

I hear a lot of people having problems with Xantrex.

[btrayfors]

The Iotas, indeed, are wonderful little chargers; I have two of them. There are models from 15A to 90A. BTW, the IQ4 adds 3-stage charging, not equalization (though "equalization" is referred to in the Iota literature...it's not really equalization). HOWEVER, since it's a gasoline boat I would probably NOT recommend an Iota because they are not ignition protected or certified for marine use.

There are lots of good marine chargers out there. One of the best these days is the Sterling ProCharge Ultra, also marketed by ProMariner as the "ProNautic P". These are wonderfully sophisticated chargers and come in several sizes up to 60A.

Bill

[sailcruiser]

Look at Victron or Mastervolt. I have a small Victron but they have more powerful chargers. I picked up mine brought Jamestown Distributors.

SC

[skipmac]

Originally Posted by btrayfors

BTW, the IQ4 adds 3-stage charging, not equalization (though "equalization" is referred to in the Iota literature...it's not really equalization).

Never knew that. I just read their promo and assumed it was really equalization. I was in the middle of major overhaul and the original charger on the boat was dead so bought an Iota, plugged it in and forgot it.

Later checked the output and realized it was very low. Forget exactly but if I recall under 13V. Is there a setting or adjustment or is mine broke?

Originally Posted by btrayfors

HOWEVER, since it's a gasoline boat I would probably NOT recommend an Iota because they are not ignition protected or certified for marine use.

Didn't notice the OP's boat was gas so I hereby rescind my recommendation for the Iota in this case.

Originally Posted by btrayfors

There are lots of good marine chargers out there. One of the best these days is the Sterling ProCharge Ultra, also marketed by ProMariner as the "ProNautic P". These are wonderfully sophisticated chargers and come in several sizes up to 60A.

Bill

I hear a lot of strong recommendations for the Sterling chargers but they sure ain't cheap.

[btrayfors]

skipmac,

Yes, it is confusing. I wish Iota would change their marketing literature to make things clearer.

The IQ-4 is pre-programmed for the following voltages:

Bulk stage....................14.8VDC
Absorption stage...........14.2VDC
Float state...................13.6VDC

"Equalization" stage........not described anywhere.

I believe Iota's "equalization stage" to be just a repeat absorption or bulk stage voltage....14.2-14.8VDC for a short time. This is not a true equalization stage. Flooded batteries need at least 15.5-16.5VDC for true equalization, extended over several hours.

The IQ-4 preset voltages are not individually adjustable. However, it is possible by adjusting a single trim pot to "pull" the voltages up or down....all of them at once.

I have "pulled" mine up a bit for 13.8VDC float level (which also pulls the other two stage voltages up a bit). For me, with my T-105 golf-cart batteries -- carefully monitored -- this works better and gives me longer battery life.

The pot is accessible behind a piece of tape at one end of the charger...you don't need to open the case.

With your batteries fully charged, you should be seeing a float voltage of about 13.6VDC. If you're seeing less than this, I would suspect your voltmeter first. Be sure you're measuring voltage at the output of the charger.

Then, compare that to the voltage at the battery terminals. If there's a big difference, you either have resistance in the wiring (terminals, wire size, etc.) OR, possibly, batteries which have been compromised in some way.

It's also a very good idea to check your voltmeter against a known good one.

Bill

[skipmac]

Originally Posted by btrayfors

skipmac,

Yes, it is confusing. I wish Iota would change their marketing literature to make things clearer.

The IQ-4 is pre-programmed for the following voltages:

Bulk stage....................14.8VDC
Absorption stage...........14.2VDC
Float state...................13.6VDC

"Equalization" stage........not described anywhere.

I believe Iota's "equalization stage" to be just a repeat absorption or bulk stage voltage....14.2-14.8VDC for a short time. This is not a true equalization stage. Flooded batteries need at least 15.5-16.5VDC for true equalization, extended over several hours.

The IQ-4 preset voltages are not individually adjustable. However, it is possible by adjusting a single trim pot to "pull" the voltages up or down....all of them at once.

I have "pulled" mine up a bit for 13.8VDC float level (which also pulls the other two stage voltages up a bit). For me, with my T-105 golf-cart batteries -- carefully monitored -- this works better and gives me longer battery life.

The pot is accessible behind a piece of tape at one end of the charger...you don't need to open the case.

With your batteries fully charged, you should be seeing a float voltage of about 13.6VDC. If you're seeing less than this, I would suspect your voltmeter first. Be sure you're measuring voltage at the output of the charger.

Then, compare that to the voltage at the battery terminals. If there's a big difference, you either have resistance in the wiring (terminals, wire size, etc.) OR, possibly, batteries which have been compromised in some way.

It's also a very good idea to check your voltmeter against a known good one.

Bill

Thanks Bill,

I've had the Victron installed for months now so the details of the Iota are a bit fuzzy but I don't think I ever saw 14 V. I was running off a portable 4.5 KW generator (250V so a bit over 2 KW each 125V leg) so maybe the output was dirty and the Iota didn't like it? I did check the generator voltage and frequency are good but haven't hooked it up to a 'scope to look at the waveform.

I was using a Fluke meter and checked voltage at several points in the system with no large discrepancies. Not a calibrated meter but compared to my other Fluke and the Victron battery monitor and all three were within +/- 0.02V which seems close enough for government work.

Initially the batteries were almost new and no bad cells so don't think that was the problem. Since the Iota is now in my spares kit think I'll bring it home and test it here.

Thanks for the tip on voltage adjustment. Will let you know how it goes.

[djmarchand]

As others have said, since this is a starting battery you don't need to replace many amphours. A 6 amp Guest charger for about $75 will work fine.

David

[fkittson]

I just want something that I can turn on and leave on and not worry about it so I gues that I would need a three stage charger then.

[Sailor Doug]

Originally Posted by fkittson

I just want something that I can turn on and leave on and not worry about it so I gues that I would need a three stage charger then.

If you want not to worry batteries should be separated by a selector switch and you need a small dual out put small 10+amp charger. This protects you if one battery fails. All low cost ones would work I do not recommend Xratrex.