AGM charger question

[brianc]

I just some new AGM's and after installing them I went to flip the switch on my Charles 5000 30 AMP to the AGM setting only to find out that I didn't have the model I thought I did. I have the 93-12305E-B instead of the (newer?) 93-12305SP-A which has a selector switch for AGM, standard lead acid, and GEL. My prior batteries were standard lead acid Interstates and it does say 'Cell Type: L.A.' on the identification plate for the charger.

Anyway, what I'm wondering is if I kept the charger that I have now, what consequences will my batteries face as opposed to if I got a different charger?

Thanks, Brian

[ranger58sb]

Maybe not much consequence. Our charger has no separate setting for AGMs, but the manual does say to use the lead-acid setting.


You could check with both Charles and your battery manufacturer...


-Chris

[NewMoon]

It may depend on which AGM's you have. Some require voltages that are more different from those of flooded LA batts than others. Lifelines, as I recall from my research some years back.

My Balmar MC612 regulator had two different AGM settings. One that produces voltages appropriate for Lifelines (Balmar designation AGL), and another for Optimas (Balmar designation OPS). Since the voltages recommended for the Deka AGM's I had for a house bank were closer to the Optima voltages than the Lifeline ones, I set the regulator to the OPS voltages. Has worked well for me.

I think you'd want to know exactly what voltages your particular AGM's require, and compare them to what the charger puts out. For an expensive AGM house bank, I'd want them to be pretty close. Not as important for a bank used primarily for starting - my Cummins pickup has AGM's, and the Dodge internal regulator does just fine.

[Stu Jackson]

That's an old charger. I wrote this is 2002:

My understanding is that Catalina is installing either the Charles 5000 or 2000 models in C34s. I saw one recently on a newer Mark II, but sorry, didn't jot the model number down. Charles also makes a ferroresonant charger. The ferroresonant charger is NOT the one Catalina is installing.

In any event, the Charles website specs are very interesting. They claim a three stage charger, but their attached table of charging only includes "8 hour bulk rate output voltage" and "Float Rate Output Voltage." The bulk rate is either 14.4 for lead acid or 14.0 for gel, and the float is 13.5.

What this means is:

1. You have to buy a model that matches your battery type, since they can't change the output bulk charge voltage inside the units. No way to switch battery types in the future unless you buy a new charger!

2. There is NO mention of acceptance phase. It appears that the chargers do an 8 hour bulk charge and then switch to float. This is nonsense, and doesn't charge batteries properly. The bulk phase is altogether too long, and the important acceptance phase is missing!. The float phase voltage at 13.5 is between the recommended 13.2 and 13.6 volts.

The Charles [claimed 3 stage, NOT their ferroresonant] charger will still eat your batteries alive.

OTOH, the Statpower, now manufactured under the Xantrex name, will allow you to change battery types by a simple switch on the unit, and, therefore, charging voltages whenever you choose to change the type of your batteries. It also includes all three phases reqired for proper charging, plus an equalization mode for wet cells. The bulk phase is not the incorrect preset 8 hours, but is based on the charger's sensing of the state (voltage) of the batteries with a time limit of about 20 to 30 minutes.

The only conclusion I can draw from Charles claiming that their models 5000 and 2000 are a three stage charger is they have included OFF as one of the stages! OFF is where it belongs, all the time.

For those of you with Charles chargers, be real careful about switching to gel cells because the boats came with wet cells. The 14.4 voltage for wet cells will fry gel cells which only need 14.0 or 14.2 volts at the bulk phase [not 14.4 volts like wet cells do].

[a64pilot]

First a 30 amp charger is no where large enough to get the advantage of an AGM bank, better to have at least twice that, and I'd get a charger that you can change the charge voltages to a custom setting, you never know, you may be going Life-Po one day and if you can change the voltages to custom ones, maybe it won't be obsolete in a few years


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[Maine Sail]

Originally Posted by brianc

I just some new AGM's and after installing them I went to flip the switch on my Charles 5000 30 AMP to the AGM setting only to find out that I didn't have the model I thought I did. I have the 93-12305E-B instead of the (newer?) 93-12305SP-A which has a selector switch for AGM, standard lead acid, and GEL. My prior batteries were standard lead acid Interstates and it does say 'Cell Type: L.A.' on the identification plate for the charger.

Anyway, what I'm wondering is if I kept the charger that I have now, what consequences will my batteries face as opposed to if I got a different charger?

Thanks, Brian

AGM batteries have varying voltages for absorption & float. This is why "dip switch" chargers are usually very poorly suited to charging AGM's unless one of the settings matches your AGM's.

You will really need to know what your battery maker recommends for absorption & float.

For example:

Lifeline AGM's = 14.4V & 13.4V
Odyssey TPPL AGM's = 14.7V & 13.6V
Firefly AGM =14.4V & 13.2V
Mastervolt AGM = 14.4V & 13.2V
Full River AGM = 14.7V & 13.7V
Rolls AGM = 14.7V & 13.7V
East Penn/Deka = 14.6V & 13.6V
US Battery AGM = 14.4V & 13.4V
Trojan AGM = 14.4V & 13.5V

Also keep in mind that every one of these manufacturers recommends temp compensated charging.

[brianc]

Thanks for the info all.

I have Full Rivers, which as Maine Sail mentions, the manufacturer recommends 14.7V & 13.7V for absorption and float.

The charger I have looks like it does 14.5V & 13.6V for lead acid which is actually closer to the battery manufacturer recommendation for my AGMs than if I had the model with the AGM switch (14.2V & 13.4V.)

@Stu - besides the three stage charging issue, you mention this charger is old, and it is a 2002 model. Do you think it's worth replacing based on that alone given the new batteries?

For whatever reason I can't find the manual for my model online so I'll have to go get it off the boat today to see what it says about temperature compensation and bulk charge rate, I thought it adjusted based on charge state and didn't just do a straight 8 hour bulk charge (it's very likely I'm wrong though.)

@a64 - fill me in, what is Life-Po?

@Maine Sail - would this charger output be consider 'close' at 14.5/13.6 vs recommended 14.7/13.7?

Right now I turned off all the DC power and the charger because I don't want to damage the batteries...it sounds like there may not be an issue leaving it on for a week or two to maintain charge while I look for a new charger...does that sound ok?

Thanks again, Brian

[Stu Jackson]

Originally Posted by brianc

@Stu - besides the three stage charging issue, you mention this charger is old, and it is a 2002 model. Do you think it's worth replacing based on that alone given the new batteries?

Brian, I followed that up with this in 2005, down below these links. Charles was never very good.

You really should get a new gen charger, like the ones Maine Sail often suggests.

Wiring a new charger From Maine Sail:

Marine Battery Chargers - Installation Tips & Considerations | SailboatOwners.com Forums and

Installing A Marine Battery Charger Photo Gallery by Compass Marine How To at pbase.com

*************************
*************************
In an effort to be fair to a manufacturer, a recent post has noted that new (2005) boats are still being built with Charles Chargers. This particular thread/post, in discussions above, had noted (a few years ago) some research on the negative aspects of the Charles chargers based on available information at that time.

It appears that Charles has improved their product line.

This consists of two things: being able to switch between battery types AND having a true 3 stage charging capability. (Equalization is separate, and doesn't appear in the catalog, or I just haven't read the whole thing yet!)

I recommend that you read the following newer thread for an update, and it includes links to Charles' website and product line:

http://c34.org/bbs/index.php?topic=2143.0

I also recommend that you check your charger on "newer" (say a 2003-4)but not necessarily "newest" (late 2004-5) boats, since I don't know when Charles started making the updated models with battery type switching AND the 3 stages of charging, nor do we know when Catalina started installing the updated products. The Charles models numbers appear to be the same, but the guts, and, therefore, the operation, may be different.

If you don't have the battery type switching on a "newer" Charles charger, I doubt you'd have an effective three stage charger, in which case the recommendations in this thread to use Statpower (Truecharge, Xantrex) would still apply.

[a64pilot]

Life-Po refers to Lithium Iron Phosphate, I may not have the acronym correct.
But the idea of being able to write your own voltages covers you if new battery technology come out that requires different voltages. We don't know what will happen inn five or ten years .
That and different chargers handle when they switch differently. My Magnum allows me to program an amp draw that triggers the switch to float as well as a max time in absorb, while my Sterling doesn't have that feature


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[brianc]

Originally Posted by a64pilot

Life-Po refers to Lithium Iron Phosphate, I may not have the acronym correct.

Oh, I get it, I was reading it as 'Life' instead of elements on the periodic table ;-)

[brianc]

Originally Posted by Stu Jackson

Brian, I followed that up with this in 2005, down below these links. Charles was never very good.

You really should get a new gen charger, like the ones Maine Sail often suggests.

Thanks, I'll start looking, it sounds like a new charger is the best option going forward.

[Quickbeam]

Nice data from Maine Sail on the different voltages for AGM batteries.

Remember the readings are supposed to be at the battery terminals, not at the output from the charger. Check the condition and size of the older wires, and clean all the connections!

If you are getting a new charger, get the temperature sensors. Charging rates and voltages change quite a bit due to temperature fluctuations.

[transmitterdan]

Brian,

Until you get a new charger you will not burn up your batteries if you charge your new bank with the existing charger. Just turn off the charger before leaving the boat. Leaving AGMs sit for weeks not fully charged isn't a good idea. But one advantage of AGM is they retain their charge a lot longer than flooded batteries.

[ranger58sb]

Originally Posted by transmitterdan

Leaving AGMs sit for weeks not fully charged isn't a good idea. But one advantage of AGM is they retain their charge a lot longer than flooded batteries.

I've purposely left our batteries uncharged over a full winter (~4 months, in that case) on the hard. Starting with fully charged Odysseys, they showed only about .1 voltage drop over that whole period.

That was 4 years ago... so our oldest bank is... even older.. and we're due for another winter on the hard this year. I intend to do no charging once we're hauled and blocked, but I also intend to monitor the charge level on our oldest bank (finished 10 seasons, now).

-Chris

[transmitterdan]

AGM self discharge rate is very low. Please don't misunderstand what I said. There is no need to keep a charger running on AGM batteries. But if they are not fully charged initially then leaving them in a state of low charge for a long time is not a good idea. So at the end of the season charge them fully and then they are find for 3-4 months.