[IanRTL]

So I was able to purchase a nearly-new CTEK 3300US battery charger/maintainer from a neighbor last week. He sold his Harley and only used the charger for maintaining its battery. Therefore, he sold it to me for next to nothing. It seems to be very well-made and quite a nifty item to have on hand.

I made sure to read the owner's manual and all information on the CTEK website before making this purchase. My intention is to maintain my Autocraft Platinum AGM battery in the truck and also my wife's regular lead-acid Autocraft Gold battery in her car. The charger has a setting for smaller batteries that can be found in vehicles such as motorcycles and riding mowers, one for wet car batteries and one for gel-type and deep-cycle batteries such as Optima and Odyssey and other types of AGM batteries. It supposedly reads the type of battery its connected to and adjusts how it charges/pulses/maintains it relative to its type and charge level. I would, of course, use the last setting for my battery and the middle setting for my wife's car's battery.

I would use this mostly in the winter time about once a month or so to simply get a full charge on both batteries. Neither of us drive very much - mostly shorter trips - so the batteries in both of our vehicles don't get much of a chance to fully charge often. My question would be does anyone have any specific experience with CTEK chargers and is it truly safe to charge/maintain an AGM battery with this contraption?

 

[cccbock]

Read all this with a grain of salt.

I have understood for many years that the AGM batteries require a very low maintenance charge amperage (less than 1.0). That CTEK unit appears to have output above this threshold.

I have used a Battery Tender Junior (0.75amp) for many years on regular lead acid and AGM. Seems to get the job done, albeit slowly in many cases. I bought the BTJ because it was cheap, not necessarily because it was the best unit.

Having said all that, I would expect a battery charger company to know a lot more about charging them than me. I might do a little bit more research before I hooked it up. I'm sure the unit will do what you want it to do, you might just need to observe how it operates at first.

 

[rollinhonda]

I have the same model, excellent charger. They sense the load very accurately and will auto adjust for ambient temp changes.
The instructions are good, one the smartest and safest chargers you can use. By it's size you can tell it is not designed for fast charging.

 

[IanRTL]

I already tried it out on a friend's truck. The battery was dead from sitting too long (it's his beater truck) and he had to jump it to get it started. He brought it over to my house and I hooked up the battery (Duralast lead-acid) to the CTEK. It took about 14 hours or so for it to get in a full charge before it went into the maintain mode, but it did the job really well. I did notice that the CTEK unit itself does get rather warm when it's charging. It's nothing more than one would typically expect from an electronic device, though.

I did read in the manual that the average charging times for a lead acid battery are between 12-14 hours and for gel-type, deep cycle or AGM batteries, it's more like 22-24 hours. The only reasoning I can think of is exactly what you had said, cccbock. The charging/maintenance amperage on the last setting must be lower to account for the AGM battery. Also, I had read a review of the CTEK on Amazon from a reviewer who had used it on an AGM battery with great results. I may connect it to the truck on a day when I don't plan to go anywhere and see how long it takes to get in a full charging cycle.

 

[ridged]

I use a CTEK Multi US 7002 on my AGM battery in the winter because I drive very little. I put it on every couple of weeks just to keep it topped off. I am very happy with the charger.

 

[IanRTL]

I use a CTEK Multi US 7002 on my AGM battery in the winter because I drive very little. I put it on every couple of weeks just to keep it topped off. I am very happy with the charger.

That's exactly what I wanted to hear. Thanks, boss.

 

[ridged]

Glad to help. FYI, my battery is a Northstar AGM 24F, which was recommended by another Ian. After I purchased the CTEK charger, Northstar started selling chargers made by CTEK, so I am confident that it was a good choice, at least for my needs. Great battery and great charger!

 

[IanRTL]

I'm not sure who is the actual manufacturer of my Autocraft Platinum AGM, but there are only a few actual battery makers left. I have no doubt that it will be ok. Just out of curiosity, do you connect the negative lead of the charger to the negative on the battery or to a metal part of the engine? If on the engine, where? It says in the directions to use a metal ground on the body or engine block, but I don't see how using the negative on the battery could hurt.

 

[rollinhonda]

It is my understanding the purpose of attaching the final connection away from the battery is in case of arcing over a build up of gases from the battery.
A very rare occurrence even in the days of batteries that one had to pour distilled water into on a regular basis.
In terms of the lowest resistance you can't beat a direct connection.

 

[IanRTL]

It is my understanding the purpose of attaching the final connection away from the battery is in case of arcing over a build up of gases from the battery.
A very rare occurrence even in the days of batteries that one had to pour distilled water into on a regular basis.
In terms of the lowest resistance you can't beat a direct connection.

That's sort of what I was thinking, too. Being that AGM doesn't produce as much (if any) gassing, I would think it wouldn't be a problem.

 

[ridged]

I have an adapter attached to the posts of the battery and just plug the charger into the adapter. Quick and easy.

 

[IanRTL]

I have an adapter attached to the posts of the battery and just plug the charger into the adapter. Quick and easy.

Yep. My charger came with that as well. I don't think I'll be using it enough to permanently affix it to the battery, though. We'll see how it goes through the winter.