Energizer CHFMWB-4 charger/4AA combo

[Buck91]

Well, I saw this for $21 the other day and decided to pick it up to check it out. So far, its nice; seems better quality than my BTY charger and NiMH AA's with more capacity. Shows the same amp draw in my 1xAA rebel light, but seems brighter?

Anyways, on the package it says its a smart charger, in the owners manual is says its a timed charger and I got the following response from Energizer's customer service:

Thank you for contacting Energizer and for your inquiry. I would be happy to assist you.

The CHFM charger that states that it has smart charging is a smart charger with a back up safety timer which automatically shuts the timer off in 8.5 hours.


Thank you for contacting Energizer. If you need further assistance, please do not hesitate to contact us.

Energizer Consumer Relations
1-800-383-7323
[email protected]
www.energizer.com
http://data.energizer.com/

I've only charged them up once, but I have some AAA Ultralast cells in there now. Is energizer being honest with me?




That brings up another question if anybody can jump on it... I've been running the same 800mAh Ultralast AAA pair of cells in my bike tail light for maybe 2 months now with probably 2hrs of run time total (I don't need the tail light as much). Anyways, I checked the voltage today out of curiosity; it was reading over 1.3v still! This seems high considering how long they have been sitting for. Are these some type of LSD NiMH cell?

 

[Marduke]

If it is the one with interchangeable faceplates, it does have Deta V cutoff, with a backup timer of 10 hours, and 55C temp cutoff.

 

[Buck91]

It does have the changable face plates, but its a 8.5hr cut off according to the manual. Cool, I guess it was a good deal for $21!

 

[johnny13oi]

Which charger is that exactly? Can't seem to find it on the internet, only seems to bring up the 15 minute charger.

 

[Buck91]

Its a 350mAh (for 2 AA batts) 4-bay charger. Claims to be a smart unit but only states anything about auto-shutoff at 8.5 hrs in the manual.

 

[Marduke]

It's probably this one, or a slight variation. There have been at least 2 editions of this charger. Perhaps you have a 3rd which hasn't made it onto their website yet.

 

[Buck91]

Intersting. The owners manual states model CHFM1 while the packaging states CHFMWB-4... Charger unit has CHFM1 stamped on it.

So there we has it. It is the one spec'd in the above PDF, therefore it has Delta V detection, and this one particualrly came with 4x2500mAh AA batts (hence the slightly different package model number perhaps?). Thanks Marduke for providing the datasheet!

 

[boydrkb]

Energizer Batteries and Charger confusion

I have a brand new Energizer battery charger Model CHFM1 with 4 triple-A (AAA 900 NiMH) brand new Energizer batteries. I put them in to charge and the charge lasted 6 hours. Without ever using the batteries I clicked the on button and the batteries went on to charge AGAIN for two more hours. Without ever using the batteries I again clicked the "ON" button and they charged for another two hours.

Confused and wondering if I have a bad charger or bad batteries.

Thanks for any help.

Boyd
[email protected] :thinking:

 

[SilverFox]

Re: Energizer Batteries and Charger confusion

Hello Boyd,

Welcome to CPF.

What you are doing is referred to as topping your batteries off. If your charger was a high output charger, you would run the risk of blowing them up. Since it is not a high output charger, you only run the risk of them venting and being ruined.

Are you charging on a chemical resistant flame resistant surface?

When the charger first turns on, there can be a time delay before the charger tries to detect the end of charge signal from the batteries. It looks like your charger has around a 2 hour delay. NiMh cells will often give a false peak early in the charge. The other thing that could be happening is that the charger is looking for the end of charge termination signal, but the charge rate is so low, and you are charging pairs of cells (instead of each cell separately) that the signal is so small it is difficult for the charger to pick it up.

I believe your charger is doing what it says it does, and the cells are doing what they say they should do. Your problem is that you have a bad operator...

Tom

 

[boydrkb]

Your expertise appears to be enlightened, and I thank you for your help.

While talking with the Energizer Battery guy at 800.383.7323 he indicated that the new AAA batteries must be at fault. He, as well as the instructions that came with the charger, said that "topping off" is fine, in fact, suggested. The energizer represenative also stated that this particular charger (CHFM1) had a detection delay of 15 minutes, thus determining that the batteries were faulty.

No where is there a warning about possible surface damage, I'll take heed, thank you.

Still testing, I completely drained the 4-AAA batteries with hopes of a satisfactory recharge. So far the charger has exceded it's initial six hour charge and is closing in on the "directions stated" nine hours charge time.

Bingo, nine hours and the batteries are charged, or should be. After letting them rest a couple of minutes I'm trying to charge to see if the green (charge) or red (charged) light is activated.

Note: I was also told that rechargable batteries have about a one and a half percent loss (without use) per day.

At least the batteries followed the charging "time" guidelines which is better than the original charge.

Thank again for your help.

Hope you have a bright New Year.

Boyd

 

[SilverFox]

Hello Boyd,

It is always "interesting" to come to a definitive diagnosis of bad cells based on their charging performance. Bad cells usually heat up during the charge, but you did not mention that earlier.

Cell health is determined by discharge capacity, and voltage under load. If you had told me that you are only getting around 700 mAh of capacity out of your 900 mAh cells, and that the mid point voltage during a 450 mA discharge was only 1.0 volts, I would have told you that your cells are bad.

I still am not sure that your cells are bad. It would be interesting to do some formal testing on them to see what condition they are really in.

I would suggest that you re-read your instruction manual. They reference "topping off" like this:

"If they (your batteries) are not used for a few weeks, "top them up" to be sure of a full charge."

This is a lot different than topping them up immediately following charging.

I must admit that I do stand corrected... :devil: Energizer has some cells that have a 1.5% or greater self discharge rate... If you do a search on high self discharge rate problems with 2500 mAh cells, you will find that a majority of the 2500 mAh cells with very high self discharge rates are Energizer, but they are not the only ones with that problem.

In general, if you have NiMh cells that are exhibiting a 1.5% or greater self discharge rate, you should place them firmly in the recycle bin... To be fair, when NiMh cells first came out, the self discharge rate was that bad, but current cells (with the exception of the 2500 mAh cells, and perhaps the 2700 mAh cells as well) have much lower self discharge rates.

Keep in mind that cells are rated by their discharge capacity. Charging times and capacity are interesting, but don't give you enough information to determine the health of your cells. It could be that your first charge with the AAA cells was with cells that were partially charged...

Tom

 

[boydrkb]

My turn, I stand corrected too.

I interpreted "If they (your batteries) are not used for a few weeks, "top them up" to be sure of a full charge." as topping them off.

My batteries never got "hot," only slightly above room temperature. I think my batteries are fine...Now I need to work on me.

Thanks again for sharing your wealth of knowledge and common sense.

Boyd