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Ritchie_Uk 10-27-2021 02:57 PM

Duracell Battery Charger - CEF22GBL-3
Hi there - I am searching for a Duracell CEF22GBL-3 Battery Charger

Its nothing SPecial, but on this Charger, there are 4 AA Bays and 1 9Volt Bay.
The 9 Volt has stopped working, but the Rest seems Ok.

1. Does anybody have a Schematic for this please, as I dont want to throw it away?


sam_sam_sam 10-27-2021 03:41 PM

Re: Duracell Battery Charger - CEF22GBL-3
Post some pictures of the board both sides of it

Ritchie_Uk 10-27-2021 07:38 PM

Re: Duracell Battery Charger - CEF22GBL-3
Hey Sam_Sam_Sam I will do,

I have been engrossed in trying to repair this.
It seems to have a Processor IC.

This is the Model, well mine is a lot older, but looks almost identical

Will Post Pics in a minute


Ritchie_Uk 10-27-2021 07:52 PM

Re: Duracell Battery Charger - CEF22GBL-3
4 Attachment(s)
Here are the Photos

In Pic 2 D5 and Q1 have been taken off

The Main Semiconductors are

Big IC - IC EM78P374NS024J

Input Area - AS393M
Input Area - A04409

I cant seem to find Schematics anywhere for this unit.


sam_sam_sam 10-28-2021 12:23 AM

Re: Duracell Battery Charger - CEF22GBL-3
This part number does not come back with anything

Either it is in-house part or some other issue

redwire 10-28-2021 12:26 PM

Re: Duracell Battery Charger - CEF22GBL-3
EM78P37x is Elan Microelectronics 8-bit OTP MCU, I think 4KB ROM for the 374.
It's a MCU custom programmed for this application. You'd have to draw the schematic, I've never seen anything published out of china or taiwan for fear of copying.

There's really no solder on the through-hole pad by R49 to B1N, and bad soldering to big through-hole parts is a common problem to look for.
How are the electrolytic capacitors? It is powered by a wall wart? Wondering if it has the 9V power it needs.

Ritchie_Uk 10-28-2021 05:42 PM

Re: Duracell Battery Charger - CEF22GBL-3
Hi Sam and Redwire - Thankyou

I have gone through every component, and they seem fine/

The 9V section isnt working.

The EM7 seems to be here and "Seems" to look similar

Its Cheap and throw away, but I dont want to throw it away, even tho I already have some new chargers I have ordered.

Ritchie_Uk 10-28-2021 05:44 PM

Re: Duracell Battery Charger - CEF22GBL-3
ps I am running the Charger with my PSU, its 12V and about 1 Amp

Ritchie_Uk 10-29-2021 09:50 PM

Re: Duracell Battery Charger - CEF22GBL-3
What’s useful?

redwire 10-29-2021 10:08 PM

Re: Duracell Battery Charger - CEF22GBL-3
Just a spammer.
Does the charger have a single 9V port? You could follow that back to the PC board and see what mosfets they are using for switches there. I imagine it's easy to connect one backwards and maybe that damages a unit?

Ritchie_Uk 11-02-2021 04:50 PM

Re: Duracell Battery Charger - CEF22GBL-3
Thankyou Redwire

Sorry for the delay in responding, but I have had so many shifts in the last week.

I need to focus on the circuitry,, and try and work iut why the 12 Volts befor the diode is Ok, then After the diode, which I am unsure of they type, possibly a Zener is Zero volts.

It seems like the main IC is really complicated for what it does, as I have had the charger for at least 10 years.

The clue could be that I have had so many problems with the 9 Volt section anyway.

It’s incredibly complicated for a small unit.
I remember reading the fact that Duracell don’t build there own units, but the exact clone is under another name,
I forgot but will search my web history

Will keep yiu updated


Ritchie_Uk 11-02-2021 04:53 PM

Re: Duracell Battery Charger - CEF22GBL-3
ps Redwire it can also Charge AA and AAA and the massive ones no one can ever remember what they are called ��

redwire 11-02-2021 05:09 PM

Re: Duracell Battery Charger - CEF22GBL-3
Duracell does have a long "guarantee" on these I think 7 years so maybe hit them up for a replacement. Not sure how they are in the UK for consumer protection.
Wild guess is whatever modulates the 12V down to 9V, might have croaked. Like a small mosfet. But the charger also has some safety routines in the MCU so it will not initiate charging unless safe (i.e. sees say 6V) and the current is not too high. So your charger circuit might work fine unless you fool it properly with a dead 9V battery, or spoof it.

Ritchie_Uk 11-02-2021 05:45 PM

Re: Duracell Battery Charger - CEF22GBL-3
Hi Redwire

Bless, you this Charger is the Workbench first thing in the morning, as I wont let it beat me.

I will keep you updated, as I am off for 2 days now


Ritchie_Uk 11-04-2021 11:56 AM

Re: Duracell Battery Charger - CEF22GBL-3
Hi Redwire - As promised an update
I have made contact with some helpful people who will attempt to source a schematic for me,
If they manage, I can pass whatever data and info if you need.


Ritchie_Uk 11-08-2021 09:40 PM

Re: Duracell Battery Charger - CEF22GBL-3
Hey Redwire - The Unit is Working now as I believe the Diode I removed was intermittantly breaking down.
Under normal conditions I found no components Shorted / Open, which was frustrating.

The only thing I havnt tested is whether it shuts off when the Battery is Full.
The 9 Volt is Charging, but the Charging light stays on.

Its amazing how complicated the Logic section is.

I still havnt recieved the Schematics yet, but if you need any Schematics, and I have many please just ask, as I have 1000's and 1000's

Regards and thanks for your response

Stay Safe

Ritchie_Uk 11-08-2021 09:41 PM

Re: Duracell Battery Charger - CEF22GBL-3
ps - If you look at Photo 1 of 4 it was Q1 and the Diode just above it that was breaking down

Sam-Sam-Sam also I really appreciete your help as well

redwire 11-10-2021 02:04 PM

Re: Duracell Battery Charger - CEF22GBL-3
I bought an Energizer ENC-2A car battery 2A charger/maintainer and played around with it and found out the software was terrible.
It would not start charging unless the battery passed a little test it did. Firmware looked at battery voltage and tried charging for a couple seconds and if it was not satisfied, it went into a fault/lockout condition and you'd have to reboot it to do anything else.
I took it back to the store for a refund because it would not charge gel cells or anything sulfated, and it also had a bunch of software timers where it would charge for a minute then think it's done.
It's not going to burn the house down or wreck the car so why all the bimbo firmware? They must get paid a lot whoever designs these in china.

Ritchie_Uk 11-11-2021 08:39 AM

Re: Duracell Battery Charger - CEF22GBL-3
Redwire oh really?
Weird that they used software, would an Op Amp or Comparitor have done the trick?

Ansmann and a Dlyful - The Ansman is really over priced and not great if you need advice or support.

The Chinese reverse engineer things, some of the designs I have seen were so bad that we sent people over to oversee them

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