Duracell CEF14N NiMH battery charger - need R28 value - Page 1
Forum section: electronics / repair

author: Hogwild
author_rank: Regular Contributor
timestamp: November 18, 2017, 12:03:27 am
content: Hi friends:My Duracell CEF14N (the old model, looks like this) died a while back. See attached image for photo.I opened it up and first noticed a bulging cap. Shame Duracell! I bought some replacement caps. Unfortunately, I didn't notice until now that the R28 surface mount resistor was burned. When I touched it, it disintegrated into dust and so now I can't see the value of R28. I Googled, but found nothing at all on this charger, maybe because it's older.Does anyone know what value and physical size that resistor is? I'd like to save this thing if I could. It was a great charger when it was working.Thanks in advance.

author: Hogwild
author_rank: Regular Contributor
timestamp: November 18, 2017, 09:28:53 pm
content: Update: It looks like the R28A resistor across from it also may be blown. It's hard to tell. I will report back my findings as soon as I get them.

author: IanB
author_rank: Super Contributor
timestamp: November 18, 2017, 10:16:05 pm
content: If it can only charge batteries in pairs I think I would retire it and replace it with a charger that monitors each battery individually. Pairwise charging was a cost saving measure that should not be needed in modern chargers.

author: Hogwild
author_rank: Regular Contributor
timestamp: November 19, 2017, 03:54:46 am
content: I prefer not putting things in the landfill. Plus, it's a challenge.

author: Hogwild
author_rank: Regular Contributor
timestamp: November 19, 2017, 07:31:02 pm
content: IanB:Can you point out any teardowns or analsyses of newer chargers which charge each battery individually? I'd like my next charger to last longer than this one.Quote from: IanB on November 18, 2017, 10:16:05 pm

author: IanB
author_rank: Super Contributor
timestamp: November 19, 2017, 07:59:49 pm
content: Quote from: Hogwild on November 19, 2017, 07:31:02 pmForum member HKJ has a webpage with reviews of many chargers here:http://lygte-info.dk/I personally own and use the Panasonic BQ-CC17. It is a smart, "overnight" charger which charges the cells individually and has good management of the charging process. I cannot say how long it would last, but Panasonic seems to be a reliable brand with quality products. I have other Panasonic chargers and they have all worked well (which is more than I can say for other brands of charger).HKJ has a review of it here:http://lygte-info.dk/review/Review%20Charger%20Panasonic%20BQ-CC17%20UK.html

author: Hogwild
author_rank: Regular Contributor
timestamp: November 20, 2017, 03:12:53 am
content: I noticed that SMD resistors R28 and R28a appear to be burned or singed. Damaged, at least. Also, capacitor C5 on the beige side seemed be bulging a bit. I have extra capacitors, but no resistors. If I get some resistors soldered in, I'll post back and share my results.Thanks for that site. Wow, that's unbelievable how many chargers and batteries he's tested.

author: floobydust
author_rank: Super Contributor
timestamp: November 20, 2017, 03:17:05 am
content: Another method is to find the controller IC datasheet/app notes/eval board and see what values are used.

author: Hogwild
author_rank: Regular Contributor
timestamp: December 06, 2017, 03:35:17 am
content: Okay, I got it fixed. In my case, it was a capacitor. I took some photos and wrote a quick guide on iFixit.Duracell CEF14N nimh charger-not charginghttps://www.ifixit.com/Guide/Duracell+CEF14N+NiMH+Battery+Charger+-+Not+charging/100409