NiMH AA slow charger recommendation - Page 1
Forum section: electronics / general

author: Circlotron
author_rank: Super Contributor
timestamp: September 05, 2017, 03:19:08 am
content: I want to get a charger for 4 AA NiMH cells, one that charges and sense each cell individually, not as many do, in pairs, and then goes to a float charge using short sharp high current pulses. Maybe even one that discharges the cell first, and maybe even gives some kind of capacity readout. Not absolutely necessary though. Overnight charging is fine. Already got a 15 minute charger and besides being a bit hard on the cells, they have to be in top condition or it either wont charge or it terminates early.Sooo.... any recommendations on what I should look at? This is for occasional domestic use only.

author: IanB
author_rank: Super Contributor
timestamp: September 05, 2017, 04:06:00 am
content: My favorite charger for this purpose is the Panasonic BQ-CC17.Panasonic chargers in general seem to be well designed, and are also good for Eneloops.

author: retiredcaps
author_rank: Super Contributor
timestamp: September 05, 2017, 05:22:54 am
content: Happy with my Charger Opus BT-C700. I had it for a year now.https://www.eevblog.com/forum/chat/aaaaa-battery-charger-suggestions/msg1104710/#msg1104710

author: Circlotron
author_rank: Super Contributor
timestamp: September 05, 2017, 06:03:31 am
content: ^^ I didn't know about that thread. Thanks. 👍

author: Audioguru
author_rank: Super Contributor
timestamp: September 08, 2017, 03:41:28 am
content: For at least 5 years the Eneloop Ni-MH batteries have been sold. All major battery manufacturers make Eneloops that are sold pre-charged because a charge lasts for one year. They say they do not need a trickle charge but if you must use it then limit it to 1/40th the mAh rating.

author: bitseeker
author_rank: Super Contributor
timestamp: September 08, 2017, 07:25:03 am
content: Lots of info, reviews, tests on batteries, chargers, etc. athttp://lygte-info.dk/. Include graphs of charging/discharging behavior and more.

author: David Hess
author_rank: Super Contributor
timestamp: September 08, 2017, 05:04:39 pm
content: I have a MAHA C-9000 which will do everything you referred to however I do not recommend it because the user interface is horrible. The design is also poor; I had to replace the aluminum electrolytic decoupling capacitors on mine because they were not derated properly.The much simpler MAHA MH-C401FS has a 4 hour charge mode and charges each cell individually. However it also suffers from the aluminum electrolytic capacitor issue.

author: ConKbot
author_rank: Super Contributor
timestamp: September 08, 2017, 08:24:21 pm
content: If you're going to charge a Ni-MH cell either do it at a trickle where there are no smarts required, and it doesn't matter if the cells are in series or not, or do it in two hours or less. The reason is that for 'fast' charging (not trickle charging) once the cell is full, the voltage of the cell drops once it starts to heat. The charger has to catch this drop in voltage to know its done. So called '-deltaV' termination. The slower the charge rate, the less heating, the less voltage change, and the more likely a missed termination is to occur, and the charger will either time out, or sense the increased temperature once the heat makes its way back to the temp sensor.Personally I use a MH-C801D charger, easy, shows individual cell status, and only two options, fast or slow charge, and condition the battery or charge only. Plus it does 8 at a time, so less fiddling with changing batches.

author: eugenenine
author_rank: Frequent Contributor
timestamp: September 09, 2017, 12:24:43 am
content: Don't trickle charge NiMH or charge in 15 minutes, they don't like either extreme, though the 15 minute chargers will kill them much faster.I have a maha c9000 but one bay is getting bad, I'm thinking of getting a nitecore now.

author: eugenenine
author_rank: Frequent Contributor
timestamp: September 09, 2017, 12:27:05 am
content: Quote from: Audioguru on September 08, 2017, 03:41:28 amEneloop is a brand that only one manufacturer makes, previously Sanyo but bought by Panasonic, they have been sold for over a decade, I have some going back to 2006.the type of battery sold pre-charged by multiple brands is called low-self discharge.

author: sasa
author_rank: Regular Contributor
timestamp: September 09, 2017, 06:29:19 am
content: Quote from: Audioguru on September 08, 2017, 03:41:28 amIn addition to already mention by Eneloop batteries, they have extremely low self-discharge characteristic. Once charged, they will retain down to 70% up to 5 years. Personally I prefer 3th generation last made by Sanyo with his 4 hours charger NC-MQN09W and I'm extremely satisfied with, using it for years.

author: MacMeter
author_rank: Frequent Contributor
timestamp: September 10, 2017, 12:17:23 am
content: Quote from: David Hess on September 08, 2017, 05:04:39 pmI own the MaHa C9000, what are the negative symptoms of a bad "aluminum electrolytic decoupling capacitor". What should I look for or be aware of?

author: David Hess
author_rank: Super Contributor
timestamp: September 10, 2017, 03:21:46 pm
content: Quote from: MacMeter on September 10, 2017, 12:17:23 amMine started randomly resetting and then resetting whenever charging started. It may have also overcharged some cells destroying them before that.When I tested the pulled capacitors, they were unambiguously shot with low capacitance and of course high ESR. I replaced them with better aluminum electrolytic and solid tantalum capacitors.

author: eugenenine
author_rank: Frequent Contributor
timestamp: September 10, 2017, 03:50:17 pm
content: Mine always thinks there is a cell in one slot so it gets stuck prompting for what to do with that slot.