EEVblog #35 - Inside The Varta 15 Minute NiMH Battery Charger




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HAL900032: hhehe I almost fall off my chair everytime you say Hi at the beginning:) got pretty strong coffee down there huh?!

Олег Макаров: Русский выучи dibel

Beaches south of L.A.: I love this guy. "Is there something dodgee going on?"

Power Max: Gees, pushing 8A charging current through a small poor AA battery! 4C!?!? modern Lipos take like 2C absolute maximum!

peter bridge (Thecrakedminecraft): Is vata a good brand? I live in the uk so I don't know.

Tom Hoehler: No way they will get 1000 cycles out of these poor AA cells. That 7-8 Amp pulse current charge will kill them quickly. I think they would probably give you 100 cycles, that might be cost effective. Thanks for the video, Dave.

Normsweb.com: I have a Bosch drill charger that can charge a 12v 1700mah NiCd/NiMh pack in 15 mins, It apparently uses a system called 'fuzzy logic' to determine exactly how much charge the pack needs and will deliver exactly that amount of charge and no more. The pack never gets hot, and according to the Bosch literature, Battery packs charged in a Fuzzy Control charger will last way way way longer than packs that are charged in a standard 'delta voltage' charger...  Would be good if Dave (or indeed Mike) could explain more about how fuzzy logic chargers work.

zwz • zdenek: I thought bullcrap to myself at first. Then I saw the beefy wall wart... Maybe? And I was in fact surprised when I instantly recognized those SMD MOSFETs (5A each, 2 per line) and knew there was something to it after all. But as everyone says, it can't be all truth because of the cell's over-estimated life.
Dave, it's 5 years now. Would you give us a follow-up on how long did those cells last?

Daniel Sauvageau: I had one of those Energizer 15-min charging kits with batteries... I don't think I got more than about 100 cycles out of those before the batteries started dying. 4C is much too harsh.

On that charger, battery detection was done by detecting current across contacts and I'm guessing the charge cycle control was done entirely based on I-V curves. When a battery ends up too far off the expected I-V curve, the charger flashes the failed battery code.

The PCB contacts behind the "spring thingies" on my charger were actually a switch to select AA vs AAA charge current. What I ended up doing with my fast-charger is cover the battery size detect pads to make the charger operate in permanent AAA (lower current) mode so my AA batteries would not warm up anywhere near as much.

Frederick Roels: Haha, he has seen to manny star trek and stargate series/movies, Got to love it!

TheSuperGZ: Varta is owned by Johnson Control

God Emperor Lionel Lauer: Learn how to read. He's right, you're wrong.

redtails: 3:26 Hope for you it won't last its rated spec, else you'll be eating those batteries!

TheCentralServices: And where is the Dilithium crystal?

Americanstu: Do you have to use the " labeled" 15 minute batteries with this charger or can you use the charger with any NiMH batteries? I have been using Eveready 2450 mAh with my Varta charger, which may be an earlier version of the one that you demo'd as it only has 1 LED per 2 batteries inserted however the LED will go on when only one battery is inserted...thank you for your post!

David Adams: You might want to watch again with your glasses on. His math is spot on. He didn't write 10C, he wrote C/10. That's 1/10th the charge rate, and 10 times as much time. A battery that has a C rate of 1 hour has a 4C rate of 15 minutes. gramar tip: It's "albeit" not "all be it".

Charles McCune: and I thought I was the only Star gate SG1 fan lol

ilusjon: THUMBS UP, IF YOU GOT THE STARGATE SG1 REFRENCE !!!

victornpb: I'm gonna make a 5 minutes charger, to see if that bitch can handle 25amps. bang

victornpb: the rated capacity is for 25mAh discharge.
Rating:
EEVblog #35 - Inside the Varta 15 minute NiMH Battery Charger 5 out of 5

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EEVblog #35 - Inside the Varta 15 minute NiMH Battery Charger