Kentli Lithium-Polymer rechargeable AAs

[Dave Britten]

Anybody have any experience with using these? They're Li-Po chemistry, but built to output 1.5 V. I'm considering getting some for my OmniBook 300 and/or 200LX, but knowing the "fun" that can be had with questionable lithium batteries (ask Samsung), wanted to make sure they're safe/reliable enough first. The Amazon reviews seem okay, but you never know...

https://www.amazon.com/Rechargeable-li-b...00SXV9Z4U/

[Bill (Smithville NJ)]

(12-15-2016 09:43 PM)Dave Britten Wrote:  Anybody have any experience with using these? They're Li-Po chemistry, but built to output 1.5 V. I'm considering getting some for my OmniBook 300 and/or 200LX, but knowing the "fun" that can be had with questionable lithium batteries (ask Samsung), wanted to make sure they're safe/reliable enough first. The Amazon reviews seem okay, but you never know...

https://www.amazon.com/Rechargeable-li-b...00SXV9Z4U/

Hi Dave,

You should check out the Jason's Electronics Blog on a similar battery (not sure if it is the same one or not).

Teardown


Performance

Self Discharge Test 1


Bill
Smithville, NJ

[Dave Britten]

(12-15-2016 11:18 PM)Bill (Smithville NJ) Wrote:  Hi Dave,

You should check out the Jason's Electronics Blog on a similar battery (not sure if it is the same one or not).

Teardown


Performance

Self Discharge Test 1


Bill
Smithville, NJ

Wow, that's a crazy steep voltage drop-off at the end there. Probably wouldn't be a good idea to use them in computers. It seems like you'd open yourself up for disk corruption or data loss with a sudden voltage drop like that. I'll just stick with boring old alkalines and NiMHs for now, I guess.

[striegel]

(12-16-2016 03:41 AM)Dave Britten Wrote:  ...
a crazy steep voltage drop-off at the end there. Probably wouldn't be a good idea to use them in computers. It seems like you'd open yourself up for disk corruption or data loss with a sudden voltage drop like that.
...

If you keep a good backup cell (CR-2032) in the 200LX, you'll have nothing to fear from the main battery dying suddenly. I have never experienced any corruption or data loss on mine in many years of use. In fact, that's true of all my LX models - 95LX, 100LX, and 200LX.

I can't speak for the OmniBook models, as I have yet to acquire my first one.

Alan

[Bill (Smithville NJ)]

(12-16-2016 03:41 AM)Dave Britten Wrote:  Wow, that's a crazy steep voltage drop-off at the end there. Probably wouldn't be a good idea to use them in computers. It seems like you'd open yourself up for disk corruption or data loss with a sudden voltage drop like that. I'll just stick with boring old alkalines and NiMHs for now, I guess.

Yep, Li-Po batteries drop off like that. All my ham radio gear use Lithium battery packs and they perform fantastic for that application - high current during transmitting with a fairly constant voltage. But they give almost zero warning. I will get a warning if I am only receiving (i.e., low current) for several minutes before they shutdown. But if I'm transmitting, then they just abruptly shut down and I find myself talking to myself instead of transmitting.

Not sure how much (if any) warning they would give on the Omnibook. I use the non-rechargeable Energizer Lithium batteries on my OB. I find that there is really no warning - the OB just beeps and instantly shuts off. No loss of data - but then I've never had it shut down while writing.

Bill
Smithville, NJ

[Dave Britten]

(12-16-2016 01:07 PM)Bill (Smithville NJ) Wrote:  Yep, Li-Po batteries drop off like that. All my ham radio gear use Lithium battery packs and they perform fantastic for that application - high current during transmitting with a fairly constant voltage. But they give almost zero warning. I will get a warning if I am only receiving (i.e., low current) for several minutes before they shutdown. But if I'm transmitting, then they just abruptly shut down and I find myself talking to myself instead of transmitting.

Not sure how much (if any) warning they would give on the Omnibook. I use the non-rechargeable Energizer Lithium batteries on my OB. I find that there is really no warning - the OB just beeps and instantly shuts off. No loss of data - but then I've never had it shut down while writing.

Bill
Smithville, NJ

That's sort of why I tend to avoid lithium primary cells too (although those don't seem to tank quite as sharply as the Kentlis apparently do). But they certainly do reduce the overall weight of the device, which is a nice side effect.

Lately I've been using DataPerfect on my palmtop and OB, and being a network-capable database program, it's pretty chatty with disk I/O, out of necessity. It would definitely be a game of Russian roulette whether it shuts down in the middle of a record/index update and corrupts the database. Think I'll probably shop around for some good NiMH kit later; the warning on those is short too compared to alkaline, but usually plenty.

[Garth Wilson]

The battery itself doesn't drop off like that. There's a switching regulator in the end cap that does its darnedest to keep the voltage constant, but when the battery is too weak to do that, the regulator shuts down instantly and you don't get any more out of it. The switching regulator is partly why it's so expensive, and why it produces a lot of electrical noise as the article says.

[Dave Britten]

(12-17-2016 08:36 PM)Garth Wilson Wrote:  The battery itself doesn't drop off like that. There's a switching regulator in the end cap that does its darnedest to keep the voltage constant, but when the battery is too weak to do that, the regulator shuts down instantly and you don't get any more out of it. The switching regulator is partly why it's so expensive, and why it produces a lot of electrical noise as the article says.

I kinda figured something like that was going on. I picked up a few 2300 mAH NiMHs for the OB; that should be fine for now. One of these days I'll track down the weird cells necessary to rebuild the "real" OB battery pack.