Roy,
I have quite a bit of association with LiPo batteries. I fly RC aircraft and LiPo's are the preferred power source. Many times there are articles of flyers charging their batteries and having them catch on FIRE. So much so that there is a combination charging bag and metal container as a charging fire suppression mechanism.
As to the bad cell in my 4 pack of NiMH, I placed in the freezer for a day and let it return to room temperature. Using my old Power Designs power supply I was able to pump in about 50 ma but the cell started to heat up. It took about 35 volts to get that 50 ma. I returned the cell to the freezer and I'll let it stay for a day and try again.
Looking for a 2/3 AAA 300mAh battery has many suppliers but who wants to pay almost $9 for a single cell. Not replacing all four cells seems like a bad engineering decision since the device is over 5 years old.
I am still not convinced the charging circuit is optimum for these cells. There is no overvoltage protection and relying on the capacitive reactance as a limiting device is a stretch.
Regards,
Dan
On Saturday, January 18, 2025 at 12:03:23 PM EST, Roy J. Tellason, Sr. via groups.io <roy@...> wrote:
On Friday 17 January 2025 12:35:23 pm wn4isx via groups.io wrote:
> As I've said, I really distrust and dislike nicads....except for the big ones rail road companies used at crossings.
I had a bunch of them a while back,? and eventually gave up on them completely.? The lower terminal voltage was an issue,? and they just didn't seem to reliably hold a charge.
> NiMH are much better behaved but a @itch to charge.
Had some of those,? too,? and gave up on them.
> Lithium Ion are better energy density wise, but draw too much current or charge wrong and you have an instant incendiary grenade.
I bought a bunch of those TP4056 modules,? and use those.? There are a couple of variants out there,? I got the ones that have the protection on the board as well as the charge control.? So far they've worked out pretty well with a bunch of cells salvaged from laptop batteries.? I had several of those,? and when you open them up there's typically only one or two cells that are bad.? The one thing that didn't work out well was putting one of those setups into a chinese dremel clone,? I'd need to find me some higher-current cells to use in that application.
> A friend had one of the troubled Samsung 'catch on fire' phones and his went up on a picnic table.
> It was a bit too exciting. Hint, do not use water on a lithium fire, that made it more exciting. And knocking it into a bucket of water was beyond exciting.
> Think "Extreme thermal event."
My first smart phone was a Samsung.? I won't buy another one,? not after those stories hit the news,? particularly.? They were just flat out irresponsible.
My last phone got interesting.? I'm not sure what I was doing wrong in my charging regimen,? but the battery bulged enough to pop the case open.? I eventually procured another battery and installed it,? but apparently damaged some other stuff in the phone so the speaker didn't work any more,? and I'm not sure what else.? The little board at the bottom of the phone wasn't available,? so I'm out the $20 I spent on that battery and the phone got replaced.
The battery got removed and placed in a metal bucket with sand in it,? until I took it to recycle at Lowe's.? Interestingly enough,? their recycle box is outside of the store...
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, ?a critter that can
be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters"
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Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
