On Tuesday, February 12, 2019 at 8:53:54 PM UTC-8, Mike wrote:

I have a little 9V charger, blissfully ignorant of balancing acts.
"Little charger" is too vague to be helpful.
If it's a little charger designed to charge these EBL batteries,
you're good to go. If it ain't, don't use it.

bonai 9V 80 mA (x1) 50 mA (x2) charger. brought the patient up to 7.68 volts. which is what one has to accept for 9V these days? or anyhow below 8.4V from what you write.




amen! and get rid of the devices that just stay on to the last millivolt.
Meanwhile, I appreciate the knowledge that allows me to wake these (still costly) batteries from their self induced coma... wish it were easier.

It's not rocket science. Set your bench supply to 4.0V. Put a 1K
resistor in series with it and charge one cell at a time. When the
voltage across the resistor gets to about zero, do the other one.
I typically let the battery sit for a day after and check the balance again.
Tweak it till they're within a few millivolts after a rest.
That's overkill, but why not...

Note that I did NOT say take any random usb 5V charger and use it.
MUST stay below 4.2V.
If you don't have a way to generate 4ish volts, throw the batteries away.

nah there's a LM317 waiting to be tickled...

BTW I used anvil type pruning shears to open the battery case. Good force, good control.