On Mon, 11 Feb 2019 14:06:06 -0800, Mike wrote:

3 years ago I switched to EBL rechargeable lithium 9V batteries.
I use 'em in low drain devices like multimeters.
Haven't had to charge any of 'em yet.
They're rated at 600mAh, but I don't have any experience with high drain
usage.
Downside is that your device has to work down to 7V or so.
More expensive initially, but can have lower cost over the long haul.

Back in the day, I tried rechargeable 7.2V NiCds. Mostly useless.
The 8.4V 7-cell NiMH were better, but self discharge was an issue.

I did exactly the same thing. Most of mine live in small instruments,
digital clocks, and portable radios now use EBL 9V LiIon batteries.
However, I have seen a few problems:
1. Some bulge when recharged. If there's expansion room in the
battery compartment, no problem. Otherwise, it might jam the battery
in the battery compartment.
2. I bought 10 of these batteries for about $40.
https://www.ebay.com/itm/EBL-Lot-of-600mAh-9V-Volt-6F22-Li-ion-Rechargeable-Batteries-High-Volume-1-20pcs/273615893492
I've only used 6 of these so far. 1 has failed the first time I tried
to charge it. The other 5 have survived about 3 recharges each
without incident. Reliability and quality seem to be an issue with
EBL batteries:
https://www.amazon.com/EBL-Rechargeable-Batteries-Lithium-4-Packs/dp/B00EJKIDHE/#customerReviews
3. Discharge test shows a bit low at 550 ma-hrs.
4. One of my cheap DVM's (Harbor Freight) quits before the battery
hits minimum voltage (about 6.8V).

EBL seems to be the least disgusting of the various 9V LiIon
batteries:
"#45 - 9V Li-ion batteries: capacity testing"
https://www.youtube.com/watch?v=9A06SPUF8i8

The good news is that I no longer trash instruments and equipment with
leaky alkaline batteries:
http://802.11junk.com/jeffl/crud/Kirkland-AAA-leak.jpg


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558