9V Lithium rechargeable batteries

[BradC]

G'day all,

I chew through 9V batteries. Back in 2011 I bought 8 Powerex Imedion 9.6v 230mAh batteries and a charger and they have been good, but very variable. Some of them have averaged 80-100 hard cycles each in objectionable thermal conditions and have paid for themselves many times over while others might have done 10 cycles and are completely dead. Now I'm down to 3 working batteries which are averaging about 130mAh. Still barely passable for short term use, but pretty duff overall. I was looking to replace them, but the lightly used ones just haven't lasted like I might have hoped.

I've been looking for a long time at the new Lithium Ion 9V batteries, but all I could find were E-bay specials which looked over-hyped and liable to die quickly.

My devices all go into low-battery at about 7V and so I was also worried about the 7.4V nominal battery voltage. 8.4V NiMh were almost useless in these devices. I was poking around looking for something else and discovered these : https://www.master-instruments.com.au/products/63235/LP702235-BP1.html

Rated at 500mAh, supplied by a reputable supplier in Australia and actually have a real data sheet (which initial measurements indicates might be accurate). I bought 2 and a charger from a store on E-bay as a test.
A couple of cycles with a 100mA discharge load sees them running out to about 550mAh with 500 of that above 7V. Devices are happy.

Time will tell how many cycles I get out of them but at the outset I'm already fairly impressed.

[tszaboo]

http://lygte-info.dk/info/BatteryDisassembly9VLiIon%20UK.html

I bought a pair of the Znter a year ago. Or something exacly like it. Charges with USB. Seems to hold capacity well, and it has a "press here for battery gauge" button.

[rdl]

Not long ago I bought a couple of 9v NiMH batteries, EBL brand)with charger, for less than $10 on ebay. I've recharged them 4 times now, so they've already just about paid for themselves. I liked them enough to go ahead and buy a couple of their Lithium versions, but I haven't had a chance to use those much yet.

[Rick Law]

If you are still OK with NIMH and not shoot for very high drain, I've a suggestion: Tenergy Centura LSD.

Back in 2013, I got some Tenergy Centura for my DMM.  God knows how many times I cycled them by now - they are still going strong.

Tenergy Centura uses 7 NIMH cells (8.4V) as oppose to 6 cells (7.4V 7.2V), that little extra gives it a lot more life.  In the mini-review I did back then, it held above 7.5V (at 70-80mA drain) till it drop off the cliff.

See the discharge graph and a mini-review here:
https://www.eevblog.com/forum/reviews/tenergy-centura-9v-and-tn141-mini-review/

I am still using the battery I tested in the post above.  Still exceeding 200mAH when I re-did the load test last year.  In fact, I was so pleased by the retest I acquired few more of them.

EDIT: corrected a math error. 6x1.2V=7.2V, not 7.4V as originally wrote.  Sleepwalking strike again.

[djQUAN]

Was looking to replace the 9V alkaline to a rechargeable in my Fluke 115. Any recommended good ones with decent life? Or just not bother and keep using an alkaline?

[retiredcaps]

Was looking to replace the 9V alkaline to a rechargeable in my Fluke 115. Any recommended good ones with decent life? Or just not bother and keep using an alkaline?

The Fluke 115 has 400 hour battery life.  If used 1 hour/day, just change out the 9V battery on January 1 each year.  Name brand 9V batteries, when on sale, can be as cheap as $1.50USD each.

If the 115 battery life was 100 hours, then it might make sense to get a rechargeable 9V.

[BradC]

Unless I have a catastrophe with the Li-Ion batteries I don't think I'll be going back to NiMH for 9V.

I've attached a discharge I did last night on one of them stopping at 7V (which is where most of my kit indicates low battery anyway). Constant discharge at 100mA.
The 9.6V (8 cell) were ok, but out of 8 I only wound up with 3 that lasted, and they are pretty hammered now.

I'll play with the Lithium and see how well they last.

[retiredcaps]

Back in 2011 I bought 8 Powerex Imedion 9.6v 230mAh batteries and a charger and they have been good, but very variable.

Another person reported short life with the above.

https://www.eevblog.com/forum/beginners/wanted-reliable-9v-nimh-battery!/

I was always under the impression that Powerex made very good high quality nimh cells/batteries, but perhaps the 9V are troublesome?

[HKJ]

I have tested a couple of different 9V batteries (18 for now, more will be added) with different chemistries, they can all be compared here: http://lygte-info.dk/review/batteries9V/Common9Vcomparator.php

[tszaboo]

I have tested a couple of different 9V batteries (18 for now, more will be added) with different chemistries, they can all be compared here: http://lygte-info.dk/review/batteries9V/Common9Vcomparator.php

Is that your website? I would like to thank you, you are doing a community service.

[HKJ]

Is that your website?

Yes, I do also sometimes post some reviews here or part of, I will need to write a format converter to before I can post full reviews, but the interest looks fairly minor here (It is reviews about power meters and DMM's).

[BradC]

I have tested a couple of different 9V batteries (18 for now, more will be added) with different chemistries, they can all be compared here: http://lygte-info.dk/review/batteries9V/Common9Vcomparator.php

Is that your website? I would like to thank you, you are doing a community service.

And then some. I've used that site and information to make many informed decisions about 1.2V nickel based cells. It never occurred to me to check there for 9V stuff.

Many, many thanks.

[djQUAN]

Was looking to replace the 9V alkaline to a rechargeable in my Fluke 115. Any recommended good ones with decent life? Or just not bother and keep using an alkaline?

The Fluke 115 has 400 hour battery life.  If used 1 hour/day, just change out the 9V battery on January 1 each year.  Name brand 9V batteries, when on sale, can be as cheap as $1.50USD each.

If the 115 battery life was 100 hours, then it might make sense to get a rechargeable 9V.

I'm more worried about alkalines leaking and damaging my expensive meter hence the plan to go Li-ion.   

[HKJ]

I'm more worried about alkalines leaking and damaging my expensive meter hence the plan to go Li-ion.   

With 9V batteries the risk of leaks is fairly low, because it will often stay inside the battery.

I disassembled a lot of 9V batteries here: http://lygte-info.dk/info/BatteryDisassembly9VAlkaline%20UK.html
Not one was looking leaky on the outside, but in a few the cells where leaking.

[Rick Law]

I'm more worried about alkalines leaking and damaging my expensive meter hence the plan to go Li-ion.   

With 9V batteries the risk of leaks is fairly low, because it will often stay inside the battery.

I disassembled a lot of 9V batteries here: http://lygte-info.dk/info/BatteryDisassembly9VAlkaline%20UK.html
Not one was looking leaky on the outside, but in a few the cells where leaking.

Trouble is, LOW != ZERO.  I got hit by 9V leakers a few time.  Latest was the bathroom scale which was so bad it became trash.

The only time I would use an alkaline primary battery is when the equipment simply cannot deal with the lower voltage of the rechargeable batteries.

Is that your website?

Yes, I do also sometimes post some reviews here or part of, I will need to write a format converter to before I can post full reviews, but the interest looks fairly minor here (It is reviews about power meters and DMM's).

Great site and great work.  I learned a lot from it.  I would not buy a charger or LiIon cell without checking out what HKJ has to say first.

(ps: Thanks HKJ)