I really wish someone (HKJ/NLee the Engineer, perhaps?) would test some 9-volt batteries for capacity - perhaps as thoroughly as they tested 18650's. I see someone did some testing in 2010*, but mAh wasn't measured at all (and the market and/or technology has changed pretty substantially). (TTA's records don't include capacity; just (internal?) resistance and voltages, which are less useful, or at least less clearly useful.)
*http://www.candlepowerforums.com/vb/showthread.php?275008-9-volt-battery-tests kicked off with:
AmazonBasics 9 Volt Everyday Alkalines are about $1.25 each nowadays.
Now, Amazon has for
$23: Combo: Tenergy TN294 4-Bay 9V Li-ion Battery Charger + 4pcs 9V 600mAh Li-ion Rechargeable Battery
AND ALSO for
$23: Tenergy TN141 2 Bay 9V Smart Charger with 4 pcs 200mAh Centura Low Self-discharge 9V NiMH Rechargeable Batteries
COMPARE:
Back then in 2010,
so ~$45 for two ~200 mAh NiMH batteries w/charger in '10 vs
~$23 for FOUR ~200 mAh LSD NiMH batteries w/charger OR
~$22 for FOUR ~600 mAh Li-ion batteries w/4-port charger in '16!
I thought that Li-ion 9v's are NOT LSD, so NOT useful in, e.g., smoke alarms, or other low-drain / very intermittent use devices. Yet, EBL claims: "Improved low self discharge makes it still maintain 75% of capacity after 3 year of non-use." (It seems I'm mistaken - good Li-Ion 9v's are appropriate for low-drain devices - my experience testing crap ones off eBay had me generalizing incorrectly. So I am now thinking that the case for Li-Ion 9v's is pretty compelling. )
Amazon also has EBL 9V 600mAh Li-ion, but while Tenergy has a reputation for quality and reliability 'round here, EBL doesn't (AFAIK). [Update 2: Per this review, the EBL 9V's do test out at ~600 mAh: they put out 560 and 610 mAh in tests. And, per this review, Duracell alkalines and Tenergy fell far short of their claimed capacity, and Maximal Energy fell clearly short.]
Amazon also has BIG ads for a SunLabz 9v that's, I kid you not, listed as NiCd. At first I thought it was a listing error though. Comments here at CPF and an Amazon review with Opus BT-C2000 smart charger mAh readings by by TecRat is positive WRT (With Respect To) the SunLabz 2600mAh AA NiMH but not the 2800mAh AA NiMH's. So there's a good chance their 9v are good.
WARNING: Amazon lumps reviews for some SunLabz AA, AAA, C and D batteries together as if they're the same product. You can confirm this by looking at the number of reviews each of these products have; you'll see that at a given time, it's the exact same number for many of them. (Of course that number changes over time; as of this writing, it's 1795 for eight SunLabz products, and 714 for 3 NiCd SunLabz products, and 1,122 for four SunLabz chargers.) Amazon also confabulates SunLabz NiCd and NiMH batteries. And also confabulates SunLabz AA NiMH 2800mAh and 2600mAh batteries. It combines the reviews for their 4-, 8-, 12- & 16-bay chargers - which kinda-almost makes sense.
Aha!: http://lygte-info.dk/info/Review%20UK.html = How to get a product reviewed. It would take about $50 to buy a variety of 9v for testing. I'd be happy to put up $10. Anyone else? 5 @ $10 would do it, if HKJ says so; I assume his rig can handle 9v.
Another Update: Interestingly, Amazon and/or MaximalPower claims Amazon has an exclusive on the MaximalPower 9 Volt Li-Ion Rechargeable Battery HIGH CAPACITY 550mAh 9V. (That is, it's claimed that Amazon is "the only authorized dealer selling MaximalPower brand products") and yet they're available on eBay. I find no reviews that measured mAh; I take the generally positive reviews (even ones that say they have a high capacity) with a grain of salt, especially given the fair number of strongly negative reviews. Oh, and the EBL price dropped, and the reviews indicate that the company stands behind its products extraordinarily well - at least they're very attentive to reviewers who have issues, that is.
*http://www.candlepowerforums.com/vb/showthread.php?275008-9-volt-battery-tests kicked off with:
AmazonBasics 9 Volt Everyday Alkalines are about $1.25 each nowadays.
Now, Amazon has for
$23: Combo: Tenergy TN294 4-Bay 9V Li-ion Battery Charger + 4pcs 9V 600mAh Li-ion Rechargeable Battery
AND ALSO for
$23: Tenergy TN141 2 Bay 9V Smart Charger with 4 pcs 200mAh Centura Low Self-discharge 9V NiMH Rechargeable Batteries
COMPARE:
Back then in 2010,
so ~$45 for two ~200 mAh NiMH batteries w/charger in '10 vs
~$23 for FOUR ~200 mAh LSD NiMH batteries w/charger OR
~$22 for FOUR ~600 mAh Li-ion batteries w/4-port charger in '16!
I thought that Li-ion 9v's are NOT LSD, so NOT useful in, e.g., smoke alarms, or other low-drain / very intermittent use devices. Yet, EBL claims: "Improved low self discharge makes it still maintain 75% of capacity after 3 year of non-use." (It seems I'm mistaken - good Li-Ion 9v's are appropriate for low-drain devices - my experience testing crap ones off eBay had me generalizing incorrectly. So I am now thinking that the case for Li-Ion 9v's is pretty compelling. )
Amazon also has EBL 9V 600mAh Li-ion, but while Tenergy has a reputation for quality and reliability 'round here, EBL doesn't (AFAIK). [Update 2: Per this review, the EBL 9V's do test out at ~600 mAh: they put out 560 and 610 mAh in tests. And, per this review, Duracell alkalines and Tenergy fell far short of their claimed capacity, and Maximal Energy fell clearly short.]
Amazon also has BIG ads for a SunLabz 9v that's, I kid you not, listed as NiCd. At first I thought it was a listing error though. Comments here at CPF and an Amazon review with Opus BT-C2000 smart charger mAh readings by by TecRat is positive WRT (With Respect To) the SunLabz 2600mAh AA NiMH but not the 2800mAh AA NiMH's. So there's a good chance their 9v are good.
WARNING: Amazon lumps reviews for some SunLabz AA, AAA, C and D batteries together as if they're the same product. You can confirm this by looking at the number of reviews each of these products have; you'll see that at a given time, it's the exact same number for many of them. (Of course that number changes over time; as of this writing, it's 1795 for eight SunLabz products, and 714 for 3 NiCd SunLabz products, and 1,122 for four SunLabz chargers.) Amazon also confabulates SunLabz NiCd and NiMH batteries. And also confabulates SunLabz AA NiMH 2800mAh and 2600mAh batteries. It combines the reviews for their 4-, 8-, 12- & 16-bay chargers - which kinda-almost makes sense.
Aha!: http://lygte-info.dk/info/Review%20UK.html = How to get a product reviewed. It would take about $50 to buy a variety of 9v for testing. I'd be happy to put up $10. Anyone else? 5 @ $10 would do it, if HKJ says so; I assume his rig can handle 9v.
Another Update: Interestingly, Amazon and/or MaximalPower claims Amazon has an exclusive on the MaximalPower 9 Volt Li-Ion Rechargeable Battery HIGH CAPACITY 550mAh 9V. (That is, it's claimed that Amazon is "the only authorized dealer selling MaximalPower brand products") and yet they're available on eBay. I find no reviews that measured mAh; I take the generally positive reviews (even ones that say they have a high capacity) with a grain of salt, especially given the fair number of strongly negative reviews. Oh, and the EBL price dropped, and the reviews indicate that the company stands behind its products extraordinarily well - at least they're very attentive to reviewers who have issues, that is.
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