NiMH comparison - 1 year test

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Hugh Johnson
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I’ve just pulled a dozen alkaline cells out of household detectors for annual refresh. They’re not dead. I’m using them in my lights and questioning why I’m doing it. As a result I’ve parked my nimh cells. There’s some satisfaction in not wasting them but it’s not really saving the rechargeables a lot of wear. It seems all I’m really doing is exposing my equipment to leaks.

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MoreLumens wrote:
Those fire detectors are only place where I still use 9V alkalines. Well other use is Garrett Pro Pointer because there just doesnt seem to be good enough 9V NiMH’s, or is there? Well I really dont have 9V charger either right now or that much use until spring and summer is here again.

9V are indeed a weakness for NiMH. Long ago, Powerex made a 9.6V NiMH “9V” cell. The capacity was even lower than usual, but the voltage satisfied even the most contrary 9V devices (some wouldn’t or won’t work with 8.4V NiMH “9V” cells). I used the Powerex cells to replace all of the alkalines in our church’s wireless microphones. We used about 3 generations of NiMH cells in these devices for about 15 years and saved a lot of money and waste, but I’m no longer involved and they’ve now switched back to alkalines Sad .

You just can’t win.

However, most devices today will operate at the 8.4V of the common NiMH “9V” cell and I believe that some of these cells are worth using. However, it remains that case that none of the 9V options are as good as the AA and AAA cells offered by major manufacturers. Unfortunately, as the 9V battery becomes less and less popular in products, I don’t think manufacturers will have incentive to produce top-quality 9V options.

RobAllen

Phlogiston
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The problem with the NiMH 9V PP3 batteries is that they’re several 1.2V cells in series and there’s no way to balance them. They rely on charging at a low enough rate for the cells which hit full charge first to survive the overcharge until the other cells catch up. It works for a while, then one of the cells inevitably wears out and renders the entire battery useless.

flydiver
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I think the above analysis by @Phlogiston is true. It’s also a function of +very +tiny cells. In my experience, the smaller the NiMh, the worse off it is in almost all ways, not just capacity.

FWIW, I have had great luck with Li-on 9v. They have decent capacity, hold way better current than any other 9v, and retain their charge well.

To Air is Human, to Respire….Divine.

MoreLumens
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flydiver wrote:
FWIW, I have had great luck with Li-on 9v. They have decent capacity, hold way better current than any other 9v, and retain their charge well.

Do you mean those that have integrated usb-charging? Just did a quick search about those, never even heard about those before.

flydiver
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Have not used the ones with USB charging. HKJ has done tests on various 9v:

I have the iPowerUS, all of them discards from a place I volunteered. Most were fine in spite of being 7-10 years old, showing capacities of 400-500 (520 claimed). It was probably a policy to replace batteries after x-years old. I seriously doubt there was anyone there in charge of battery QA beyond simply tracking and replacement. Meaning no one likely did capacity tests or had the equipment to do so. It is a time consuming process. The manpower costs would be way more than the battery cost.

I also Got some EBL 6F22 from there. These do not have a date code so I can’t tell age. They appear newer. They also show capacities of 400-500 (600 claimed).

The iPowerUS has a proprietary charger, which I do not have. I use a hobby charger which works fine.

Supposedly the EBL have a charge/discharge limiting chip so you can use a stock 9v slow charger. I frankly don’t trust that and use the hobby charger, which works.
If you look at Amazon reviews it would seem that the quality is highly variable. I suspect mine are OK as the ‘duds’ probably were discarded as soon as they gave problems. In spite of probably being much newer they do not seem as good as the iPowerUS…quite.

Both are WAY WAY better than NiMh 9v. No comparison. I’ve gotten rid of my NiMh 9v as soon as I got my hands on these. I even use them in smoke alarms that are easy to reach. They last ~6 months.

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hammerJoe
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Has anyone tested the “new” Amazonbasics?
Im wondering if they are the same as the old ones and I need new cells.

Im not gettin the duracell Ion anymore as they dont last for very long even with some mild usage.

flydiver
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The Amazon reviews indicate they are no longer Japan make, now from China and aren’t as good. I have some Chinese Eneloop AA and they are not as good.
The older Basics were from Japan and most likely Eneloop rebrand. No idea what the new ones are.

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flydiver wrote:
The Amazon reviews indicate they are no longer Japan make, now from China and aren’t as good. I have some Chinese Eneloop AA and they are not as good. The older Basics were from Japan and most likely Eneloop rebrand. No idea what the new ones are.

I’ve seen the same claims and myself suspect that these are now Chinese cells. However, it should be noted that the bulk packs of AmazonBasics NiMH cells are cheap enough that they are still a good value, especially if you get them on sale or with an instant coupon (see HERE). They’re about $1.25/cell.

A 16-pack of Eneloops costs $32 and the Eneloop Pros are $65. That’s $2/cell for standard Eneloops, which is reasonable, but $4/cell for the Pros, which is even more expensive than the 16-pack of 2450mAh Duracells. The Duracells are $5/cell in smaller packs, though, which is ridiculous, though still smarter than buying alkalines and magnitudes better than buying useless heavy duty packs.

You can still get the older style of AmazonBasics High-Capacity (2400mAh) cells HERE, but it’s a pack of 4 AA’s and 4 AAA’s, which is a bit strange. The pack thus averages $2.23/cell at the time of this posting, which isn’t bad if you want both sizes.


Though some individual reviewers can be trusted at Amazon, I would not trust the overall review scores at Amazon for any sort of technical product. I don’t want to be mean, but most buyers are just ignorant about technology and tend to give every product either 1 star, even if they simply didn’t know how to use it, or 5 stars, even if it’s an average product.

A month or two ago, I saw one reviewer give a product 4 stars when it arrived broken and the company never responded to his requests for assistance. Huh? Facepalm What would a company have to do to earn 1 star from this guy? Murd*r his family? Nah, he’d likely still give them 2 stars for showing up Silly .

I’m sure most BLF members already know this, but I would never purchase something from Amazon just because it has 10,000 positive reviews and has earned their “Amazon’s Choice” banner label. There are some extremely popular products on Amazon that are absolute crap. User reviews are nearly worthless in the modern era, as users are just not knowledgeable or patient enough to review products Sad and have been trained to give any working product 5 stars.

RobAllen

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