HW 4-Pack 9V 1400mAh USB-C Rechargeable Lithium Batteries w/ Cable $12.45 + Free Shipping w/ Prime or $35+ Orders

DarthF

Feb 17, 2026 5:25 PM

4 Comments

Joined Feb 2018

DarthFFeb 17, 2026 5:25 PM

4 Comments

Decent deal

darksiderising

Feb 17, 2026 5:39 PM

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Joined Nov 2012

darksiderisingFeb 17, 2026 5:39 PM

1.2K Comments

Who else can hear the sound of a smoke detector chirping for low battery in your head when seeing this?

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RugerRedhawk

Feb 17, 2026 5:41 PM

12K Comments

Joined Sep 2007

RugerRedhawkFeb 17, 2026 5:41 PM

12K Comments

Quote from darksiderising

:

Who else can hear the sound of a smoke detector chirping for low battery in your head when seeing this?

I wonder how these work in smoke detectors, lithiums don't drop off the same way as alkaline so I believe it would just go straight from working to dead.

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darksiderising

Feb 17, 2026 5:44 PM

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Joined Nov 2012

darksiderisingFeb 17, 2026 5:44 PM

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Our community has rated this post as helpful. If you agree, why not thank darksiderising

Quote from RugerRedhawk

:

I wonder how these work in smoke detectors, lithiums don't drop off the same way as alkaline so I believe it would just go straight from working to dead.

Oh that's a good point for battery only detectors. For hardwired with a 9v battery backup, these should still function properly with the low/dead battery notification.

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Scotty73

Feb 17, 2026 5:52 PM

31 Comments

Joined Jan 2013

Scotty73Feb 17, 2026 5:52 PM

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These are not lithium primary cells and will self discharge much faster than Alkaline or Lithium Primary 9 volt. The best lithium primary cells in 9V are from Ultralife.

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harley48

Feb 17, 2026 6:31 PM

484 Comments

Joined Mar 2016

harley48Feb 17, 2026 6:31 PM

484 Comments

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I have a couple different brands of these that I've tested thoroughly on lab grade equipment. The BEST of these is ~600mAh WHEN BRAND NEW.
Absolutely no way these are 1400mAh. The bigger the lie, often the more disappointing the product.
USB charging puts extra electronic components and absolutely takes some capacity out.
Won't work well/properly in music type applications. The voltage converter makes interference.

I could only find ONE capacity review, 1*. 400mAh is what I would have guessed. It will probably lose 50-100mAh/year based on my experience with EBL 9v lithium rechargeable.

[[I put this battery on a constant 20 MA load to test its capacity. It is nowhere near the1000 MAH that is advertised. It shuts down completely after 20 hours. That amounts to 400 MAH, not 1000. Even considering the voltage is being boosted with a switching regulator from two 3.7V Lithium cells, it still falls far short of 1000. This is not surprising, given that there is simply not enough physical space in a 9V battery for that level of capacity. I've grown weary of Amazon allowing this kind of false advertising on its website.]]

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Ditch

Feb 17, 2026 6:47 PM

739 Comments

Joined Feb 2009

DitchFeb 17, 2026 6:47 PM

739 Comments

What is the use case for this sort of battery?

lawrnk

Feb 17, 2026 6:55 PM

718 Comments

Joined Jun 2010

lawrnkFeb 17, 2026 6:55 PM

718 Comments

Quote from Ditch

:

What is the use case for this sort of battery?

Metal detectors. Other handheld devices that use 9v.

BottleKid

Feb 17, 2026 7:11 PM

74 Comments

Joined Jul 2013

BottleKidFeb 17, 2026 7:11 PM

74 Comments

I like that they're "widely & compatibility".

2

puncturepremium

Feb 17, 2026 7:39 PM

574 Comments

Joined Jul 2018

puncturepremiumFeb 17, 2026 7:39 PM

574 Comments

getting another set to use as swap when I change out batteries every 8 months since rechargeables aren't awesome for hardwire smoke detectors

BeigeCrow552

Feb 18, 2026 1:04 AM

307 Comments

Joined Nov 2024

BeigeCrow552Feb 18, 2026 1:04 AM

307 Comments

Quote from Ditch

:

What is the use case for this sort of battery?

Multimeters, garage door openers that use 9V. Not good for cases where battery replacement is difficult as capacity isn't great.

Last edited by BeigeCrow552 February 17, 2026 at 05:27 PM.

armedmetallica

Feb 18, 2026 1:10 AM

6.5K Comments

Joined Feb 2004

armedmetallicaFeb 18, 2026 1:10 AM

6.5K Comments

Quote from Ditch

:

What is the use case for this sort of battery?

Not this brand but I had another brand on my garage door opener keypad. This way if the battery were to die I can pop it out and charge it real quick and re-energize the keypad from outside.

That was before I switched garage door openers and added to home assistant. Now I just really don't ever use the keypad.

BeigeCrow552

Feb 18, 2026 1:26 AM

307 Comments

Joined Nov 2024

BeigeCrow552Feb 18, 2026 1:26 AM

307 Comments

Quote from harley48

:

I have a couple different brands of these that I've tested thoroughly on lab grade equipment. The BEST of these is ~600mAh WHEN BRAND NEW.
Absolutely no way these are 1400mAh. The bigger the lie, often the more disappointing the product.
USB charging puts extra electronic components and absolutely takes some capacity out.
Won't work well/properly in music type applications. The voltage converter makes interference.

I could only find ONE capacity review, 1*. 400mAh is what I would have guessed. It will probably lose 50-100mAh/year based on my experience with EBL 9v lithium rechargeable.

[[I put this battery on a constant 20 MA load to test its capacity. It is nowhere near the1000 MAH that is advertised. It shuts down completely after 20 hours. That amounts to 400 MAH, not 1000. Even considering the voltage is being boosted with a switching regulator from two 3.7V Lithium cells, it still falls far short of 1000. This is not surprising, given that there is simply not enough physical space in a 9V battery for that level of capacity. I've grown weary of Amazon allowing this kind of false advertising on its website.]]

lol yeah 1400mAh @ 9V is 12,600mWh. No way that 9V form factor is packing that much energy. An Energizer one-use lithium has about 800mAh. An Energizer alkaline 9V has about 500-600mAh.

BeigeCrow552

Feb 18, 2026 12:17 PM

307 Comments

Joined Nov 2024

BeigeCrow552Feb 18, 2026 12:17 PM

307 Comments

Quote from harley48

:

I have a couple different brands of these that I've tested thoroughly on lab grade equipment. The BEST of these is ~600mAh WHEN BRAND NEW.

I think I figured it out. 1400mAh is probably the 3.7 battery they use internally. Converted to 9V it's around 575mAh (1400x3.7/9) which is around the ballpark mAh you tested to.

harley48

Feb 18, 2026 2:04 PM

484 Comments

Joined Mar 2016

harley48Feb 18, 2026 2:04 PM

484 Comments

Quote from BeigeCrow552

:

I think I figured it out. 1400mAh is probably the 3.7 battery they use internally. Converted to 9V it's around 575mAh (1400x3.7/9) which is around the ballpark mAh you tested to.

The math works, but I don't think the marketing is up to claims. I've tested a LOT of lithium rechargeable, mostly AA and AAA. The best (not many) hit about 90% capacity at very low amp draw. The decent do 80%. Sorta OK will do 70%. An unfortunate lot of them (~40%) will be down in the 50-60% range. AAA are particularly poor. The space is just too small for the battery chemistry + electronics.
Still using them to see how long they hold up. Reliability is an unknown. I suspect the marketing claims for cycle life is WAY off. It'll take years to figure that out. By then the field will have changed a lot I think.

Last edited by harley48 February 18, 2026 at 06:10 AM.

HW 4-Pack 9V 1400mAh USB-C Rechargeable Lithium Batteries w/ Cable $12.45 + Free Shipping w/ Prime or $35+ Orders

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