ALTIZURE 9V Batteries 1000mAh Large Capacity Rechargeable Li-ion Batteries (2 Packs) Charge with USB Cable Suitable for Smoke Detector, Multimeter, Alarm System (Brown) (Brown-2)

Got tired of constantly quick-changing out the 250mAh Tenergy rechargeable batteries I use to drive a Sustaniac in one of my guitars, so I purchased these thinking it would be a nice upgrade. After all (in theory at least), 1000mAh should be considerably "more" than 250mAh, right?! Unfortunately, that was not the case here.These batteries are a millimeter or so thicker AND wider than a standard 9V battery, making it impossible to use them without tearing them up in spaces designed for a standard 9V battery - like the battery quick-changer on my guitar. The second I tried pushing them into the standard size sleeve it damaged the very fragile plastic shrink wrap that they are encased in. Made CHEAPLY in China. The build quality is considerably poorer than the Tenergy batteries that I use, with the usual attempts at English (i.e., "Must charge with specific charge!", etc.)"Oh, well", I thought, "can't return 'em now because I damaged them trying to actually 'use' them" - but "maybe they will do wonders for my wah pedals?" which also currently run on the 250mAh Tenergy rechargeable batteries I mentioned above (fairly decent batteries themselves, BTW, but fit tight as well in standard 9V spaces and don't last very long before needing changed out.) As it turns out, these 1000mAh ALTIZURE's do not run my pedals any longer than the 250mAh Tenergy's that I already use.So the only benefit of a higher mAh rating appears to be that they should last longer than lower rated batteries. For me, this benefit is considerably diminished when the batteries can't do what I want them to do (because they do not fit in standard 9V spaces) and do not outperform my existing batteries with much lower mAh ratings. But at least they are certain to do all this for longer.

First, I was surprised at how light these were. About 25 grams compared to a regular 9V which was almost 50. I fully charged them until the light was green but the batteries only measured 8.3V. I left it plugged into a device that was off, and in the morning it had drained itself down to 1.5V. I plugged it in to be charged, and 10 minutes later it said it was full.The package says it delivers a constant voltage, but measuring it under load showed that's not true.There's no way this is a 1000mAh battery. I wasn't expecting it to be for the price, but I was expecting more than this. Ended up returning it.

The media could not be loaded.  When this product arrived i was immediately sceptical because It felt cheap and proved itself to be just that. I bought these to use as a back up for my Carbonmonoxide/natural gas detector incase there's a power outage. It swole while in the unit so much so that the wrapping was pulled. No good!

Excellent product. Great value. Bought to power a Fernandes Nomad guitar with on board speaker and effects unit. One 9volt battery will last 30 to 45 minutes. Would recommend.

These rechargable 9v batteries are a huge improvement over store-bought ones for musicians who have active pickups installed in their guitars, or use effects pedals. Just connect your 5-9v phone charger after the gig and in a hour or so your ready to go for another gig.

One battery did not work at all and would not charge. It also swelled inside the device and was difficult to extract. The other seemed to work as expected.

The batteries won't charge up to 9 volts. 8.49 is the best it will do.

Great product. Easy to charge. No complaints so far.