Kratax 3500mAh Rechargeable Replacement Battery for Harman Kardon Onyx Studio 1/2/3/4 Wireless Bluetooth Speaker, Real Capacity, Same Quality as Original Battery

Kit is ok, I've used 3 of them now in a Onyx 2 and two 4's. Battery is smaller than the OEM cell but regular 18650's can in theory have the advertised 3500 capacity. I haven't been using them long enough to verify, but they are basically drop-in, charging works as normal, and the speakers work as normal again.The problem is if you leave them plugged-in all the time, the Onyx is just going to kill the battery again over time because there's no good shut-off behavior for charging while plugged-in. This is what is killing the battery, and it'll just happen again.What I've done is wired a simple switch into the positive battery lead and mounted it in the bottom of the carry handle recess. Charge the battery up, flip this switch off, and now you can leave the speaker plugged-in all the time without killing the battery. If I'm going to use it on battery power, switch the battery back on, top it off if need be, and unplug and go. Self-discharge of the battery is slow with it unconnected like this.I'm not sure if this is really worth the effort because the battery life is short no matter what, but I didn't see the point of even bothering with replacing the battery knowing it would just get killed again. The 2/3/4 are really great speakers and short of this battery issue mine have all held up for many years with nothing really beating them for the size/performance. If you regularly run yours off the battery then it is definitely worth the effort.

Okay, for some reason when I purchased my speaker. I did not realize it was supposed to be wireless. By that time. The warranty was out. I opened it up. I replaced it with this battery system. It wasn't too difficult and it works just great. It's nice to have that feature. I have the battery at least 5 years

The toolset for replacing the battery was completely up to the task, as I've managed to disassemble my Onyx 4 device and replace the battery as explained in the YouTube video.Speaking of the battery, it charged fine and the device was capable playing on the battery power for hours. The only drawback came from the mechanical aspect - unlike the original battery pulled from the device which snuggly fits the battery compartment, the purchased replacement was a bit shorter and a bit slimmer. The non-snug fitting was one of causes of auddible rattling when audio signal was loud in the low range. Fortunately, it was easy to overcome by wrapping the battery in a piece of paper towel. Just for the record - another smaller magnitude cause of rattling was incomplete tightening of screws connecting the two halves of the loudspeaker.To be completely fair - it could be that the replacement battery has been designed to fit multiple devices.All in all, I am happy to have been able to prolong the life of excellent product. The mechanical adjustment didn't turn out to be a bid deal.

easy replacement, however, it did not have the wire wrap like original or the wire holder where it clamps in at. a small cut to the rubber grommet on the original and it was able to be installed with the replacement.

Did exactly what was asked. Even had the tools to install! Great product!

Just installed and took me 15 min. Works will update after it has charged and I have used. I have a 4 so tool they sent was worthless. Mine had Philips head screws. Don’t waste time if your has the rubber water proof covering the screws. I used needle nose they came right out. Also the plastic tool is great to start but to get off you have to lift whole cover straight up which I didn’t know until I finally got it off. Also don’t do what I did and use the big felt wrap on the better it is meant for the wires. 2 smaller one is for battery. I watched how to you tube video before I started. So far very pleased. thought I was going to have to throw away a kick but speaker but I dont

Saved $300 by installing a new battery. Does not come with instructions so refer to product description. Be patient when installing take your time and you will not be disappointed. Be sure to wrap electrical tape around each end of the battery on install to stop it vibrating in the speaker when used. So worth the time and effort has extended life of my Speaker for another 5 years at least!

Less than a year from purchase and the battery would only hold a partial charge. Now it holds no charge. And it's just out of warranty. Don't waste your money. Original battery was good for 5 years.