3500mAh Battery for Harman Kardon Onyx Studio 1/2/3/4 Wireless Bluetooth Speaker HK-OS4

Installed in a momenta an Harman Kardon revitalised. Perfect

This battery wasn't supplied with instructions but found a video on YouTube that showed every thing you need. Came with good quality tools for the price. Replaced in 10 minutes and I actually get more play time than the original, 7.5 hours compared to 5. I did cut the plastic grommet off the old battery leads and glued it on the new leads before installing. Well worth the money.

Very good quality 18650 battery ready for easy fitting.The battery comes already wired up with the PCB plug & built in charge protection circuitry, making fitting to your audio device a breeze.After fitting, I found the device ran for a really long time, proving the battery is doing an excellent job. After depleting the battery fully, I charged it and took some measurements of the battery capacity - the first charge came back with a result of 2690 mAh. Not too bad for the first charge.Pack even comes with a little spudger and a nice little T10 screwdriver. Brilliant little DIY battery replacement kit.

I received this for free for review as part of Amazon Vine.This is a Harman Kardon Onyx Studio replacement battery. It comes with a decent torx screwdriver, and a cute little metal spudger. The battery is listed as 3500mAh and weights about 50g.I put the battery through extensive charge and discharge cycles to test its capacity, and found it had a useable capacity of 2500mAh. I'm not sure how the battery rating is calculated, but given a LiPo can't be discharged to zero volts, and wouldn't work in the Onyx below a minimum voltage, I can't recommend the battery's rating sticker.At 2500mAh this is close to the original battery’s capacity, so it is a worthwhile replacement. However, I'm dropping one-star as none of this is made clear in its listing.

Batteries are perfect replacement, it was easy to fit and there was plenty of guides online.If you’re not sure check YouTube or Google, and you’ll find various threads explaining how to do it and videos.Capacity seems the same as the original, and is working perfectly. Very happy with this order. Good quality, happy to recommend.

Not the cheapest 18650 battery on the market but a doddle to fit with the tools supplied and my speaker sings to me again. Satisfied.

I like that a lot of kits for replacing batteries come with tools to help the job. One of the issues with those tools is they really are designed for single use and quite rubbish. I was surprised when out popped two tools that had good quality. The torx screwdriver was solid with a palm spinner top. Even better the pry/spudger wasn't flimsy and actually had a lot of strength and didn't bend under use!The battery is a good fit with the correct connector, everything looks good in that respect. I liked the foam around the ends too. This is a kit where no corners were cut and worth the money.

My original Onyx Studio 1 would only power on when plugged in to a socket, so I picked this up to see if replacing the battery would fix the issue. In less than ten minutes I swapped out the older and smaller capacity 2600mAh power pack for this 3500mAh version (that should power the speaker for longer between charges) and the Harmon Kardon is working perfectly again.This battery is a good example, supplied well packaged alongside a T10 hex key (that fits the Onyx Studio body and battery cover) and a pry tool; that I didn’t need to use as my Onyx opened easily. The battery itself has reasonable cables and is prepared with a protective foam coating on the ends. The original battery had a rubber grommet around the cables that best sealed the battery inside the speaker case, so I carefully cut that off and swapped it to the new battery before installation. After checking all wires, screwing the lid back closed, and putting it on charge for a few hours the Onyx is back and working as well as ever.It’s a bit of a shame the battery didn’t come with any installation guidance, but it was easy to find how-to video’s online, and it was very easy to do. The battery is pre-fitted with the correct terminal that clips straight into place on the circuit board. For less than a twenty pound note the replacement battery is a bit of a no brainer and has saved my Onyx from the recycling centre. Highly recommended.