Mar 5, 2020
Welcome to the Bose Community! Sorry to hear that you need a new battery for your product, this isn't a part that we sell.
If your product requires service, I would highly recommend getting in touch with our customer service team via clicking this link, then kindly scroll and select your region, once this is done please scroll to Contact Us. The team will be on hand and ready to help.
Please do let us know if you have any issues reaching your regional support team.
Jun 15, 2018
@GrampsThe battery is not user replaceable. I do not work for Bose so this next comment is to let you know that Bose does not like it when customers open up their units. They say it will void the warranty (which I believe is normally for a year). With that said and assuming your unit is over a year old and you are a DIYer and good with a soldering iron, you could probably figure out what the battery is or fine some post somewhere in this or the over ear forum to provide you with more battery information.
With that said, I am not a DIY and had (and posted here), two Revolves that were not holding a charge after I charged them to 100%. So I sent them back to Bose. Cost me somewhere around $70 to $75 each - I don't recollect the exact amount. They replaced a board and battery. Now I am not exactly sure why the returned items were still not holding a charge. It may or may not have had something to do with my turning off the units with the multifunction key (which is the only way to completely turn it off and keep it from being in BLE [bluetooth low emission] mode which let's it be turned on by something else). So I sent them back a second time and got back completely new units (with 1/28/20 manufacturing date). As I posted here, first time I charged them (and then upgraded firmware from v1 to v3), one of the units was at 60% after a day. I have gone two or three days now at 100% but have use the top power button to turn it off.