Sorry, I don´t know where you can get one, but you need this one

Good luck

Thanks Beozip.... that might help having the battery model number

I used mine for about 10 years until it gave up on me, quirky but a great little thing. I used to always call people rather than texting/whatsapp though I did keep an ipod touch for music on the go and a bit of web browsing if I was in a bar/cafe waiting on someone to arrive.

I guess I'm trapped in the smartphone world now because I have a youtube channel and I use the video/camera/memos stuff a lot but I do miss having a phone that lasted several days between charges. I always remember how I got the Serene at university and was mocked by a few friends for spending £800 on a phone. Then Jeremy Clarkson had a Serene on Top Gear and they quickly shut up because he was treated like Chuck Norris in our group.

Search for this:

samsung sgh-e910 battery

I found one for a very crazy price .... in Spain 🙁

https://www.ebay.de/itm/Bateria-original-Telefono-SERENE-de-BANG-OLUFSEN-Fabricada-por-Samsung/193278909654?hash=item2d00521cd6:g:33wAAOSwh~pd7opZ

..... and one in Italy 🙁

https://www.ebay.de/itm/BATTERIA-SAMSUNG-SERENE-SGH-E910-ORIGINALE-GENUINE-BATTERY-AKKU/401984150165?hash=item5d981f5a95:g:rOYAAOSwv7ld56Jh

I've tried using Samsung in the search. I did see the batteries for sale but those prices are crazy. One ad can't even confirm if the battery even works properly. Actually even the prices of the phones are quite high, quite surprising. 

Try this one,from India.

I did try them. Paid them then they refunded me my money as they couldn't get stock. I've really tried everything. Thanks though for everyone trying to help!