Another RadRover 6 plus battery problem

[web1]

I purchased 2- 6 plus bikes 13 months ago, my wife's step through battery is dead, will not light up or charge about a week after last using it. i installed my high-step battery in it and it works fine, so for sure it's the battery that is the problem. The bike only has 127 miles on it, of course Rad will do nothing for me because it's it's 1 month out of warranty. They offered to sell me a new battery for 100.00 dollars off the normal price of 499.00. I took it apart after watching some videos and this one had the black shrink wrap around the battery and I could not find a accessible fuse to check or replace. Any help or suggestions  would be appreciated.

[Naranja_CT5+]

There was a post floating around with an image of semi-integrated battery. The image shows a different type of fuse. It looked more like a transistor or diode than a fuse https://www.tti.com/content/ttiinc/en/apps/part-detail.html?partsNumber=0451010.MRL&mfgShortname=LTF&customerPartNumber=&minQty=1000&customerId=.

I am sorry I cannot give you a link where I read it. But it's located almost on the same area as the blade fuse. A multimeter should tell you if it's defective or not.

UPDATE:
https://www.radowners.com/index.php/topic,2583.msg13266.html#msg13266