Nintendo 3DS Low Voltage On Battery Charging Terminals

Hi, ı recently bought a 3ds it was sold as untested and I realized that the f1 fuse was blown and the the device was not charging but it turnes on with a charged battery and has no other problems. I bypassed the fuse with solder to see if it was only needing a fuse replacement. After that there is now some voltage (1.8V) on the battery terminals which ı believe is very low and it still doesn't charge the orange light doesn't turn on eighter. What could be the cause of this?
Thanks in advance to everyone who helps out.