ThinkJet 2225B battery pack question

[Dave Frederickson]

What we know about the battery pack:
1. A good battery pack fully charged outputs 8.5V
2. Typical output is 7.2 to 7.6V
3. The Power LED will indicate a low battery and flash if the voltage drops to 6.2 to 6.5V
4. The fuse is rated at 5A.

If the fuse was derated by 25% then the output would be 3.75A.
So a power adapter with an output of 7-8V at 4A should work fine.