The HP 88014B Battery Back Instruction Booklet (HP pn 88014-90005, Printed in U.S.A. 12/1/85) has this to say about rechargers:
CAUTION
This battery pack is designed specifically to work with an HP recharger; HP is therefore not responsible for damages caused by using a non HP recharger.
The rechargers listed next are recommended for use with the HP 88014B Rechargeable Battery Pack.
Model AC Voltage Identification
HP 82059B 90 to 120 United States
HP 82066B 210 to 250 Europe
HP 82067B 210 to 250 United Kindgom
HP 82067B Opt 001 210 to 250 Republic of South Africa
HP 82068B 210 to 250 Australia
HP 82069B 90 to 120 Europe
Oh yeah, along with the 20V~/500 ma MAX. INPUT on the battery label, can't you read the part "WARNING: NO USER SERVICEABLE PARTS INSIDE. USE ONLY WITH ADAPTERS NOTED IN THE INSTRUCTION MANUAL."
Whatever. I hope that the little charging circuit inside the battery case is fairly robust, and could probably take 20V no problem, even though a Malaysian-made 82059D adapter says it puts out 8 VAC 3 VA max.
Sorry for the lack of information-added.
Summary:
1. Open the box.
2. Replace the battery.
3. Replace the fuse, if needed.
4. Give it some AC and charge it up.
Have a great day,
Dan