Anonimjones,

The OEM NiMH charger is 36v 2.6amps. It's badged with EMS# 11057-001, but I doubt it was design from scratch for just the E+. It has 3 leads. Red, Black, plus a blue one that connects to a thermistor in the battery pack and stops charging if it gets hot. It's likely a standard NiMH charger except for the connector. I think any charger close to those specs would work fine. The D cells can handle a little higher charge current so 2.6-3.0 amps should work.

The battery is probably zero volts if it hasn't seen a charger for a while. They can be sometimes be revived but you shouldn't spend a lot on E+ stuff until you know you have a good battery.

Good luck with the bike. I hope you find a controller display cheap.