u/AnyAccountant8422

I bought a sailboat with an older ePropulsion Spirit 1.0R.
The battery fully charges, but under load the motor only runs for about 5 minutes before shutting off, which makes me think the battery is at end of life.
From what I can tell, this older battery is no longer readily available.
Before I spend roughly $3,600 replacing the motor / battery / controls, I wanted to ask:
Has anyone successfully used a non-ePropulsion external battery with the older Spirit 1.0R?
Is there an adapter or workaround for the older analog version?
Is battery refurbishment even realistic, or am I wasting time?
Mostly using this for sailboat docking / low-speed maneuvering.
Any owner experience would be appreciated.

ePropulsion Spirit 1.0 battery losing capacity — external battery options