While the es-31b is supposed to do 144v, there is a similar vehicle on the EV album that 'burned up'. Looks like a brush spring got hot and shattered:
Jonathan Trotter's 1973 Sebring
The comments on the page may be sour grapes, but if it is a similar failure...
On the other hand, this guy seems to really like that motor:
Ken Barbour Jr.'s 1991 Geo Metro Convertible
(late note - this fellow upgraded to 120v in April. He was running 72v before...)
But he is only running 120v. May be the difference between fun and fire.
There are several others running an es-31b, but almost all have less than 200 miles.