EVTV sold a bunch of them, AFAIK folks are using ~$1000 chargers with a constant current phase (till a predicted voltage achieved) followed by constant voltage phase (till a predicted current is achieved), charging them in a string. Might find some discussions about it.
Some specs at the bottom of this page:
EVTV Motor Verks Store: 1 Renault Influenza Battery Packs, NEW ADDITIONS - THIS JUST IN!, Betterplace