Published December 29, 2012: Updated August 12, 2014
Geo Metro EV Conversion Part 2
A smart charger and BMS (battery management system) were absolutely necessary too. By going with a 72 volt system and using large 160Ah cells, I was able to keep the cost of the battery management system down yet still have a decent battery range. Lower battery voltage is also much safer to work on.
My greatest mistake on this car was that I didn’t buy my batteries, BMS and charger from a local distributor. I was seduced by the false promises and low prices of a dealer called EVLithium who is located in China.
His prices were so much lower that to me it was well worth the risk. But if something is too good to be true, it probably is. By the time the batteries eventually showed up, I ended up paying nearly the same price as the local dealer but with more headaches because of shipping delays, import fees and extra shipping costs that were not disclosed up front. After being without my hard-earned money for so long, I was very relieved that the shipment actually made it at all.
Sadly, the battery charger would not communicate with the BMS and in turn, it would not charge the batteries.
I made every attempt to RMA the charger back to EVLithium but they refused, insisting that it worked perfectly before it left the factory.
Lesson learned: If for no other reason, buy your hardware locally so you can have good and reliable tech support and a store-front that will accept defective product back.
I bought a new battery charger from Elcon out of California and 2 days later, my EV was up and running with a working, on-board battery charger.
Battery Placement:
Originally, I was going to put 13 of the 24 cells into a cage I fabricated under the rear set where the original gas tank used to reside. Just to get the car on the road, I temporarily set the remaining 11 batteries in the rear hatch-back area.
With almost no weight on the front tires, the Geo handled terribly. When driving faster than 40 mph, I felt like any wrong turn would cause me to over-correct, sending me into a zigzag, following by several barrel rolls.
Going back to the drawing board. I made some new battery boxes so I could mount 16 batteries in the front engine compartment and 8 in the box under the rear seat.