Who runs Fun-EV?

AFAIK, the owner of that site is DanCar on these forums. He's selling the EFun-D bike.

Interesting that he's offering a LiFePO4 E-Fun D ~with or without~ a Battery Management System....

Am I wrong in assuming that without a BMS you are just about guaranteed to have problems with a lithium pack?

Am I wrong in assuming that without a BMS you are just about guaranteed to have problems with a lithium pack?

We need more information at this point, but my bet is that you definitely would. According to Battery Powered Systems:

These "Lightning Bolt" batteries will remain balanced as long as you do not exceed 3C in discharge. If you exceed 3C in discharge they will become imbalanced over time. This will not damage them but it will require that they be individually re-balanced to regain their full capacity. To avoid the hassle of taking your packs apart to balance them we recommend that you employ automatic balancers in your packs...

You may use almost any pure DC isolated charger to charge the packs if you employ the PakTrakr and BatteQ technology in your vehicle. Set your upper limits at 3.8VDC per cell, and your lower at 2.7VDC per cell and you are all set.

Interesting that he's offering a LiFePO4 E-Fun D ~with or without~ a Battery Management System....

Am I wrong in assuming that without a BMS you are just about guaranteed to have problems with a lithium pack?

It depends on the time frame and driving conditions. They have been used for 6 months (10-14 mile commute) with out slightest battery imbalance. Summer heat might may help create an imbalance. Based on this data I'm telling people if your have a similar commute you don't need a charge management system until after a year.

http://www.fun-ev.com

It depends on the time frame and driving conditions. They have been used for 6 months (10-14 mile commute) with out slightest battery imbalance.

I find this surprising. Can you provide cell voltage readings at the end of charging that support this? What is the volts per cell that you are charging them to?

Here is what I specified to the mfg.