Lithium cell balancing modules

Here's a picture of one of the 53 cell balancing modules I received last week from EV Works in Australia. Each module sits on a cell and monitors its voltage to ensure it stays within appropriate cell limits (2.5V-4.0V). Its signal wires (yet to be soldered on) are daisy chained to neighboring cell modules, and the whole loop is connected to a BMS controller. The BMS controller is inline with the AC line to the charger. If the charger does not taper current back when the cells reach the appropriate voltage during charge, the BMS can literally cut the charger off at the knees. There is also an audible alarm (although unclear how loud) the BMS has to warn of cell anomalies.

Note that this system only protects against over-charging. The Zilla controller already has configurable safeguards for over-discharge of the cells.

I guess I will start soldering wires this weekend. Lots of wires. Fun!

Lithium order increase, and BMS change

I was a little uncomfortable shelling out ~$2K for a Elithion BMS that had very little documentation and not a lot of explanation from the company, so I started hunting around. Folks that have Thundersky LiFePO4 batteries have also gone with a much cheaper battery balancing system from EV Works in Australia, here's the link:

EV Works BMS controller

This controller costs $AUD 350, which is around $315. Coupled with the 'cell balancing modules' ($AUD 16.90 or $15.21 ea), I should have a reasonable overcharge protection system. The Zilla already protects me from over-discharge, so no worries there. Based on this change, my BMS budget shrank to ~$1000, sooooo... I increased my battery order from 45 to 53, and that still fits in my car, and my budget.

The good news here is that 53 x 3.2V = 170V traction pack. Very close to my original peppy 180V voltage, but with much less weight!

These are the lithium cells I am buying (45 of em)

Sky Energy SE100AHA LiFePO4 cell info

My winter project: LITHIUM UPGRADE!

I just placed my order for 45 Sky Energy LiFePO4 cells from evcomponents.com. This new traction pack will be a third the weight of my current pack, and have at least twice the range. Oh, and the voltage will be higher (144V vs. 96V). Don't know when I will get them (they get shipped from China), but pics will be posted when they show up!