Better Place Pack Performance

I tested a few of the Better Place modules for capacity. The starting voltage was 3.28V. Cell was charged at 30A until 4.2V at 3A. It took 58.3Ahr to charge fully. For discharge, the cell started at 4.15V (soon after charge was completed) and it was discharged at 30A. This resulted in a capacity of…


Better Place Pack Specifications

We managed to get our hands on a Renault Fluence ZE battery pack as part of the Better Place bankruptcy. This pack is basically the same as in a Nissan Leaf, the same cell count, cell manufacturer and basic specifications. Here is the original pack: Specification Value Voltage 387 V Topology   96S2P, 48 Modules in…

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Pack Re-Assembly

Just finished testing the last of the cell groups that had cells replaced. Here is a summary of my findings. Since there are six 10 Ahr cells in each group the original capacity  when the cells were new was 60 Ahr. The “Starting Capacity” column shows the capacity of a group before cells were replaced.…


Pack Evaluation

The rear pack is still out of the 240SX and I’m now in the process of getting the pack back together and back into the car. The overall result of my testing is complete and it’s not all that good. The lowest cell group in the pack is now at 42 Ahr, down 30% from…


Faster Charging

My charge setup uses a Vicor MegaPac with a 5V 40A module. A JLD404 Intelligent Ammeter is used to track the energy into the battery and cutoff the MegaPac charger once the voltage reaches 3.65 Volts.


Faster Discharge Testing

Discharging a Lithium battery is actually quite simple. Put a load on the cell and wait until the cell voltage drops to 2.5 Volts then stop discharging. The load should be between 0.5C and 1C and you probably need a way to measure the amount of energy you have removed from the cell. I decided…


Battery Testing

Testing batteries is the most boring process imaginable. After 3 or 4 manual tests I decided some automation was necessary. In my case that means it’s time to build something. After reviewing the BMS logs I came up with 4 cells that seemed to be the weak links in the pack. They were the ones…