Is going to BugBlast – McCalla, AL…

It's lowering time!

Started a new binder and notebook… First page is only remaining page of the previous one… 🙁

DOH! – This morning while driving Gwen to induction day at Taylor Elementary, I forgot to shut the engine access hatch. On top of it was my notebook and ring binder with all my engineering notes from the last 3 years!

It wasn't until I got to the office I noticed, by then the notebook and ring binder had dropped through the hatch and on to the road…

I did find 1 page from binder and 1/2 page from the notebook at the entrance to the school… if you picked either please let me know.

Connected up the SOC output to the fuel sender. With a bit of calibration (and a 470ohm resistor)…. Voila! Full = Fully charged.

Cleaned all terminals and bus bars… now all cells above 3.09v during 160A test run. Well except cell 26… pesky thing… cleaned again just for good measure, too late tonight for another test run. Will try full scale test in the morning, when I drive to work!

Fixed a minor BMS issue cell 26, was causing bank C to report only 2 cells. Replaced the cell board. All 12 reporting in correctly. Still finding "rtv" under the bus bars. Only another 20 to check…

Mystery Missing Volts – Solved

To remove all imbalance I'm individually charging cells to 3.60v. It would have been easier before I assembled the pack 😉

Things I have learned about LiFePO4 batteries… balance your pack BEFORE you assemble them. Foolishly I assumed that since they all read 3.29v out of box that they were all somewhat at the same SOC. After several adjustments and consulting with the experts. What you are supposed to do is, parallel up all the batteries and charge them at constant voltage 3.6v. Right now I have them all around 3.45v, but it took 3 days to get here… if let the balancing continue this way it could take another week to get them all perfectly balanced. So I have ordered a variable voltage high current PSU, so I can hit individual cells and bring them inline with their brothers.