balance

Step 34:  Watch cells balancing at night.  The battery side charging fuse is an Edison base type, 30A (it is rated for 125 volts alternating current but I've verified performance with direct current to be used plus I like its thrift - fuse holder is a ceramic flood lamp socket).  If needed I can do balancing sessions by swapping the fuse for a light bulb of chosen wattage to match the cell balancing load electronics.  A 200W light bulb limits the charge current to a little over half an amp.  My cell balancing loads are around a fifth of an amp, a 75W bulb.  A little imbalance may take a while to bleed off. 

Kits are available to increase balancing capability but I would avoid expense by manually bleeding the highest cell in the pack, and seeing how that went.

Every second the BMS communicates with the circuit board on each cell causing it to blink.  When a cell is being bled down to equalize the pack it leaves its light on.  I don't think I'll have to put up Christmas lights this year.

dc/dc

Step 33:  Install DC/DC converter to keep 12V system charged.  Up until now my 12V system has just been running off a 12V car battery.  This works but lights are dimmer and I would worry when having to run wipers and lights for extended periods.  The Mean Well S-350-12 DC/DC is wired to be on all the time.  It sits next to the motor controller in the trunk.

ac repair

Step 32:  Repair air conditioning.  A high side hose crimp blew while picking the kids up from school making a violent sound.  I had the hose repaired $20 and was pleased to see that the system was serviceable from underneath. Haste during the repair broke the condenser that came with the car.  So it was replaced with an aftermarket unit $84.  The system was open during some rain so the dryer $15 was also replaced before charging $32 back up.

broke

access

What you want is ~24psi on the
low side and 160psi on the high
side.  I left the high side
slightly lower, at 150psi.

new condensor

revisit 24

Step 31:  Revisit step 24.  After tightening one of the charger output fuses the output jumped up 20A.  I can now fully charge in 5 hours.  The charger may be put in the trunk someday but for now I charge at home.  The charge stations in town cost 6x the rate I can get at home.

I replaced the charger outlet behind the drivers front wheel. 

26.7A

This charge is for a 31.7 mile drive, mixed driving, 60mph, some traffic, not hypermiling.  That's 333Wh/mile, or 100 miles per (cost of a) gallon (at $3/gal).

power brakes

Step 30:  Install power brake vacuum pump.  Without any vacuum one could sufficiently stop, but holding the car on a hill would get old quickly.  A purpose built electric vacuum pump and reservoir from an electric vehicle supply house is added to help out.

A bracket to hold the reservoir is fabricated, you may recognize it bolted to the top of the motor in step 5.

It fits in front of the battery.  The reservoir takes a few seconds to pump up after every application of the brake pedal.  It works really well!  Power brakes really improve the driving experience.

monitor

Step 29:  Monitor battery.  Add instrumentation to monitor battery.

I wired a plug-in clock to the BMS controlled charging relay (DPDT).  I set the clock at noon and start the charge.  The duration of the battery charge is recorded when the clock stops.  My charge is constant current so I can then calculate amp hours consumed since the last charge.  

The 12V output in the old charger is broken, I've replaced it with another 12V charger.

old school

I can communicate with the BMS using a terminal app on my iPhone.  The terminal app is what logged the run around the block in step 28.  If the BMS has a fault this is how I read it.

new school

The old school is producing a number around 315Wh/mile.  The new school 290Wh/mile.  I have more trust in the old school at this point.  While driving the new school appears to blank out under high current getting stuck for periods at 0A or 497A.  I need to rewire the current sensor using shielded cable.

new school current sensor

range

Step 28:  Figure efficiency.  

I can go 45 to 55 miles on a charge.  


I found the bad connection that was not allowing my BMS current sensor to work.  With the new current sensor operating I logged a run around the block.