First long drive to get fireworks on July-4

I say adventure, they say it's no fun to push a car up a hill.

We took Jane out to go get our July-4 fireworks at the nearest (1 mile away) fireworks stand.  Well it was mostly downhill to the stand, so that went well.  On the way home, things were going well and then we hit the first reasonable incline.  The motor cut-out but then was right back, basically pulsing with a thump-sound.

We pulled to the side, to check things and then started out again, only to have it repeat.  Every time I pushed on the accelerator, it would thump and not go.  Everything under the bonnet looked OK, no error indicators on the controller, batteries seemed to have sufficient power.  No logical explanation.  I had changed a couple of settings in the controller that morning.

So we hopped out and started to push it up the hill.  Luckily a neighbor was driving by and a stranger both joined in for the steepest part of the hill.  We made it home and everyone was a little winded.

Today, I spent with the car up on stands, just testing.  On the stands it performed well, spinning the wheels up to 35 mph in 4th, about 2,100 RPM.  This right inline with the estimates based on 36 volts of batteries with minimal loading.  Reset the settings that were changed yesterday.

So I figured, I could lower it back down and see.  The thumping returned just trying to back-out of the drive.  Back up on the stands.  No thumping.  Back-down and it seems to be running well again.  Up the steep hill with no problems.  Makes no sense.  Recharging the batteries now and then I'll head out for around block testing again.  

So far it's made it 2 miles on a charge with reasonable hills.  Given the quality of the three lead-acid test batteries I've been using, the best I can estimate is with the 60AH of LiFePo4 @ 84V that are planned, the car should be 15-20 miles on a charge. Eventually, it will be easy to double the battery pack to double the range.  Just a cost management situation at this point.  In a small town, 15 miles should be good for a day where nothing is much farther than 3 miles away.  Based on the charger, it should be able to recharge in about 4 hours.  More on that in near future.

This is a GPS plot of the 2 mile journey   Blue Line is speed (15-20 downhill, 7-8 up hill in 2nd gear).  The  gold line is the grade of the road.  You see the hills around the 10% range.  Fairly steep for an electric.  The Greenline is elevation (Green scale on the left).  A 5% grade requires twice the power.