New controller & Kill A Watt

The Kelly KDH14800D finally arrived. It is larger than the B model and uses a 0-5k ohm throttle. So, I had to cut out the 5v input to the PB-6 because it was causing a ton of interferance with the potentiometer. The controller has great pick-up from a stop and could even accelerate from 30 mph pretty well. It topped out at 73 mph.

I drove 10.4 miles and recharged the pack. With a kill a watt meter it registered 4.47 KwH. So, 429 wh/mile. Hmmm, room for improvement? The brakes might be rubbing a bit, the tires need inflating, I was pushing the car to see what it could do and the Kill A Watt is measuring from the wall so it takes into account any loss in the charger.

New controller & single cell charger

Kelly Controls sent a new KDH15600B, which is 11" long compared to the 7" KDH14401A. It fits into the same spot as the smaller model with only one new cable needed. Notice the paktrakr resting there. I'm waiting for an extension cable to run from the last remote in the trunk. Then I'll strap the remotes and display in a permanent location.



Single Cell Charger
After the initial charge to the TS cells and they rested the voltages were all between 3.32V and 3.36, which is pretty good. I bought a single cell LiFePo4 6A charger to manually balance the cells in the interim before I can find an inexpensive and adequate BMS. The single charger has a 3.8V cut-off and each cell charged for 1-2 hours then after rest the cells are all at 3.50V. The weather was a little colder the past few days, -5F and the garage was cold too and each cell appeared to dip a little to 3.48V. I expect when they warm up they might come back to 3.5V.

According to the ThunderSky charging curve 3.8V is 75% charged and the remaining part of the charge curve is at 4.2V with a tapering current for about 30-90 minutes. So, I'm not sure that shunt style BMS that limits part of the current to 3.8V is appropriate unless it can "release" all the cells once they are balanced to finish the charging cycle.

Snow Driving

We took the del Sol out for a drive today. All-in-all very good but the acceleration was very choppy and slow and after about 5 minutes at about 40 MPH the controller cut out. I pulled over and it wasn't hot to the touch. I've been warned about overheating with the Kelly KDH but it isn't a hot day (see the pictures below and notice the snow). I'm more than a little concerned that the Kelly controller is both underpowered and easily overheated.


It took 5 attempts to get up the drive way between the choppy startup and the summer tires on the slick snow. Since the car came with studded snow tires I'll have to put them on soon.

After contacting Kelly Controlls customer service they said the KDH14401A (144V/400A w/ Regen) was underpowered for the vehicle. They recommended an upgrade to the KDH15600B (156V/600A). The A models are 7" while the B models are 11" and the web site says the B's are a newer design. I'm hoping that will take care of this problem.