I started bottom balancing the first module of the Better Place battery pack last week and wanted to hook up a my JLD404 to measure how much capacity it was holding. I got the meter hooked up with a shunt and plugged in 2 1500 watt spot lights and was pulling 15 amps. I had to unplug the lights to stop the discharge, so decided to add a cutoff switch to the circuit. I was running low on crimp connectors, so had to fumble around a bit to get everything hooked back up but finally had the switch in the circuit. When I turned it on, something was not right, the lights did not come on and there was a pop and smoke billowing out of the JLD404 meter. Then there was a louder pop and I hit the kill switch. Seems I forgot to hook the lights back into the circuit but fortunately, my fuse (the 200 amp shunt) blew! All of this took place in 5 to 10 seconds that seemed like 5 minutes. Oh, if you run into Brian Couchene or Mark Weisheimer, keep this story to yourself, they already get a chuckle out of my past history of plowing up electrical equipment. As you can see in the picture below, the copper on the circuit board is vaporized. On the bright side, I guess I did find an alternate to Damian McGuire's spanner to test C rate.
Not to worry, Light Objects sells new ones and this time I got the red display, as I believe the red shows up better in daylight than the blue did. So on to continuing the bottom balance. All of the individual cell voltages were recorded and the lowest voltage cell was marked. A volt meter was attached to the lowest voltage cell and the 3000 watts of spot light was turned back on and the battery pack was pulled down until the low cell hit 3 volts. Then all of the cells were checked again to make sure that this was still the lowest cell. I then hooked up a 40 watt light bulb and checked the voltage on the cells again to make sure this was still the lowest cell under load and it was. I took the cells down until the lowest cell hit 2.5 volts and then let the pack settle for 24 hours. The next day, the lowest cell had come back up to 3.05 volts. I realized then that this was going to be a real battle getting this pack bottom balanced. The 40 watt bulb was used to take the pack back to 2.5 bolts and then I used a small night light that allowed the pack to start going back up in voltage but was still draining the pack.
LOAD SET UP
I left the night light on until the pack settled at 2.695 volts and then let the pack come back up to 2.7 volts. I will carefully hook up the "NEW" Jld404 to cycle the night light until the lowest cell settles at 2.7 volts.
LOW CELL AT 2.7 VOLTS
While the pack was draining, work was done on mounting the Dell Venue 8 pro. A template was made of the opening on the top of the console and a piece of ply wood was used to make a covering. The suction cup was removed from the mount I purchased last week and the front and back of the base were ground down so it would sit on the plywood. Then the bracket was positioned on the plywood and a hole was marked and drilled to fasten the mount to it. A thin vinyl was glued to the plywood and all of the pieces were mounted.
Another wire harness was made up to go to the rear of the Fiero, as the shunts and voltage readings will move to the motor compartment when the Better Place packs are installed.
The next project will be making a cover for the radio opening to mount the JLD 404, placing a micro switch on the heater controls to turn off the heater, and figuring out how to make a switch to short the data wires on the usb when the Venue 8 is booted up. The data wires have to be shorted to start charging but then can be un-shorted to allow for data processing.
Thanks for visiting,