Wednesday, October 23, 2013

NOBODY TOLD ME

Last week started out good as my 8mm SS bolts and wedge lock washers arrived on Thursday, so that evening, I started connecting the terminals. I continued on Friday night and also started strapping the packs to keep them from moving. 

Saturday we went with my family on the Coshocton County Fall Foliage Tour that features stops at local points of interest. This year, most of the leaves had not changed yet and the weather was chilly and rainy but it was good spending time with my mother, sister, nephew and niece. Upon returning home, I continued hooking up the batteries and by late evening had them all connected and strapped.


BATTERIES CONNECTED & STRAPPED

Sunday I removed the charger from the rear of the Fiero and put it on a a work bench in front of the car. I wanted to monitor the voltage during the first charge as the Zivan NG3 charger was going to need to be manually shut off, so I thought the Powerlab 8 could be hooked up just to monitor voltage. This would give me a nice graph of the voltage when finished. Seemed like a great idea until I plugged in the positive lead and heard a loud POP, right before the Powerlab 8 went dead. I emailed the manufacturer to inquire about the warranty but am not very hopeful the damage will be covered.

So on to hooking up the JLD404 to monitor the voltage. I had not used it for awhile, so had to go inside and read the manual but finally got it working and the voltage reading the 108 volts my volt meter was reading. When I had it hooked up in the Fiero when it still had the lead acid batteries, I could not get the amps to read correctly. The negative lead on the JLD404 is common and the shunt was on the front battery pack and the voltage wires were off of the controller terminals, so there were two leads on the negative terminal on the JLD404. There was a long 2/0 cable between the two negative leads and I believe it was acting like a parallel circuit, throwing off the amp readings. This time I hooked the shunt on the negative battery pack terminal using the negative shunt lead as the only ground. Then hooked up the positive side of the shunt to the 75 mv terminal of the JLD404 for the amp reading and the 500 volt terminal was connected to the positive terminal on the battery pack. That must have been my problem before because when the Zivan NG3 was connected the amps came right up to the 17.5 volts I was expecting and the voltage was at 108 volts and then started climbing.
 


JLD404

I monitored individual cells several times and when I felt comfortable everything was working correctly, went out and mowed the lawn. When I got back into the garage, the voltage was 130 volts, or about 3.4 volts/cell for the 38 cells and the pack had taken about 30AH. I noticed that the heat sinks on the diodes were getting pretty warm and thought if I put a piece of copper bar on top of the hottest ones, they would help dissipate some of the heat. With the cover off of the charger, the air was not being pulled through the heat sinks very well, so was afraid they were overheating. I put a bus bar on one of the heat sinks and when I put one on the other hot heat sink, kind of dropped it onto the top. It bounced and made contact with the one beside it, then a loud POP! This sound is getting too familiar and I am going to have to start being more careful. Two pieces of equipment blown in one day is not good. NOBODY TOLD ME THERE WOULD BE DAYS LIKE THIS!


I met Mark Weisheimer at EVCCON a few years back and have been told he is really good at repairing electronic components, so shot him an email. Mark agreed to look at the NG3 and CellPro, so I am taking them over to his house tomorrow night, with my fingers crossed that I did not do too much damage.

Monday evening after work, I took the blown components over to Mark's and got to see his 1975 Honda Civic Wagon . It  was a very clean build, there was no rust, and is a very solid car. Behind it was a crate of CALB CA 60 AH cells to be installed, so it is going to be a really great EV when it is done.

You spend so much time alone in the garage when building an EV that it is really great to talk to a fellow converter and always come away with many new ideas to use on your build.

 
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