Saturday, July 13, 2013

First time traction battery charging

Before connecting the motor controller to the traction battery pack I wanted to test the connections made so far as well as the PCM board and the charger bought for the 72V battery pack.

I first inserted the mini blade fuses in their fuse holders at the battery terminals. The fuses were inserted starting from the cell closest to the pack's negative terminal and then proceeding to the next cell connected to it. This connecting procedure was adwised by some PCM's and I decided to follow it as the PCM I received did not come with any manuals.

Before inserting the last fuse I checked that the mosfets in the PCM board were turned off. Once the last fuse was inserted the PCM's mosfets were turned on which is correct as all cells had a voltage of about 3,3V.

The charger was plugged in and a charging current of 10A was measured. I was beforehand a bit worried about the PCM's mosfets heating, but the heat dissipation with 10A charging current was measured to be just 0,5W divided by two TO-220 packaged mosfets so they only warmed up barely noticeable. I do not know which mosfets have been installed on the PCM as all of their markings have been sanded off for some reason.

I did not make a full charge as I want to be around with my multimeter learning about how the top balancing behaves and how the CBMs and everything else heats up. So I'll continue charging while working in the garage ready to stop charging if something fails.

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