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[raystl]

Well I got my MY18 DSR powertrain setup to work in the plane I;m building. Tried to turn on for a final check but nothing happened. No dash even. All high voltage fuses checked out ok.

Eventually traced back to the always on power (signal pin 1) from battery. Opened doghouse to get at feed from contactor. Raw voltage at battery is 114.2.

Hoping the fuse holder was bad, (about the only thing i could replace myself) I cut the output line from the holder to bypass that fuse. Unfortunately fuse holder was not the problem.

So problem is between the holder and the Pin 1. The single wire goes into the bowels of the battery and comes back out as 2 wires going into Pin 1.

Measured weird voltages between various points in the disconnected battery.

red                  black       Volts
Contactor         Pin 1         0.002
Contactor        -Post         114.2
Contactor        +Post        106.5
-Post                 Pin  1     -113.7
+Post                 Pin 1     -106.1
+Post                 -Post     0.006

Looks bad. Help.

Thanks

[pacificcricket]

No dash even.

Isn't the dash powered from DC-DC ? Have you checked if DC-DC is getting / putting out power ?

[raystl]

The dash backlight uses the low voltage DC converter, specifically through the run light circuit. Dash operation does not require the DC converter. You can remove it from the harness and the dash will function, without a backlght.

With considerable outside help, I was able to do some testing that uncovered two things:
1. My main board was dead
2. Voltage measurements on an isolated battery are invalid. It needs to be connected to the harness.

I ordered a new board yesterday.

I did learn something surprising. The key switch receives an always on 12V  (Yellow grey line) from the battery pack.

[pacificcricket]

I did learn something surprising. The key switch receives an always on 12V  (Yellow grey line) from the battery pack.

Probably BMS is putting out that 12v ?

[raystl]

Makes sense.

I find it interesting that the main board gets the always on high voltage, 12V and the ground from the battery pack as well as the low voltage (~13.8V) and its ground from the DC converter. These grounds are isolated from each other.

And there is another ground in the system. The input charger's ground pin is only connected to the bike frame and shell of the battery.

 

[pacificcricket]

Makes sense.

I find it interesting that the main board gets the always on high voltage, 12V and the ground from the battery pack as well as the low voltage (~13.8V) and its ground from the DC converter. These grounds are isolated from each other.

And there is another ground in the system. The input charger's ground pin is only connected to the bike frame and shell of the battery.

Zero uses Sevcon DC-DC, and it's an isolated unit, so naturally its ground will be isolated unless interconnected.