Today was very exciting but ultimately a little frustrating. I've been working on the HV junction box and after changing my mind about 10 times I decided to go with the layout below.
View attachment 268533
I'm using the contactors, fuse, pre-charge resistor, pre-charge relay and a cut down portion of the plastic frame from the eGolf battery junction box.
The two cables coming in from the bottom of the photo are the HV cables from the battery pack.
The Battery pack Pos goes to the fuse, then through the fuse to the top contactor. The Neg goes straight to the contactor.
The two modules below are timer relay modules that trigger the relay and contactors after pre set delays. These are cheap ebay modules so I wouldn't be confident they are reliable so I'll probably come up with something different for the final build but they will do for testing. The timing is as below.
1. Ignition on sends 12V to the neg contactor and the two modules.
2. The pre-charge resistor is on the NC of the second timer relay so it comes on immediately sending pack voltage to the inverter via a 30R resistor.
3. After a couple of seconds the first timer relay triggers sending 12V to the main Pos contactor.
4. A few seconds later the second timer relay triggers disconnecting the pre-charge relay and sending an enable signal to the Damien Maguire VCU.
These timers are very cheap and probably not very reliable so I don't think I'll be using them going forward but for testing they are fine.
So I spent the morning securing the contactors etc then dug out the VCU and hooked it together then connected the battery pack together and held my breath while turning on the system.
No smoke, no bang, just leds flashing as expected. Phew!
Then after rigging up a manual 12V disconnect (power lead through the window that I can yank out if necessary) I gently pushed the accelerator pedal and....
Almost nothing.
The 1500W ebike controller was more powerful.
After some initial confusion I think it is because the last time I used the VCU it was during bench testing when I probably had the max current cranked all the way back to prevent over speed. Unfortunately I had no time to make any changes due to family commitments so the first proper test drive will have to wait until tomorrow.
Wish me luck.
