Cutting out for no apparent reason

[Alibro]

Nissan Leaf Gen 1 inverter and motor
Outlander PHEV charger
Damiens VCU for the above inverter.

Hi guys
My EV conversion is on the road and for the most part is working great however I am having issues with it intermittently cutting out while driving and
to get it going again I need to pull over, turn off the ignition wait for the Inverter voltage to drop then turn it on again.
I always have to wait 10 seconds or so after I turn off the ignition, is this normal? Could it be related?
Yesterday I drove around 30 miles without any issues, parked for an hour or so then while driving the 9 miles home it cut out 4 or 5 times.
The odd thing is it does not seem to matter if I am accelerating or just cruising along it seems to be random. Once it happened when starting off and the other times I was doing a steady 50mph.

I think it might be worse when the pack voltage drops below 360V but this may be a red herring as it should have at least another 25 miles at that voltage.
I also thought it might be connected to the vacuum boost pump so wired a diode across it to prevent spikes but this didn't help last night and when it cut out I hadn't touched the brakes so the boost pump should not have been operating.

My dc to dc charger is connected via a relay which is driven by the VCU output 2 (Output for the main contactor) and I can see it is still active so think the issue is with the Inverter but can't be certain.

I plan to hook up a laptop and monitor the CAN data to try and see what the issue is but would appreciate any suggestions.

[andybpowell]

are there no errors on the vcu ?

[Alibro]

are there no errors on the vcu ?

Good question but I'm not sure how to tell.
It was still sending out the temps info to the WiFi module. At least I think it was, it's kinda hard to be sure because if the VCU Freezes the info on the WiFi screen freezes too.
I've never seen any relevant info on the serial monitor

[andybpowell]

what vcu are you using

[Alibro]

what vcu are you using

Damiens Nissan Leaf Gen1 VCU.

viewtopic.php?t=179

[andybpowell]

so it's just a can controller for the leaf, didn't know he did one to be honest

[jrbe]

Vacuum pump could be pulling hard on the ground lines / wires. You have decently thick and well connected grounds for the controller?

Make sure the can lines are connected well, twisted, and terminated properly. If they have to go near any noisy or high current areas try to cross at 90° but avoid these things if possible.

[Alibro]

so it's just a can controller for the leaf, didn't know he did one to be honest

I think it ended up being the predecessor of the Zombieverter, Fiachra Cook used the same controller on his Audi

Vacuum pump could be pulling hard on the ground lines / wires. You have decently thick and well connected grounds for the controller?

Make sure the can lines are connected well, twisted, and terminated properly. If they have to go near any noisy or high current areas try to cross at 90° but avoid these things if possible.

I thought the same about the vac pump so will rewire the ground for it. I already have a separate 12V pos going through a relay for it.

Good call on the CAN lines, I am a bit concerned the CAN terminator (at that end of the bus) is too far from the inverter so I may open it up and solder a 120R resistor internally. I don't know where the inverter came in the CAN network of the Leaf but it's not terminated and I have probably extended the CAN lines beyond what is advisable.

Thanks for the suggestions.

[Alibro]

I spent a couple of hours working on it this evening and have ensured the pos and neg for the vacuum pump go directly to the battery.
Maybe it's a stupid question but would I be better having the neg bolted to the chassis of the car instead? I also have a TVS diode connected across it to help prevent back emf.

I also took the top off the inverter and soldered a 120R resistor across the CAN wires. I had it in the LV connection box before so it was almost a metre from the inverter connector, hopefully this will help.

While I was in the LV junction box I changed the power up sequence for the Inverter and now when I turn off the ignition I only need to wait a second or so before powering on again. Previously I needed to wait almost 10 seconds.

I'll report back later after more testing.

[jrbe]

..would I be better having the neg bolted to the chassis of the car instead?

To the battery is usually cleaner.

I also have a TVS diode connected across it to help prevent back emf.

You could do a 100pf 80+volt capacitor across the + & - as close to the motor as sensible. This will help gently absorb the brush noise and spikes.

[Alibro]

To the battery is usually cleaner.


You could do a 100pf 80+volt capacitor across the + & - as close to the motor as sensible. This will help gently absorb the brush noise and spikes.

Any suggestions what type of Capacitor would be best? I've found several types of ceramic, polypropylene, polyester and mica?
Or just go for whatever I have lying around?

[janosch]

If its cutting out randomly that could be many different things, of which the vacuum pump could be one.

It would be good to get visiblity of the error flags in the inverter, you lose access to that webinterface when it cuts out, too?

[jrbe]

Any suggestions what type of Capacitor would be best?
Or just go for whatever I have lying around?

Whatever is easiest to install and most likely to survive.

[Alibro]

If its cutting out randomly that could be many different things, of which the vacuum pump could be one.

It would be good to get visiblity of the error flags in the inverter, you lose access to that webinterface when it cuts out, too?

To be honest when it happened I was more concerned about finding somewhere to safely stop on a busy dark road and didn't spend any time looking at the webinterface. It only gives me Voltage and temps anyway so I didn't think it would help much.
Since making the changes I've driven around 20 miles with no issues so will do more testing to see what happens. If the issue persists I'll figure out a way to monitor the CAN going too and from the inverter.

[Alibro]

I'm still having issues with the car cutting out randomly so spent a bit more time trying to sort it.
Initially I had thought all the issues were related to the brake boost vac pump but several times it happened were on straight bits of road where I hadn't touched the brakes, also on one occasion it cut out when I flashed the headlights.
That made me think something else was going on then the other day while working on one of the leccy windows I heard the contactors in the boot trigger off and on. It made me think maybe there is an issue with the ground which connects directly to the chassis or the live which is fed through the inertia safety switch. I decided to run cables directly from the LV connection box to the boot and bypass the inertia switch.
This all happened on Christmas Day while the wimmin were watching Strictly so I still have to test some more to see if it makes any difference.
If it turns out the issue was just dodgy Landrover wiring Then I guess I've nobody but myself to blame for being daft enough to trust it in the first place.

[Alibro]

Looks like the issue is still there.
I drove around 30 miles today and it cut out once when pulling away from a parking space. This time it was when I turned the lights on so I'm wondering could it be something like a dodgy earth.
I have the 12V capacitor bank that was in the Nissan Leaf and was wondering if there is any point in trying to hook it into the system somewhere.
What do you guys think?

[jrbe]

How old is the wiring in the vehicle?
I've seen some mid '80s cars have huge voltage drop from corroded wiring, fuse blocks, and connections. I mean old copper wire that isn't oxygen free. Cut in the middle of a long length and it's green inside. Saw about 7v on a12v system and was running rough. Found that and decided to replace all the wiring.

The capacitor won't solve the root cause. Your 12v battery should be plenty of a buffer if wiring and connections are good.

Sounds like a bad ground to me as well.

I imagine you should see some kind of voltage drop from being parked and turning on different power consumers like high beams. Should be able to narrow it down chasing that.

[Alibro]

How old is the wiring in the vehicle?
I've seen some mid '80s cars have huge voltage drop from corroded wiring, fuse blocks, and connections. I mean old copper wire that isn't oxygen free. Cut in the middle of a long length and it's green inside. Saw about 7v on a12v system and was running rough. Found that and decided to replace all the wiring.

The capacitor won't solve the root cause. Your 12v battery should be plenty of a buffer if wiring and connections are good.

Sounds like a bad ground to me as well.

I imagine you should see some kind of voltage drop from being parked and turning on different power consumers like high beams. Should be able to narrow it down chasing that.

Sorry mate, I thought I had replied to you already.
The car is a 2004 Freelander so the cabling should be OK but maybe not the earth points. Another odd thing is the reversing sensors work sometimes but not other times so there must be a bad connection there.
I tried putting a meter on the 12V for the inverter and VCU then playing with the lights and other high current devices but didn't see any change.
I know the capacitor block was in the rear of the Nissan Leaf beside the charger so I guess it had something to do with charging rather than preventing the inverter from cutting out.

[tom91]

Along with the Inverter kicking out drive there also was a charging issue on this vehicle.

This is now apparently resolved it turned out to be the way a combination of timer relays was used to control the HV contactors.
viewtopic.php?p=65938#p65938

Fixing the issue in project thread.
viewtopic.php?p=66051#p66051

[Alibro]

I was hesitant to call this fixed as I've only been testing for a few days but it appears to be sorted now.
As Tom91 said a positive feed to a timer module was shared with a couple of other devices in the LV junction box and when other electrical items were turned on like the brake boost pump or even headlights the module would drop it's relay. This is the relay that was holding the positive contactor open and the contactor would then open causing the car to cut out.
I now have a latching relay holding the positive contactor but am still triggering it from the timer module.
The timer module is there as a secondary safety measure to prevent the positive contactor from closing before precharge is complete. I believe in certain circumstances my VCU can lock up with the outputs for the contactors stuck on which could (if I'm correct) cause a loud bang and a blown 300A fuse when the ignition is turned on.