[I've retyped this message three times as I'm worried it sounds like having a go, which I'm not meaning to, so read between the lines] Surely if a bit of debris can cut through an orange plastic conduit, it would also cut through a plastic trunking? I accept that there is a need to protect the cables, that's a good shout.Might this be another opportunity for Ali to show off his sheet metal skills and fold up guards that protect the cables? I'd suggest doing them in stainless so they don't rot and become rusty and chaff the cables with raggety rusty bits. That'll need more rivnuts, and cobalt drills.

And just to throw another consideration into the mix, isn't there also a potential need to expose the cables to air flow for thermal management, in much the same way as you are supposed to pay out all the cable on an extension cable (which I never do). So it's protecting them from big debris, while allowing air flow? Perforated stainless sheet metal guards?
 
Jayridium said:
Surely if a bit of debris can cut through an orange plastic conduit, it would also cut through a plastic trunking?
Click to expand...

It gives just an air space between the impact on the plastic trunking and the cable inside, which should reduce the pinching effect of flying debris between the impactor and the body beneath.
I'm not saying that if a huge chunk of iron is thrown up, then it'll protect the cables, but for smaller items it gives just a little extra protect.
 
Jayridium said:
I accept that there is a need to protect the cables, that's a good shout.Might this be another opportunity for Ali to show off his sheet metal skills and fold up guards that protect the cables? I'd suggest doing them in stainless so they don't rot and become rusty and chaff the cables with raggety rusty bits. That'll need more rivnuts, and cobalt drills
Click to expand...

Well yes stainless will add a huge amount of protection, much more than an EV, which normally just run the cables in a plastic trunking under the vehicle.
Jayridium said:
And just to throw another consideration into the mix, isn't there also a potential need to expose the cables to air flow for thermal management
Click to expand...
If Ali has done his sums correctly (he has), the cables are over specced for the current they will be carrying.
 
The thought of trunking had crossed my mind but what material trunking to use, how big it needs to be and how to secure it are all questions I don't have answers to yet. It would need to be tough enough to take stones and such from the road hitting it so normal electrical trunking would not be suitable. Any suggestions welcome. ;)
Mounting it from one side only would also be difficult as I don't want to drill holes in the floor of the car.
The cable I'm using to carry the current from back to front is 50mm2 welding cable which is rated for way more than the 220A max it will see. VW deemed 35mm2 big enough for their car with higher power and lower voltage.
 
Jayridium said:
[I've retyped this message three times as I'm worried it sounds like having a go, which I'm not meaning to, so read between the lines] Surely if a bit of debris can cut through an orange plastic conduit, it would also cut through a plastic trunking? I accept that there is a need to protect the cables, that's a good shout.Might this be another opportunity for Ali to show off his sheet metal skills and fold up guards that protect the cables? I'd suggest doing them in stainless so they don't rot and become rusty and chaff the cables with raggety rusty bits. That'll need more rivnuts, and cobalt drills.

And just to throw another consideration into the mix, isn't there also a potential need to expose the cables to air flow for thermal management, in much the same way as you are supposed to pay out all the cable on an extension cable (which I never do). So it's protecting them from big debris, while allowing air flow? Perforated stainless sheet metal guards?
Click to expand...
Like I mentioned above I want to hold the cables using the existing holes which are on the side of the chassis rail. Supporting steel trunking this way would be a challenge.
 
Drill lots of holes in your trunking, some of them get cable ties going through them, others get dome head cap screws going into your aforementioned rivnuts. simples.
 
Jayridium said:
Drill lots of holes in your trunking, some of them get cable ties going through them, others get dome head cap screws going into your aforementioned rivnuts. simples.
Click to expand...
Mmmm, I'm not sure this would be secure enough if only supported from the side.
I have a great idea though!

I'll put off a final decision until later. :p
I'm not bothering with the BMS connections yet so with only two HV wires to support cable ties will do and I'll come up with something when I need to.
Nodge mentioned that many OEM's have HV cable exposed but they are using higher quality shielded cables so can get away with it.
 
I've made a bit more progress the last few days in the HV junction Box. :)
A few days ago I dug out the timer relays I used months ago to enable the HV to go to the inverter through a (precharge) resistor first before enabling the master Positive contactor. This is important to avoid a massive current surge into the inverter when the HV is turned on. It would destroy the contactors and possibly the inverter too.
After some testing It seems the timer relays are not as reliable as I need them to be. :(
This is the type of module I was using.
s-l1600.png

https://ebay.us/i0exZE

One of them should have turned on after the other but I noticed sometimes they turned on at the same moment which would be a bad thing. :eek:
I had planned to use a more dependable setup anyway so dug out an Arduino Uno and a relay module I had bought ages ago and started browsing T'Internet for a program to plagerise. :rolleyes:

I've always found Ralph's videos very good and not too hard to follow so started by copying his sketch.


It was a simple job to make the necessary changes so now the timing is being done by an arduino ;)

IMG_20221126_151934561.jpg


You can see from the photo I managed to find a 12V source that is switched by the ignition pos 2 and T'd into it with an inline fuse holder. I'll solder the pos connection when buttoning up. Once I confirmed the sequence was correct I made the last of the HV connections so now when I turn on the ignition I have 350V at the inverter and charger. :)

Next step is to get the brake boost vacuum going, hook up the power steering pump, reconnect the EVBMW VCU and charger controller.
 
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Nice update Ali.

I've thought about pre-charge some time ago Ali, and came up with an idea which uses just 1 timer and the start section of the ignition switch.

My idea involves using the start position on the ignition switch to initiate the pre-charge and a timer to close the main contactor after a set time, connecting the battery to the inverter.
 
Nodge68 said:
Nice update Ali.

I've thought about pre-charge some time ago Ali, and came up with an idea which uses just 1 timer and the start section of the ignition switch.

My idea involves using the start position on the ignition switch to initiate the pre-charge and a timer to close the main contactor after a set time, connecting the battery to the inverter.
Click to expand...
There is a lot more to it than just activating the precharge John.
The sequence goes like this

Ign on - Precharge relay and neg contactor come on.
After a couple of secs the pos contactor comes on
A second or so later the precharge turns off and the vehicle VCU gets power so the car can drive.

Edit: The VCU will only get power when the key is turned to the start position. I'll probably do this by using a 12V relay to latch itself on. That way the car cannot drive accidentally by just turning on the ignition.

The sequence above is only for normal driving, for charging the sequence is the same accept the VCU doesn't get power and the ign is not turned on.
I still need to figure out the charging bit.
 
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Nodge68 said:
Thanks for sharing the sequence Ali.
It's more complicated than I imagined.
Click to expand...
It's not just the timing that is important but I want the car to be safe if someone climbs in who is not familiar with it. I want it to behave exactly like a normal car as far as starting, turning off etc is concerned. ;)
 
I couldn't resist a wee test drive today. :D
Unfortunately the sound was turned off so you don't get the full tyre squealing effect but I was really pleased with the test.
The first run was in first gear and the second run was in second gear.

 
Brilliant, well done for persevering and solving all the probs so far. There may be more !!o_O I'm sure that you are chuffed to bits.
 
Nice to see it moving again Ali.
Spinning the wheels in second gear too.:eek:
You really need to reinstate the AWD. ;)
 
Nodge68 said:
Nice to see it moving again Ali.
Spinning the wheels in second gear too.:eek:
You really need to reinstate the AWD. ;)
Click to expand...
Yip. :p
In fairness there is probably a bit less weight on the front wheels than there was with the diseasil engine so it would spin the wheels easier. I remember when I ran my K series without the prop shaft for a few weeks it was horrible, spinning the wheels everywhere and under steering at every corner.
Still it was great to see how quick it is off the mark and the battery is pretty low too. :)
 
Alibro said:
Yip. :p
In fairness there is probably a bit less weight on the front wheels than there was with the diseasil engine so it would spin the wheels easier. I remember when I ran my K series without the prop shaft for a few weeks it was horrible, spinning the wheels everywhere and under steering at every corner.
Still it was great to see how quick it is off the mark and the battery is pretty low too. :)
Click to expand...
You've now got twice the torque of the K1.8, and probably a bit more weight on the front tyres.
I think you'll be spinning the wheels a lot in normal driving, so AWD would definitely help.
 
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