After reading lots on diodes I see that a the 1N5822 is rated for 3A continuous, I did a test yesterday with it using a decent size DC motor and applying a load the diode did not heat up. So I think it's a safe bet. I'll do a test with the in car fan connected before closing everything up.

 

Yep. That would do it.

 

So another thing I'm questioning myself on is the ground wire for the 200v & 12v. Since I wired in the volt/amp display the ground for both are common. This is because the display has an internal ground link of its power and sense inputs.

I'm not sure what the risk is here... I could still add a separate dc supply for the display, just wonder what could go wrong with both the display and fan(12v circuit) having common ground with the 200v?

 

The configuration you describe is pretty common. Should be fine. Just make sure the charger housing isn't part of the ground.

 

Ahh, thanks for the info, I've confirmed the psu case and compete charger case are not part of the 12/200v rails, just the ac220v earth.
So just waiting for an opportunity to open the car again to hookup the harness.

I'll report back once it's in and tested.

 

How did you get 200V out of those 2X 90V supplies? Where they that inaccurate?

I've purchased a similar version of one of those signal generators (came up along with the unit you purchased):

https://www.ebay.com/itm/283294001111

Single channel only, screw down terminals and cut out mounting... more because it ships from a vendor in the states, but I'm okay with that...

 

Yea those supplies where not accurate. At least they are 1-2v within each other. Maybe under load they may drop voltage, do you have any suggestions for a test load?

I'm guessing any incandescent bulbs would be too much? Maybe not...(BTW 220vac here)

Really nice display you got, great for a professional looking charger!

 

Pretty impressive they're that far off. You sure your meter is accurate?

Incandescent bulbs have lower resistance when they aren't white hot, and it varies with voltage, so it might work, but I don't know if it will allow you to verify peak voltage (probably not)... just whatever voltage the current/resistance combo permits.

You'll find out when the pack peaks. Since you're also wired to monitor current, you'll know your max current when you first start charging. Hopefully, that will stay the same/near same until at least 195V. If they are actually only 90V, you'll never get the battery fully charged at 180V because the current will eventually slow to zero as the voltage maxes out the power supplies.

 

I've checked with three multimeters and the display. So certain of the voltage. I'll wire up a discharge cable and bulb socket tomorrow, will at least let me try the supplies against a bulb to see how they behave connected to a load.

 

Tested the charger with a 40w bulb
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The cold resistance of the bulb is 153Ohms
Measured voltage after the bulb is 84.29v
Current measured was 100mA

Not sure what to make if the results, but at least the meter seems to be working.