[tomofreno]

I took a photo but cannot focus as close as you so it doesn't show enough detail. My heater core had the terminals clearly marked + and -. I thought ceramic heaters worked on the Peltier effect, so polarity would matter. If the heater is resistive then of course polarity doesn't matter. I am unclear on this. I did not use the fuse holders that came with the kit as they looked more like 10A holders to me. I bought heavier "inline" 20A ones at Radio Shack. Don't think that would have anything to do with your problem though. You might call or email Wistar at kta. Maybe he has had other customers with this problem.

[dtbaker]

Originally Posted by tomofreno

I took a photo but cannot focus as close as you so it doesn't show enough detail. My heater core had the terminals clearly marked + and -.

hhhmmm, I dunno!
so on yours, is black=neg, or black=pos ?

I can certainly swap the ends on mine and try again... worst it will do is blow another fuse.

[dtbaker]

Haven't tried switching heater wires +/- yet, but did post a bunch of photos of the whole heater installation starting with

http://www.envirokarma.org/ev/galler...heatduct11.htm

[Wistar]

My first thought is that the diode is installed backwards. If this is the case, the diode would present virtually a dead short across the battery pack. The diode is there to extend the life to the contacts on the relay. You could disconnect the diode and see if everything works OK.

If it works OK, then either the diode was installed backwards, or the diode has failed in a shorted state. Check the diode before putting it back into the circuit. If you have a multimeter that has a diode checking setting, you can use that to make sure that current only flows one way. You can check the resistance, but with no voltage on the diode, the readings will both be pretty high resistance, infinite one way and about 1 MOhm the other. I just hook the diode up to a lab power supply, set the voltage to 1.5Vdc and then slowly increase the current limit. The current will stay at zero when the diod is hooked up one way and current will flow freely in the other.

Wistar Rhoads
KTA Services, Inc.
www.kta-ev.com
20330 Rancho Villa Road
Ramona, CA 92065
760-787-0896
760-787-9437 (Fax)

[dtbaker]

ok....
I THINK the diode is in correctly, but I'm gonna yank it and test (after I get some more fuses!) Probably won't get to it until week after next as I am out of town most of next week.... The 'arrow' is supposed to go neg->|pos right?

[Wistar]

Yep, bat- >| bat+

[dtbaker]

ok, I removed the diode, and am STILL blowing a fuse when the circuit closes! I see no wires touching, and poking here and there shows no unexpected shorts on the contacter itself. AAAGGGHHH.

the low-voltage circuit to open/close contacter seems faultless... keeps clicking open and closed with fan.....

Only non-standard thing tonite is that radio shack was out of the slo-blo 20 amp-250v fuses, so I had to get fast-acting 20 amp-250v fuses.

Any more ideas of things to disconnect or test?

If the core was damaged in some way, could it still be operational (as when I applied 96v directly bypassing everything) but perhaps pull higher amps than expected?

Or, could the contacter have some short I am not seeing when the circuit closes? I see nothing bridging between the HV pos and neg.... any other possibilities?

[Dave Koller]

Dan
Have you pulled off the heater wires and place a bunch of 100 watt bulbs (in parallel ) to see if it blows... sounds like it could be a short in the core -- better yet put a 110 pigtail socket on the output and plug in a space heater or a hair dryer and see what happens... Your core could have a short that show after it heats up slightly...

[Dave Koller]

Originally Posted by Wistar

My first thought is that the diode is installed backwards.

Since you took it out then I guess it was not that - BUT - I also thought that from your red line /arrow sketch over your picture... I tried to see where you had it hooked BUT it was hard to see - scribble a schematic... I could not get to http://localhost/EnviroKarma.org/ev/...heatduct11.htm

to see what pics you have !

[dtbaker]

Originally Posted by Dave Koller

Since you took it out then I guess it was not that - BUT - I also thought that from your red line /arrow sketch over your picture... I tried to see where you had it hooked BUT it was hard to see - scribble a schematic... I could not get to http://localhost/EnviroKarma.org/ev/...heatduct11.htm

to see what pics you have !

I put in the link wrong at first... try this
http://www.envirokarma.org/ev/galler...3_heatcon1.htm
and several pix on either side of this one

- checked diode, it was in correctly neg->|pos and has differing resistance in one direction versus other, so is probably ok.
- I REMOVED the diode, and still blow fuse
- I bypassed heater contacter/fuses by hardwiring from main contactor to heater, and it worked.