Paul & Sabrina's cheap DIY 144v motor controller

[jackbauer]

Must ..........have..........

[Weisheimer]

That is looking sweet!

You might get the driver tomorrow or Saturday. I dropped it at the post office Tuesday night.
Worst case, Monday/Tuesday as I sent it via small priority box.

[esoneson]

Originally Posted by jackbauer

Must ..........have..........

Now, Cole, when you shift the gear and that little needle on the ammeter goes into the red and reads 1000 Amps, that's bad.

In this case........that is still good

Eric

[adamj12b]

Originally Posted by esoneson

In this case........that is still good

Eric

Haha! Nice one Eric! I love it.

-Adam

[jackbauer]

Ok I updated it

[JoeG]

Boy, things are looking up. Not 1, but 2 new 1000A DIY controllers in the pipeline. Keep up the good work Paul & Adam. I received my $5 temperature switches from China this week and wired one up to my CPU fans on my 500A controller. The switch has a P/N KDS 301 on it, which seems to be pretty common on Ebay. I heated it up with my heat gun and at 95deg(35c N.O) or so it switched on. After about 5 miniutes of cooling off it went open again.
My next question for all you guys out there is what are you doing to seal your controllers, if anything? I was thinking of caulking all the gaps bettween the case, buss bars and cover with some silicone caulk to keep moist air from entering the controller which might condense in the cold mornings. What do you think, is it a good idea, or bad one?
Joe

[MPaulHolmes]

I don't know the best way to seal from the elements. I've been using regular silicone sealant, but I think it's better to use some weird sort of dow corning stuff that's more expensive since it doesn't have corrosive gasses.

[Weisheimer]

I couldn't remember what it was either, so I searched the EV Tech archive.
So this is Quoting Otmar from the EV Tech list Dec 15, 2009 so the pricing is probably higher now:
---------------------------------------------------------
"I use this in the Zilla:
From McMaster:

Dow Corning 748 Noncorrosive Silicone Sealant 10.1 Ounce Cartridge, Off-White
In stock at $15.34 Each

748 Noncorrosive Nonflowable Low Odor- Use with
corrosion-sensitive electrical and electronic equipment. Plus, it
doesn't have the harsh vinegar smell of other silicone. Bonds metal,
plastic, glass, and rigid PVC. Resists moisture and weather. Begins
to harden in 30 minutes. Complies with FDA CFR21 177.2600 covering
indirect food contact. UL 94HB listed.


--
-Otmar-"
-----------------------------------------------------------------

It seems to be the same thing used in many power supplies etc to stabilize the components.

[JoeG]

I found a bunch of options by doing a google search for "non-corrosive silicone sealant". Dow Corning has a 832 sealant that is non-corrosive silicone and Loctite has a number of them also. I ended up purchasing on Amazon Loctite 51387 non-corrosive silicone for $14 shipped. None of the local home improvement or automotive stores stocked any of the non-corrosive stuff. I found that all the standard Silicones had some type of acid listed on material data safety sheets. The non-corrosive ones didn't have any acids listed. What got me checking, was at my local auto parts store they had Permetex silicone seal that listed sealing electical connections as one of the uses on the package, but didn't say it was non-corrosive. I was able to find the material data sheet online and it did have acid in the mix and therefore was corrosive.
Joe

[amino]

Hi Paul,

I built the 500 amp controller from the kit last Month and after testing it a couple of weeks ago at 16 volts (2x8 volt batteries) with just the motor connected, all seemed well. I decided to install it in the car and test it at the pack voltage which is currently 80 volts, as I needed to test the precharge time, using a small 7 watt bulb through a solid state relay setup which I already had for the old Kelly controller.

When I switched the circuit on to activate the relay, the bulb did not light up. Instead there was a small puff of smoke from inside the controller, at the rear (M-) end , so I took it all apart and looked for the source of the smoke, but did not see any sign of damage anywhere! No burnt smell, no charred components.

I measured the Gate-to-Source resistance on all the Mosfets and they seem fine (infinity), although the one at the back (Q1) at first seemed shorted, but when I measured it again a little later, it also showed infinity between Gate and Source. Any suggestions while I have it apart?

Thanks,

Amin