[ClintK]

I've pretty much worked out a wiring diagram for the car. The current plan is to use ElectroCraft's EVMTC60-192V motor controller http://pages.interlog.com/~dgv/dc.html

I based my diagram off the one shown on their website (with some modifications). Notes of interest...

Instead of using 2 contactors, I'm planning on having only 1, but it will only be powered if both the key is in the on position and the pedal is depressed.

The fans switch on as soon as the key is turned to the on position.

My voltmeter / ammeter are positioned such that they use the same fuse as the rest of the high voltage system. Of course now that I look at it, I'm thinking the voltmeter / ammeter really needs their own low amperage fuses as well - I'll add those.

I'll also rig up a cable system to help pull the cut-off switch in case of emergency.

The car doesn't have power steering or brakes.

I don't show the charging connections or DC-DC converter, but I'm thinking about connecting those via a fuse directly to the main battery pack.

I've read a decent amount about pre-charge resistors that you need or you'll damage the motor controller, but the sample wiring diagram for this controller doesn't show one so I assume I don't I need it.

Any opinions / suggestions / etc.? Thanks!

[ClintK]

Originally Posted by Ron Atkinson

if I remember correctly the "Spitfire" has a very lightweight chassis, so the acceleration could be quite "mind-blowing" at first. Power/weight ratios are the "name of the game sir, good luck with your conversion!!!

Thanks! The car is definitely light. I went with a 6.7" motor, so I'm thinking my acceleration will only be 'ok'. I bet this car could win some races with a 9" motor and Lithiums though.

[brent.massey]

Congrats on your first test drive Clint! You've got 'the grin', thats for sure!

What's the price on that controller from ElectroCraft? I can't find prices on their website anywhere

[ClintK]

Originally Posted by brent.massey

Congrats on your first test drive Clint! You've got 'the grin', thats for sure!

What's the price on that controller from ElectroCraft? I can't find prices on their website anywhere

Here's what they quoted me a couple months ago (may have changed since then)...
Our EVMTC120V-400A has the following features:
- above 20KHz chopping operation, so it is quiet.
- 400A is its peak limit. So, 200A is no problem at all.
- It has its internal 120V to 12V converter ( for Key-switch). So, you
do not need an external 12V
- It will fit your car and motor.
Price is $849 plus shipping ($ 35 to North American destinations) delivery 3 to 4 weeks.
1 year warranty, will work up to 250V

I don't know anyone else who has used them, but considering the price, features, and warranty, I'll give them a shot.

[Bottomfeeder]

Two comments and a compliment.

First of all congratulations on your 12V test drive. I did the same thing (although much more crudely) in my Spit when I got the motor under the hood. It sure is a great feeling.

A second contactor adds just a bit more safety redundancy to the vehicle. Contactors can and do weld themselves closed, or so I hear.

Also, a precharge resister may not be required, but it will surely help prolong the life of the capacitors inside the controller. I'm sure a 10W, 1K resistor won't break your budget. You'll probably also need a relay and a slight altering of your schematic.

Keep up the good work. I wish my Spit looked half as good as yours does.

[ClintK]

Originally Posted by Bottomfeeder

Two comments and a compliment.

First of all congratulations on your 12V test drive. I did the same thing (although much more crudely) in my Spit when I got the motor under the hood. It sure is a great feeling.

A second contactor adds just a bit more safety redundancy to the vehicle. Contactors can and do weld themselves closed, or so I hear.

Also, a precharge resister may not be required, but it will surely help prolong the life of the capacitors inside the controller. I'm sure a 10W, 1K resistor won't break your budget. You'll probably also need a relay and a slight altering of your schematic.

I appreciate the comments!

I've been going back and forth on the multiple contactors. My thinking is that since the contactor will only close when I apply pressure to the foot pedal, if the controller fails the car will only 'run away' when my foot was on the accelerator pedal. In theory if my foot is on the pedal then it should be clear in front of the car. If I lift my foot off and the power continues, then I've got the manual circuit breaker to pull. Right? Now I've sent my Christmas wishlist to Santa, so if I get another contactor I may end up installing 2 after all.

I'll definitely ask the manufacturer about the precharge resistor. What would an additional relay be for? To open/close the resistor?

Originally Posted by Bottomfeeder

Keep up the good work. I wish my Spit looked half as good as yours does.

Thanks! I don't know about that though... You're restoring your Spitfire the proper way - that's going to be a -sharp- car when you're done. Mine looks good on pictures because cameras can hide flaws.

[Bottomfeeder]

If you have a precharge resistor, then there are three states that you need to achieve:
Precharge Off
Main Power Off

Precharge On
Main Power On

Precharge Off or On
Main Power On

You can't do that with only one contactor. You'll need another switch in there somewhere.

I'm going to use my two contactors and my ignition switch. When the switch moves to "Ign" the negative contactor closes and precharge begins. When I move the switch to "start" the positive contactor will close and I'll have full voltage. The switch will spring back to "Ign" but I'm using a relay latch to keep the positive contactor energized.

There are many other ways to do it, of course. You could use a small relay just on the pre-charge for example. As long as it comes on first for a second or two, you should be fine.

Unfortunately, I don't have the money to dump into making my Spit look fantastic. The interior will be a little worse for wear until I get the dough to make it look great. It's just a little harder to find some parts for the older Spits, too. I'm very lucky my seats are in usable condition!

[Tolliver]

Ive always thought about using a spitfire. My Granfather had one for years and it went to my aunt and uncle in DC when he died. They've still got it and drive it in the summers on the weekends. I still wouldn't mind getting ahold of it one day.

Congrats man and good luck.

[ClintK]

Originally Posted by Tolliver

Ive always thought about using a spitfire. My Granfather had one for years and it went to my aunt and uncle in DC when he died. They've still got it and drive it in the summers on the weekends. I still wouldn't mind getting ahold of it one day.

Congrats man and good luck.

My wife and I were at a nearby outdoor mall, and a guy had a convertible Alfa Romeo Spider parked on the street. I was jealous, and it gave me even more motivation to get this conversion done!

Originally Posted by Bottomfeeder

If you have a precharge resistor, then there are three states that you need to achieve:
Precharge Off
Main Power Off

Precharge On
Main Power On

Precharge Off or On
Main Power On

You can't do that with only one contactor. You'll need another switch in there somewhere.

I'm going to use my two contactors and my ignition switch. When the switch moves to "Ign" the negative contactor closes and precharge begins. When I move the switch to "start" the positive contactor will close and I'll have full voltage. The switch will spring back to "Ign" but I'm using a relay latch to keep the positive contactor energized.

There are many other ways to do it, of course. You could use a small relay just on the pre-charge for example. As long as it comes on first for a second or two, you should be fine.

If you are precharging the controller, does that mean the PotBox microswitch is not used? I thought most people used that microswitch with a contactor to open the main power circuit when their foot was off the gas. It sounds like precharging requires the main power to be closed at all times? Or does the precharge only need to happen before the first acceleration?

Updated wiring diagram below with charger and DC-DC converter...

Thanks!

[Jimdear2]

Originally Posted by Bottomfeeder

If you have a precharge resistor, then there are three states that you need to achieve:
Precharge Off
Main Power Off

Precharge On
Main Power On

Precharge Off or On
Main Power On

You can't do that with only one contactor. You'll need another switch in there somewhere.

I'm going to use my two contactors and my ignition switch. When the switch moves to "Ign" the negative contactor closes and precharge begins. When I move the switch to "start" the positive contactor will close and I'll have full voltage. The switch will spring back to "Ign" but I'm using a relay latch to keep the positive contactor energized.

There are many other ways to do it, of course. You could use a small relay just on the pre-charge for example. As long as it comes on first for a second or two, you should be fine.

Unfortunately, I don't have the money to dump into making my Spit look fantastic. The interior will be a little worse for wear until I get the dough to make it look great. It's just a little harder to find some parts for the older Spits, too. I'm very lucky my seats are in usable condition!

Howdy All,

The new SD series of contactor/disconnect may be the answer you need. go to http://www.curtisinst.com/index.cfm?...tID=7&siteID=1 and look up the SD series specs.

Look at the attched diagram I made up and see how you can acheive the three states with one unit.

I just ordered one of these, with mag blow outs and auxillary contacts, from the US distributor for $133.00 plus local shipping. 6 to 8 weeks delivery from England.

It's worth a look.

Jim