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Bumblebee Triumph Spitfire Build Thread

65K views 202 replies 31 participants last post by  brian_ 
#1 ·
I haven't really had a build thread, but figured I've got some good progress so might as well start one! My wife has come up a good name for the car, Bumblebee ("transformed" from gas to electric...).

This past weekend I cut out my adapter plate. (With lots of help from xrotaryguy, thanks man!) WD-40 is definitely your friend when cutting metal.

I still need to drill the mounting holes in the plate for the motor and transmission but that will be pretty easy. I'll hopefully get my first (very low speed) test drive in the next couple weeks! :D
 

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#2 ·
Looks great Clint! I've been following your progress on your blog, and I'm impressed! You're really making headway.

I'm still looking for my donor. I've been looking for an MG nearby, but the few I've found are all rusted to hell. I'm working a lead on a 76 Triumph TR6 that is here in New Orleans, probably go check that out later this week.
 
#4 ·
Only 50% done with the conversion, but I've had my first test drive with the Spitfire!



No motor controller, but I did rig up my contactor to the Pot Box so I had power on / off with a single 12V battery. Even at 5 mph, it was really freaking sweet!
 

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#6 ·
Looking good! Did you cut the center hole with the jig saw? How well does it fit the motor or did you just cut it for clearance? I'm to the point I need to start making my adapter plate.

Thaniel
 
#9 ·
Thanks all!

Looking good! Did you cut the center hole with the jig saw? How well does it fit the motor or did you just cut it for clearance? I'm to the point I need to start making my adapter plate.
I cut the center hole of my adapter plate with a jig saw. I oversized the hole so clearance with the shaft/coupler wasn't an issue. The coupler needs more exact dimensions and you need some good machining equipment for it, but I think anyone can make their own adapter plate.

I've just had to sell my 1977 MG Midget as I didn't have a garage to store it in. But my plan for the future is an MG/Spitfire electric conversion very similar to the one you are doing.

I'll spend some time running through your Blog and see what you've got, but I may be stealing your ideas..;)
I highly recommend the Spitfire! (Do anything I did with extreme caution :).)

Bumblebee...hmm...
Sure wish Vista supported my old Photoshop program.
A couple of black stripes and it can be a Superbee... :D
Or at least a BumbleBEV ;)
The car is 'close' to this... right? :D

 
#8 ·
Just a quick note to say great project.

I've just had to sell my 1977 MG Midget as I didn't have a garage to store it in. But my plan for the future is an MG/Spitfire electric conversion very similar to the one you are doing.

I'll spend some time running through your Blog and see what you've got, but I may be stealing your ideas..;)

Chris
 
#11 ·
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!
 

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#14 ·
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.
 
#15 ·
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.
 
#16 ·
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?

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. :)
 
#17 ·
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!
 
#20 ·
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?fuseaction=cDatasheets.dspListDS&CatID=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
 

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#18 ·
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.
 
#19 ·
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! :)

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!
 

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#21 ·
There are definitely lots of ways to achieve safety. Personally, I don't want to hear clicks every time I put my foot on the pedal. I am using the microswitch to prevent the contactor turning on with my foot on the pedal. But once the contactors turn on, they stay on until I turn the vehicle off. On the very first post of my thread, I have a schematic. If it doesn't make sense, let me know. But, there are lots of ways to implement the safety interlocks. Just make sure it jives with what you want...
 
#22 ·
I asked ElectroCraft about a precharge resistor, and they highly recommend it. Also after thinking about it, I don't want to completely shut off power to the controller as it needs the power to supply its internal 12V components.

I've been searching through the forum for "precharge resistor" and trying to figure this out... a few questions...

If I only use 1 contactor, I would have it triggered by the key switch and the resistor would always be active in the circuit. I have a hard time believing the standard Radio Shack resistor can handle 400 Amps at 120V. Any comments?

If I use 2 contactors, 1 contactor would be triggered via the key switch. The other contactor would have a standard Radio Shack resistor over the 2 terminals and be triggered by the Pot Box microswitch? In general I like this approach, but I am concerned that if I lift my foot off the pedal the contactor opens but the controller may still try to be trying to pull a significant amount of current through the resistor. Any comments?

Sounds like the way to go is what you did. :) 2 contactors, 1 triggered by key switch to "on" position. The other with a resistor in parallel closed when the key switch is in the "on" position and open when the key switch is in the "start" position. When I first turn the car on I can hold the key in the "start" for a couple seconds for the precharge then release to have a clean closed circuit.
I'm having difficulties on what components I need to rig together that setup however. I don't understand the box you have just to the left of your controller in your first build thread post.

Thanks!
 
#23 ·
I built a step-start delay to first turn on my precharge relay and then, after a delay, turn on the main contactor. I also added the option of monitoring the vacuum pump and not turning on the contactor until the brake vacuum reservoir was 'full'. I've been driving the car for a couple of weeks now and have worked out the bugs.

*:eek:*WARNING, a shameful commercial advertisement follows!*:eek:*
I have extra parts and circuit boards, so if anyone is interested in buying one let me know.
*:)*End of shameful commercial advertisement.*:)*
 
#25 ·
You can calculate the capacitance of the controller by measuring the voltage across the precharge resistor and noting the time it takes for the voltage to drop 63%. For example, if you initially have 120V across a 1000-ohm resistor and it takes 10-seconds for the voltage to drop to 44V (63% is one time constant) then your capacitance is C(Farads) = 10(Seconds)/1000(Ohms) or 10,000 uF.

With this information you can determine what the voltage across your contactor will be for any precharge resistance value and time period.
.

So, for a 750-Ohm resistor;
One Time Constant (Seconds) = 750-Ohms * 0.01-Farads = 7.5 Seconds

In one Time Constant the controller will charge to 63% of the applied Voltage.

In two Time Constants (15 seconds) you will have 86%, in three TCs 95%, in four TCs 98%, and in five Time Constants you will be above 99% (or zero volts across the contacts).


On another note, How come nobody has flamed me for my earlier commercial message?
 
#27 ·
rfengineers,
Do you have a good feel for how charged the capacitors need to be to prevent long term damage? Some people never pre-charge and their systems work fine (for now, that is) and you could wait 10 time constants for a rather thorough charging, but that would be ridiculous. Where is the middle ground? How long does your step-start relay wait?
 
#29 · (Edited)
The caps don't care if you precharge them or not. They can take it.

The precharge is to prevent contactor arcing. This significantly reduces the chances of your contacts welding together.

I let the Voltage across the contacts drop to under 75-V before I close the contactor. For my Curtis 1231C-7701 and a 1000-Ohm resistor, it takes 20-seconds. That is just about enough time for me to get my seatbelt on, the mirrors adjusted, window rolled down, radio tuned in... I have the option of forcing the contactor to close after only 10-seconds by twisting the key a second time.

The time delays can be customized when you order the device. Oops, was that another ad?!
 
#30 ·
Sure, Lets say you put in a 100-Ohm, 5-Watt resistor across the contactor. If you have a 120-Volt system then for the first few moments you will have 120/100 Amps flowing through the resistor. That's (1.2*120) Watts. (144-Watts)

If you have 0.01 Farads of capacitance, then one Time Constant would be 100*0.01 = 1 second.

Initially the resistor will develop 144-Watts of power.
After one second that will drop to (0.444mA*44.4V) = 18-Watts
After two seconds (.018mA*18V) = 1/3-Watts

I bet it would blow up:eek:!
 
#31 ·
It makes sense that the caps can take the inrush current better than the contactor, but most of the things I read say that the pre-charge resistor saves the controller. Either way it saves something, I guess, so it doesn't even really matter.

20 seconds seems like an excessive amount of time to me, but I don't have the best feel for this stuff.
 
#33 ·
Well on Christmas I'll find out how many contactors my car will have. :)

Let's say I only have 1 contactor, and it is triggered via the key switch. I just need to find a resistor that has a power rating high enough to handle my voltage? So for example, I have 120V nominal, for safety I'll say 140V. If I have a 750 Ohm resistor, I need to make sure it has a power rating of at least V^2/R or 26W?

Or how about a resistor rated for 50W, 1k Ohm such as this one http://www.newark.com/jsp/search/productdetail.jsp?SKU=98K2902&CMP=AFC-GB100000001 This, "always on" (in series) with my main pack will waste a tiny bit of power but will safely precharge my capacitors? It's just odd connecting 2/0 cable to this tiny resistor.

Sound right? Thanks!
 
#34 ·
it actually wont waste much at all, even if it is always on, because as your caps charge up, the current through the resistor (and power loss) goes to 0.

the way i have it is that the circuit breaker cuts all power (including dc/dc converter and precharge) but otherwise the precharge resistor and dc/dc are always on with one contactor.
 
#38 ·
The relays I am using have 5 connections, but you certainly don't need 5. Just ignore the wire that goes straight down to my "Ign" light. It's an idiot lamp for me so that I know that the car is "off". I'm not sure of what the proper terminology is, so I'll make up my own. The relay has coil connections and switch connections. The switch is normally open. One side of the coil is grounded, so that if the other side of the coil sees 12V, it actuates the switch. Very simple. I put the "on" wire onto one switch connection. The other connection goes to both the solenoid on the contactor and to the coil connection on the relay itself. Of course, when the "on" wire has 12V, it can't actuate the relay because the switch isn't closed yet. So, the "start" wire also goes to the coil. It actuates the relay (ignore the interlock through the potbox microswitch for now). Once the switch is closed the "on" wire can now keep power to the coil. In this way the relay "latches" closed and stays closed as long as there is voltage on the "on" wire. I had to make sure that my ignition switch didn't cut off power to the "on" wire while in "start". But, that was a simple test. I hope I didn't make things more complicated.
 
#39 ·
I've got the motor finally mounted in the car! (As opposed to just resting on the support beam.) I'm pretty happy with how the mount turned out.

Controller is to arrive in 4-5 weeks... On the one hand that's good, because it forces me to space out my purchases. On the other hand I really want to get my controller parts installed! :D
 

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#40 ·
That looks like it will do the job! Great work. I would suggest that you start working on the battery racks. I don't know how much thought you've given to battery placement, etc. You might also need to upgrade your suspension a bit, depending on what batteries you'll be using and where you'll put them. It's not too big of a deal, but there are plenty of things you can do while waiting for your controller. Great to see the progress! Now I just need to find the time to make progress on mine.
 
#41 ·
Thanks!

Very true... I should go to the store and take exact dimensions of the batteries to start on the boxes. I've been debating about the total number of them. The batteries are 65 lbs each... 650 lbs total. I'm shooting for 4 under the hood (260 lbs) and 6 in the trunk (390 lbs). How hard do you think that will be on the suspension? Know any cheap / easy suspension upgrades for the Spit to get me started? I saw you changed out your springs, how much did that cost?
 
#46 ·
heres a good one that i did...

http://triumphspitfire.nl/rearspringpads.html

you just replace the old rubber bushings with those teflon ones in your rear leaf spring and it adds about an inch to the rear. My machinist charged me 8 bucks to make them, and the stock was like 10. Actually, if i can find the leftover rod, i could ship you the teflon stock i have. no use for it anymore...
16. Remove any perished bits of rubber you find. and clean up the individual spring leaves a bit with a steel wire brush.
17. Restack the springs using the new discs in the indentations.
Are the teflon bushings you're talking about the "new discs" mentioned in the how-to? My Spitfire is definitely doing the rear end sag right now, but I don't remember it being this bad when the engine was still in.

Would installing a pair of spring shackles in the back be too much of a bastardization to raise the rear of the car a bit?

The truck and 4X4 guys do it all the time as it is cheap and effective.

Other things to consider is:

-Installing another "helper" leaf in the leaf stacks
-Bolt on helper spring added
-Coil over shocks
-Taller or rear air shocks (one mentioned in the "Suspension" category in the link beow)

Good info about Spitfires in general.
http://www.geocities.com/motorcity/speedway/1080/spitfaqs.html
For the rear, though, you'll definitely need to do something. You only removed the gas tank and some exhaust pipes from the rear, and the rest is stock. I put in rear air shocks for mine, and they seem to work great. It wasn't a cakewalk putting them in, though, as the bushings had to be removed from the rubber in the shocks. Anyway, now I can raise or lower my rear end by quite a bit just by adding air pressure. If you go this route, don't forget to roll the car back and forth after adjusting the pressure to allow the independent rear suspension to correct itself to the new height.
Definitely sounds like rear air shocks are the popular way to go.

Thanks for the suggestions guys, I'll look into it!
 
#43 ·
also: right now i have 4 batts in the front and 8!! in the trunk. my batteries weighed in at around 55 lbs apiece, but its still lowriding in the back. However, with the new teflon bits and new shocks, its just a tad lower than its supposed to be, and i still have quite a bit of play.

eventually, im going to attempt to move two batts to the front, but we will see how that works.
 
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