[favguy]

Hi all,

Well I thought it was about time I got round to writing up my build, I actually started it 3 years ago, and have just got back to it due to life getting in the way!

I'm calling it the "FavElec" short for Favorit electric. For those of you not familiar with the car, it's a Czech built VW Golf sized Hatchback, nice and light, so hopefully a good candidate

Anyway, as I hadn't a lot of cash spare to buy the main electric drive parts, I started by sorting out the car itself, then moved on to the battery boxes.

The car was already very good, having only done just under 20,000 miles from new, but it did have a few knocks from its careless elderly owner (and his dog!) So I started by attending to the following:

* New bonnet was painted and fitted. The old one was a replacement following a minor collision in the past and had rusted due to having an inadequate paintjob!

* Removed, repainted and refitted the drivers side wing. Again this had been replaced before, with bad paint and fit!

* Removed, repainted and refitted the front panel. As above bad paint and chipping.

* Repainted both small panels above the rear wheel arches. This was due to minor scratching/dents, thankfully no rust was present!

* Refurbished and repainted all four wheels. lots of curbing on the fronts!

* Replaced the door bump strips on the drivers side rear and passenger side front doors as the old ones were bubbling from the steel inserts in them rusting.

* Replaced the front and rear bumpers with good undamaged used ones.

* Same for the rear mudflaps.

* Stripped and repainted the passenger side mirror housing as the alloy had corroded.

* Replaced the drop glass in both rear doors. Owners Jack russel had been busy scratting at the glass!

* Replaced both the rear door cards with good undamaged used ones. Jack russel again!

So having done that little lot, which took me several weeks on and off the whole car body was worked over with Farecla G3 then G10 polish and the interior was hoovered, cleaned &shampoo'd, the results are below, sorry they aren't high resolution, my camera is limited (as is it's user!):

So now the car was looking like it just left the factory, it was time to start cutting it up!

More to come soon...


Paul

 

[favguy]

The plan (so far) is to build a 144V, 500A system, utilising a 9" DC motor, Open Revolt controller, and Thundersky cells, most likely 160Ah. I'm hoping for a comfortable range of 70 miles if possible...

Anyway, on with the cutting...

The next job was to remove all the existing systems out of the way ready for the body modifications and fitting the battery boxes in the rear and mid sections of the car.

So the spare wheel, parcel shelf, rear seats & carpets were all removed and safely stored out of the way and the floorpan was carefully measured and marked up ready for cutting.

The exhaust was removed from the cat back. The centre silencer was modified and temporarily remounted, to expell exhaust gas out to the side of the car, this allows the car to remain mobile for the time bieng. The exhaust heat shields were then also removed. All the now redundant exhaust hangers were then removed or cut off.

With the exhaust out of the way, the petrol tank was drained and removed along with the filler pipe assembly. The petrol pump was removed from the tank and mounted in a 5 litre petrol can which in turn was mounted into the engine bay and connected up to give a temporary fuel source to allow the car to still be moved about whilst work is in progress. Next all the front to rear fuel lines were removed.

Now with that lot gone, we can start the really fun stuff...

The rear box was cut out using a combination of jigsaw and good old hand held padsaw where I couldn't get the jigsaw in. This was a little tedious! the edges were then all filed to get to exactly the right size and de-burred All the exposed edges were primed and painted.

Also got this bit left to play with :rofl:

So the next job was to do the same again to the underseat section. This was easier to cut out using just a jigsaw. Again the cutouts edges were all filed to exactly the right size and de-burred. Due to the pressings in the steel at the front edge of of the hole, there was some additional work to be done here though. The edges of the pressings were cut and the steel panel beaten completely flat along the whole of the front edge. (This was necessary to allow for fitment of the box and reinforcing frame below later) Once flat, the cut sections were welded together and the area sanded smooth, cleaned and painted.

And yet another bit left over!

Before going any further, the original brake lines had to be re-routed as they now crossed the cut out for the box.

So the old lines were cut out and new lines were made up and routed around the box hole

Next... boxes and frames, construction and fitting. :thumbup:

 

[favguy]

So we now have two large holes, it's time to make something to fill them with.


Starting with the mid box, this was contructed from 1.2mm thick galvanised sheet steel. Folded and then seam welded into a complete box to exactly fit the cut out. It was then etch primed and painted matt black on the outside. The inside was then painted with several coats of insulating rubberised paint.

An additional support brace was constructed from 20mmx20mm box section steel to give additional support to the frontal area of the box, as the metal this is being fixed to is only single skinned at this point.

The rear box was again constructed from 1.2mm thick galvanised steel sheet, folded, welded, and painted, but an additional reinforcement of 18mm thick marine plywood was bolted into the base to give additional support and remove any possibility of sagging to the centre of the box.

A support frame to interface the sheet metalwork of the box to the irregular edges of the cut out and provide additional reinforcement was again made from 20mm x 20mm box section steel.

Once made, the boxes and frames were trial fitted and all mounting holes were drilled through the boxes, frames & car body. Everything was then dis-assembled and cleaned. All the drilled holes were then de-burred, primed and painted ready for final assembly.

After drying, black polyurethane bonding and sealing mastic was then applied around the mid box aperture and the box was bedded into this. Both the box and frame were then finally bolted into place permanently using 6mm A2 grade stainless steel bolts of varying lengths to suit.


You'll also notice three countersunk bolts in the bottom centre of the box below, these hold the clamps for the handbrake cables. (previously secured to the bottom of the fuel tank)

A different technique had to be used for the rear box as it was not practicle to apply mastic between the frame and car due to the gaps at various points, so the frame and box were first bolted in, again using A2 stainless bolts, with the mastic seal bieng applied between body and box from the underside. Only a 1mm to 2mm gap existed at any point between the rear box and cut edge making this very easy to do from below.

The polyurethane used is structural in strength, similar to that used for windscreen bonding, or in place of welding for panel assembly on some modern cars, so will add to rigidity, particularly of the mid box area.


The final result, no more holes, and two completely watertight battery boxes!

So next we'll look at altering and re-fitting the rear seat to provide additional height for the mid box batteries, along with making the cover for the rear box.


Back soon...


Paul

 

[favguy]

Right, time for a bit more. Now a problem I did have was I could only go so low with the battery boxes under the car, as I didn't want to go any lower than the rear axle and risk any bottoming of the boxes on rough or bumpy roads. This isn't a problem for the rear box, as we can raise the top section into the boot space as much as we we need to, but it could have meant losing the rear seat base to allow for the mid box battery height.



So what to do... Anyway after much head scratching, I figured out a good compromise. I stripped apart the two rear seat bases, cut them up, and remade them into one using 20mm x 20mm angle steel & 12mm plywood to make a built in box lid. After much welding, sawing and painting, it was ready for reasembly. I then cut the original foam for the outer part of the base and glued it back onto the ply box outer edges. Then using new, much higher density foam, I cut and shaped it to form the main centre part of the seat base, the hhigher density foam giving support over the now much thinner top section. This was again glued on, and a final 5mm layer of very high density foam was glued over the whole lot to help even out the differences in density. The original seat covering was altered and sewn together from the two parts making up the two seat bases and refitted over the now one piece base.



The result is a seat base that looks completely original, still gives some cushioning, but is harder to sit on than the original seat. Also, we still have split folding upper sections of the seat for loading odd shaped luggage, but we now have a one piece folding base. Overall, I'm very happy with the compromise, and I get to keep the rear seat and original looks

Next... rear box top

 

[favguy]

Now onto the rear box top...



Quite simple this one, using 12mm ply again, a box top was constructed with the rear edge partially open to allow it to swing up over the batteries for access. The box was sealed then had matching carpet glued to it and trimmed off. It was mounted using two hinges fixed to 2 of the front box mounting bolts. Once closed the lid is held firmly secure by the two shootbolts that go into receiving holes (lined by nylon inserts to avoid rattles!) in the rear cross section as you can see below.

Very neat, simple solution, looks nearly factory and we only lose about 4" of boot height in total too :thumbup:



The boot carpet was then cut to suit and reinstalled, job done.


The finished mid box from underneath, rear box can be seen on earlier rear end shots:

We'll need to revisit these boxes to drill holes for conduit entries for cabling, and of course battery mounting at a later date, but thats it for now.



Next, Ohh... my Favorit bit, (pardon the pun!) the instrumentation :thumbup:



Paul

 

[favguy]

I think before we get to the instrumentation bit, we'll have a little interlude and I'll tell you about the charging point



As said before, I really want to keep the car looking as standard as possible, and for the modifications to look as though they might have been from the factory so to speak. So with this in mind, I needed to be able to keep the charging point looking similar to the original petrol filler arrangement.



This was my solution. Firstly I cut the top section off the original petrol filler pipe and entry point down to just the plastic screw thread and flange that sits up against the rear of the panel, under the wheel arch. This was nice and easy as it's made from a very malleable plastic.



Next, I stripped out the filler cap, just leaving the outer shell of it.



Then I got a pair of these :thumbup::

The male plugs casing was modified slightly so the two halves screwed together with the filler entry in the middle. This meant a little bit of reaming out of what was left of the filler point until it all fitted together nicely.



The female plug was completely chopped up, leaving just what I needed of the outer female section to plug into the male on the car. This was then screwed to the outer part of the original filler cap through what was originally the key hole, using a suitable "dished in" stainless steel washer and countersunk screw. This was then finished off with a plastic trim cap of the right size and texture glued over the centre of the filler cap as you can see below.


The last task was to drill a small hole towards the bottom of the filler cap to allow for a small key I made to slide in and pull off the cap when it's time to charge.



I don't have a photo of the back of the cap, or the key at present, but I'll post one when I get time to snap one.



Anyway, I think the end result looks pretty slick, and it doesn't allow water into the plug terminals, when the caps on so, I'm a happy bunny.

Paul

 

[PatricioIN]

Looks very nice and professional.. We'll be watching with interest!

 

[favguy]

OK, where have we got to? before I start on the instrumentation, I'll tell you about the heater.

Well believe it or not, this is what I decided on to heat the cars interior:

Yes, that's right, a hairdryer!


But it has to be the right type of hairdryer...


This is a dual voltage 120v/230v 1500 watt model. I chose this as in the 120v setting it will work just fine with 144v DC. This is because all small hairdryers use DC motors anyway, rectified for use with an AC power source and the voltage is in the tolerence range of the element.


The fact it's 1500 watt also means its really powerful and can produce large volumes of hot air quickly. I also chose this particular model as it's compact, so will fit where it needs to. It also had a three year guarantee, and although I realise I won't be able to take it back if it goes wrong! lol, it does hopefully mean its bearings etc. are up to the task of lasting a while, remember these things usually get used and abused daily for years!


It also had a heavily domed metal grill on the rear end which allows for both easy mounting in the box it goes in, and good airflow into the rear of the unit when mounted.


Oh, and it only cost a tenner in a sale!!


This is the component box we also needed:

Of course we first have to modify the hairdryer body considerably ready for mounting in the box:

And the finished article, all ready to bolt into the original heater matrix box:

The heater matrix box itself had to have the end face opened up a little with a hole saw to accomodate the new heater. The assembly was then screwed to the end, with a small foam gasket fitted between the boxes to give an airtight seal:

The end result works very well, it is activated by a 12v relay that in turn applies the 144v main pack voltage to the heater when both the cars fan is switched on and the heater slider is pushed over to the right to the heat setting. (Utilising a strategically positioned microswitch behind the dash!)


Ok, so next we get onto my favorite part, the instrumentation and dashboard alterations.


Paul

 

[favguy]

Right then, on to the dashboard instruments.

When considering this, I spent a good deal of time thinking of the best way to keep the dash looking as "factory" as possible. I also wanted to avoid a homemade look that so many other electric car conversions seem to end up with, especially with the instrumentation. Also there isn't a lot of spare room on the dash for the gauges needed.

I need to keep the original tachometer and drive this from the motor with a suitable sender, so this stays. The original fuel and temperature gauges are no longer of any use so they were to go. (This at least gives a little space for some of the new instruments.)

We needed to somehow incorporate all of the following somewhere:

* Voltmeter - 144v battery

* Voltmeter - 12v battery

* Ammeter - 144v battery

* Ammeter - Motor current

* Temperature - Motor

* Temperature - Motor Controller

* Individual realtime cell pair performance meters x 24!

* System active warning light

* Controller pre-charge warning light

* Motor overtemp warning light

* Emergency system disconnect

* Cruise control on/off & set switchgear

So with that onerous task, I set about planning where it would all go and the best type of guages to source. I decided on backlit LCD meters as opposed to analogue as they are more compact and the style chosen blend nicely with the original dash style I think.

It was decided that the centre left air vent and storage tray beneath it would be sacrificed to make room for the main meters.

The headlight adjustment system and bulky switch for it to the left of the steering wheel was also removed to make room for some of the new kit. This was really no loss, as it didn't work anyway!

OK, so below is the style of meter chosen for the voltage and current readings, these will go in the new centre panel to be built:

And the temperature readouts that will go in place of the cars original fuel and temp. gauges, these are actually much smaller than the above gauges, as you'll soon see:

The temperature gauges are only available in 5 volt form, so had to be fed via a miniature 2 watt 5v - 12v converter built into the rear of the instrument pod.

The 24 battery performance meters had to be both compact and arranged in a format that would allow for instantanious comparison of the whole pack at a glance, so a "graphic equaliser" style panel was needed for this task. More on this later.

Ok, so now we have our components, it's time to once again start chopping things up!

I think we'll start with the new centre panel, back soon...

 

[favguy]

So here we have the original centre of the dashboard prior to starting:

The left hand vent and oddment tray beneath were first removed. The left hand vent ducting was blanked off and the holes now left by removal of the existing parts were further cut out and modified to allow room for installation of the new meters.

A new panel was cut to size from a suitable grained plastic sheet. This was fixed to the centre panel and sprayed matt black to match the sheen of the surrounding plastics. The Ammeter, (top) 144v meter, (middle) and 12v meter, (bottom) were installed. This sounds easy, but cutting the holes needed accurately enough to have them all line up perfectly was surprisingly difficult, I had to throw away the first panel and make a second!

To the right side of the panel you see a switch, installed to allow the Ammeter to display either battery pack current draw or current being supplied to the motor from the controller. Below this were mounted two diffused LED warning lights. The amber will show system active and ready to drive (remember there is no noise from a running engine to tell you this!) and the red, controller pre-charging (a bit like the old glow plug light on a diesel). All the necessary wiring was run from behind the panel area and into the engine bay/fuse box as appropriate.

The finshed result:

And when active:

The meter backlighting doesn't show very nicely in the photograph, it's actually a very nice shade of blue as shown in an earlier post showing the single meter. I'm very happy with the end result and think it blends quite well with the overall dash styling.

Back soon with the original instrument cluster modification...

 

[favguy]

So, the first job on the instrument cluster was to strip it down and remove the fuel and temperature gauge's. Here they are now surplus to requirements:

The resulting holes in the instrument face plate panel needed to be made good with matching material. I scratched my head for a bit until discovering that 3.5 inch floppy disk case plastic was exactly right for this, so got busy cutting up a couple of old floppy's to salvage the plastic. This was cut to suit to both blank the original holes and provide new apertures of exactly the right size needed to install the new temperature gauges. The new guages were then installed into the face plate using appropriate bonding sealant.

Once the sealant had cured, a little modification using a dremmel tool was needed to the plastic casing of the instrument cluster to allow clearance for the back of the right hand meter where a moulding for the low petrol warning light had once been!

The finishing touch prior to re-assembly was to add the "C" & "M" logo's under the gauges to signify which is which for the motor and controller. These are the same size and font as the MPH under the speedo, they are also exactly in line with the original lettering under the speedo, hopefully this adds to the "original" feel of the job.

Following this, all the parts were carefully cleaned and the instrument panel re-assembled. The gauge supply wiring was then soldered to the appropriate part of the circuit board at the rear via the small 5v-12v converter. The temperature probe wires were fed through the bulkhead to the engine bay and all was re-assembled. You can see the finished results below:

Again, I'm very happy with the results, and the colours and style of these gauges when lit (see earlier post) go quite well with the existing clocks in the binnacle.

More soon...

 

[favguy]

Ok, time for a bit more on the instruments.

I took the opportunity to include the facility to see the outside ambient temperature, pressing this switch will allow you to toggle between motor and outside temperature. (The plastic blank you can see to the right of this fills what was the original immobiliser keyslot for those who were wondering):

The following before and after pictures show the old headlamp adjustment switch and then the new cruise control panel, this was screwed to the original stripped out headlighht switch panel, again with the help of some floppy disk plastic to finish the job!

Beneath this you can see the emergency stop pull. (This is in exactly the same position as the choke cable on the Mk1 Favorit, the support moulding was still in the dash plastic for this!) The other end of this cable activates the main breaker, isolating the main battery pack voltage from the system just for use in the case of a catastrophic emergency, hopefully it'll never need to be used :

Before:

And after:

Ok, so next we're on to the battery monitor array...

 

[Harold in CR]

You certainly have the necessary detail skills to make this build at least as good as any factory look. Very impressed.

I imagine the rest of the build will be as neat and clean as this part is.

 

[rwaudio]

I do like what you've done keeping the stock gauge appearance, but since you replaced a temp gauge with a temp gauge, why not use the existing one? It might require a bit of tweaking to get the temp range you are looking for but it would be 100% stock. I would do the same with the gas gauge, source another temp gauge and either flip it upside down or fit it to the other gauge.

I like the attention to detail on the whole build though, very good work. How much do those battery boxes weigh?

 

[favguy]

Hi guys,

Thanks for the comments so far.

rwaudio,

The stock guages only give a rough indication of temperature, wheras the digital ones give the exact temperature, plus I liked the look of them

Battery boxes don't weigh in at much at all as they're mainly sheet steel with a little bit of ply wood, truth be told, I don't actually know what they weigh

Now a little bit of an update for you all....

As I'm planning on using 46 or 48 160Ah Lifepo4 cells, I wanted a way to monitor them against each other in real time and ensure that none of them move out of kilter too much with the rest of the pack. This isn't a BMS system so to speak, I'm still undecided as to what I will or won't use for that, but it does give me instantanious indication of the state of the cells.

As a display of 46/48 was just too big, I decided to monitor pairs of cells using an array of 24 of the 10 LED bargraph type displays built and calibrated to work at lithium voltage. By monitoring pairs I know instantly if any one of each pair pulls the reading out of kilter and where to investigate

Ok, so onto the build. This had to be built from scratch and actually turned into quite a fun project, at least it gave me plenty of opportunity to practice my soldering skills!

Firstly the centre console was dismantled and the centre section removed for attention. The top section of the console that was initially used for storing cassettes (like we need them now!! lol!!) was sacrificed to house the array. I started by cutting out the rear of the cassette box as needed. I then made up a front plate from appropriate sheet plastic and bonded it to the console. A main on/off switch for the array was then fitted to the lower centre of the cut out.

The next job was to create a tinted face plate for the display, 2mm clear perspex was cut for this then tinted using light tint spray to the correct shade, so the LED displays show through very nicely when lit, but it doesn't show through when turned off.

I then got to work making up the array. Stripboard for circuit building was cut up to the right size to accomodate a total of 24 circuits, with 2 to each board, one above the other, this meant a total of 12 boards. The copper strips were cut in various places on all of the boards and several jump links per board were also added to create the necessary circuit pathways. Following on from this, the 20 segment LED's were soldered in place, each of these provides for 2 of the readouts. The 24 control chips were then added to the boards, followed by several resisters, 2 potentiometers, a diode and capacitor per circuit. From start to finish of all the individual boards took the best part of 4 days of assembly and soldering!

The boards were superglued together via the LED displays to form the array and additional stripboards were also glued to the top, bottom & rear of the unit to give rigidity and allow for mounting. The circuit on/off relays are glued to the rear of the back board.

All the displays were temporarily hooked up in parallel and calibrated using a bench variable DC supply to set the upper and lower voltage limits.

After this another few very tedious hours ensued as the temporary parallel conections were unsoldered and the circuits were wired to the appropriate relays and in turn, the relays wired to the master switch and output plugs that will eventually go to the individual batteries.

The complete array was then mounted into the rear of the console.

And the finished result from the rear:

And in the car:

My favorite display so far

Back soon

 

[Ziggythewiz]

Awesome instrumentation, especially that last bit. How much did each display set you back in time and $$?

 

[favguy]

Hi,
The last one ended up costing me about £250 (about $400) in total and an absurd amount of time, probably 10 days work in total including prototyping the housing and mounting, which I ended up doing twice as wasn't happy with the first effort!

All the other guages were quite low cost, about £75 in total ($110 ish) and loads of time input!

 

[rwaudio]

Hi,
The last one ended up costing me about £250 (about $400) in total and an absurd amount of time, probably 10 days work in total including prototyping the housing and mounting, whichh I ended up doing twice as wasn't happy with the first effort!

All the other guages were quite low cost, about £75 in total ($110 ish) and loads of time input!

That last one is a pretty sweet display. I really like the tinted front!
Are you running pack voltages into the console for your monitor? If so make sure you take some precautions like add a resistor in line with the +/- wires so that even if it shorts out you just get a few milliamps.

 

[favguy]

I am, but all the wires will be fused at the cell end with 100mA fuses, so no harm could come to the cells or wiring, also entry will be right under the console safely away from access by anyone in the car.

 

[favguy]

Motor time...

I'd liked to have bought an off the shelf ADC 4001, or Warp9, but as I'm more hard up than a stone someones trying to get blood out of, had to settle for a used forklift motor

So I went to visit a place in Chesterfield called Fork Truck Services that Woodsmith had told me about a while back. The website is: www.forktruckbreakers.com

They had a shed full of old motors, most were either too large or too small, pump motors, or had female shafts, but I spotted a "goldilocks" just right candidate amongst them. It was filthy and all the brush springs had snapped with age fatigue whilst it had been sat in the shed for what I assume must have been at least 10 years, so I couldn't test it. Anyway, it was 9&1/4" in diameter x 14&1/2" long without the shafts, just right for my project and the output shaft came with the female part it went into, so good for making a coupler. It also seemed a good weight and was series wound.

It had rumbly bearings and one poles shoe bolts had worked loose causing it to rub a little on the armature. The field coils were also shorted to ground. But... the comm. was in very good order with 65 bars, the armature looked good, and the coils, from what I could see of them looked in good order aside from the short. It's a Prestolite and looked quite well made. The chap selling them wanted £250 and wouldn't negotiate, so I agreed to buy it at which point he kindly gave me £30 back due to all the springs being snapped, so it stood me at £220.

So at this point, I was thinking i've either bought a very expensive doorstop, or it's a rough diamond, here it is: