Holden Barina 1994 EV Build thread
 

So i think i should start a build thread. If only to stop me polluting everyone else's threads with stuff about my build. :)

The plan.

Take the cheapest car i can find and convert it into a zippy EV.

On eBay and Gumtree the cheapest car is consistently the infamous Holden SB Barina.
A car made in Spain, imported into Australia.

First i went hunting for the reasons this car is so bad.

Practically everything i found that was wrong with this car was related to the engine.
Sweet, didn't want the internal combustion engine (ICE) anyway.

Now most people will think i am crazy but i really like the look of the Barina.
It is an honest car. Not trying to be something it isn't.
It doesn't have Mercedes look-a-like headlights. No BMW inspired styling.
It is a basic hatchback that just tries to be a basic hatchback.

The fact that it's engine woes make it super cheap is just a bonus.

Basically it blows head gaskets like it was an Olympic event.
Replacing the head gasket (a $10 part with a $700 labour charge) makes it non-viable for most people to repair.
Which makes it a prime target for recycling into an EV (well to my wacky perspective it does) :)

So car chosen, the search begins.
The tricky thing is to get one that has air conditioning (this is Australia after all) but is early enough to not have air-bags. No engineer in my state will touch a car with air-bags unless it is re-crash tested. A fact i only found out after removing all the ICE equipment and repairing all problems with a lovely silver hatchback. But that is a story for another thread, one with many tears.

The non-airbag vehicles were produced in 1994 and early 95. Unfortunately air conditioning wasn't standard until 1996. So i was looking for an early build but one that the original owner had taken the optional dealer fitted air conditioning.
Yes, that did narrow the field a bit. But eventually a donor was found.
Surprise, surprise it had a blown head gasket.:)
It was only 1000 kilometres away (600+ miles)... whoohoo roadtrip.
Well that was a long couple of days, a non stop 2000 kilometre (1200 miles or so) trip with a tandem trailer.

It was quite an adventure and well worth the effort if only to say we did it. :cool:


http://i1310.photobucket.com/albums/...psc2317b25.jpg

http://i1310.photobucket.com/albums/...ps1da61ce8.jpg

Once the car was in the garage the first thing i wanted to know was why the head gasket had blown. Not really required but i was curious. I found an intermittent coolant fan relay that only seemed to operate 50% of the time. A radiator full of gunk that totally insulated the temperature sensor from the coolant.
And a radiator fan that had one broken blade that had been wobbling so much it had been eating its way into radiator itself.

http://i1310.photobucket.com/albums/...ps54ea1775.jpg

This car was never going to run again as an ICE vehicle.

So then the deconstruction began in earnest.

I kept the A/C circuit intact but the rest just had to go.
Shazam!
http://i1310.photobucket.com/albums/...ps779d2a1e.jpg

I will leave this first post there.

Interesting. Do you have a motor and battery type in mind? What are you expecting for range? How are you going to power the AC?

So what are the plans for the conversion?

Electric motor will be a 3 phase industrial motor, rewound to suit an EV.
Supplied buy Catavolt it is a 132m frame 75kw motor Custom wound to spec.
Partialy motivated by budget but also by wanting to do something a bit different. (yes, that will be a recurring theme in this build :D).

Gearbox to remain.
Clutch to remain, may go with a different flywheel just to reduce weight.

Controller will be the most excellent Paul and Sabrina designed AC controller.
This controller is one of those rare devices that no accountants, marketing experts or cost cutting committees have been allowed to touch. It is built how the designer originally intended. If you don't know about this controller then give yourself a slap from me and head on over to Paul's thread.

Batteries will be Winston 40Ah cells, as many as will fit. The small size of the cells allows them to be squeezed into smaller areas of the car at the expense of more cells required and more cell top BMS modules. The plan is to mount them under the rear seat, taking the place of the fuel tank. If more cells are required than will fit in that space then they will go in the engine bay.
The pack under the rear seat will be a self contained and removable unit. It will also house the main contactor and the pre-charge contactor.
That way pack voltage will only leave the pack module when either the pre-charge or main contactor are active.
Monitoring this pack will be the Low Cost BMS. This will provide individual cell monitoring, charge control and top balancing on every charge. The low cost allows me to use smaller capacity cells which should be easier to squeeze in to the available space.

Power steering will have it's pressurised fluid supplied by a second hand electric power steering pump. These are available from most car wreckers for less than $50. Just make sure they are well mounted with their vibration insulators correctly attached. They can generate quite a bit of noise if not mounted properly.

Heater, this will be a cannibalised ceramic heater. It will take the place of the existing heater core. Very cheap, very effective, quick to heat up and very light weight.

Brakes. The vacuum assisted brakes will get their vacuum from a second hand vacuum pump (Hella UP28, 30 or 32) controlled by a Summit racing vacuum switch and relay.

The air conditioning will be via a pulley mounted to the rear shaft of the electric motor. I have read that the pressure generated whilst moving is enough to keep the A/C working whilst stopped at traffic lights. If not then i can always remove the existing compressor and fit an electric one sourced from a hybrid vehicle.

Well that's it for the second post.

Woohoo, another EV build. I love these. :)

I have added the motor, battery and AC details.

The range is going to be minimal. This vehicles job will be to get me to and from work each day (well each day i bother to go :)).
Round trip is a 42klm (26 miles).
I may have the option of topping up the charge whilst at work but i am not counting on it and so the daily distance will be 42klm.
Lots of traffic lights so the ability for the AC motor to do regeneration will help.
The speed will be quite low due to low speed limits. This will help as well as the wind resistance will be very low. Most of the trip will be limited to less than 60kph (37mph).
Also there will be no passengers further reducing weight and energy consumed.

.

This should be a interesting build. :thumbup:


That car has power steering...???

It is equivalent in size to my Metro and it does not have power steering or needed.

>

You can always try something else to improve the efficiency of the air-conditioneer setup, such as adding some gel-filled pads that keep a little colder right after the compressor stops.


I also like its look.


[/QUOTE]

I have some previous experiences with the Brazilian Chevrolet Corsa, which is basically the same car, and never had any head gasket issue. The only thing that really bothered the hell out of me was once that an ignition coil failed in a '01 Corsa sedan (which I guess was never available in Oz), leaving the engine firing only in 3 cylinders, about one month after getting the engine pressure-washed.

If i find i am stopped long enough for the A/C pressure to drop enough for the cooling effect to reduce then i can always slip the gearbox into neutral and give the motor a little rev to get the pressure back up again.

Subscribed.

I had the same response as redneck: "this has power steering?"

I know, it doesn't really need it. But because it was originally fitted with power steering the regulations say it has to have it after conversion to an EV. :(

Here are some of the weights for what has been removed and what is going back in.
The weights removed from the car are real world figures weighed as each piece was removed. The fluid weights were derived from the service manual figures for each fluids capacity and the fluids Specific Gravity.
The weights of the items going into the vehicle are mainly estimates and so are likely to creep up.
Also these weights were from the first car i stripped (same model) and i removed the A/C Compressor in that one whereas i will be retaining it this time.
So it is really only 2 kilos lighter not the 8.7 shown in the table.

I haven't removed anything other than the ICE related stuff. I still have all the interior untouched, spare wheel, jack, factory steel rims all round, etc.
The weight of the 12v accessories battery may change as i am still trying to decide if i will use a small motorbike battery or some form of LiFePo4 battery. I am leaning towards the motorcycle battery as it will not require as much monitoring or charge / discharge control.

If i stumble upon some crazy cheap alloy rims i may swap them over. But so far i am happy with ~200 kilos (441lbs) removed. :D

http://i1310.photobucket.com/albums/...psccdbd4d1.jpg

I assume it's Department of Safety or similar regs that require retention of power steering?

What if you could find and install a manual steering system from another Barina? Being that it was standard equipment on an equivalent example, would that satisfy the regulations?

Afraid not, well at least not in my state here in Australia. I spoke to the engineer to see what was allowed and it was a big no. If the car was manufactured with power steering then it has to remain. The engineers are the ones that have the final say, they determine how each regulation is to be interpreted. If the regulation says the batteries need to be in a box and the engineer interprets that to mean quarter inch plate, fully welded and painted pink then that is what is required. After all it is their butt that is on the line if they sign off something and it is later found to be unsafe or the cause of an accident.

The National Code of Practice says

Man, that bites.

In light of that I would hold out for another clean example that never had power steering, because that parasitic loss to keep the pump running is a big drag on your capacity. As you say they're cheap and plentiful due to the Achilles heel of the engine.

It's interesting to me to see how different countries and even states regulate vehicles.

There are lots of states in the US that have required annual vehicle inspections, some for emissions and some for general vehicle condition, often both. In the counties of Tennessee where I live and work, there are no inspections at all. You see some serious junkyard dogs rolling around here as a direct result. If it runs and you can register it, off it goes.

No visible smoke, though. There are regulations on the books that permit cops to pull you over and give citations if you're smoking up the place.

.

Just a thought. Maybe you could add a couple of micro switches to the steering wheel shaft that will turn on the power steering pump when either 9 o'clock or 3o'clock is exceeded. This would remove continuous parasitic loss of the pump on the system.

And yes, I do realize that this will not pass initial testing.

Like I said, just a thought.

:)

>

The plan is to generate the required signals to allow the electric power steering pump to reduce its load as vehicle speed increases. So you get maximum assistance at low speed and zero assistance once you get moving at a decent speed.
There is a thread on the DIY Electric Car forum that describes some members efforts at getting these working.
There is also a YouTube video of one being bench tested which shows they can be very quiet. I have seen one other video in which the pump sound was deafening. So hopefully i can work out which one is the quiet one. :)
YouTube video

I found the videos with one being quiet and one being loud. Well it appears that way anyway. Sometimes it is hard to tell without other noises on the recording to judge relative volume levels.
Quiet Loud
Maybe i should go with the louder one. Might stop people saying electric cars are too quiet. :rolleyes:

My understanding is that at least some Barina/Astra pumps only require a VSS signal to operate in this manor. I have a MR2 pump with only three connections, power, ground and VSS.

Yes, i am leaning towards the MR2 pump. Seems quiet and easy to wire up.
I like the idea of hiding it away under the front fender and only having the reservoir in the engine bay. That would save some space and neaten things up a bit, may even make it quieter once the plastic wheel well liner covers it up.
Also being able to just get it to run initially and then add a more controlled VSS signal later makes it seem easier.
I think the newer models of the MR2 pump have a few extra wires for things like diagnostics and warning lights. Those extra connections don't need to be hooked up but as i have a Power Steering warning light as part of the existing instrument cluster it makes sense to get the pump that can use it.
I think next week a friend wants to go on a bit of a scavenge at the wreckers so i will keep an eye out for a MR2 pump.

Is self quoting allowed? :p

I just measured the parasitic draw on the accessory battery with car all off.
I wanted to know how quickly a small motorcycle battery would be discharged with the parasitic load.
The current draw is 5.27mA.
So about 55 days to flatten a 7Ah battery to dead flat.
Maybe count on a month before the voltage drops too low to be useful for energising the contactors. If the contactors can be energised then the DC-to-DC converter will fire up and the car will be good to go and the accessory battery will start charging.
If that is correct then i should be able to ditch the massive 12.6kg (27.8lbs) standard car battery and replace it with a battery that takes up about a quarter of the space and saves over 10kg (22 lbs) in weight.

I will have to check the regulations to find out how long the accessory battery is required to continue without input from the traction battery via the DC-to-DC converter.
Checked, it has to be able to power the hazard lights flashing for a minimum of 20 minutes.
So 6 globes. (rear 2 x 21W, front 2 x 21W and side 2 x 5W) 94watts or 7.8A at 12 volts
50% duty cycle (flashing) lowers it to 3.9A averaged.
So 20 minutes should only need about 1.3Ah from the 7Ah battery
Looks like it may be doable. :)

Bit of an update.

I now have an engine hoist on loan from my brother-in-law which should make the removal of the engine block easier. That should happen in the next week or so.

Here are a couple of photos of the electric motor.
I managed to weigh it and it is 74 kilos (163 lbs). This is actually less than i expected. I was expecting around 85 kilos (187 lbs). So that was a pleasant surprise. It would have weighed even less if i had went for the lighter flange but i like the idea of the motor mounting bolts being as far as possible from the shaft to reduce the torque they are subjected to.
The feet on the motor will be removed which will knock a little bit more weight off as well.
Of course now that it has the nice big flange mount, there is the possibility that it may need some surgery to prevent it fouling on the axle that runs past the motor.
Won't know for sure until i get the ICE engine out of the engine bay to do some measurements.



http://i1310.photobucket.com/albums/...ps7fad7b9f.jpg

In the next shot you can see the wires exiting a small hole, these are for the encoder bearing which is internal to the motor.
http://i1310.photobucket.com/albums/...psb31971a9.jpg

Regulations say the high voltage cables need to be orange in colour so i have several meters of orange heat shrink which will go over each of the phase cables.

I may also change the terminal box as i don't like the way two of the phase cables are squeezed into a single hole. I may put a new box on it with three appropriately sized holes and add some cable glands to stop them moving and abrading.

I will also see if i can remove some of the blue paint that was sprayed over everything including the cables. :(

I'm quite familiar with those motors. We use them on all our equipment here at work. :)

They are just the common 3 phase industrial motor but with windings swapped out for a more electric vehicle type of wind.
In my case a 48V wind.
It should certainly be solid enough. :D
Custom EV Performance did mine.

Do you ever get motors that may have damaged windings? Salvaging a faulty motor may be a cheap way to get a reasonable AC motor for an electric vehicle. I am guestimating that getting a motor rewinder to rewind a motor for EV use would be somewhere around $1000. I could be way off with that estimate but certainly cheaper than a brand new HPEVS AC50 or similar. So if you can source a motor carcas for scrap value then it could be well worth it.
Even if it is only 80% as good as a designed from the ground up EV motor then it may be more than enough for some users. That's what i am hoping for. I don't expect the same performance as an AC50 but something approaching that level of performance would be more than enough for me.
It is all an experiment. Hopefully if it all works out then it will give other EV'ers another affordable path to AC drive. :thumbup:

As for power steering - some later production (but still "B" generation) Corsas had full electric power assisted steering column instead of hydraulic rack. It's easy to find complete kit in UK because it's often used to retro-fit PS into oldtimers or kitcars; here's first search result at eBay. In Poland it would cost ~100€ because we've imported a lot of UK cars and RHD stuff is useless...
You'd still have to check if there were some changes in body bracket for steering column between hydraulic and EPS cars; even with some mods needed I think it's still worth it!

Finally finished enough cell top modules (53) to cover the number of cells going into the car (48). All built and tested. :D

Here's some pictures of the result. Not shown in the picture is the many sleepless nights, strained eyes and singed fingers. :)

This is the system described in the Low Cost BMS thread.

I used a modified version of the cell top PCB. Another forum member, Arber333 made many changes to the PCB for me. Mainly to suit the smaller terminal spacing on the 40Ah cells. But he also added a resistor and LED in parallel with the load resistors so that i can see when they are in use. Very handy.

I have 4 Winston 40Ah cells that i am using for testing. Another 44 cells will be added later. The communications connections between cells will be changed for shorter lengths later to make things neater.

http://i1310.photobucket.com/albums/...ps143da51e.jpg

I changed the LCD from the 2 line version to a 4 line version as there are some additions to the set up that i want to add later that will require more screen area.
I also changed the master modules micro controller to a 16F1847. This is a drop-in replacement for the 16F1827, but it has more memory which should increase the number of cell top modules it can keep track of.

http://i1310.photobucket.com/albums/...ps8172b204.jpg

As you can see the cells are quite out of balance due to testing each of the cell top module's load resistors. These cells will now be individually charged and brought back into balance. Cell 1 is the highest with 3.34v and cell 3 is the lowest with 3.28v.

Some more pictures.
http://i1310.photobucket.com/albums/...ps63b14737.jpg

http://i1310.photobucket.com/albums/...ps144d466c.jpg

I mounted the load resistors with a bit of air space between them and the PCB to allow for better heat dissipation.
If i built them again i would swap the two capacitors around so that the capacitor with the metal can wasn't so close to the load resistors.
I didn't put any pins in the programming port as i found it wasn't necessary, simply putting the programmers pins in the holes and keeping a small amount of sideways pressure gave good contact for the couple of seconds required to program the micro controller.
This saved me soldering 265 extra connections and it also reduces the chance of a stray communications connector coming into contact with a pin on the programming port.

I suspect that sort of swap wouldn't be approved by the engineers here in Australia. :(
I have found a company here in Australia that sells kits for doing the swap but they only talk about doing the swap in race cars not road going passenger cars.
I have shot them an email to find out.
For the moment i will continue with the electric hydraulic as planned just because it is a less than $50 cost and i know it has been used by other EV conversions without issues getting it past the engineers.
I may look at changing it over to EPAS later if i find out it will be legal.

I received a reply from the company that supplies EPAS kits.
They say their kit is suitable for on road use but it needs to be approved by an authorised engineer. Seeing as how the whole car is going to through the engineering inspection for the EV conversion this should not be an issue. I will have to have a ferret around on the internet to see if any of the Corsa B models imported into Australia were fitted with EPAS units.
Thank you z_power

I'm currently tweaking last 10% of my FIAT Cinquecento conversion (as we all know this step takes >90% of total work time) and around 98th percent there's scheduled upgrade to EPS from younger Seicento.
We (Poland) still have quite liberal regulations regarding technical approval but after joining EU there's drift in the same direction, maybe not as strict as in Germany, OZ or NZ but definitely not into liberal side like in US. Ahh, "the more freedom, the more control" - heard it yesterday in punkrock song in radio ;)
Good luck with your build, euro Corsa B was on my list of potential gliders for first conversion, too :)

Well i finally managed to get several things on site at the same time.
The engine crane, my father-in-law and myself. :)

My father-in-law is going to help me with the adaptor plate and shaft coupler. He has access to heavy machining equipment. :thumbup:

We wanted to be able to take measurements of all the pieces and my father-in-law needed to be able to see how it all goes together so that my crazy descriptions could make sense.

After a little bit of struggling we managed to convince the car to release its burden.
http://i1310.photobucket.com/albums/...psad897085.jpg

http://i1310.photobucket.com/albums/...psfea262e4.jpg

http://i1310.photobucket.com/albums/...psedc89196.jpg

The last time i removed a motor from a SB Barina it was super easy but this time there seemed to be something stopping the motor from clearing the bell housing.
In the end we just removed the clutch and pressure plate which cleared the obstruction.
I didn't have to do this last time.
Once the motor was out it was easy to see what the problem was.

The input shaft to the gearbox was different. It was extra long, it protruded well past the bell housing. On the other Barina there was no smooth area to the input shaft just the splined section. It was that extra inch or more that had us tricked. When we thought the clutch should have been well clear it was still entangled with the input shaft.
We think we will cut off this extra length as it is not supported by the crankshaft. The hole in the crankshaft is much larger than this shaft extension.
But for the moment it gives us a nice centre reference that protrudes beyond the flat plane of the bell housing so should hopefully help with getting accurate measurements for the adaptor plate holes.

http://i1310.photobucket.com/albums/...psd625b04a.jpg

But at least we got there in the end.

http://i1310.photobucket.com/albums/...ps9b19ff33.jpg

http://i1310.photobucket.com/albums/...psac6016c2.jpg

Then we spent a little while measuring everything and working out a strategy for the creation of the adaptor plate and the coupling hub.

But that's for another post. :)

How are the rules there regarding EV conversion? Here in Holland we can't have a motor or controller be DIY or from something else, it has to have a certificate for use in a road vehicle, and to get one, costs a ton of money. Strangely enough, importing cars that have been approved in other EU states with much less strict rules is totally okay, so if I can find one that lets me use an old forklift motor or an industrial AC motor and a self-designed controller, then I can afford an EV conversion too. :) (Not going to put €20k of motor/controller in a €1k car..)

De-iced, nice! :)

Well, the rules are slowly getting tighter but as usual in our part of the world execution of these rules is... not so tight, to say. While registration of scratch built cars became painful and expensive, conversions of already registered ones are not that hard to legalize. I'd say ~500€ is upper limit on expenses (legal fees, expert opinions and tech examinations).

I still didn't legalize my conversion because it's not clean enough ("messy" contactor box, heater noot installed etc.) so no 1st hand experience, but I already did research at local registration office and at examination stations. Will let you know when I pass it.

I can imagine, you only want to go once and get it right, and not have them say "no" and take your plates away, making further test driving impossible.

The only reason I'd do it as quickly as possible, is because we pay a lot of tax each month, and electric cars are (for now) not taxed. A pretty good saving, that makes the conversion a little more wallet-friendly to run. :)

Please. :) I'm quite curious how it will go.

Some more progress.
I visited a local wreckers and found a electric power steering pump.
Took a little while to extract it from the car, i have no idea why manufacturers put things where they do. Eventually it was extracted and the cost was $50.
I also found a vacuum reservoir to complete the brakes which cost me $10.
Also located a few items for my ICE vehicles.
So quite a productive rummage at the wreckers.

I welded up a bracket to mount the P/S pump using some existing mount points in the engine bay. Next i will have to get the hydraulic hoses joined up. I will get the high pressure line made up professionally, way too many PSI for my skills. :D

The A/C hose looks close but it will move once the A/C compressor is mounted to the motor. I may need to make alterations to the mounting bracket but i will wait and see where the hose ends up.
At the moment there is about an inch of clearance between the top of cap on the P/S module and the underside of the bonnet. So there is some room to move vertically but not much. The module could be moved horizontally further back towards the battery. Where it is at the moment was the easiest spot given the existing mount points available. If it needs some refining later then that is ok.

http://i1310.photobucket.com/albums/...psb81bd725.jpg


I welded up a bracket to mount the electric vacuum pump.
I just combined an existing bracket for a part that is no longer required with the bracket that came with the vacuum pump.
It will live under the wheel arch out of the way.
The vacuum reservoir will be mounted under there too.

As i look at this bracket now i am wondering if i should have added some diagonal bracing to help support the pump. The spot welded joint may not hold up long term. I will have to ponder that some more.

http://i1310.photobucket.com/albums/...ps91723b8a.jpg

My father-in-law and i thrashed out some more details on the hub and adaptor plate setup. The plan is to use a taperloc in the hub. This should give the hub a nice snug fit. Combined with the keyway there shouldn't be any movement.

I ordered the rest of my cells for the traction pack. I already had 4 cells that i was using to test the BMS modules on as i built them. Now i have ordered an additional 44 cells to make up the 48 cell 156 volt traction pack. This was the most expensive purchase of the entire build. About a quarter of the total build cost is the batteries.

I have started welding up the battery rack for the traction pack. Looks like it will fit neatly.
Still lots more welding to be done on it before it is complete.
The battery rack It is going to be a self contained battery module with the main and precharge contactors integrated into it. So when the contactors are de-energised the high voltage is only inside the pack. It will be attached by several easily removed bolts so that the entire pack can be easily removed for maintenance and inspections.
It needs easy to remove as it will be mounted under the car in the void left by the petrol tank which would be too awkward to work on without removing the pack. Well that's the plan anyway.

How did I miss your build thread!? Thank you for showing your progress. That was really fun to read.

Well, the lack of diagonal bracing did wear away at me. :o

So i added in some bracing and while i was at it i re-did the power steering pump mounting bracket as well.

Re-work is so much fun.:rolleyes:

At least now i feel the brackets are all they should be. Below are the vacuum pump, throttle and power steering brackets.
http://i1310.photobucket.com/albums/...ps524b1fe5.jpg

The Power steering bracket was modified to allow the pump to sit further back in the engine bay and slightly higher, giving more clearance for the A/C hose in front of it and the clutch cable below it.
http://i1310.photobucket.com/albums/...ps7aa85269.jpg

I cable tied both sections of power steering hose together. The section that came with the Astra's power steering pump and the section from the Barina's steering rack.
I marked across both so i would know how long the joined hose will need to be.
I will take it round to the hydraulic hose guys to make a single hose out of it.
Way too many PSI (1200 to 1500) for me to consider doing myself.
Not sure if they will join the hose sections or just replace the entire hose part.
The hose sections my be dissimilar and incompatible.

http://i1310.photobucket.com/albums/...psd54f071e.jpg


The hall effect throttle assembly was mounted to the bracket.
http://i1310.photobucket.com/albums/...ps2a6ae22f.jpg
I went with the hall effect type of throttle as it will be immune from wear that can cause noisy signals when using a resistive type. Just make sure whatever controller you use it supports hall effect throttles.
Paul's AC controller supports hall effect throttles so that will be perfect.

Then the bracket was mounted to the firewall and the throttle cable attached. It all fitted first go. Didn't need to adjust anything. Had to happen eventually. :)
http://i1310.photobucket.com/albums/...pse21bb16e.jpg


The Barina throttle connector is a ball and socket type. I found a suitable ball on ebay that fitted perfectly.
Throttle Linkage Ball 5 16" OD 8mm 43706 | eBay
http://i1310.photobucket.com/albums/...pscc912cf4.jpg


From there i made a start on building a replacement for the cabin heater core.
Stripped down a ceramic heater for it's element and holder.
Then i fabricated a metal box to the same dimensions as the heater core. (It will look better once painted up :))
I know, nobody will ever see it again once it is installed but i will see it every time i look at the car. A bit obsessive maybe but i need to have something to blame for how long the build is taking.
http://i1310.photobucket.com/albums/...psbab8aebc.jpg


Here is a roughly how it will come together. I still need to cut the hole below the element and then glue and rivet the the element holder in.
http://i1310.photobucket.com/albums/...ps067a9479.jpg


I tested the element to see if it will work ok with DC rather than AC. 96v was all the charged 12v batteries i had handy.
Oh and by the way, yes, 96v DC does give a bit of a tingle when you decide to include your body in the circuit. :eek:

I had read that the ceramic element is self limiting. As the temperature increases the current reduces.
Sounded a little too good to be true but when i tested it that was exactly what happened. Initially current increased as the elements temperature increased but then as the element got to about 180C the current started reducing. The current continued to reduce until an equilibrium was reached and the temperature stopped at around 205C.
This was with no air flow through the element.
Blowing a small amount of air through the element caused the current to increase slightly and the temperature to remain at 205C.

The element has a thermal switch mounted to the side of it. This cuts the power when the element reaches about 180C and turns it back on when the temperature drops below 140C.
Not sure if i should run the element at its equilibrium temperature of 205C or let the thermal switch cycle the element on and off.
Not sure which is best for long term reliability. Is running the element at 205C going to shorten its life or is the thermal switch going to fail as it is now switching 156v DC rather than 240v AC?

I'd rather run it at the thermostatically-controlled temperatures, both for long-term reliability and to avoid fire risk to the car parts surrounding the ceramic element :thumbup:

I think you are right.
I ordered a couple of extra thermo switches. One 130C and one 105C.
One of them should replicate more closely the temperature the original heater core generated.

You can also consider to add some thermal insulation behind the dash, and around this metallic case you're making for the ceramic heater, in order to keep the dash more protected from that heat blast. That could eventually also make the heat irradiation more efficiently-directed thru its original HVAC ducts.