Miles ZX40ST refurb project

wb9k

10 kW
Joined
Jun 29, 2013
Messages
820
Location
Metro Detroit area
Hi all. I'm just getting into my latest project...the re-assembly of a Miles ZX40ST electric truck. Here a link to the album on Photobucket...more pictures will come as they are taken.

http://s935.photobucket.com/user/mollysplayhouse/library/Miles%20ZX40ST%20Truck%20Restoration?sort=3&page=1

The original AC drivetrain of the truck was damaged by the original owner (a University) when they towed the vehicle after depleting the lead acid traction battery. This sent damaging electrical impulses to the controller and maybe damaged the motor too...I'm not sure exactly. The original batteries, controller, and motor are all missing. The truck came to me with the chassis in tact, but the pieces of a "new" drivetrain all loose--a 12 inch DC series wound motor, Chevy S-10 transmission, and custom driveshaft and other bits and pieces for connecting it all together.

Looking at the truck, it's not hard to understand why Miles is out of business. The engineering on this thing is pretty poor, even by homebrew standards, IMO. The truck chassis (made by Hafei Motors of China) is light duty, but reasonably well built, but the upfitted drivetrain put in by Miles was little more than a golf cart drivetrain dropped into a truck. The original HV (72V, to be exact) electronics were mounted under the seats. You can see in one picture I have up already that the tray that stuff sat on is completely open to the elements from underneath--you can see lots of ground looking through this compartment. If GM tried selling something like this, their execs would wind up in jail. Top speed was originally limited to 25 mph, so this was originally designated an LSV, or Low Speed Vehicle, which is only street legal on a very limited number of roads in the US. I cannot even legally leave the little subdivision where I live in an LSV, so I strongly disagree that these are a viable alternative to conventional cars for any but a small handful of city dwellers.

With the freshly rebuilt DC motor and transmission (which I'm not crazy about using....may look to remove it later if possible) I plan to make this thing capable of 55-60 mph. I'll be able to drive it anywhere but on expressways, where I probably wouldn't want to take it anyway. I'm OK with that. Fortunately, the truck came with a clean "normal" title, so the legal hurdles of street legalization have already been cleared for me.

Because this is a relatively cheap Chinese chassis, I suspect the steel may not be of the best quality. The truck is 7 years old, but only has 800 miles on it. Still, there was some overall surface rust just from being out in the weather, mostly confined to the frame--body sheet metal still looks very good. So, I've got the truck partly torn down and I'm removing all rust first. This will be followed by rust inhibitor, bonding primer, and underbody coating on the entire frame. I plan to drive this in the rain and snow, and it needs to survive. Most rust has been easy to get to with wire wheels, but I bought a small soda blaster from Harbor Freight to reach the areas a brush couldn't go. After fighting with the blaster getting it set up for a couple hours, I finally got it working right and it did the job quite well.

Rust removal is almost done now. It won't be warm enough here to start applying anything to the frame until Wednesday this week, I should be able to get started on that then. Updates will come as they happen...I hope to have this thing on the road within a month or so.
 
I know soda will take paint off, but I thought it wasn't hard enough to do iron oxide. Did your's appear to take rust off steel?
 
gogo said:
I know soda will take paint off, but I thought it wasn't hard enough to do iron oxide. Did your's appear to take rust off steel?

It can get to bare metal pretty quick. Rusted parts aren't made shiny, but they are free of loose debris and ready for rust inhibitor, which was my goal. It's very messy though....I'm only using it where I can't get a wire wheel--in corners, crevices, and interior parts of the frame tubing/box structures.
 
wb9k said:
gogo said:
I know soda will take paint off, but I thought it wasn't hard enough to do iron oxide. Did your's appear to take rust off steel?

It can get to bare metal pretty quick. Rusted parts aren't made shiny, but they are free of loose debris and ready for rust inhibitor, which was my goal. It's very messy though....I'm only using it where I can't get a wire wheel--in corners, crevices, and interior parts of the frame tubing/box structures.
That sounds like the best that can be done for avoiding rust in MI. The brine they use here in Iowa sticks to everything!
 
dnmun said:
you can use dilute phosphoric acid on the rust to remove it and convert it to a stable phosphate which you can prime.


Yeah, a few methods out there. "Naval jelly" is dilute phosphoric acid. Even with a sprayer and liquid, I don't think I can satisfactorily clear all the rust that is inside the frame with acid, and I'm not crazy about playing around with acid to begin with. My plan is to use Extend "rust destroyer" after removing all the loose stuff from the worst-corroded areas. It's really not that bad overall, but it will go south in a hurry after a winter or two here if I don't do this.
 
For areas inside the chassis that you can't reach to clean or paint I have found a good quality cavity wax to be the best solution :)
 
Punx0r said:
For areas inside the chassis that you can't reach to clean or paint I have found a good quality cavity wax to be the best solution :)

Thanks...I'll look into that one.
 
the commercial products like the 'rust destroyer' and 'metal prep' are all dilute solutions of phosphoric acid. if you can buy it in gallon jugs from a cheap source that will give you a lot of acid to work with and if you can lay plastic on the floor underneath the vehicle and recover the runoff then you can reuse the acid that drips off the frame. it requires no subsequent treatment beyond rinsing it off and letting it dry. then prime the surface. the iron phosphate is solid and will protect from further rusting. even in detroit.

i had a honda wagon from detroit. i could not jack it up from underneath and eventually it rusted so bad there were huge holes in the structural supports for the frame holding the motor. loved that car. worked it like a truck the size of yours.
 
Thanks for the suggestions, guys, I appreciate it. This beats abuse any time! :lol:

I've added some captions to the photos in the album and some new pics of the freshly rebuilt 12 inch DC series wound motor. The custom aluminum plate and pieces holding on the flywheel were put together by the last owner and some helpers. Same with the custom driveshaft. The bits and pieces that hold all that together still need some attention. Still pondering controllers. I have a Lebowski chip, but that's going to take longer to get going than I have, so I'm looking for something that can handle 150 Volts and maybe 400 or 500 Amps to get the thing rolling soon. Anyone who has such to sell, please let me know.
 
wb9k said:
so I'm looking for something that can handle 150 Volts and maybe 400 or 500 Amps to get the thing rolling soon. Anyone who has such to sell, please let me know.
You might want to post a detailed ad in the Items Wanted section both here on ES and over on DIY Electric Car forums, for those that aren't following your build thread. ;)


BTW, I didn't see anything about your power source. I assume you'll be using lead-acid, right? :p
 
Power source isn't here yet, but I have it secured. It's a prototype pack built for Chinese OEM SAIC that got scrapped. Four Amp 20 modules in 25S2P. The pack is complete with all supervisory electronics and a cooling plate (which will probably be used mostly for heating cells in the winter). It's all in a watertight container that should fit neatly under the bed. Integrating the electronics into a working control system is going to be the biggest challenge.
 
If you intend to keep the truck, consider Epoxy Mastic 121. I used that on our '84 Classic Mini and my only regret is not using more of it. Dries even under water and takes an angle grinder to get off again. +1 for the cavity wax.
 
I've tried a few places locally for cavity wax. Nobody in the US seems to have ever heard of it...I'm starting to think it's mostly a EU thing. Looks like I'll have to buy online. I'm still interested in using it to protect a few areas internal to the frame structures that are otherwise difficult to get into.

I've posted some new pics at

http://s935.photobucket.com/user/mollysplayhouse/library/?sort=3&page=1

Most of the rear frame work is done and the bed metal is almost finished. A little more work to the frame under the cabin and I'll be ready to start fitting the motor, trans, and driveshaft and working on finding a final home for the battery pack, which I hope to have home this weekend. The drivetrain was sort of test-fitted into the vehicle by the previous owner, but has never actually been hooked up and run. The biggest issue there is the custom yoke for joining the driveshaft to the differential. It's not finished, and I'm not sure I like the looks of what is there. My dad worked in a Detroit fab shop for 30 years and will probably be down to help out this weekend (he lives "up north"). It should be fun to watch him wrap his brain around the paradigm shift away from the ICE. I'm also going to need to come up with some kind of clutch and shifter arrangement. I want to shift gears electronically because a mechanical linkage to the trans is not going to be a good option. In the back of my mind, I keep wondering if it makes more sense to just get rid of the tranny altogether and drive the differential directly with yet another custom driveshaft. Then I would just do reverse electrically. More fab work, though.

The other aspects are slowly coming into focus. CAN communication to the battery pack will likely be accomplished with a spare diagnostic tool we developed at work a couple years ago that never really took off. It can send and receive CAN messages and even program electronics as well as display various values. Failing that, some type of Arduino-based setup is also possible.

I've tested the 12 Volt harness and everything is working except the reverse lights. Given that the motor and reverse switch mechanism isn't connected, that's not really a surprise. All other lights look OK, but current draw is pretty high. LED's will be in order soon. The (toasted LA) 12 Volt battery is going to be replaced with a li ion unit based on 26650's in 4S4P using brownrdb2's kit and an A123 starter battery board for supervision.

Still working on a controller, main charger, and DC/DC converter. Feeling alternately overwhelmed and excited....
 
I guess cavity wax is mostly popular where the climate is damp enough to cause serious corrosion problems ;)

Looking on, 3M do a product that a local supplier might be able to order in:

http://catalogue.3m.co.uk/en_gb/gb-aad/Coatings/Inner_Cavity_Wax/td~Inner_Cavity_Wax_-_Amber~nocode

I saw a couple of U.S.-based suppliers pop up online, but frankly, they seemed quite expensive.

BTW, I can second the recommendation for the epoxy-mastic type chassis paint (brushable 2-pack isocyanate). It's a bit awkward to work with but sticks like nothing else I know of that's available to the DIY user.
 
I happen to have a grey 1.25 like pack that I got from http://millersoilsireland.ie/epoxy-mastic-chassis-paint/ and which I could ship at cost if you're stuck. I decided to use it on the inside, too so would need it in black...
 
My father (who worked 30 years in a Detroit prototype fab shop) came to visit and pound away on the truck this past weekend. This (and some input from over on DIY Electric Car) enabled me to make a number of key design decisions. It has been decided the truck will have no transmission. The motor will drive the differential directly. Motor rpm's should be around 4500 at the target top speed of 60 mph. I imagine it will be capable of higher speeds if I wanted to go there.

After making that decision, we removed the clutch, flywheel, and big aluminum adapter plates from the motor and fabricated essentially new motor mounts using most of the original mounts that were still left and some new mild steel stock. This pic shows the drive end of the motor as it presently exists.

\

I still need to finish the motor mounts, but they're mostly done. The drive adapter that originally held the flywheel and clutch will be refitted by a machinist to include a section of the output shaft of the original transmission:



I have this piece out of the tranny now, but no pics yet. This assembly will mate to the original driveshaft. After the motor is in place we'll be able to see how much the driveshaft needs to be extended, which will also be done by a specialty shop of some sort here in town. I expect this to be the hardest part of the whole process for me. Placing the battery pack and fabricating the mounts for that will probably be second hardest. Ironing out CAN communication will probably be next in the difficulty ranking. So, it's pretty exciting to have these details more or less figured out. Here's another shot, showing the opposite end of the motor:



Still looking for a controller, hoping to spend a max of $1,000 on that part.
 
Been a while since posting, but progress has continued on the truck. New photos can be seen at

http://s935.photobucket.com/user/mollysplayhouse/library/Miles%20ZX40ST%20Truck%20Restoration?sort=3&page=1

My dad came by for the weekend again, and we've managed to get the motor fully mounted in the vehicle, which took fabrication of an additional bracket to prevent fore/aft movement of the motor on the mount. The fit couldn't be tighter...just about perfect from the looks of things. We were able to determine that the driveshaft angle will be ~5 degrees, worst case (7 is a typical max), so all is looking good.

The next big thing to be done that we could properly attack at this point was fabrication of some kind of belly pan. We (meaning my dad) decided that three 2' x 4' sheets of steel would be needed to make the pan, and some 3/4" plywood would be needed to make a form for the job. Some scrap cardboard were the only other materials. We used plywood, some clamps, and some more plywood to make a primitive brake for the sheet metal. Took some time, but it worked and the finished piece looks pretty good. There's no way I could have done that without the help my dad was able to give with all his fab experience. I've learned a ton about working with metal on this project already

Then on Monday, I got my driveshaft adapter back from the machinist. Looks really good to me, I think it will work just fine. Next step is to cut the driveshaft and get it measured and ready for lengthening. Then it will be on to the electrical side of things. I'm hoping to have this thing on the road by the end of June.
 
Been a while since I've posted, but the truck project continues to motor along. Here's a shot of the motor/driveshaft adapter I had made in place on the motor:



Here's the driveshaft after I cut it, fit it in place, and tacked some angle iron on to hold the form so the driveshaft shop could rebuild to the right size:



Here's the driveshaft as received back from Automotive Supply Company of Livonia, MI. They did a beautiful job:



I have videos of the motor driving the wheels at 12 and 24 Volts, but am having problems getting them to play back online. You might be able to download this 12V video and play it back locally (it's really in AVI format):



And now....on to the battery pack. It's a 12.3 kW A123 pack, a prototype for a PHEV by Chinese OEM SAIC:



The pack was originally configured 92S2P, or ~300V, 40 Ah:



I have reconfigured it to 46S4P, or 150V, 80 Ah. See if you can tell the difference:



The pack software will require a minor change to accomodate this, but all pack safety and monitoring functions will be retained.

I had thought that transverse mounting of the pack would be the way to go, but this would render the MSD inaccessible with the pack installed:



It appears the best way forward will be longitudinal mounting. This moves some weight distribution toward the rear (good in the winter) and also leaves all connectors out in the clear for easy access:



Controller will be ordered today (NOS Raptor 1200). Pack installation is the last big mechanical job remaining. Until that happens, I have a couple of 72 V controllers I may rig up temporarily to get a better idea of what I can expect in terms of performance and any thermal management requirements for the motor. I hope to have the truck in a usable state by the end of June.

More photos and details can be seen at the Photobucket album link given in previous posts. All questions, comments and feedback welcome.
 
Continuing the slog forward.....

I took a short ride in another of these trucks over the winter, and was underwhelmed at the amount of heat the cabin heater generated. So, I wanted to get a look at the heater core in my truck before it got cold out to see what might be done to improve things. I was pleasantly surprised to find a PTC ceramic-type heating element, apparently made by Pelonis Technologies:



I was previously unaware of this technology, but am quite taken with it. The element self-regulates it's temperature as the DCR of the ceramic material changes with temp. Surface temps stabilize around 450 degrees F and stay there. Heat output is thus adjusted by airflow over the element. Max output is over 1000 Watts of heating power--plenty for the job. Very safe and efficient. Can anyone speak to the reliability of these units? I have not found any data regarding failure modes or rates online. The big downside in this little venture was that the dash panel had to be torn down a long way to remove the blower and heater core. The dash has no clips, everything is held in place by screws, many of which are inserted from the back side of the dash panel. All ductwork is attached. Apparently the wiring was the last thing to be put in, because it's so intertwined with the HVAC ducting that the dash cannot be removed from the vehicle without pulling all the harnessing out of position. We simply stopped once we could get to the blower unit:



I've also managed to reconstitute a 25S3P module from a split up 28S3P module. I removed 3S from one of the halves and recompressed the rest with bar clamps. Using the original stainless steel straps, I stretched the strap back into position and welded the ends with a MIG wire welder. Careful adjustment of weld power yielded welds with good penetration that didn't blow the stainless apart. We'll see how they hold up over time:





The plan is to have three batteries: The drive pack, a small 12V battery, and this module which will be used only to power HVAC and a DC/DC to drive the 12V system. In this way, 12 Volt and HVAC needs will have no bearing whatsoever on vehicle range. I'm considering adding an inverter to the truck that will also be powered by this module to provide remote AC power on occasion. Now to put that dash back together.....

Oh, I also got my controller (Raptor 1200) and have tested it out--all is good. May do some driving with this module running things to gauge performance. If I can meet my performance goals with this Voltage, I may opt to set up the drive pack in 23S8P. Can we add more hours to the day?
 
you could use a propane heater inside the cab for heat too. or even use one of the old gasoline type used in the VW bug. but a propane tent heater might be available online too.
 
dnmun said:
you could use a propane heater inside the cab for heat too. or even use one of the old gasoline type used in the VW bug. but a propane tent heater might be available online too.

You probably saw my post before I actually finished it...sorry. The complete post probably changes your outlook ....
 
heat and defrost is the big hassle for me in winter here too but we don't have real cold, just wet.

i disconnected the big resistance element type heater in my ZENN car because it eats so much juice. i don't try to keep the entire cabin warm either.

instead i bot a little 12V plug in windshield defroster from harbor freight. the kind that has the handle and a little heater core but takes much less juice than my car heater core.

but i always preheat the cabin with a fan type space heater before i drive. i use it for an hour or so when i do my final charge up before i leave in the car and that will keep the windshield defrosted for about 20 minutes and then i use the defrosting gun and hold it so it blows against the windshield in front of me so i have a clear view ahead, not much heat though.

but i have to crack the window a little then to get the humidity down inside from my breathing and then i will run the fan on my windshield defroster to keep air moving across the inside of the windshield so it doesn't fog up. both the defrost gun and the defrost fan of the car keep it clear over about 70% of my side so i can still go even in cold wet conditions. but not fun. my car is really best in mild conditions. but i stay away from cold now too. now portland has california weather with global warming so it should be the beginning of a long string of warmer and drier winters too.
 
I second the auxiliary heater idea. They are very common in Germany. Search for ThermoTop Air to get an idea. Half the time your extra pack is just dead weight...
 
marcexec said:
I second the auxiliary heater idea. They are very common in Germany. Search for ThermoTop Air to get an idea. Half the time your extra pack is just dead weight...

I've looked at the Webasto heaters you mention here, but don't want to go that way for a few reasons.

1) As a rule, I burn oil/gas strictly as a last resort. To me, gas is good for one thing--making electricity when you can't get it any other way. I have just one gas-powered tool left in my garage--a generator.
2) The PTC heater that is already in place appears to be perfectly adequate for the job, is very safe, and quite efficient.
3) The truck is already set up for A/C, I just need to find a proper compressor and add a few pieces of plumbing. I would use the same battery to power that system as well. This probably won't happen until next year, but it's a strong possibility.
4) I'm a bit concerned that the truck is actually too light for safe winter driving. Placing my extra battery (which only weighs ~50 or 60 lbs) toward the rear of the vehicle will help with this.
5) I like the idea of having remote/backup 120V AC power available from the truck (a la VIA), which would also be powered by the extra pack.

So, I don't really see this extra module as "dead weight", but an option that adds significant utility and functionality to the truck without sacrificing a single mile of range that would otherwise need to be actively managed by the driver against all these other needs.

I may use an electric space heater to pre-heat the cabin in extreme cold, but this will not always be possible when out and about. I want this vehicle to be as user-friendly as possible--I certainly want to avoid the kind of hassles and gymnastics that dnmun describes with his ZENN. And, I don't want to ever touch oil or gas again unless I absolutely must do so.

I suspect the main reason this type of arrangement is not already common is cost. I'm very lucky for that to not really be a factor for me when it comes to getting batteries. Cells won't be expensive forever though. Maybe this type of design will become more common as cell prices decline.
 
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