Electric Cadillac Elescalade Progress

We’re finally making a bit of progress on the Cadillac Elescalade Project.

Lucien completed our auxiliary adapter plate for the 11 inch motors. This is our enormous polish friend from Cape Precision Machine. They have taken a good bit of time with this project, but it’s true I had told them there was no rush as we are waiting on batteries. In any event, the final product seems worth the wait.

This is a 7/8 inch adapter plate of 6061 aluminum. It is recessed both to accept the boss on the face of the motor, and the motor itself and so you can tap it on with a hammer and it probably wouldn’t even need screws. We do have eight flathead allen screws that secure it.

This plate provides mounting for our Air Conditioning Compressor and the Power Steering Pump. We put in an idler from the Cadllac, a tensioner from the Cadlilac and in fact used a Cadlllac Power Steering Pump pulley as the drive pulley.

The drive pulley was the key. They had to hog out the existing diameter on this and put in a new bushing, properly centered, to fit the 7/8 inch auxilliary shaft of the motor. But wait! There’s more!

We want to use the Engine Control Unit (ECU) on the vehicle. This little computer gets inputs from all over the car, but by far and away the most important is engine RPM. Without the RPM signal, it thinks the engine is stopped.
Acutally it is GONE entirely but we want it to think our electric motor is somehow an ICE engine.

So we were able to order what is termed a RELUCTOR RING from GM that normally resides on the crankshaft of the L2 engine. A small pickup unit then is threaded into the block to pick up a series of pulses from the teeth of this ring.

We dont’ have a block. We don’t have a crankshaft. So we mounted this ring on the drive pulley. We’ll then mount the pickup on the adapter plate and hopefully provide the ECU with accurate RPM information in a format it likes.

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The plate also provides mounting for a couple of aluminum billet brackets to properly locate the air conditioning compressor and power steering pump. To change these, we’ll simply unbolt the normal mounting bolts and pull straight up. They come right out.

The Power Steering pump is actually part of a larger project. We are going to replace the vacuum assited brakes with brakes using a unit GM calls “hydroboost”. These are often used on diesels who do not generate sufficient vacuuum pressure. They work off hydraulic pressure from the power steering pump, which then powers both steering and brakes.

One of the hangups was using a stock belt. I kind of insisted on this. Lay it out however you want, but use a stock 6 rib serpentine belt I can buy at NAPA. This way, if we lose a belt, we can obtain a normal NAPA part number belt off the rack. The result was 71 1/8 inches of belt. We had them scribe the part number INTO the adapter plate. 12 years from now when this is an issue, I can write down this number, go to NAPA, and hopefully they can make me well.

The unit ran totally silently, with no wobbles or vibrations at all. This is the kind of thing where you can save a few bucks on a conversion by doing it yourself, and most people doing a car will do this. I can’t fault it, but for me, it’s kind of important to get this part right. And we’ve had some adventures with the mechanix of these things anyway on the Mini Cooper.

In this episode, we also tackle the battery box. We’ve centered on a main pack of 57 Winston Battery COmpany 400 AH LiFeYPo4 cells. I started with Thunderskys’s, went to Sky Energy, and now back to the yellow batteries. Why? I like the flatter discharge curve of the CALBs. But I had not had cells from TS since the addition of the Yttrium to the cathode material. This appears to lengthen the life and in fact, they are claiming 5000 cycles at 70% discharge.

Ultimately, beyond power, beyond energy density, I am about cell life. I actually think we may have accidentally stumbled onto something with the Chinese battery suppliers putting us at an advantage over the Panasonic’s and LG Chems favored by the OEM auto makers. Yes, we forfeit a bit of energy density, though precious little. In return we get a hardy package, and cell life. The Panasonics used by Tesla appear to be rated for 300 cycles. We have a “secrete” internal memorandum with page after page of concerns over this, so I’m not alone in this, plenty within Tesla are concerned as well. We actually picked up an interesting thing from this document. Apparently, the Panasonics lose 20% of their capacity per year just sitting – if fully charged. If discharged to 50% SOC, this deterioration drops to 4%.

This is in line with our belief system about keeping the cells as close to 50% as possible for long life. But how do you keep a cell at 50% when you’re driving the car. The natural propensity is to fully charge it. That way its ready if you need it. But apparently the batteries would last longer if you would NOT park it for days on end at full charge.

I dont’ think we have a 20% capacity decrease per year. But we probably have some, and this more or less holds true four our cells as well, just probably to a much lesser degree, and perhaps to a degree where it doesn’t really matter.

In any event, the 3000/5000 cycles in the Winston Battery Company cells appear to be the top of the mark. And up from the 2000/3000 cycles prior to the Yttrium rare earth additive. So we wanted to try them.

400 AH cells will be the largest we’ve done and in fact the largest we’ve seen done in a passenger vehicle. These cells are fully 18 inches wide, though their height and thickness are quite familiar from the 160 AH models.

We think we can do three rows of 19 cells in a package 50×56 inches. That’s 1696 lbs of cells in a 3/4 ton pickup truck. And it will give us 191 volts at 400 AH for 76380 watt-hours of energy. I’m looking for the truck to come in about 7500 lbs in the end, which should indicate about 750 wH per mile. I don’t know if we will gain efficiency or lose it in going to this size, but I would be willing to guess that the wH/mile could be almost anything BUT 750wH/m therefore.

In any event, that sounds like 100 mile max range, 80 mile safe range. Familiar. No matter what size vehicle we do, that’s about what it comes out to.

I actually have 70 cells coming. We may do some further packs under neath the frame. That would take us to 93800 or about 115 miles perhaps max range.

We have two Soliton 1 controllers each capable of 1000 Amps and we want none less from this pair. 2000 amperes of power. But in truth, this would normally be for a second or two. That would be 5C for these cells. well within their capability. Recall that we did simliar testing in REDUX Speedster at about 5.5C and the CALB cells worked marvelously. So despite two eleven inch motors and two Soliton controllers, I expect these much larger 400Ah cells to be loafing most of the time.

We have noticed sluggish batteries in the dead cold of winter – easily 15% degradation. Given the expense of this pack and it’s size, we’ve decided to make provisions to heat them.

And so a special battery box with a false floor and PEX 180degree Fahrenheit tubing in the bottom. We’ll heat glycol and water and use it to heat ourselves first, and our batteries in the rear. We’re also going to add an AC pump and block heater to gently heat them while charging overnight.

Enjoy the video.

Jack Rickard


31 thoughts on “Electric Cadillac Elescalade Progress”

  1. Don’t know if you have any room around the box but are you planning any insulation for the pack? Seems as if you could reduce your heating needs with some insulation, as well as keep temperatures more even between cells. I’d imagine the cells in the center of the pack might be significantly warmer than those on the perimeter, which might lead to imbalance.

  2. Fabulous front plate for the motor. That is just so perfect. Quality is top notch. Smooth and quiet. That will do well for future business at Cape Precision Machine. What a huge box 🙂

    An idea for the clear top that is not the right size. I thought of putting a solid narrow plate across the middle and then mount two clear removable lids so you can pretty much have a clear top but get around the mismatched size issue. The solid plate would only be wide enough to cover the odd size. It would work and might look decent too.

    Pete 🙂

  3. I rather like the center brace idea. We were going to do a piano hinge and some gas struts but the tonneau rail is right above the top about five inches and so we would strike it. A center beam with two polycarbonate plates sure decreases the polycarbonate costs.

    I’ve actually heard the insulation theme several times already. We do not insulate battery boxes at all.

    1. The cells do generate heat. In August, insulation is NOT what we’re after. We may well be cooling the glycol at that time of year.

    2. Size is the primary issue. We ordered the box at 49 1/2 inside dimension. Each side is about an eighth. Some how that all came out to 49 and 13/16. Our bed is 50 inches. And we have very little inside extra for cells. This is always the case. We wind up fighting for a 1/32 of an inch to make our battery schemes work. The idea of even a 1/4 of insulation winds up being absurd. We don’t have it. We’ll never have it.

    Yes it might lead to imbalance, at about the same time it led to the cells becoming chia plants. I have explained this 739 times. The temperature differential doesn’t lead to imbalance because the imbalance theory requires a self discharge shuttle process similar to that of Pb or NiMH cells. LiFePo4 is a “rocking chair” ionic transfer process and doesn’t exhibit that because it doesn’t have it in the first place. There is no analog for it in these cells. The “cell drift” mythology so popular on your forums was an unknowledgeable “plant” by the BMS guys.

    It makes sense. It never was so. Or should I say that it is of such small potatoes that like the Peukert effect, it can be safely ignored with no ill effects.

    We have a 55 cell box in the Mini Cooper and can detect no variation in anything between the center cells and the edge cells. Our efforts there at cooling were also just not appreciated. They just don’t get that warm, and the box is able to radiate the heat sufficiently that the fan never comes into play.

    But in January, the car is sluggish. It charges oddly in really cold temperatures. And we might have spent more effort on heating. We will with this large pack in the Elescalade.

  4. Jack & Co.:

    Take a tip from the racing community on mounting the aluminum panel on top of the battery box:

    Don’t drill and tap the box and top for screws. Use Dzus fasteners, which have been used for decades to mount aluminum panels on race and hot street cars. They are available in a wide variety of styles and materials, and your friends at Summit racing have them.

    It the end of the day, I don’t think a big sheet of aluminum in that application is going to be satisfactory, nor will a sheet of polycarbonate. Both will be heavy, and since the box doesn’t have a a stringer across the middle to support it, the lid has got a tough job being stiff enough to make that span without flexing, oil canning or twisting.

    The only thing I can think of that will actually work is a relatively thick composite structure, say 3/4″ of foam with CF or Kevar epoxied on both sides. You could actually sculpt this thing with ribs on the back like a trunk lid has, which would then allow you to put in a few of the thin clear polycarbonate viewing windows you want.

    If you use aluminum or lexan, every time you go over a big bump the whole top is going to flex, and the middle cells are surely going to go up and down in there despite being “retained” positively. The box top just needs to be stronger and much stiffer.

    That crossmember at the back you’re struggling to get around is actually a boon, and an ideal place to tie your box into the chassis. You really also need a substantial lip-type fixture on the floor in front of the box (and some cross-stringers along the front face of the battery box for strength) to restrain the whole mass from forward movement. My concern isn’t with the lightness of the aluminum you are using per se, but with its ability to truly retain the batteries in any kind of frontal impact or even severe braking. You’re going to have, what, 1700lbs in there? Think of how much force your box (and fasteners and mounting areas) are going to need to withstand to hold that in a mild 2-5g deceleration. If you slid the truck off into a ditch and hit a culvert just going around a corner in the snow, the last thing you’re going to want is 3/4 of a ton of batteries joining you in the cabin. This is a daily driver. These things happen. Think it through, Jack.

    Also, I noticed you have dropped the alternator. I’ll be interested to see where you get the amps in the alternative, likely a Vicor MegaPAC as Mark Weisheimer brought you, either fully slotted with 12V modules, or 80 amps worth of 5V bricks, in 3S2P configuration, which might be enough.

    See you Friday,


  5. We have picked up on the Mark Weisheimer trick and are probably goign with a 15v system instead of 12. I can’t think of anything that cannot deal with the 15 volt. We use three pairs of 5 volts for 80 amps, and then two 15v units of 10A each for an additional 20 giving us a 1500 watt unit.

    Oh, and we built two of them. They work remarkably well. I’ll never solder another Vicor Brick in my life. I love these Megapacs. They have their own enclosure and fan, great terminals to connect to, and they can do the power. On the Escladade, we’ll likely use TWO of them. But that should provide 3000 watts of 15v if necessary.

    Yes, Tom. Safety first. We haven’t decided exactly HOW to affix the box to the truck yet. But you’re quite correct, we don’t want it in the cabin with us. A steel angle iron across the front connected to that cross member is the most likely candidate.

  6. Jack – loads of well meant advice on here that you have probably thought through already; but maybe I can add another bit? It would be nice if the lid or battery tie downs were strong enough to cope with rollover. A roll followed by any kind of impact might otherwise result in a jumble of batteries coming in through the rear window…

  7. I still think Jack should try out his twin 11″ in the GT40. Fire it up and listen to the roar of those cooling fans under(?) the bonnet.

    The ladies will be throwing their panties at you.

    Whoarrr! 😉

  8. Well, its an AC Cobra, not a GT40. And I think twin 11’s might be a little much. We are still researching the drive train and I can’t say anything because nothing is final. But it might indeed be interesting…..

    Jack Rickard

  9. John:

    Why don’t I just not wreck it or roll it?

    The problem with all that is the amazing number of things that can happen in an accident. Ultimately nothing is safe in a flattened burned out car.

    We may look a bit at restraint to prevent a forward slam. Perhaps a bit of angle iron across the front lip and bolted through beneath.

    I don’t picture the vehicle rolling, and if it does, the more likely tragedy would be batteries strewn for a quarter mile. We’lll not worry about that too greatly.

    But no, I’m seeking such advice. I’m always amazed at the level of safety admonishment, and I’m not sure where it derives. I’m rather more interested in the why don’t you just “duh” moment when I think, that’s a great idea, why didn’t I think of that?

    And some ideas have to ferment. I’m sure I’ve received advice on heating cells for several years now and again. It didn’t “just occur to me” to put a heating system in to perk the cells up in winter. BUt it did rather need the right car, and I’ve had to stew over it for some time what I would want that to look like. One of hte ongoing issues is SPACE even in an Escalade. I think the pex tubing and liquid heating is probably the best trade there. I’ve never really warmed up to the resistive mat type heaters, so to speak. A pumped liquid lets me change my mind later and cool it instead of heating it, or both.

    But yeah, let’s drop the safety. Give me suggestions to make it COOL so that of course more CHIC’S DIG IT.

    Seriously, I like durablity. I like performance. I like smooth and elegant. And my favorite suggestions have led to things like the Nordlock washers. I’ll probably chase down the dzus fasteners. For me to learn more about fasteners and hardware is good. And for many of our viewers its good as well. Just picking up the battery terminals from Rebirth is a neat way to get through the module wall without the possibility of a rubbed insulation for example. I love the gland nuts we have been using lately, another viewer suggestion in the same vein.

    Sources for pumps and block heaters and that sort of thing is appreciated.

    Admonitions that I’m about to get us all killed really aren’t anything I’m interested in. I’ve lived too long now by all accounts. But I do want the casket to have the latest fittigns and fasterners, to be stylish in all respects, and to roll silently and efficiently down the aisle of the church. And of course to last until the second coming.

  10. AndyJ:

    It’s a BLACK Escalade. It’s always BEEN black. Yes the tonneau is black. Does it get hot in the sun? I never asked. It never said. IT’s a tonneau cover for a pickup truck. I like it black. It would look silly silver. That it might find it more comfortable in the sun is not something I would care about. It might be hard work being my tonneau, but really Cadillac is the one who did it.

    At least it does not have a black interior. Those are murder in summer. These seats actually have all these little holes in them and teh AC blows up through them. I love that.

    It’s the best truck I’ve ever had as to creature comforts. The STEERING wheel is heated. The windshield washer is heated. It has ONSTAR.

    The navigation system sucks HEROICALLY and COMICALLY. We often just ask it directions to places we know how to get to just to see how badly it will route us. It HAS to be the worst GPS navigator in any vehicle anywhere.

    I want to replace the entire system with a hacked version that will let m euse it as a carputer screen. We’ll put a Mac Mini in at some point to do a lot of things, once I can get it to display on the screen.

    Jack Rickard

  11. John:

    We’d have to do more than that I’m afraid to convert this Escalade EXT into a Tesla.

    Of course, they use entirely different batteries as well.

    Now that I think of it, I wonder how many 26650’s WOULD fit in the truck bed of an EXT?????

    Which direction does heat go in a Tesla? Sideways?

    Jack Rickard

  12. Cardnal:

    Four times the number of cooling loops would be heroically difficult to do without introducing a lot of connections inside the box. And I don’t think it would accomplish much. Anhy manufacturers data would be gibberish in this application.

    First, the radiant heat is a function of the temperature of the glycol/water. Second, PEX tubing is tradiionally buried in concrete or fastened to wood subflooring. In this case, we are going to “smash” it just a hair against a 50×56 inch aluminum plate.

    Aluminum is magic with regards to heat conduction. This is one of the reasons you have to use an AC TIG welder to weld it. It wicks away heat so fast that it is difficult to weld, won’t spot weld at all,. I’m kind of counting on that plate sucking heat out of the PEX at a phenomenal rate. We have a huge amount of aluminum heat sink going on here.

    As to the insulation concept, we actually have a truck bed and rubber mat underneath, and a truck bed and plastic molding on each side with I’m sure some pretty large dead air voids in them.

    We’ll probably hook up the heater next week and do the feel test. You may be right. But I’m betting I have a toasty warm box in minutes.

    Jack Rickard

  13. The Cobra. Apologies and silly me. I should know better, GT40’s usually run on lead.

    I still think your twin 11″ in that sports car will bring big smiles.

    The caddy-lacs cooling/heating:
    It’s a pity it’s too tight to allow good insulation and natural circulation. Cooling underneath the cells won’t be so effective.. A small circulation fan or few should help? On that score, a small evaporator/radiator blowing over the cells inside the case and drawing the air from underside? It’s a lot of very heavy cells to use a minimalistic case.

    I’ve fitted hundreds of the old fashioned dzus fasteners in my time. The build specs made me fit the springs with rivets. Ugh!
    There are more modern versions with enclosed springs. More expensive but much easier to fit like any anchor nut.

    Have a feast on the multitudinous different types around now:

    Sorry its an English site. Google keeps doing that to me.

  14. Hi Jack, I’m inclined to agree with Cardnal about the efficacy of your Pex loops – I don’t think it will be able to heat or cool at a rate high enough to justify its cost/bother. If you find this is the case, one answer (without scrapping the whole concept and trying something else) would be to go for a spiral pipe layout instead of zig-zag. You could get maybe ten times the amount of pipe in there with this layout and you probably would not need your deck strips. The only drawback would be that you would have to bring one end of the coil out through the bottom of the centre of the box.

    Whilst I’m at it, I think a layer of bubble-wrap-type silver foil-backed insulation would be a good idea as it will reflect a lot of the heat that will otherwise just come straight out the bottom of the box.It’ll only add about 5 mm to the height. Good luck. MW

  15. On reflection with a big block of 400A cells the internal volume/mass against it’s external area might only be affected externally quite slowly but the day is long.

    Cells tend to get hot from the top. The electrolyte is not as mobile as lead acid and it might stratify with temperature if cooled from underneath. Brings me back to a stiff lightweight insulated lid and cooling from the top. Stiff means less fasteners. 🙂

    Chennic are advertising in-wheel hub motors. Are they in the ‘vapourware’ category like LiS TS cells too?

  16. Well, we’ll see then. I think it will provide pretty dramatic heating in the battery box. Of course it is all a guess at this point. We don’t really want to cook our batteries. We want to get them up to 25C.

    Cooling has just not been a problem. I thought it would be on the Mini simply because we have 55 cells packed into a monolith. We drilled holes in the bottom of the box in a kind of pattern and added a fan, with a probe in the dead center of the pack. It never comes on. The temperatures when charging at 15 amps or when driving at 2C-3C are simply not an issue at the top end. We just do NOT need to cool these cells. The tonneau will keep the sun off them directly.

    It is heating in winter that is the issue. We get noticeably sluggish performance and erratic charging below freezing temperatures. We don’t need to cook them, we need to get them above freezing. I want gentle heat from underneath. Again, by combining it with the heat for the cabin, I kind of lose a fine level of control here. They get what comes out of the heater core. But we will be able to measure the temperature drop across the box, so we’ll know soon enough.

    I’m hoping for an interesting effect in the summer. Simply run the pump and hope the battery box is warm enough to provide some heat to the air conditioning environmental system. It may be that it needs a little when air conditioning, believe it or not.

    Again, the concept is heating the cells. I just don’t have any practical need to cool them.

    Does our little bit of pex looping have enough surface area to transfer any meaningful levels of heat? I guess we’ll see. I think we’ll drop 30 degrees across this box.

    Again, we don’t need to cook em. By running a very small block heater and pump off the charger input, they will BE warm in the morning. If I drive the vehicle with heat, they should stay that way. With 14kw of heater, it should warm the cells, but starting from totally cold soaked at 10F, it would likely take awhile to bring them up. I don’t think that will be the scenario most of the time.


  17. I think that cold soak scenario is so onerous as to be worth defaulting against by running the warmers all the time below some value, which you could experiment with, but 50 degrees seems like a good place to start.

    If you let that 3/4 ton mass truly cold soak, and then use ice cold batteries to warm themselves up full blast, it would seem you’ve suffered the very loss of power you installed the warmer to prevent- only doubly so now, because you’re probably also trying to drive the cold car, and maybe even warm the cabin, at the same time. All that on cold battery power. Doesn’t seem good at all.

    You could do as Roland Wiench in Montana does with his big 6600lb El Camino every day all winter, and head out with a pack warmed from the wall. Once heated up, his “tonner” pack of floodies stays warm many, many hours in far colder weather than you’ll see in MO, but his box is insulated…

    An any rate, it seems to make more sense to never let the pack, or even the interior of the truck for that matter, cool off at all. Basically, you never want cold batteries. You will almost certainly have plenty of heating capacity to do that with the PEX in there now, and lord knows you have the electricity. Your tubing density is actually higher than would be used in a building, and you have more heating capacity for that area and mass than most buildings, too. The hand wringing about is almost as funny as the rollover battery box structural integrity concern…


  18. Precisely so Tom. Actually, as I said earlier, we’ll have an AC block heater and AC pump in series. It will use the charger power input, through a switch. Turn the switch ON in November and off in March.

    Anytime we plug in the charger, we’ll. Be heating from the walll. Cabin as well.

  19. Hi Jack
    Why don’t you use something like this to cover the battery’s

    or here

    Light strong and flat and you can even walk on it.
    A hinge up front a catch at the end
    A pair of gas struts to lift it up.
    And a custom mat from thick rubber like material on top so you can still chuck stuff on top.
    Like this but designed to sit inside the tray on top of the batteries and built from aluminium honeycomb


    here is another photo


  20. Hi Nicholas
    The site I linked to earlier also has honeycomb sheets but I disregarded them for foam filled; for better thermal insulation.

    It has to be said honeycomb structures are very impressive. Used on certain missile wings shows they can really take an incredible structural beating in place of their solid winged counterparts. But they are weighed, made with test pieces and x-rayed for quality.

    I bet Jacks pulling his hair out over this box lid/pex tubing business by now.
    It’ll be fine! 🙂

    Here’s hoping Jack ‘n team are having a ball this weekend.

  21. When I installed hydronic heating between our subfloor and hardwood floor, a heating contractor suggested that I lay a bead of silicone adhesive in the bottom of the routed track for the tubing to improve the thermal coupling between the tubing and the aluminum disperser in the bottom of the track. You might want to do the same with the top plate in your battery box. Also, my gut feeling is that with so few loops of PEX in your box, getting a 30°F drop, even with a significant ∆T, is going to take a pretty low flow rate. You’ll probably be okay as-is for maintaing temperature but don’t expect that kind of drop. -Klaus

  22. Martin, if you wanted to avoid “having to bring one end of the coil out through the bottom of the centre of the box,” couldn’t you just run a double spiral with a U-turn at the center, thus leaving the two end connections on the outside of the spiral. Doug

  23. Jack,
    I know Cape Precision Machine has added a reluctor wheel to their assembly. Do you know at this point what it does? I too have a LS2 in my C6 Corvette. I contacted JR at http://teamzr1.com/fstore/index.php?main_page=. He said if I were to have the data from the reluctor wheel I would also need it from the cam positioning sensor, OR..you do not use the reluctor wheel at all. The process to get the Escalade to run, if it is like the C6 is to remove the PCM…find a pig tail to plug into it for your 12vdc and ground and also plug in a flash sensor. The flash sensor can then be download as a file on to your computer. Send that file via e-mail to JR. He will do his magic and he will then send a file by e-mail to you can reflash your PCM which then communicates to you body control module and then you can start your Escalade amoung many other functions.
    Mark Yormark

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