# Planning 96" wheelbase 1929 gazelle replica conversion



## madderscience (Jun 28, 2008)

AGMs have just as much gibberish (BMS) requirements as does lithium. The only type of battery that doesn't require (but will still benefit from) a BMS is flooded lead, aka golf cart batteries. 

Your performance/range goal is pretty modest it sounds like, so you could probably get away with a lithium pack without completely blowing your budget. I would really stretch to figure out how to accommodate that. even 100ah at 72v in a car weighing 1500lbs is going to give a solid 30 mile range under pretty much all normal conditions.

The dual motor/chain drive setup is exactly the same as what I initially considered as have a lot of other people. However this requires more complex controls and a lot more fabrication. The kit body will probably be pretty light, so you can get away with direct drive without a lot of power, but there are compromises here. The smaller motors I was thinking about (Perm 132 pancake motors) were torquey enough but have a low maximum RPM. I would have had to accept either a limited top speed or no low end torque; a problem in a hilly area. 

If you want direct drive, if the car is going to be very light and rear wheel drive, a single 8" motor aimed at a rear axle with about 5:1 reduction will probably work with your soliton just fine. If you need differential ideas, check out the 1984-1986 celica supra non-turbo IRS differential. It is on the big end (7.5" ring gear) for a lightweight car, (it is what I am using in my 3000 pound scion xB conversion) but you can get ratios from the 3's up to almost 6:1 for it, and the ring and pinion are extremely common as this differential is used in nearly every 4 cylinder toyota pickup in existence from the 70s through the 90s. LSD, torsen, and locking carriers are also available.

If you can budget a bit more, seriously consider the 67Hp HPGC AC motor and curtis controller. you would get AC for around the same cost as a similar power DC system. The only limitation is it is a fairly low voltage (108 nominal) system. However in a gazelle replica weighing sub 2000lbs, that will be plenty of power.

If you haven't, attend an OEVA meeting and bring your ideas. You have some well known and very active EVers in your local community.

Good luck


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## anachlores (Sep 8, 2012)

Thanks for the reply.
I agree, with your conclusion about the batteries. I was under the impression AGMs didn't need a BMS, but since they do, I'm planning on switching to around 28 100AH wilson lifepo4 for a nominal of around 95-100v, though I could probably get away with a nominal of 80 and be fine for suburb driving. The price isn't nearly as bad as I thought it would be and I don't think it'll be much of an issue considering how much I'm putting into this anyway.

I'm still smitten with the idea of loosing the trannie and going with direct chain drives. Not so much due to weight, but to get rid of as much as I can of the old, crotchety ICE remainders. That and I know chain drives well. I don't mind the fabrication work that I know will be the trick in getting this to mount right. I am thinking about twin ADC L91-4003 for my motors since they are small and cheap-ish but should be able to provide enough kick if I need it. 2 of them will probably cost me slightly under $2000. I did the math and I think 5:1 is ideal, giving me 25-35mph at 1.75k-2.5k rpm at the motor shaft with 24" OD wheels. 4:1 will get me 1.4-1.9k rpm at the shaft but higher speeds are pretty much out of the question. I may have to test it out once I get everything built.

I'm hoping to run them in parallel off a single controller. I may run into speed synch issues and I know if one wheel looses traction, I could burn out the controller, but this is a fair weather, road only vehicle anyway. I may also switch to the soliton 1. I feel like I won't need more than the 250amps/motor the jr. can provide, but I'll need to do some torque calculations for hills to be safe and avoid stalling in traffic like a tool in a manual.

I estimate the body will end up at around 4-600 pounds or less, depending on how fancy I get with the interior and diy hardtop roof. Batteries will weigh in at ~230lb, not including the BMS and stupid amount of copper I'll need. frame and chassis weight is highly variable due to availability of donor vehicles and how crazy I go in overbuilding the frame.

As far as fabrication, I can source the 5:1 chain gearing fairly easily, the only trick will be getting the CV joints on the frame and the sprockets interfaced to the motor and cv shafts.

I do hope to get around to an OEVA meet, but it's a bit far away and I'd take me a while on the bus. I'll get around to it eventually. I won't be able to start building anytime soon anyway. Insuring the donor car at my age will cost an arm and a leg.


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## anachlores (Sep 8, 2012)

Just a quick conceptual update...

Pack voltage is to be upgraded to 160v or higher @ 100AH. A far cry from my original 96v @ 100AH, but this seems to be the sweet spot for range vs. cost and weight. I still hope to go with the balqon/winston batteries, though their stock seems to flux a lot. If not, Calb it is.

I decided to build the chassis from scratch. I'll be honest, the deciding factor was the amount of crap I'd have to deal with when gutting the car for the custom body. Ad that's only talking about what is supposed to be in the donor car, not the 5-20+ years of dirt, grime, human detrius (and dried fluids), and other garbage that you know will be in there... does that sound like fun to you? So instead, I'll be using a Heidt mustang II IFS front end with a TEAM321 "Daryl Armstrong" IRS. I'll have them fab the CV joint adapter where the diff. would be and then make an adapter for two 52 tooth, 530 sprockets which o-ring chain to the 14-tooth motor sprockets. I don't want to risk damage to the front sprockets, or I would be using a 12 or 11 tooth for a higher reduction. I am worried that the 3.7:1 will be too low, but I don't have many choices unless I shell out for some custom fab sprockets with 60+ teeth or try and fab up helical gearboxes. Manual brakes and steering, no AC or heater (it's a (currently) topless convertible in portland, you can only drive it 1/3 of the year anyway), LED lights, including 2x10W <900lm headlights.

I didn't want to, but I think I'll use a DC-DC to power the aux battery instead of an alternator or none at all. I did the maths and with the range i have, I could get away with no charger, but that's an irresponsible and stupid place to skimp out.

Of course, I could just switch to a pumpkin and be done with it (besides the adapter), but I have an irrational dislike of the idea of using a diff. in my EV. It feels excessive and icky.

I think I'll hop up to the soliton 1, finances permitting. I should have jumped on it when the price was lower last year. The overhead will be nice and I'm still not sure how the parallel motors will draw power once mounted. 

I still want to use two L91 in parallel. I think the higher pack will also help offset the slow 3C rate of the prismatics if the step-down works as advertised. At 25mph, the motor rpm is 1300, and that's less than a third of the max rpm @ 144v so the controller will have tons of room to work with, even with two motors drawing current, at least I hope.

One big issue I'll run into is the weight bias. I get the feeling that the 385+ lbs of battery will push the ratio to 60/40:F/B or worse. On a manual steering car, it'll be a pig to drive at lower speeds, like on those roundabouts that Portland has in those random places. On the other hand, actually calculating the weight, it doesn't seem that bad after all. The motors weight 80lb each, and will be mounted right next to the rear axle plane. The batteries are between the front axle and COG while the driver and passengers are either right at the COG or behind it. This might not be as much of an issue as I thought. All i need is to add back the spare tire and voila, close to 50/50. Well, maybe...

Wheels will be narrow LRR jobbies with classic mustang alloys because I don't want to have to mount the tires myself and that combination is what will fit the car. It'll look a bit funny, but I can always upgrade those later if it bugs me enough.

Far into the future, I will fab a DIY fiberglass hardtop so it's not useless during the "rainy season."

Anyway, that's it for now. I hope to finish designing and testing the custom chassis before the end of the year (11 months, no pressure...) and then get the car in a drivable condition by the time I hit 24/graduate from college. By then, my insurance premiums will be low enough that I won't have to factor THAT into my EV budget.


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## anachlores (Sep 8, 2012)

Some bad news, Team321 racing has been non-responsive about building the rear suspension I designed for the dual motor chain drive system. So unless he emails me out of the blue tomorrow, looks like that's out. (the Team321 design also has heim joints used improperly, significant points of failure according to some armchair engineers)

I've also been thinking about the dual motor system and have some thoughts for the next poor soul who considers it...

The biggest issue most people mention is the complexity and custom fabrication necessity to make it work. Well, mechanically, it's actually not that bad. All you need is independent rear suspension and a box to mount the second set of wheel bearings to, which holds the inner cv/u-joints. An alu plate to the sprocket, chained to motors in a hanging mount, and you're golden.

The biggest issue I've found is synchronization. The dual motor mini by MalcomB doesn't seem to be affected by it, but if the two motors are spinning at different rpms, the car should pull to one side. 
If it's a small difference, you might be able to increase the resistance of the circuit to the fast motor. Maybe mess with wire lengths, but resistors would be out of the question.
You might also be able to mess with the timings (brush advance), but that will mess with the entire rpm response curve.​You could also use a DC-DC PWM speed controller, but I'm not sure you'd want to, and I don't know how much one that could handle 500A peak at 100v would cost.
You could also use two controllers, instead of one controller with parallel motors. RPM sensors could adjust the voltage curve to a desired rpm curve. The main problem I have with that is safety. If one controller dies, you're boned, regardless of the mode of failure. 
If it dies off, then you accelerate and veer off into oncoming traffic or a pedestrian.
If it dies full on/welds the contactors closed, you veer into oncoming traffic, or a pedestrian, or off a cliff.​Just a bad idea.

Unless I can assuage my fears of mismatched motors (I'd rather not have to rewind anything) I'm probably going to end up with a single 8 or 9" motor, through a differential. It does mean I can use any OTS stock IRS rear-end with relative easy. I'm just not entirely happy with the solution. I wanted to get away from the ICE components as much as possible. Some figures I found put the differential at ~60lb. That's a week's worth of watermelons, or another battery pack, that is!

AC is now possible (2 motors, 1 controller, AC system, doesn't work) but those curtis controllers make me nervous and I'm not entirely sure about the alternatives.


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## MalcolmB (Jun 10, 2008)

Hello again,

I wouldn't worry too much about the motor mismatch issue. If you buy two new motors of the same model, and make sure the motor cables are the same length it shouldn't be a problem.

If you do go for dual L91 motors I would recommend going with the Soliton 1. According to the torque curve I found for this motor, if you used the Soliton Junior your maximum thrust at the wheels would only be around 300 lbs (assuming motors in parallel, 24" wheels and a 3.4:1 single reduction ratio). That seems borderline to me even with a lightweight car. The Soliton 1 would double that figure.

Having said that, I would recommend going with a larger single motor hooked direct to a diff. The main reason I went with dual drive was that I don't have space in a mini for an inline motor and diff, and because I already happened to have two 7" motors. The fabrication work for a dual motor setup is time consuming and you need extra cabling, an extra reversing contactor, some form of rpm limiter for the second motor in case you lose a chain, etc.

I totally understand your dislike of using a diff, but it makes life a great deal simpler and is just about maintenance-free.


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## anachlores (Sep 8, 2012)

Yeah, at the end of the day, I reached the same conclusion. It does help that diffs have reduction build in, so I don't have to worry about sprocket gearing. 
I might even go silent chain, since the motor will be right behind the passenger "compartment"

The controller power issue is a side with respect to the batteries. I'm looking at (enerdels), which will only supply me with 2c (5c for the expensive ones). The 600A max pull for the jr. would be over the peak draw of my batteries.

Still, the single motor option is the easiest. The chain is no longer spinning down the long axis of the car as a bonus! I just need to make a nice firewall to stop the motor from flying into my back in a crash.


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## toyolla2 (Jun 21, 2010)

http://www.typepad.com/services/trackback/6a00d8341c4fbe53ef017eea5dbdc0970d
Dual Motor Rear Drive Unit
Twin independent 75-kilowatt (kW) motors
Total Power 150Kw
330V 9Kw Battery with BMS
1500Nm
EV range 30Km
EV mode Vmax 130kph
　
The Agilit-e Hybrid Power Unit has twin independent 75-kilowatt (kW) motors, and can be easily integrated with any two-wheel drive powertrain. Simple "bolt-on" installation between a vehicle’s suspension components creates an all-wheel drive hybrid system, allowing a vehicle to operate in four different drive modes:
• Front-wheel drive powered by the internal combustion engine;
• rear-wheel drive powered by the battery and electric motors for electric-only operation, suitable for city driving;
• hybrid mode, for a combination of city and highway driving;
• all-wheel drive mode, ideal for snowy roads or situations that require optimal handling.

Linamar’s demonstration vehicle, a Cadillac SRX, can run about 20 miles just on the lithium-ion batteries. Even after the internal combustion kicks in, the batteries can provide extra power to boost acceleration when needed. 

Hi anchalores ,
I guess it is incumbent upon me to advise you that the hobby/vocation of automotive electric conversions has recently entered a new period in that starting a new project at this time is akin to buying a Blackberry smartphone despite knowing that the holding company is for sale and rumoured to exit the consumer market.

In the case of EVs the action of Nissan last August to reduce monthly leasing charges to $199 with $999 down for a new LEAF vehicle has wiped the slate clean of a home brew design being anywhere near close to an economic proposition. With a performance rating of 0 to 60 in 10 secs and a 90mph top speed it is not surprising that some constructors are putting their partially completed designs into storage or `on hold`as a consequence.

The upside is that there will be more interesting options for constructors who are motivated to 'drive electric' ranging from Leasebuster takeovers to the restoration of damaged vehicles which are likely to occur amongst the tens of thousands of vehicles that will be circulating in the following months. Since these vehicles are now being built in the USA manufacturing facilities it is predicted that procuring replacement parts is not going to be a problem.

Leasing has become attractive because conversions have always had the financial model of the customer having to provide all the cash investment up front to the supplier. Then it may take a couple of years until the benefit of that investment is realised. Leasing on the other hand has the advantage that only a small upfront investment is required and you get to drive the vehicle from Day One.


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## anachlores (Sep 8, 2012)

toyolla2 said:


> Hi anchalores ,
> I guess it is incumbent upon me to advise you that the hobby/vocation of automotive electric conversions has recently entered a new period in that starting a new project at this time is akin to buying a Blackberry smartphone despite knowing that the holding company is for sale and rumoured to exit the consumer market.
> 
> In the case of EVs the action of Nissan last August to reduce monthly leasing charges to $199 with $999 down for a new LEAF vehicle has wiped the slate clean of a home brew design being anywhere near close to an economic proposition. With a performance rating of 0 to 60 in 10 secs and a 90mph top speed it is not surprising that some constructors are putting their partially completed designs into storage or `on hold`as a consequence.


And I can buy a OEM computer, instead of building one, and buy microwave dinners instead of cooking. Your point?

Also, I'm not sure why you post an advert for a diy bolt-in EV system, and then tell me that there is no point as I can lease an EV and the DIY EV market is dead. Why are you even here?


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## Duncan (Dec 8, 2008)

anachlores said:


> I might even go silent chain, since the motor will be right behind the passenger "compartment"
> 
> The controller power issue is a side with respect to the batteries. I'm looking at (enerdels), which will only supply me with 2c (5c for the expensive ones). The 600A max pull for the jr. would be over the peak draw of my batteries.
> .


Hi
If you use a diff you can use a short prop shaft and have the motor where the gearbox would normally be - in between your legs and your passengers legs
I have an 11 inch motor there in my own small roadster
http://www.diyelectriccar.com/forum...-dubious-device-44370p8.html?highlight=duncan

If you go direct drive - then you don't need a clutch pedal which gives tons of space

_The 600A max pull for the jr. would be over the peak draw of my batteries._

This is a common misapprehension (I suffered from it as well)

Your controller is a power in - power out device,
by means of electromagnetic magic it converts battery voltage and current to motor battery and current

Example - approximate numbers depending on your motor (ADC/Warp 9inch/11inch...) and battery voltage

0 rpm - 
Motor current 600 amps motor voltage 15volts
Battery voltage 150 volts - battery current 60 amps

1000 rpm
Motor current 600 amps motor voltage 50volts
Battery voltage 150 volts - battery current 200 amps

2000 rpm
Motor current 600 amps motor voltage 85volts
Battery voltage 150 volts - battery current 340 amps

3000 rpm
Motor current 600 amps motor voltage 120volts
Battery voltage 150 volts - battery current 480 amps

Anyway you can get a lot more motor current - just where you want it
without overloading you batteries

If I could afford it I would get a Soliton 1


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## anachlores (Sep 8, 2012)

Duncan said:


> Hi
> If you use a diff you can use a short prop shaft and have the motor where the gearbox would normally be - in between your legs and your passengers legs
> I have an 11 inch motor there in my own small roadster
> http://www.diyelectriccar.com/forum...-dubious-device-44370p8.html?highlight=duncan
> ...


Nice little car, the diamond plate fenders are neat.

I was planning on the soliton 1, I just couldn't remember why. Thanks for jogging my memory, I totally blanked on step-up-down/buck converters. That said, a 2c enerdel will still only give me ~408 amps (3p3s). So acceleration at 3k rpm will be interesting.

The 1929 chassis is only 40" wide in the passenger compartment. I could put the motor under the seats, but access would be a pain in the rear and I'd need to raise the seats. It would leave me with a ton of boot space though.
Thing is, I also want as much weight in the back as possible. She's front heavy enough as it is...

The worst part is that I have to keep reminding myself I'm not building a performance vehicle. I want a daily driver and it needs to be comfy, not crazy fast.


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## toyolla2 (Jun 21, 2010)

There are plenty of people to debate with here. I am just one of them.

Our objective is to see you get the most bang for the buck. However you must know that you are late to this particular party.

I have been researching twin drives since 1985. Then 6 months ago Linamar - a parts supplier to the big 3 - announced this powertrain package. It is similar to what you are attempting. They are marketing it around and it is possible that they might lend/lease a unit to interested colleges and universities. The link on my post which will work, but sadly not from DIY, gives the phone number and name of the marketing manager here in Ontario.


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## Duncan (Dec 8, 2008)

anachlores said:


> The 1929 chassis is only 40" wide in the passenger compartment. I could put the motor under the seats, but access would be a pain in the rear and I'd need to raise the seats. It would leave me with a ton of boot space though.
> Thing is, I also want as much weight in the back as possible. She's front heavy enough as it is...
> 
> The worst part is that I have to keep reminding myself I'm not building a performance vehicle. I want a daily driver and it needs to be comfy, not crazy fast.


The Device is 44 inches wide where I sit
But with an Independent Rear Suspension the diff is very long (to resist wheel torque)
So the front of the diff is in-between the seats

I have a tunnel 11 inches wide at my butt - going to 13 inches wide where the motor lives

With your layout (sitting about a foot further forwards) the tunnel would only need to be about 7 inches wide at your butt - giving you the same space I have

If you use a 9 inch motor then you will only need 11 inches at the motor

This would put the motor in the middle of the car

I have a 55% rearwards weight distribution - you could get the same by putting some batteries in the back
If you mount them right at the bottom you will have some boot space above them


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## Duncan (Dec 8, 2008)

I have just remembered

One of the reasons I needed so much space for the front of the diff is that it is not in the middle of the car - it is offset to the right
This is a pain as we sit on the right hand side (drive on the LHS)

As you guys drive on the wrong side of the road this would enable you to steal a bit of space from the passenger to give to the driver - if you are really short of space

Incidentally my seats are raised about 5 inches off the floor - feels more comfortable


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## anachlores (Sep 8, 2012)

The diff in the jaguar suspension I'm planning on using is a 9" ford and it's actually quite short, only extends an inch or two past the LCA. It's also centered, so not much issue there. The reason my weight distro is so front-heavy is that the gazelle has a stupidly long nose that is perfect for a bunch of batteries. The back, not so much. I'm shortening the body by a foot or two, so the back seats you see on the stock kit car will be where the engine and suspension will be, right above the rear wheels. 

Also, there will be an X-brace in the center of the ladder frame, so unless I shorten the cross, the motor may be a tight fit where it's pictured below. That said, I really don't want to have to lift the car (or remove the seats) to get at the motor.

Still debating seating position. Too high and the door will only go up to my thighs, too low and I won't be able to see over the hood. The doors are a foot tall in the back at best...


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## Duncan (Dec 8, 2008)

Hi
_The diff in the jaguar suspension I'm planning on using is a 9" ford and it's actually quite short, only extends an inch or two past the LCA. It's also centered, _

I probably said that wrong, my diff (Subaru) is also in the center - but - the input shaft is off center - only by an inch or so

I think you will have problems if you mount the motor straight onto the diff,
Diffs (and motors) move a bit on their rubbers
You will either have to make a "cradle" that solidly (and accurately) mounts both or you will need a drive-shaft
Mine is about a foot long

This will allow you to move the motor forwards to get more room for your butt

_so the back seats you see on the stock kit car_

Mine is a 2 seater - makes lots of things easier

_The doors are a foot tall in the back at best..._

Doors? - I operate on the KISS - Keep it simple stupid - principle

Do away with the doors - with your running boards you won't need them - just step over the side to get in


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## Duncan (Dec 8, 2008)

I forgot to mention
That is one pretty car
Looks a ton better than my device!


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## anachlores (Sep 8, 2012)

Duncan said:


> Doors? - I operate on the KISS - Keep it simple stupid - principle
> 
> Do away with the doors - with your running boards you won't need them - just step over the side to get in


LOL, thanks duncan, I like the car too. Slightly boxier than I'd like, but I got the fiberglass body for "cheap" and I doubt I could find the MG TD body as easily. 
Getting rid of the doors seems like a pretty good idea. Finding handles that look nice has been a pain. I'm ready to put quick-release pins in it and have them fully removable like a jeep.​I'm not actually too concerned about the motor-to-diff mount. It's a lot easier than my previous plan, and I had that all worked out. A chain drive has slack in the vertical and width-wise axis (with a good tensioner). The only axis I have to be OCD about is length-wise, and I'll need to support the shafts well with pillow blocks.

Also, the diff is mounted to a frame (direct mount) with no vibration damping (kinda dumb) right below the motor, so it should be one solid unit by the end of the day. One of the reasons why I insisted on an IRS.
She should handle like a sports car (albeit with manual steering) with minimal unsprung weight. Just the tires, front calipers, rotors, and control arms will be unsprung!

A bit of paint and the device will be pretty sweet. Maybe a classic racing green but in high-gloss...


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