# Update on my EV Porsche fiasco.



## DavidDymaxion (Dec 1, 2008)

At best you'll have about 1/2 the power of the Tesla -- if launched perfectly the Porsche might take it in 1st gear, maybe keep up in 2nd, but at higher speeds the Tesla will definitely dominate.

Something to consider is a high power pack; you can trade range for power and cost. I'll assume 144V and 1000A.

Flooded lead acid: . . . . . . $1,000, 700 lbs,. ~24 rwhp
Optima 50 Ahr lead acid: . . . $2,000, 540 lbs, ~108 rwhp
Thundersky/CALB 200 Ahr pack, $12,000, 700 lbs,. ~65 rwhp
Headway 80 Ahr pack, . . . . . $8,000, 300 lbs, ~130 rwhp

The lead acid might not drive as far as you'd want (40 miles is pretty optimistic I'd think). Also, one lithium pack should outlast several lead acid packs and could be cheaper in the long run (provided they don't get ruined by ovecharging or a failed BMS or something, admittedly lead acid is tougher).

I liiked the service I got with Manzanita Micro (still have to install my Headways, though).

http://www.manzanitamicro.com/produ...page=flypage.tpl&product_id=61&category_id=29



daniel1948 said:


> ... One option would be to install a new lithium pack at around $12,000 to $15,000. One of the people who's been working on the car insists that with a new pack it would beat the Tesla Roadster that I bought almost a year ago, after giving up on any hopes that the Porsche would ever actually be finished. I don't believe that. ...
> 
> The Porsche has a completely shot battery pack, and is not worth more than about 1/5 of what I've put into it. I don't want to spend another $15,000 putting a new lithium pack into it. But OTOH, I no longer need the 125-mile range I wanted when I embarked on the project. The Roadster is and will remain my daily driver and my main car. But if I could get the Porsche back on the road, with top-notch performance, even with only 30 or 40 miles of range (for 15 to 20 miles range to 50% DoD) I could drive it to the store and back, and for occasional short errands.
> 
> So I'm contemplating putting lead-acid batteries in it. Lower cost and simpler battery management might make it worth my while, and I'd get some use and enjoyment out of the car (it is a *beautiful* car!) At least it would be on the road and not rusting away in the corner of a shop somewhere. The lower impedance of lead should allow high power, at the cost of greatly reduced range, now that range is no longer important to me. ...


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## somanywelps (Jan 25, 2012)

144V was a mistake for a high-performance vehicle.


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## rwaudio (May 22, 2008)

What controller did you end up with? I would recommend a very small A123 pack using the 20Ah pouches, you could get something for a decent price as long as you or someone at the shop has the skills to build a pack out of them.

They are small/light and high power, you wouldn't end up with much range, (30-50 miles) but you could probably max out the controller or at least come close.

It would be a fun short range car!


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## daniel1948 (Jun 6, 2009)

Thanks for all the ideas. I'll run them by Gordy and Tim when I next talk to them.



> 144V was a mistake for a high-performance vehicle.


Too high, or too low???

(The fellow at NetGain said the voltage is ideal for the motor.)

The controller is from EV Source, designed in cooperation with and endorsed by NetGain. Since the Porsche is not at my home now, I cannot tell you the model name, but it's something like the third iteration of the controller. I was originally going to get one of the very first of these controllers, but because of delays in the project due to all the additional things that turned up wrong with the car, I ended up with a much-improved version of the controller.


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## rwaudio (May 22, 2008)

daniel1948 said:


> Thanks for all the ideas. I'll run them by Gordy and Tim when I next talk to them.
> 
> 
> Too high, or too low???
> ...


The controller would be the Warp Drive and is software upgradeable to different voltages and current levels, it should handle any upgrades that you want to do (at a price). 144v is low for a Warp motor with good brushes, after sag you wouldn't have as much voltage to the motor. A better idea would be to add 10-25% on top of the voltage the motor can handle and limit the motor voltage in the controller settings. The key to all this is the battery system though and keeping the weight off.


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## Ziggythewiz (May 16, 2010)

Why not just do a small lithium pack? 5K would give you good performance with a nice little range. No tesla killer, but quite the grocery getter.


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## Joey (Oct 12, 2007)

Lead is going to be too heavy to be fun in your car. I agree with the others that a small capacity, high power lithium pack is worth looking into. The headway cells have been used successfully in a lot of cars. The A123 would be a little more difficult to integrate, but they look like very good cells. Bumping up the voltage is a good idea too, if you can get the controller upgraded. My Warp9 is rated for 170 volts max, with the brushes advanced. With neutral timing the voltage is lower. You will want to look into this so that you don't risk your motor.

Sorry to hear about your ordeal. I'm glad you are not soured on the whole project and you're willing to consider how to salvage the project.


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## daniel1948 (Jun 6, 2009)

Well, this was a short-lived idea. But I wouldn't have known if I hadn't asked, so I appreciate all the replies. The Xebra seemed to do much better with lead than lithium, but I am hearing from all sides that lead does not have the characteristics I imagined.

So Tim (who is working on it while Gordy is still busy building his house and shop) is going to get the motor re-balanced and is going to go over the pack, remove the bad cells, and see what he can put together from what's left.

I'll post again when there's news. My goals now are much more modest than they were at the beginning. Then I wanted a reliable 100-mile range. Now a local grocery and errand capability would be sufficient, since the Tesla is my main car and I don't need the Porsche to go long distances. (Though Tim wants to put together a proposal to make the Porsche into a Tesla-killer. I told him if he wants to give me some numbers, I'd listen.)

Tim thinks that with the 11" Warp motor, a new lithium pack, and a 1,400-amp controller, the Porsche would do 0 to 60 in 3.5 seconds in third gear from a stop. (Shifting through the gears would take me several seconds, so if it can't do it all in one gear it will never match the Tesla.) But the motor has a very narrow torque curve, unlike the Tesla, which has only one gear. I don't think the Porsche will ever match the Tesla, but I do know that it can perform very respectably with the present controller.


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## DavidDymaxion (Dec 1, 2008)

Would you be doing the 144V Warp or the Warp 11HV (something like 220V?)? The numbers below assume you have a higher voltage pack, so when it sags the controller can still deliver the max voltage the motor can take.

1400 A * 144 V ~= 200 rwhp
1400 A * 220 V ~= 300 rwhp

300 hp is not enough in a car that heavy to do a 3.5 s 0 to 60. The Cayman S, with 320 hp, PDK, and awesome traction control is "only" about 4.5 s. The regular Cayman has 265 hp and does 5.5 s.

As a counterpoint, the Tesla does 0 to 60 in under 4 seconds, with about 300 hp -- but there are some caveats. Its AC motor has a broad torque curve, and it has awesome traction control. This would be tough to duplicate with a series DC motor. The Tesla is also likely lighter than your Porsche would be.

It also depends on the batteries, high power lithium will be faster (lighter and more power) than Thundersky/CALB type batteries.

My vote would be to go for performance, but don't expect 0 to 60 in 3.5 s.


daniel1948 said:


> ... Tim thinks that with the 11" Warp motor, a new lithium pack, and a 1,400-amp controller, the Porsche would do 0 to 60 in 3.5 seconds in third gear from a stop. (Shifting through the gears would take me several seconds, so if it can't do it all in one gear it will never match the Tesla.) But the motor has a very narrow torque curve, unlike the Tesla, which has only one gear. I don't think the Porsche will ever match the Tesla, but I do know that it can perform very respectably with the present controller.


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## somanywelps (Jan 25, 2012)

daniel1948 said:


> Thanks for all the ideas. I'll run them by Gordy and Tim when I next talk to them.
> 
> 
> Too high, or too low???
> ...


Too low. The voltage is ideal for the motor, but not for the vehicle. If you want to go netgain, Warp 11HV + Soliton 1 (or maybe a netgain 1400A controller, does anyone have feedback on those?) 

288V*1000A=288kw == 386 HP *.87 eff == 335 HP at the output shaft. 
288V*1400A=403kw == 540 HP *.87 eff == 470 HP at the output shaft 
(Caution, this is a lot of strain on the motor) 

Other options are the Kostov 11" 250V or the Kostov 11 Alpha (Electric Forced Cooling).


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## EVfun (Mar 14, 2010)

Perhaps take stock of the parts in the conversion as see what the upper voltage limit is. From there build a pack of Headway P or HP 8 amp hour cells in a series/parallel arrangement until it should meet the power needs. Based on some testing by Manzanita Micro the 8 amp hour P cells should be good for 200 amps each. If you can handle a 48 cell in series pack and you want 1000 amps for the ground then a 5p48s pack would work for a list price of about $4500. I bet when someone asks for 250 cells (a few spares) they will get a price break.


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## daniel1948 (Jun 6, 2009)

DavidDymaxion said:


> Would you be doing the 144V Warp or the Warp 11HV (something like 220V?)? The numbers below assume you have a higher voltage pack, so when it sags the controller can still deliver the max voltage the motor can take.
> 
> 1400 A * 144 V ~= 200 rwhp
> 1400 A * 220 V ~= 300 rwhp
> ...


I don't know the difference between those motors. All I know is that mine is an 11-inch Warp motor, and the fellow at Netgain said 144 v. was ideal for it. I don't want to do anything that might harm the motor. I want good, respectable performance, but this will not be a racing car. It will be a show-off car. 



DavidDymaxion said:


> As a counterpoint, the Tesla does 0 to 60 in under 4 seconds, with about 300 hp -- but there are some caveats. Its AC motor has a broad torque curve, and it has awesome traction control. This would be tough to duplicate with a series DC motor. The Tesla is also likely lighter than your Porsche would be.


The Tesla is definitely lighter. These are precisely the points I made in talking with Tim. Especially the torque curve and no shifting of the Tesla. Tim and I are not exactly on the same page. We can still work together, but he would like to build a Tesla-killer to show off what he can do. I just want to be able to drive this beautiful car without people asking why it's slower than a Honda Civic.



somanywelps said:


> Too low. The voltage is ideal for the motor, but not for the vehicle.


Okay. But as I said above, this is not a race car for me. It would be an around-town show-off car. I want respectable performance from it (I was originally promised 6 to 8 seconds to sixty) and I don't want it to be capable of so much power that it damages itself. I gather that racing cars often need extensive work between races. I don't want something I have to keep repairing. I can floor the pedal in the Tesla without worrying that I'll break something.

Tim is finishing up some other projects, and soon he'll start again on the Porsche, by having the motor balanced and then taking out the bad battery cells and reorganizing the remaining ones. I don't have a time line, but it would surprise me if it's ready before fall. Actually, after 4 years it will surprise me if this car is ever in good driving condition.


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## drgrieve (Apr 14, 2011)

daniel1948 said:


> I don't know the difference between those motors. All I know is that mine is an 11-inch Warp motor, and the fellow at Netgain said 144 v. was ideal for it. I don't want to do anything that might harm the motor. I want good, respectable performance, but this will not be a racing car. It will be a show-off car.


You might have an old version of the motor. You could contact Netgain again and ask what voltage you can run your particular motor at - and what it would cost to be able to run at 170-192 volts like the current models. This is basically upgrading the brushes - I think this is around $200.

It would help if we knew what type of controller you are using. Knowing that we can make recommendations on the battery pack.

Also if you can tell us the what batteries are being used (manufacturer, ah rating, quantity, series / parallel configuration) then there are several options we could also recommend.


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