# How can I get speed from electric car



## mattW (Sep 14, 2007)

Well it depends if you want speed/acceleration or you want that and a long range... And it depends on your budget. What sort of driving do you do and what sort of money were you thinking?


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## lucky99 (Jun 17, 2008)

10 to 15 miles range would be fine I just need the solution to getting the speed.
Thanks
Lucky99


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## MrCrabs (Mar 7, 2008)

This guy knows the secrets to a quick EV.
http://www.plasmaboyracing.com/
http://www.evalbum.com/035.html


Dual 8 or 9 inch motors, lots of batteries that can pump out the juice, and a Zilla controller.


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## VDubber (Jun 2, 2008)

lucky99 said:


> 10 to 15 miles range would be fine I just need the solution to getting the speed.
> Thanks
> Lucky99


Three words:

Expensive AGM Batteries.

Enersys 'Genesis' EP series or Odyssey is a good choice. You will also need a controller that can properly exercise these beasts. Given that a PC2150 can fire off 2,150 amps for 5 seconds and 1,750 amps for 20 seconds, A Zilla is pretty mandatory.


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## lucky99 (Jun 17, 2008)

Can I get specs on the drive and batteries so I can match specs and not brand names, also are the drive systems similar to the inverter drives on industrial machines many of the inverters even have digital displays to adjust speed and direction some can interface with computers.

Would it be possible to remove part of the rear-end and use a dual shaft to turn both wheels I guess there may be deferential problems.

Also as far a weight to power what about using a diesel generator running off of biodiesel to stay a little green, some of these are very quiet and put out enough power to run 3 phase welding machines and are very efficient, could pack it under the hood or vent out of the trunk with no problems.


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## frodus (Apr 12, 2008)

torque = current, RPM = Volts

Add more of either one, and you get more out.

You want more speed? Pack as high a voltage pack as you can get into the vehicle. Realize, that this may limit the size of each battery (i.e. you may only be able to fit in a 120V pack of 30Ah batteries in the space of 72V 55Ah batteries). It'l be less torque, but higher speed.


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## lucky99 (Jun 17, 2008)

Any information on gear boxes I know there are many very powerful industrial machines out there and they will cut you into pieces at any speed, and these gear boxes are strong and many are small, also there are gear boxes on motorcycles I am just curious as to what has been done with all the different gearing choices.

One more think does anyone remember seeing a invention on TV from a guy making batteries from what I think was fiber glass strands coated with lead he stated it was 80% lighter and 60% more powerful because of more surface area I remember this from the 1990s can find anything on the net about it.


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## VDubber (Jun 2, 2008)

frodus said:


> It'l be less torque, but higher speed.


Not true. The 1000A+ batteries I mentioned are available in formats as low as 20Ah. Hence the need for premium AGMs - they handle high current much better then floodeds. Currents up to 50C is not unheard of from these batteries. 

So if you want lots of power but don't need alot of range, they work out quite nicely.


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## frodus (Apr 12, 2008)

VDubber said:


> Not true. The 1000A+ batteries I mentioned are available in formats as low as 20Ah. Hence the need for premium AGMs - they handle high current much better then floodeds. Currents up to 50C is not unheard of from these batteries.
> 
> So if you want lots of power but don't need alot of range, they work out quite nicely.


why don't you reread what I said .... I said "you may only be able to fit in a 120V pack of 30Ah batteries in the space of 72V 55Ah batteries"... May, as in *might*... and then I gave an example about the fact that it may give higher top speed, but not much off the line starting current. 

Many people (obviously not you) go by the Ah rating, not max amps, mostly because when the peukert effect comes into play, you get less range. MUCH MUCH less range. He said he wanted 10-15 miles, not 1 or 2 miles. So I'm still right*.* A 20Ah battery, sucking 1000A for a short time, its going to cook those batteries, I don't care what technology you start "quoting". It also severely hurts any desire he has for range. It also severely hurts any desire for battery life longer than 50-100 cycles. All bats are not created equal, true.... but GENERALLY SPEAKING, the larger Ah capacity battery will supply more current continuous than a smaller one. Thanks for pointing out that some smaller ones can supply more instantanious than a larger one.... but it'l hurt range and bat life.

So, don't you mean to correct me for not saying that its *not always true*? 

He needs to pick a good technology of bats so that he can get some of the pep he needs, but also the high speed. I agree with that, but don't discount the statement below:
Voltage = RPM, Current = Torque


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## VDubber (Jun 2, 2008)

frodus said:


> why don't you reread what I said .... I said "you may only be able to fit in a 120V pack of 30Ah batteries in the space of 72V 55Ah batteries"... May, as in *might*... and then I gave an example about the fact that it may give higher top speed, but not much off the line starting current.
> 
> Many people (obviously not you) go by the Ah rating, not max amps, mostly because when the peukert effect comes into play, you get less range. MUCH MUCH less range. He said he wanted 10-15 miles, not 1 or 2 miles. So I'm still right*.* A 20Ah battery, sucking 1000A for a short time, its going to cook those batteries, I don't care what technology you start "quoting". It also severely hurts any desire he has for range. It also severely hurts any desire for battery life longer than 50-100 cycles. All bats are not created equal, true.... but GENERALLY SPEAKING, the larger Ah capacity battery will supply more current continuous than a smaller one. Thanks for pointing out that some smaller ones can supply more instantanious than a larger one.... but it'l hurt range and bat life.


That is what I was reffering to. Some 30Ah and less AGM batteries have been proven by the EV old-timers to happily put out 1000A+ on a regular basis with little loss in life. Some even have been shown to have less lifespan if you* don't* draw heavy amps from them on a regular basis. As for Peukert, not all batteries are created equal:



EVDL said:


> ...the Peukert exponent for the EP26s is 1.057. 1.000 is perfect. Golf cart batteries are typically 1.2.


So little range is lost when drawing heavy amps on occasion - *if you pick the right batteries*. And the actual experience from EV owners is that the correct AGM batteries will last up to 500 cycles even at this level of use - but you *do* need some form of BMS while charging.

Yes, generally speaking (and especially with flooded lead acid) your description is accurate. But you made it sound like you *couldn't possibly* get a high voltage, high current, mid Ah pack that last over 300 cycles. My point is that a few EVs (driven around for years now) have proven that you can.



frodus said:


> So, don't you mean to correct me for not saying that its *not always true*?


Yup, sorry I wasn't clearer. "Not always true" would be a more accurate way of putting it. I was just in a hurry at work.



frodus said:


> He needs to pick a good technology of bats so that he can get some of the pep he needs, but also the high speed. I agree with that, but don't discount the statement below:
> Voltage = RPM, Current = Torque


I am not discounting it. But you can have both (high voltage & high current) in a ~800lb pack that is proven to give 15-30 miles range for up to 500 cycles. It just is expensive. About $3,000-$5,000 for a 144V pack using the minimum level of BMS (Lee Hart's Zener Regulators).


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## frodus (Apr 12, 2008)

Sorry for getting defensive, just seemed like you were arguing the bottom line that I was trying to illustrate.

Essentially what I was saying, is that if you look at lbs of lead. I was trying to illustrate that if you keep the same "volume" of batteries (to fit in the same space), and keep roughly the same lbs of lead (but divide it into smaller 12V batteries with less capacity).... you'll have a pack with the same kWh, but it will be higher voltage/lower current capability. This is mostly true if you stay within a certain technology of batteries, but its apples and oranges when you cross compare flooded/agm/lifepo/etc.

My motorcycle project uses 12 18Ah batteries, for 144V 18Ah and putting it into my controller. We're limiting battery amps to the max continuous of the batteries, and letting the controller do whatever it wants as long as it stays below that max Amps. The power of my pack is similar to a 72V 36Ah pack (I said simliar), but I'm just carrying less current on the bat side, and it COULD go higher speed. It might be better to do 2 72V packs (less peukert effect), but we're developing a 156V 600+A motor controller for cars/small trucks and my motorcycle is a good test bench, and as long as the controller limits my amps, its very similar in performance, with the added bonus of being able to go fast as shit 

I'll let you know in a week when she's running. I'll be able to switch 72V parallel packs, or 144V single pack with just a couple of cable swaps. I should be able to get some logs off the controller (its got built in flash for data logging/failure debugging). 

I'm basically doing what I was telling the OP... taking the same volume/weight in batteries, and just making 2 packs of batteries, in the same space, as opposed to one pack. One is HV/Lower amps, the other is LV/Higher amps. But with how the controller is working and limiting amps, it doesn't really matter. Its just to test, we'll run more efficiently later....

There's just something cool about being high voltage


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## VDubber (Jun 2, 2008)

frodus said:


> I'm basically doing what I was telling the OP... taking the same volume/weight in batteries, and just making 2 packs of batteries, in the same space, as opposed to one pack. One is HV/Lower amps, the other is LV/Higher amps. But with how the controller is working and limiting amps, it doesn't really matter. Its just to test, we'll run more efficiently later....
> 
> There's just something cool about being high voltage


LOL - that is true. You gonna put one of those "DANGER - HIGH VOLTAGE" white and red placards on the side of the battery pack (visible to passerbys)?

Might make bike theft less of a worry, eh?

I have always been interested in *Hybrid Packs*. There was recently a report on the EVDL from someone testing a lithium booster pack. It was a string of small (2.3Ah) high power lithium cells of the same voltage as the main lead acid pack, wiring in parallel. They reported seeing much more range then the 2.3Ah addition would account for (5-6 miles more then the additional Ah should've given him).

It appears that placing a string of small high current batteries parallel to a string of large low current batteries is significantly decreasing the overall observed Peukert effect. If the small bat string is acting as a "current buffer" for the larger bats - which some suspect - then it should also significantly increase the lifespan of the large low current batteries.

A string of Odyssey PC625 drycells in front of a string of T105 would give me a $1400 96V/225Ah pack capable of comfortably dishing out 625A for 5 secs and 450A for 30 seconds. This is enough of a pulse length to get me up to speed rather quickly in my donor. Since the PC625 have a much lower resistance then the T105, the voltage sag under a given load is less. This means that as you pull more total current from such a hybrid pack, proportionally more of it comes from the "buffer string". Pull just a small current (say 50A) and it will mostly come from the large bats. Pull a larger current (say 200A), and it will come mostly from the small bats. Pull a peak current (say 500A), and it will come almost entirely from the "buffer string".

The different resistances also means that the PC625 would be constantly charged from T105, so you would use the well tested "pulse discharge" max current rating as well as the "standby power" cycle life (cut down a bit depending on how often you pulse them) of the PC625.

The above is just an example. Pick any large/high resistance/low current & small/low resistance/high current strings you want. Hopefully we will get more people trying this so we can get more data...


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## frodus (Apr 12, 2008)

I'll be posting my data. Right now we're just logging onboard with a timestamp... so we'll know the bat voltage with relation to performance... then we can recharge and do everything over again. I'd like to get a F/R contactor and just do it on the fly... we'll see how that goes.


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## VDubber (Jun 2, 2008)

Oh, and before anyone calls me on the price quote I gave: T-105 refers to a battery standard, not specifically to Trojan Batteries. I was referring to Costco T-105 cells. It's also called "size GC2 with a 105 nominal reserve time".

They just got lazy and used the standard code for model numbers.


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## Bowser330 (Jun 15, 2008)

I am on forums where people are always calling people out. Its just not what I want for this forum and not what I am sure the rest of us want. 

Please lets keep this forum clean of defensive comments, if you dont like how someone addressed your comment then why not ask them what they meant by it, instead of (or at least before) writing a confrontational post?

We are on these boards for a reason....and its a great feeling seeing the progress of you all and this technology...Thanks!


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## VDubber (Jun 2, 2008)

Sorry, it was not written in a confrontational spirit.

I was just attempting to clear up some potentially confusing information I gave - in an offhanded manner. Not sure I succeeded though. Didn't mean to offend.

I guess I have just been around forums too long... old habits die hard.


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## SuperChuck_A11 (May 29, 2008)

More info on the 500 cycles please 
that seems like not very much. So what exaclty is ONE whole cycle ??

If I cycle the batteries ONCE per day, are you saying I'll get less than 2 years of sevice ??


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## VDubber (Jun 2, 2008)

SuperChuck_A11 said:


> More info on the 500 cycles please
> that seems like not very much. So what exaclty is ONE whole cycle ??
> 
> If I cycle the batteries ONCE per day, are you saying I'll get less than 2 years of sevice ??


Cycles for batteries are typically stated at 80% DoD (depth of discharge).

The cycle life increases in a non-linear way when the DoD goes down. So you will usually get double the cycles at 50% as 80%. 

Here is a hypothetical battery life chart:

25% = 1600
50% = 800
75% = 400
100% = 200

Each battery has a different curve, but most lead acid will follow this general rate. So if you only pull out 40% out of your bats for each time you charge, you will have much more then double the rated 80% cycle life. Closer to 3 times as much.

500 cycles at 80% DoD is pretty darn good for any lead acid battery you can pickup with two hands (excluding those huge stationary ones). This would usually give you well over 1000 cycles at 50%.


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## electro37 (May 18, 2008)

I once worked for a British Railroad and when the first "high speed" locomotives entered service I found they were "double-wound" (series-shunt) 1000volt DC motor-propelled... a driver would accelerate up to his cruising speed with plenty of torque etc, but then; when he wanted to go faster he "weak-fielded" the motor, so the current draw lessened but the revs increased. Very similar to a mechanical "overdrive"!! Less torque, but more speed as a recompense.


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## manic_monkey (Jun 24, 2008)

If you want more speed, use the gearbox from a diesel car, rather than a petrol. the gearing is normally longer, and much better suited to lower reving forklift motors.

If your motor isnt reaching near its speed rating though, then its time for a bigger motor


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## GeeDub (Jun 25, 2008)

frodus said:


> Essentially what I was saying, is that if you look at lbs of lead. I was trying to illustrate that if you keep the same "volume" of batteries (to fit in the same space), and keep roughly the same lbs of lead (but divide it into smaller 12V batteries with less capacity).... you'll have a pack with the same kWh, but it will be higher voltage/lower current capability. This is mostly true if you stay within a certain technology of batteries, but its apples and oranges when you cross compare flooded/agm/lifepo/etc.


Well, *that* was a lot clearer to a newbie like me than all that stuff that led up to it. I *was* getting really lost.


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## Hi Torque Electric (Dec 23, 2007)

Hey all

As to getting more top end speed from a motor, you can add more brush advance which will lower the torque but allow the motor to see higher RPM's. Nothing for free but for those who are looking for higher speeds (and lets say running an ADC motor that's advanced at just 10 degrees it's a viable option for those who might be PM limited via their voltage.
Hope this helps
Jim Husted
Hi-Torque Electric


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## AtomicVette (Jul 8, 2008)

Hi Torque Electric said:


> Hey all
> 
> As to getting more top end speed from a motor, you can add more brush advance which will lower the torque but allow the motor to see higher RPM's. Nothing for free but for those who are looking for higher speeds (and lets say running an ADC motor that's advanced at just 10 degrees it's a viable option for those who might be PM limited via their voltage.
> Hope this helps
> ...


very intersting, so now we just need variable brush timing on the motors, then you get the torque when you want to accelerate and the rpm when maintaining speed.


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## VDubber (Jun 2, 2008)

AtomicVette said:


> very intersting, so now we just need variable brush timing on the motors, then you get the torque when you want to accelerate and the rpm when maintaining speed.


Check Jim's site. He already has built that and yes, it's very cool 

I believe he has a kit for the DIY to mod their own motor with variable brush timing. Jim?


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## AtomicVette (Jul 8, 2008)

VDubber said:


> Check Jim's site. He already has built that and yes, it's very cool
> 
> I believe he has a kit for the DIY to mod their own motor with variable brush timing. Jim?


I'd like to see it.. Who's Jim? Sorry I've only been a board member for a day now. Still ingesting all the good info on here. i'm 100% newbie to electric vehicles.


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## VDubber (Jun 2, 2008)

Jim is the guy that posted above talking about the motor advance 

Jim Husted
Hi-Torque Electric

http://hitorqueelectric.com/

Variable mechanical advance mod kit for the Advanced DC FB1-4001 9" motor:

http://hitorqueelectric.com/gallery/v/Variable+timing+rings/


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## Hi Torque Electric (Dec 23, 2007)

Hey all

First off thanks to those getting some info out as I’d meant to get back to this earlier but just couldn’t find the time . It’s also kind of nice to just to see some of you out there actually read my stuff 8^o I’ve mapped out timing rings for the 6.7’s, the 8’s, and the 9’s are actually a stocked item now 8^) although the flex leads needed to rotate the brush assy are still custom fitted in. My ultimate goal is to work up comm. plates where one could exchange it out and send back the core which I feel would work well for people who are up and running already but want to tinker with their timing 8^)

Jim Husted
Hi-Torque Electric


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## AtomicVette (Jul 8, 2008)

Hi Torque Electric said:


> Hey all
> 
> First off thanks to those getting some info out as I’d meant to get back to this earlier but just couldn’t find the time . It’s also kind of nice to just to see some of you out there actually read my stuff 8^o I’ve mapped out timing rings for the 6.7’s, the 8’s, and the 9’s are actually a stocked item now 8^) although the flex leads needed to rotate the brush assy are still custom fitted in. My ultimate goal is to work up comm. plates where one could exchange it out and send back the core which I feel would work well for people who are up and running already but want to tinker with their timing 8^)
> 
> ...


 
So right now the timing is manual control? any plans or thoughs of automating the timing? maybe via throttle position or something?


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## VDubber (Jun 2, 2008)

AtomicVette said:


> So right now the timing is manual control? any plans or thoughs of automating the timing? maybe via throttle position or something?


Hmmm. The perfect timing would be based on RPM, volts and current, right? This can be done quite well with a micro and a servo, but some may want a simple mechanical setup.

Throttle position would give you a more-or-less current level (the further you press down, the more current you tend to use). Would a simple cable hooked to a bellcrank rotated by the throttle cable work sufficiently well? 

Maybe not, as you want less advance at a lower voltage to get more torque. How about a pure RPM based advance? I can't seem to think of a purely mechanical way to do that that isn't horribly complicated - anyone got any ideas?

Of course, one *could* use a simple electromechanical setup. A larger RC servo can be had, made for vibration and harsh environments. It can be mounted to the firewall and a push-pull cable attached from the 'horn' of the servo to the arm of the advance mechanism.

These servos use a simple PWM signal to represent position. Here is a simple analog circuit to drive one with a pot:










Now, put that circuit in a little plastic box next to the servo. Mount a weatherproof pot with a small spring-loaded sheetmetal vane on the side of the motor. The vane should cover a small portion of the exhaust slot. The faster the motor spins, the more air is blown out, and the vane is pushed away from the motor turning the pot - thus advancing the motor.

Small ICE engines like lawn mowers and outboards use this same concept as a throttle governor. It is easy to adjust and calibrate. Just rotate the pot and the servo in their mounts to adjust the two baselines (minimum RPM and minimum advance), and mount the cable to the different holes in the servo horn to adjust the ratio (RPM per degree of advance). One could change the size of the vane to adjust sensitivity.

P.S. Yes, one could tap the throttle pot to drive that circuit. But I'm not sure you would want to... any thought's about that Jim?


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## Hi Torque Electric (Dec 23, 2007)

Hey guys

There are actually a few people looking at different ways to make my timing units self adjusting. In huge ways I have to leave this in the hand of you good gentlemen though, as you guys pretty much run me ragged as it is 

I don't have time to completely view Vdub's input but will throw it to some of my dogs to see how it chews out though 

In general though, EVen used just as a static device one can set these to each of your particular coversions.

If looking at the fact that "the first 9" was a 72 volt Prestolite lift pump motor that ADC copied and installed a drive shaft and advanced the timing to 10 degrees and changed the voltage rating to 120 to 144? and then redone with 12.5 degrees with the Warp motor and rated to 170 volts, you can see that timing plays a huge role in how a motor performs under different voltages. IMO there are far to many low volter's using 12.5 degrees and the same amount of high volters using 10 degrees and the reason I came up with the timing plates to begin with. That said, It'll be fun to see how it plays out.

Cya
Jim Husted
Hi-Torque Electric


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