# AWD Hillclimb EV



## Duncan (Dec 8, 2008)

Hi

All sounds good

Max voltage - 
You can't over-volt a DC motor,
You can over-speed or over-current a DC motor

Your controller will reduce your battery voltage to the voltage required to get your requested (by the throttle) current

Your 400v x 40Ah pack should be enough range BUT

400v x 40A = 16Kw - at 3C = 48Kw continuous
at 8C = 128Kw for 10 seconds

Not really enough for what you want

I would suggest that you need more powerful batteries 
Headway, 123, or LithiumPoly (as used by RC people)

These are rated at higher C values - so you can get more power out

400v
I think this is too high for the controllers available
I would be looking at 2 off Soliton's (front and rear) 
So the pack should be sized to match the controllers


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## Tomdb (Jan 28, 2013)

Do you have a budget in mind? Cause i might know some good sources for motors/controllers if you are willing to spend money.
And where are you based?

EV's will dominate hillclimbs hands down. Strange no-one really has decided to go the EV route in Germany/Austria or England in the hillclimb scene.


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## mistareno (Jul 15, 2014)

Duncan said:


> Hi
> 
> All sounds good
> 
> ...


So if I ran 2 x Soliton 1's with a big pack of 46 x 7.4V or 30 x 11V LiPo that would be a better way to go?

If I could accurately add up how much a/h capacity would be required it would help as I could have multiple packs (like a giant R/C car) and if on a longer track, I could add 2 in parallel.

A quick search found these - http://www.hobbyking.com/hobbyking/store/__8932__Turnigy_2200mAh_3S_20C_Lipo_Pack.html

They are 11.1V and 2.2AH.

If I made pack of 30, the pack would only cost $500 odd, and weigh 6kg so having 4 or 5 wouldn't be out of the question. I wonder how far 2.2AH would get me?

The online calculator at EV Source says 5.98 miles if I can keep weight to around 500-600kg which is heaps for what I need.


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## Tomdb (Jan 28, 2013)

Next problem is the power you want to draw from them. 

c-discharge rate = Engine power (Kw)/ Battery energy (KwH)

have a look at the assault and battery thread assault-n-battery-build-thread-

These guys have a great small pack for drag racing, which would be quite suited for hillclimbs

site for battery info and price http://www.lifegeode.com/ampahaulic_products.html


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## mistareno (Jul 15, 2014)

Tomdb said:


> Do you have a budget in mind? Cause i might know some good sources for motors/controllers if you are willing to spend money.
> And where are you based?
> 
> EV's will dominate hillclimbs hands down. Strange no-one really has decided to go the EV route in Germany/Austria or England in the hillclimb scene.


Based in Australia. Yeah, not sure why no one has tried an EV. The format of racing seems ideally suited to it.

If it works well, I might build a scratch car around the concept.


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## mistareno (Jul 15, 2014)

Thanks for the link, I'll have to do some reading.

One question I thought someone may be able to help with is Controller programming.

Can a controller be linked to an RPM sensor on the motor, and then programmed to only allow the RPM signal to rise at a pre programmed 'optimium' value, like a pseudo traction control.


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## mistareno (Jul 15, 2014)

After doing a bit of trawling, I found these batteries:
*Spec:
Capacity: 5000mAh
Voltage: 12S1P / 12 Cell / 44.4V
Discharge: 65C Constant / 130C Burst
Weight: 1717g (including wire, plug & case)
Dimensions: 300x52x56mm
Balance Plug: JST-XH*

If I ran 8 in Series x 2 in parallel I would end up with 355V and 10AH.


That would give me 462kw battery power (burst) and 230kw constant.


The Battery pack would weigh under 30kg and would easily fit in the passenger seat location for easy access and balance.


Anyone know the best way to balance the cells on Lipo?


Could I make it so the individual packs can be rotated so the same battery never sees the same location in the pack in relation to the charger?


If I can keep the car weight to around 500kg, it would give me close to or above 1hp/kg, but I'm not sure it works out that way...


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## Tomdb (Jan 28, 2013)

Capacity: 5000mAh
Voltage: 12S1P / 12 Cell / 44.4V
Discharge: 65C Constant / 130C Burst
Weight: 1717g (including wire, plug & case)
Dimensions: 300x52x56mm
Balance Plug: JST-XH[/SIZE][/FONT][/B]

If I ran 8 in Series x 2 in parallel I would end up with 355V and 10AH.
Soliton will not work with this.
Running prepackaged cells in parallel will cause problems. 

That would give me 462kw battery power peak and 230kw constant.
not really, depending on where you found your cells and specifications these can be greatly expurgated 

The Battery pack would weigh under 30kg and would easily fit in the passenger seat location for easy access and balance.
Ideal location in a single seater 

Anyone know the best way to balance the cells on Lipo?
I would run a bms system for safety (low and high cuttoff voltages)

Could I make it so the individual packs can be rotated so the same battery never sees the same location in the pack in relation to the charger?
There is absolutely nor reason to do this.



If I can keep the weight to 500kg, it would give me close to or above 1hp/kg, but I'm not sure it works out that way...
Which motors do you have in mind? (heaviest components)
And again what are you willing to spend?


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## Duncan (Dec 8, 2008)

Hi
You will need to keep the voltage below 310v for maximum current with the Soliton

I would suggest
6 of those packs in series with a "Batt Bridge" - to warn if something has happened
http://www.evdl.org/pages/battbridge.html
As a "string"

Use four "strings"
Two for the front Soliton - two for the rear Soliton 

You will only be able to use 500 amps (battery) at those voltages 
The Soliton will turn that into 1000amps (motor)

Then you need two 9 inch forklift motors,

I found 11 inch motors to be more common but they are heavier

I think you will find that the Soliton can be programmed to do all sorts of things

But as it uses a simple throttle input there are lots of ways of making an electronic gismo to do things like comparing speeds and changing the throttle


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## Duncan (Dec 8, 2008)

I personally would not run a BMS

I prefer to be the manual BMS - especially for a competition system

The Batt Bridges will warn if one pack has died or is dying

The individual packs can be charged using an RC charger/balancer - about $25 from the likes of Hobbyking


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## mistareno (Jul 15, 2014)

Duncan said:


> I personally would not run a BMS
> 
> I prefer to be the manual BMS - especially for a competition system
> 
> ...


Out of interest, how long would an individual pack like the one linked take to charge?

I have no issue with making them individually rechargeable and allowing me to be the BMS.

It's not going to be a daily.

Thanks for the info about the 310V limit for the Soliton 1.

I'm not sure I understand how it sends 1000Amps to the motor though?


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## Batterypoweredtoad (Feb 5, 2008)

The 310 Volt limit on the Soliton shouldn't be a problem. Even if you used 100 Calb cells charged to 3.5 Volts each for the maximum allowable pack voltage of 350 Volts it would rest around 330 Volts. Any load that would have you asking for 1000 Amps would likely sag the pack below 310 Volts and make the 310 Volt cutoff a non issue. Use just a few less cells to start with and it will never be an issue.


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## dougingraham (Jul 26, 2011)

mistareno said:


> I'm not sure I understand how it sends 1000Amps to the motor though?


Motor controllers don't send amps. The motor requests amps and the motor controller restricts the current by lowering the voltage that the motor sees which causes the motor to request less amps.

In an ideal motor there is a direct correlation between voltage and RPM. The current that the motor draws is directly proportional to the torque required to turn at that RPM. In an unloaded ideal motor there would be zero amps drawn because there is no torque load on the shaft. Changing the voltage would simply change the rpm. We don't have ideal motors so there is always some load and even an unloaded motor draws some current. This load comes from several places, bearing drag, brush drag, air drag and iron losses being the principal places.

Hope that helps!

Motor controllers like the Soliton 1 constantly monitor motor amps, battery amps, motor volts, battery volts, motor rpm, throttle position sensor and adjust the motor voltage to keep all of these things within specified ranges. Your foot tells the throttle position sensor which then tells the controller the desired torque and since torque is proportional to amps this actually commands the allowed upper limit on motor current.


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## Duncan (Dec 8, 2008)

mistareno said:


> Out of interest, how long would an individual pack like the one linked take to charge?
> 
> I have no issue with making them individually rechargeable and allowing me to be the BMS.
> 
> ...


1000amps

Your motor (DC) only requires a very small voltage to drive a lot of current through it when stopped (15v for 1000amps - ish)

Your controller effectively works by adjusting the motor voltage until you achieve the desired (throttle) current

So stationary you only need ~ 15v to get 1000amps
As the motor speeds up it develops "Back EMF" which must be countered

so 
Zero rpm - 15v
1000rpm - 15v + 50v (ish) = 65v
3000rpm - 15v + 150v = 165v

Your controller is a power in = power out device

15v x 1000amps (motor) = 300v x 50amps (battery
65v x 1000amps (motor) = 300v x 217amps (battery

So you need less current than you think - except at high speeds


Charging
The type of charger I was thinking about would need an hour or so to charge each cell

Probably best to bulk charge them all together and then use the RC charger to top off 
After a few goes you may find that you only "top off" and balance occasionally


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## TooQik (May 4, 2013)

mistareno said:


> Based in Australia. Yeah, not sure why no one has tried an EV.


I've heard of a couple of older (read old technology) EVs involved in hillclimbing in Australia over the years, although I never saw them personally.

I'm also aware of a build that's been underway for a couple of years now using current technology but the vehicle is yet to be brought to an event yet (that I'm aware of). I believe the builder was having problems with batteries but I don't know the specifics and I haven't spoken to him directly. Hopefully he gets it sorted and we see it competing in the Victorian Hillclimb Championship next year.


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## mistareno (Jul 15, 2014)

Duncan said:


> Then you need two 9 inch forklift motors,
> 
> I found 11 inch motors to be more common but they are heavier


Is there some reason for using fork drive motors over something like a warp9?

Cost? Durability?

I was intending on using Warp9's (unless someone can advise me of a better solution), but I might start with a single Soliton1/Warp9 for the rear to get things running.

Also, how much abuse would the smaller Warp7 handle for short bursts before turning into a molten lump?


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## Duncan (Dec 8, 2008)

Hi
The reason is that I'm a Scotsman
A Warp9 is a 9 inch forklift motor with
A nice coat of paint
Brush advance

I bought my 11 inch motor for $100 - and advanced the brushes myself

If buying new - go for Warp!

BUT you can get good old forklift motors for 1/10th the price

_Also, how much abuse would the smaller Warp7 handle for short bursts before turning into a molten lump?_

I expect you to be getting close to melting a 9 inch - in fact as you go on I would expect you to zap at least one 9 inch
A 7 inch? - probably not worth trying


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## mistareno (Jul 15, 2014)

Duncan said:


> Hi
> The reason is that I'm a Scotsman
> A Warp9 is a 9 inch forklift motor with
> A nice coat of paint
> ...


Pardon my ignorance, I'm an IC bloke, but I assume advancing the brush position allows for more efficiency at higher rpms?

Does that sacrifice any low speed running or durability?

Could you have an rpm based advance mechanisim for the brush holder?


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## mistareno (Jul 15, 2014)

As a Scotsman, this might be close to your heart...or maybe not

It looks rather heavy...


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## dougingraham (Jul 26, 2011)

mistareno said:


> Pardon my ignorance, I'm an IC bloke, but I assume advancing the brush position allows for more efficiency at higher rpms?
> 
> Does that sacrifice any low speed running or durability?
> 
> Could you have an rpm based advance mechanisim for the brush holder?


Advancing the timing for high voltage is essential to keep the motor from self destructing. It slightly lowers the efficiency at very low rpm but you don't notice it there. The worst issue with heavy advance is that it is very hard on the motor if you were to operate it in reverse.

There is a way to electronically straighten the timing so you don't need any advance. It is the addition of interpoles. The WarP 11HV has them and the Kostov motors have them.


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## Duncan (Dec 8, 2008)

mistareno said:


> As a Scotsman, this might be close to your heart...or maybe not
> 
> It looks rather heavy...


Not sure about that motor - you need some good photos then post them on the "electric motors" thread and hope Major reads it and helps

As far as heavy is concerned 
These things are heavy,
You will be looking at about 60Kg for a 9 inch and 100Kg for an 11 inch


Brush advance
If your motor has "interpoles" - you don't need it 
Interpoles add their own inefficiencies - 
There Ain't No Such Thing As a Free Lunch

If not
The brushes are designed to "switch" in a quiet part of the rotation
As you increase the speed this moves

If you advance you will be effectively "retarded" at lower speeds and loads
- This is not normally a problem

When you go backwards - now you are in the wrong zone
But unless you are honking backwards that is less of an issue

There have been automatic advance/retard mechanisms for brushes,
I believe the overall decision was - not worth the hassle


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## mistareno (Jul 15, 2014)

I had a think about what I wanted to achieve and I may have thought of a simpler/lighter/better solution.

If I get a single larger more powerful 'double ended' motor I could mid mount the motor behind the drivers seats, I could run one end directly to the rear diff center and one end to the front diff center via a prop shaft.

I would fit a viscous coupler from a Landrover Freelander in the front prop shaft to prevent bind up.

Could I get 300-400hp from a single 11 inch motor? If so, any suggestions on the best controller for the job?


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## Hollie Maea (Dec 9, 2009)

mistareno said:


> Could I get 300-400hp from a single 11 inch motor? If so, any suggestions on the best controller for the job?


Sure, for a short period of time. The amount of short term power you can get out of a series wound motor is more a function of controller than motor.

A series wound motor doesn't like more than around 170V, so too get the power you specified, you would need about 2000A. So you're looking at a zilla.

Alternatively, two smaller motors in series could work at double the voltage and half the current. That would allow you to use a Soliton 1. Both solutions would work fine.


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## major (Apr 4, 2008)

mistareno said:


> As a Scotsman, this might be close to your heart...or maybe not
> 
> It looks rather heavy...


Yep. I imagine quite heavy. Also, nameplate indicates compound wound which is a loser. I'd skip over this motor.


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## mistareno (Jul 15, 2014)

Hollie Maea said:


> Sure, for a short period of time. The amount of short term power you can get out of a series wound motor is more a function of controller than motor.
> 
> A series wound motor doesn't like more than around 170V, so too get the power you specified, you would need about 2000A. So you're looking at a zilla.
> 
> Alternatively, two smaller motors in series could work at double the voltage and half the current. That would allow you to use a Soliton 1. Both solutions would work fine.


A Kostov K9 Dual can be wired in series and parallel. I've never seen one used in a drag car application though. 

It's long, but I might be able to make it fit.

Why is parallel advantageous? Higher top speed due to higher voltage?


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## mistareno (Jul 15, 2014)

Hollie Maea said:


> Alternatively, two smaller motors in series could work at double the voltage and half the current. That would allow you to use a Soliton 1. Both solutions would work fine.


Do you mean 1 'Soiliton 1' controlling 2 motors?

I had considered that, but I wondered what would happen if one axle (motor) lost traction while the other maintained it?

ie - if you had the boot in around a corner and the front lost grip, wouldn't the front motor go redline on revs really quickly and grenade itself?


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## dougingraham (Jul 26, 2011)

mistareno said:


> Do you mean 1 'Soiliton 1' controlling 2 motors?
> 
> I had considered that, but I wondered what would happen if one axle (motor) lost traction while the other maintained it?
> 
> ie - if you had the boot in around a corner and the front lost grip, wouldn't the front motor go redline on revs really quickly and grenade itself?


What happens with the motors in series but separate shafts (not Siamese) is if one loses traction the torque demand from that motor (current) goes away and the motor that still has traction will lose torque so traction should come back fairly quickly. But you are correct that the one that loses traction will go ballistic until traction is reestablished or the rev limiter kicks in. In series both motors must produce the same torque. In parallel both motors tend to want to turn at the same RPM but if one goes completely unloaded it will still go up in speed. This would be kind of a poor mans limited slip arrangement. Since the Soliton has only a single tach input you would probably want some device that watched the rpm on both motors and provided the highest rpm of the two to the Soliton. In your example you would want to put the single tach sensor on the end that tends to lift off first.


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## mistareno (Jul 15, 2014)

Has anyone tried using a C02 spray system to cool the motor for drag racing? It could be temp activated or just running the entire 1/4 mile.

You could plumb one spray nozzle near the brushes and one near the fan.


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## Hollie Maea (Dec 9, 2009)

mistareno said:


> Do you mean 1 'Soiliton 1' controlling 2 motors?
> 
> I had considered that, but I wondered what would happen if one axle (motor) lost traction while the other maintained it?
> 
> ie - if you had the boot in around a corner and the front lost grip, wouldn't the front motor go redline on revs really quickly and grenade itself?


You would need the motors to be locked together axially, to control then with one controller.

It's just a method to utilize the whole voltage capability (and, therefore, the whole power capability) if a Soliton, which can handle twice the voltage of a set of brushes.


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## mistareno (Jul 15, 2014)

Been a bit busy over Xmas but have stripped my donor vehicle. I have decided to keep it RWD to start with for simplicity.

I have been looking at Battery options and had found a Water Cooled Battery (for model speed boats) that was rated at 5000mah and 22V. It claimed a peak of 150C (750A) with a nominal of 500A...

I was going to run 2 banks of 15 Batteries. So 10Ah at 330V with 1500A peak and 1000A nom.

Would a Soliton handle that load?

I was going to plumb liquid CO2 nozzles into the motor housing to cool the brush holders.

An average hillclimb run would be under a minute. Would the battery specs I provided do the job?

Probably thinking a single Warp11 at this stage.


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## Tomdb (Jan 28, 2013)

Got a link to the batteries? 

Batteries for the RC hobby are usually greatly over spec-ed. I would certainly run some tests before committing to buying large quantities. 

Just out of curiosity you have pictures of the car its going in?

solition 1 manual

http://www.evnetics.com/downloads/Soliton_Manual_1v4_rev2.pdf

I would lose two batteries, because its rated at nominal, fully charged will give you (4.2*6 [cells per battery])*15=378v and this is above the 340v limit.
(4.2*6)*13= 327.6V

A soliton 1 is rated for 1000A max, and is limited to this so you will never draw more. This still means you will be pumping, depending on the voltage sag up to 300Kw through your warp11.


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## dougingraham (Jul 26, 2011)

mistareno said:


> I have been looking at Battery options and had found a Water Cooled Battery (for model speed boats) that was rated at 5000mah and 22V. It claimed a peak of 150C (750A) with a nominal of 500A...


A 5 AH battery at 150C should be capable of producing 750 amps. In order to do this without popping the wires it would have to have wires no lighter than 5 gauge. The fusing current of bare copper 5 gauge wire is 794 amps while bare copper 6 gauge wire is 668 amps. When you add insulation to the wire this rating goes down considerably. 5 gauge might be able to do 750 amps for a few seconds. So you can tell they are lying about the 150C spec if the battery comes with cables lighter than 5 gauge. The supplied connectors are often the second limitation. A connector with a diameter of less than the 5 gauge wire is not going to cut it. 5 gauge wire is 4.6mm in diameter. Since they are not usually made of copper or are plated with something with more resistance than copper you will find that you need considerably larger than connectors than this. I doubt that 8mm bullet connectors would reliably handle 750 amps even for only 10-15 seconds. What size wire do these batteries come with? I think the largest wire I have seen attached to RC packs is 8 gauge which means the fusing current is 473 amps with a continuous duty rating of 73 amps. More commonly you see 10 gauge or 12 gauge wire with continuous ratings of 55 and 41 amps respectively. Exceeding the wire ratings will lead to nothing but misery.



mistareno said:


> I was going to run 2 banks of 15 Batteries. So 10Ah at 330V with 1500A peak and 1000A nom.
> 
> Would a Soliton handle that load?


The Soliton will limit the current to 1000 amps. As previously mentioned by Tomdb your voltage is too high for the Soliton 1. At the peak voltage of 4.2 per cell the most you could use would be 81 cells in series and that is fudging it by a tiny bit. If you don't fully charge the cells to 4.2 volts you can do a cell or two more than this. The Soliton will limit power over 310 volts if I remember correctly. But this will not be a problem because at those power levels these cells will sag quite a lot.




mistareno said:


> An average hillclimb run would be under a minute. Would the battery specs I provided do the job?


10AH * 81cells * 3.7 volts = 2.9 kwh. This would drive my car about 10 miles. What is an average hill climb and what kind of grade and speeds are you looking at?

For a number of reasons I don't believe this is going to be enough battery. The 150C is going to be a 10-15 second rating at best. I would guess that if you pretend they are 25C batteries you will have a lot better luck. That means you would need 40AH of batteries. But having pack voltage twice what the motor needs would cut this back in half to 20AH. The motor limits on the Soliton will be set to 1000 A and 170 volts. The batteries would have 300 volts nominal and would only see 567 amps. At 25C you would need 23 AH so you would need to parallel 5 of these packs to get over that. 567 amps divided by 5 would mean each pack would see only 113.4 amps at peak so it would take 5 gauge wire to do this continuously. You could probably do 8 gauge for a minute or so but there will be voltage drop and there will be heat.

Good Luck!


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## jwiger (Oct 18, 2014)

mistareno said:


> I was going to plumb liquid CO2 nozzles into the motor housing to cool the brush holders.
> 
> An average hillclimb run would be under a minute. Would the battery specs I provided do the job?
> 
> Probably thinking a single Warp11 at this stage.


Has anyone else done this yet? I'm interested in trying it at the dragstrip.


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## mistareno (Jul 15, 2014)

jwiger said:


> Has anyone else done this yet? I'm interested in trying it at the dragstrip.


I haven't seen anyone try it but It should work...famous last words...


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## Hollie Maea (Dec 9, 2009)

dougingraham said:


> The 150C is going to be a 10-15 second rating at best.


Nevermind the heat...at 150C, the cells will be DRAINED in 24 seconds. Less actually since capacity drops below nominal at those rates...


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## mistareno (Jul 15, 2014)

The average Hillclimb run is under a minute with probably half that on full throttle. If I decide on an output Voltage I can possibly set it up so that on a longer event I can add a few 'packs' as the Soliton will only pull what it needs, just for longer.


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## RIPPERTON (Jan 26, 2010)

Read your first post and though this guy has got to be an aussie. 

http://ygspower.com/prosecond.php?pid=5

Heres a link to the cells I use and you wont be impressed with RC packs, bad quality and no cooling. You will get a lot of failures and bloated cells. The YGS have tabs at each end and are easy to clamp together.

Forget about Co2 cooling, in your case (drag racing) you wont need very complicated cooling.
I have the front diff from my Mira project (5.5:1) you can run upside down because its sealed.


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