# Highway cruising amps?



## Guest (Sep 1, 2008)

At the speed you are expecting you may be pulling 60 amps. Just a guess. At 55 in mine I am pulling 45 to 50 amps. You may not get a consistent 45 amps while running your generator and keeping the batteries from draining but even if you don't match the amps you need you can extend the time your pack will need to be charged. It will increase your distance by using a small genset. If you build a nice cool looking small trailer you could install your genset in that and just pull it along when you need to go the extra distance. I plan on to build one later but I plan on using a closed loop water cooled marine diesel generator for a boat. It will be heavier but on a trailer it will help. It will also be able to use a larger gen and should give me enough consistent amps for cruise speed saving my batteries for later. If I can't match my amp draw I will still slow the drain on the pack. I can also charge on the road if needed. But I will be using a diesel. Maybe a Kubota diesel too. I will want a turbo diesel and run biodiesel that I make my self. Or a nice small car motor with a turbo and use ethanol I make myself. I want to stay away from petrol as much as possible. A small Geo Metro 3 cylinder engine with gen head should provide good power output.


----------



## TX_Dj (Jul 25, 2008)

What about for a heavier vehicle, lets say around 4000-4500 lbs fully converted S-10?

I was guessing somewhere around 125a or so @ 60 mph on a 144v system.


----------



## dimitri (May 16, 2008)

gottdi said:


> At 55 in mine I am pulling 45 to 50 amps.


At what pack voltage? Are you measuring battery current or motor current? What type of motor?

My Miata sucks 100-150 Amps at the motor to keep 55-60 Mph on level road. This is in 3rd gear at 4500 RPM I wonder if I am missing something, I'd love to improve this figure somehow.

Thanks


----------



## KiwiEV (Jul 26, 2007)

dimitri said:


> At what pack voltage? Are you measuring battery current or motor current? What type of motor?
> 
> My Miata sucks 100-150 Amps at the motor to keep 55-60 Mph on level road. This is in 3rd gear at 4500 RPM I wonder if I am missing something, I'd love to improve this figure somehow.
> 
> Thanks


You're the same as me then. I seem to get around 120 amps at 100km/h (if I can find a flat section). My car is fairly rectangular which means at 35mph and over it's pushing a lot of air. 
It's not a DreamCar123, but it's not far off when it come to aerodynamics.


----------



## BikerA (Jan 9, 2008)

The only time I get below 200amps is going down hill. You guys have it made.


----------



## EVBug (Aug 19, 2008)

Dang guys, some of you are struggling. My '74 Beetle despite it's curves has a horrible drag coefficient. I draw 60 battery amps at 35 mph, 80 at 55 mph, and 120 at 65 mph (all on flat surfaces).

You all know about the regular checks like brake drag, transmission drag, tires etc. but what about your driving techniques? I've found the best way to get the most out of my pack is to keep the RPM's high. 

My ADC L91-4001 is 6.7" and has a max RPM of 6500. I know some of the larger motors have a lower max RPM, so what you should do, is look up the gear ratio for each gear of your car, figure out the RPM's at various speeds, and then compare that with the max RPM for your particular motor. Then you'll have a better idea of where to shift at, and how high you can spin your motor instead of just "ear-balling" it. 

I also found that tires are just plain critical. I started out with some stock sized Khumo's that are rated for 45 PSI max. Then I bought some nice wheels for my car that had a good set of Yokohama's mounted on them so I threw them on. They were only rated for 27 PSI max. I pumped them up to 30 PSI but it was still no comparison. It was like driving through oatmeal. My range went down, my amps went up and my coasting ability was almost as bad as an ICE car. Even though it was a pain in the ass, I swapped the Khumo's onto the new wheels and I've been satisfied ever since.

Try those things out and let's hear what happens afterward.


----------



## dimitri (May 16, 2008)

EV Bug, you didn't mention your pack voltage and weight of the car. Your motor model probably explains how you get lower Amps, and chances are your bug is relatively light.

I used very scientific methods to figure out ratios and I made shift marks on the speedometer to drive at most efficient yet safe RPM. Still, 100-150 Amps at the motor to keep 55 Mph at high RPM. I have 9" ADC 4001 motor and 144 Volts pack. Car weighs 3200 Lb.

I don't know how to figure out if my tires are low RR, these are newer tires and I am not going to throw them away, so it is what it is until they wear off.

The car rolls from stop at the slightest incline, so I know the brakes don't stick.

It also rolls pretty good in neutral and in gear with no power, so I don't think there is much drag from tranny, my fluids are all premium and low viscosity. 

I can't see what else I could possibly do to lower cruising Amps short of major investments with unknown improvement results.

I wonder if measuring Amps at the motor and at the battery would produce much difference at high RPMs? I don't feel like rewiring my car to find out.


----------



## Guest (Sep 2, 2008)

I am pulling 45 to 50 Battery amps at 55 mph. 9" GE Series Motor running 72 volts with 12 GC2 6 volt Energizer batteries. I do not have my motor amp gauge here yet but it is on it's way. I plan on checking both battery amp draw and motor amp draw at different speeds to get and idea of how each is performing and what I can do driving style to keep things to a minimum but still have decent performance. I an using a GolfTech controller 72 volt and 550 amp max. It is a silent controller. Works fine. I can go all the way to 144 volts with my motor. Upgrades will come later. 

Pete : )


----------



## dimitri (May 16, 2008)

Pretty amazing numbers for 72 V system, what type and weight of the car? I would have thought that lower voltage would mean higher amps  not lower amps.

Thanks


----------



## dimitri (May 16, 2008)

Just trying to apply some math to your figures, 50 amps at 72 V is 3600 Watts, at 55 Mph makes it 65 Wh/mile. That is 3-4 times less than typical car, how did you achieve this number? This is not a motorcycle, is it?

I am sorry, I don't mean to doubt you, and I am certainly not an expert in this, just going by the books I read so far. I would love to get anywhere close to these numbers with my own conversion.

Thanks


----------



## TX_Dj (Jul 25, 2008)

In my query, I'm more concerned about pack amps than motor amps, because I'm concerned about peukert's law on my Ah capacity.

I.E. I don't care so much if the controller is pumping 200 amps into the motor, so long as it's drawing a more reasonable amount from the pack.

The reason why I asked this semi-relevant question (polite way to say why i hijacked this thread for my own twist of the original question) is because I have a list of curves for "minutes capacity" at various amperages for the battery I'm considering for the S10. While I know the "minutes capacity" isn't very appropriate in an EV context, because we will often go above or below that, I'm looking to construct a "rule of thumb" to help estimate my range at speed.

Whereas I know that if I pull 300a to get up to speed and then cruise at 125a, I know that I won't get the number of "minutes capacity" as rated at 125, because of the time spent nearer to 300a while getting rolling, but just rying to know what the overall average will be for such a trip... 

*shrug*


----------



## EVBug (Aug 19, 2008)

Sorry about that, nominal pack voltage is 128v, car weighs around 3000 lbs. 1086 of that is pure battery.

Sounds like you have things pretty well thought out. The drag is probably your gear box or maybe your tires. When you're on one of those very slight inclines, put the car in gear and see if it slows or stops.


----------



## dimitri (May 16, 2008)

DJ, we are all concerned about battery amps, its just that some EV schematics put amp meter at the motor, some at the battery and some in both places. When comparing our data we should be comparing apples to apples, so its important to know where particular measurement was taken. If there is someone with both amp meters reading this thread, please tell us how much of a difference there is at high RPMs between battery amps and motor amps. Theoretically the difference should decrease as RPMs increase.

I wonder if there is more value to have amp meter at the battery than at the motor? Maybe I should rewire?


----------



## EVBug (Aug 19, 2008)

dimitri said:


> I wonder if there is more value to have amp meter at the battery than at the motor? Maybe I should rewire?


It's not that one is more valuable than the other, it's that they serve different functions. The battery ammeter serves to monitor and protect the batteries, the motor ammeter serves to monitor and protect the motor. 

And...you don't need another meter, just another shunt and a 3-way toggle switch. You can just switch between them. True, you won't be able to monitor both at the same time, but after a few time switching back and forth, you'll learn how many motor amps you pull for a related number of battery amps and vice versa.

I only have an ammeter that is tied to the battery but I am aware that a Curtis 1231 will output battery amps X 3.1 to the motor when the motor RPM's are at their lowest. 

That means that if I'm pulling away at 5 mph in 2nd gear, and I'm drawing 100 battery amps, I'm putting 310 amps to the motor. As the motor comes up to speed, the motor and battery amps begin to equalize and they almost match. If I'm cruising at 55 mph in 2nd gear, and I'm drawing 80 amps from the battery, I'm probably putting 80-100 amps to the motor, well within it's continuous rating.

I'm not interested in turning my car into the bridge of the Enterprise so I'm going to forgo the separate ammeter and just toggle back and forth when I buy a new shunt.


----------



## Guest (Sep 3, 2008)

I agree the numbers are pretty darn good but I am only giving you what the gauges are giving me. It is a VW Ghia. I have no clue on the weight but the battery weight is pretty high at around 760 lbs. It is a heavy car to me but again it is only a 72 volt system. The motor is a good motor and the controller is a good controller. 



dimitri said:


> Pretty amazing numbers for 72 V system, what type and weight of the car? I would have thought that lower voltage would mean higher amps  not lower amps.
> 
> Thanks


I will soon have another amp gauge and I am glad to hear I can use one gauge for two purposes. I have the switch and I will have two shunts. That sounds like a neat thing to do. One gauge and two outputs to watch. Mmmmm. Thanks for that advice. 



> And...you don't need another meter, just another shunt and a 3-way toggle switch. You can just switch between them. True, you won't be able to monitor both at the same time, but after a few time switching back and forth, you'll learn how many motor amps you pull for a related number of battery amps and vice versa.


----------



## notnull (Jul 30, 2008)

Pete,

What kind of range are you getting? I took a look at the specs on your batteries and it says 92 minutes at a 75A discharge, so 138 minutes at 50A. That is over 110 miles at 55 mph, where you are only drawing 50A. 

Steve


----------



## bblocher (Jul 30, 2008)

Sorry if you already mentioned this Dimitri but where is your shunt located, motor or battery?


----------



## Bowser330 (Jun 15, 2008)

I have noticed gottdi's car from other sites, the motor is the ever interesting shunt starter generator motor, mil-spec type, normally rated at 72V and 400a, but with cooling they can go up to 500a+ and i guess 144V...

They ares not suppose to be as efficient at series wound motors however his range should be extended due to the regen that the generator function can provide...

now what about that same motor with a lighter car and lighter battery pack (lifepo4 type)...with the figures he is already getting, just think how all that less weight would help...


----------



## Guest (Sep 28, 2008)

Battery amps at cruising. I will have my motor amps checked here soon. Actually the 50 battery amps were checked with my GE series motor and not that nice little generator/starter motor. 




notnull said:


> Pete,
> 
> What kind of range are you getting? I took a look at the specs on your batteries and it says 92 minutes at a 75A discharge, so 138 minutes at 50A. That is over 110 miles at 55 mph, where you are only drawing 50A.
> 
> Steve


----------



## Guest (Sep 28, 2008)

Any motor will be better with lithium batteries. Regen will only get me at best 10% back but that does help. I do need to put the generator/starter motor back in my Ghia and do some controller tweaking to see if I can increase the performance of the motor/controller with the Ghia and keep the parts cooler. 



Bowser330 said:


> I have noticed gottdi's car from other sites, the motor is the ever interesting shunt starter generator motor, mil-spec type, normally rated at 72V and 400a, but with cooling they can go up to 500a+ and i guess 144V...
> 
> They ares not suppose to be as efficient at series wound motors however his range should be extended due to the regen that the generator function can provide...
> 
> now what about that same motor with a lighter car and lighter battery pack (lifepo4 type)...with the figures he is already getting, just think how all that less weight would help...


----------



## POP-evolt (Aug 16, 2010)

dimitri said:


> EV Bug, you didn't mention your pack voltage and weight of the car. Your motor model probably explains how you get lower Amps, and chances are your bug is relatively light.
> 
> I used very scientific methods to figure out ratios and I made shift marks on the speedometer to drive at most efficient yet safe RPM. Still, 100-150 Amps at the motor to keep 55 Mph at high RPM. I have 9" ADC 4001 motor and 144 Volts pack. Car weighs 3200 Lb.
> 
> ...


sounds normal to me, haven't done much over 50mph testing, but see about 100-125 amps to maintain 40 in 2nd gear, 92,S-10 FB1 4001 144v,1231C-86XX Curtis controller, 24 USB batteries, this is motor current 
if you are monitoring motor current, what do you see from standstill acceleration ??


----------



## EVfun (Mar 14, 2010)

I've got an EV beach buggy that weighs only 1420 lb. It has a 120 volt pack of Optima AGMs. It used to have a shunt on the battery side and I tested it at various speeds both ways on a couple of different level road stretches. It turned out that the amps used almost perfectly fit the formula mph^2 / 24 = Amps. It only takes 26 amps to go 25 mph, 50 amps to go 35 mph, 105 amps to go 50 mph, and 150 amps to go 60 mph.


----------



## Bowser330 (Jun 15, 2008)

probably was already said, but worth repeating, to reduce cruising amps I would focus on making the car more aerodynamic..

grill blocks, smaller or internal side mirrors, flat belly pan, lowering, front air dam, low rolling resistance tires, etc.


----------



## Guest (Aug 17, 2010)

You could drive slower. That will be a tremendous help. 

Pete 

Max speed limits are not what you have to drive. Just because it's 65 you can drive at 55 if you like. Just remember to allow faster traffic by.


----------



## modern_messiah (Dec 8, 2010)

> That means that if I'm pulling away at 5 mph in 2nd gear, and I'm drawing 100 battery amps, I'm putting 310 amps to the motor. As the motor comes up to speed, the motor and battery amps begin to equalize and they almost match. If I'm cruising at 55 mph in 2nd gear, and I'm drawing 80 amps from the battery, I'm probably putting 80-100 amps to the motor, well within it's continuous rating


Hope some one can reply to this...probably better than starting a new thread. 

I'm totally new to this and am currently bringing my knowledge up to speed a bit.

Can some one please explain to me the difference between battery amps and motor amps? I thought the motor would simply pull the right amount of amps from the batteries to maintain the desired rpm? How can the battery provide 100 amps but the motor use 310?

I feel like I am missing something pretty obvious here.


----------



## GerhardRP (Nov 17, 2009)

modern_messiah said:


> Hope some one can reply to this...probably better than starting a new thread.
> 
> I'm totally new to this and am currently bringing my knowledge up to speed a bit.
> 
> ...


Look at my post #6 in this thread:
http://www.diyelectriccar.com/forums/showthread.php?t=50984&highlight=transformer


----------



## Tesseract (Sep 27, 2008)

modern_messiah said:


> Can some one please explain to me the difference between battery amps and motor amps?
> ...
> I feel like I am missing something pretty obvious here.


Yeah, you're missing voltage, because power out = power in (well, except for the couple of percent lost as heat). So, that means battery voltage * battery current = motor voltage * motor current.

If motor current is higher than battery current, then motor voltage must be lower than battery voltage by the same proportion.

The magical device that does this is called a buck converter, or chopper, and it is the basis for all modern dc motor controllers. What the chopper chops is battery voltage, and the percent time that it is "on" is called the duty cycle. Thus, you can also say that:

Motor Current = Battery Current ÷ Duty Cycle
Motor Voltage = Battery Voltage * Duty Cycle

The motor, by virtue of having a lot of mechanical inertia (and the electrical equivalent, inductance), smooths out the pulses from the chopper so it will behave much the same whether it is fed from 144V chopped into 72V average or a 72V battery.

The throttle in an EV - very roughly speaking - controls the duty cycle of the chopper. Pressing down more on the throttle generally results in a higher average voltage being delivered to the motor until the battery voltage and motor voltage are the same - ie, the chopper isn't chopping anymore, it's just 100% on. Note that motor current and battery current will also be the same, then.

We are a friendly bunch here for the most part, but it never hurts to use the search function. Of course, I realize that you have to understand at least a little about how EVs work before you'll even know what terms to search for, which is why I hope that one day someone more Wiki-inclined than me will turn this into a Wiki entry.


----------



## modern_messiah (Dec 8, 2010)

Between GerhardRP and Tesseract I get it now. I think.

Basically while the rpm of the motor is low and you are accelerating the voltage will be low and the current high to drive the engine harder. As the rpm's increase so does the voltage, but the current decreases because the engine does not have to work as hard. As the car speeds up the motor/battery voltage/current approach parity because the engine isn't working as hard...unless you go up a hill of course, then the motor needs more current to maintain rpm (because the voltage is dropping).

So the battery provides the exact same voltage and current at all times, but the motor is fed the modified voltage and current based on the performance (duty cycle) needed.

Correct or still off the mark? If I can confirm my understanding of the above is correct it will go a long way to helping!



> it never hurts to use the search function


I understand this big time, especially from other forums I have been frequenting for years now. To be honest a search using the term "motor battery voltage" would probably have done the trick. Hell I spent 40mins looking through Wikipedia.

I simply didn't think to actually search the forums themselves this time!


----------



## Tesseract (Sep 27, 2008)

modern_messiah said:


> So the battery provides the exact same voltage and current at all times, but the motor is fed the modified voltage and current based on the performance (duty cycle) needed.


Close... The battery voltage sags when loaded down (ie - the more current drawn the more the voltage sags), but you can assume it is constant for theoretical purposes. The amount of current drawn from the pack varies with load, however. Remember, POWER OUT = POWER IN - LOSSES. The battery won't have to supply any current at all if the motor isn't drawing any current, either.

Roughly speaking (there's that phrase again, and I use it intentionally), motor RPM is proportional to voltage and motor torque is proportional to amperage. This is more precisely correct if the opposing variable is held constant (ie - if torque demand is constant then RPM is pretty much directly proportional to voltage).

However, the torque required from the motor often goes up with speed in a vehicle, especially once aerodynamic drag dominates the power requirement (which starts somewhere around 80-100kph depending on the vehicle). 

It is true, though, that duty cycle (average voltage) applied to the motor is very low and that current can be quite high - as much as the controller is capable of - when accelerating from a stop, and that duty cycle must increase with motor rpm to maintain that level of current.


----------



## major (Apr 4, 2008)

Hi modern,



modern_messiah said:


> So the battery provides the exact same voltage and current at all times,


Of course not.

@ 0 mph, Ib = 0A, Vb = 100V, Pb = 0kW

@ 5 mph, Ib = 20A, Vb = 99.4V, Pb = 1.99kW

@ 40 mph, Ib = 100A, Vb = 97V, Pb = 9.7kW

@ 80 mph, Ib = 400A, Vb = 88V, Pb = 35.2kW

@ 20 mph*, Ib = 300A, Vb = 91V, Pb = 27.3kW

*uphill, all other cases are level road, steady state meaning no acceleration.

Just an example, not real numbers from a real car.

Ib = battery current
Vb = battery voltage including sag (Vb = 100v - 0.03Ω * Ib)
Pb = battery power = Vb * Ib

Vb as used may be typical of a 96 volt nominal battery pack where 100v is the open circuit terminal voltage and 0.03Ω is the internal resistance. This is just an approximation as it will vary with SOC (state of charge) and temperature and other things. 

You can see battery current changes drastically with regards to load. And battery voltage changes less so.

And please call an electric motor a motor, not an engine 

Regards,

major


----------



## modern_messiah (Dec 8, 2010)

I may be thinking too hard about this.

Earlier I was of the understanding that to travel at say (random number time) 40mph the motor () would need 100A and 97V to miantain speed. Which means the battery would be providing "Motor Current * Duty Cycle" Amps and "Motor voltage / Duty Cycle" Voltage.

So why bother with this duty cycle control scheme and just provide the motor with 97V and 100A direct from the battery? Or is that how it's done - the controlling part of the circuit draws what's required from the batteries and the duty cycle is how the output to the motor is controlled?

Hence the closer you get to 100% PWM the closer Vb, Vm and Ib, Im get.

I think I get it. Have to let it digest.

Apologies for being a pain. I've learnt so much in the last 24hrs and it's made my understanding of the whole process so much clearer, but at the same time more answers lead to more questions. It all helps but!


----------



## major (Apr 4, 2008)

modern_messiah said:


> So why bother with this duty cycle control scheme and just provide the motor with 97V and 100A direct from the battery


That's the beauty of a DC system. If you want to go a specific speed at a specific load all the time, you don't need a controller 

major


----------



## modern_messiah (Dec 8, 2010)

> That's the beauty of a DC system. If you want to go a specific speed at a specific load all the time, you don't need a controller


True, but from what I understand AC is the way to go (and more expensive too). What are these warpdrive/HV 11/9 etc thingies? AC? I'm assuming as much.


----------



## major (Apr 4, 2008)

modern_messiah said:


> True, but from what I understand AC is the way to go (and more expensive too). What are these warpdrive/HV 11/9 etc thingies? AC? I'm assuming as much.


Yeah. Better read up a bit on that


----------



## ECCM (Apr 13, 2010)

2008 Toyota Highlander Hybrid
5600 lb GVW.
To maintain 60 MPH on level highway, ~30 kw. According to dashboard instrumentation.


----------



## dtbaker (Jan 5, 2008)

ECCM said:


> 2008 Toyota Highlander Hybrid
> 5600 lb GVW.
> To maintain 60 MPH on level highway, ~30 kw. According to dashboard instrumentation.


A nice number to have... but the power required has little to do with the GVW, much more to do with frontal area, AWD, and aerodynamics.


----------



## Tesseract (Sep 27, 2008)

dtbaker said:


> A nice number to have... but the power required has little to do with the GVW, much more to do with frontal area, AWD, and aerodynamics.


He provided the year/make/model of the vehicle, so one could either look up the CdA (most useful) or calculate the frontal area based on published specs and estimate the Cd value.

So, more useful than not providing any data at all, eh? (ahem...)


----------



## EV_dub (Aug 30, 2010)

I have also been thinking about building a range extending trailer.

My vw golf at 120v system: (on the flat once up to speed)

battery amps:
60mph= 70-80amps- 8400w-9600w
65mph=75-85 amps- 9000w-10200w
70mph=85-95 amps- 10200w-11400w

My golf weighs in at 1280kg

10x trojan 1275 150ah = 380kg 

I was thinking on the lines of a 12kw generator system. Conventional generators dont seem all that efficent and often noisy. My idea is to use a 2x 6kw or 1 x 12kw genset and swaping engine(s) for a more efficent motorcycle or marine engine. Diesels use less fuel but dirtier. Petrols are quieter and cleaner and could run on LPG or maybe Hydrogen??

Dave


----------



## Bowser330 (Jun 15, 2008)

Thanks for the information.

I think a range extender is a great idea, especially with currents limits with battery technology.

http://www.duropower.com/item.asp?PID=294&FID=2&level=0
850$ for max ac output of 9.2kw! 250lbs though, not lightweight meaning you would probably want a hoist of some kind to take it in&out of the car...

With that genset you might be able to sustain up to 60mph... 

You might also want to consider switching to lithium and you will gain a lot of performance and range from the better battery technology.




EV_dub said:


> I have also been thinking about building a range extending trailer.
> 
> My vw golf at 120v system: (on the flat once up to speed)
> 
> ...


----------



## dtbaker (Jan 5, 2008)

if you need more than 100 mile range, you may want to consider bio-diesel.

on a practical note, don't forget that added a trailer will add a whole new set of aero drag, and a little mechanical drag (not much) from two more wheel bearings and tire rolling resistance.

I would say, if you really want a hybrid, then get one. The expense of trailer, generators, invertor/electronics to charge or power on the fly are going to be substantial, and I dunno about laws regulating engines in trailers RUNNING as you drive along the highway.


----------



## EV_dub (Aug 30, 2010)

dtbaker said:


> if you need more than 100 mile range, you may want to consider bio-diesel.
> 
> on a practical note, don't forget that added a trailer will add a whole new set of aero drag, and a little mechanical drag (not much) from two more wheel bearings and tire rolling resistance.
> 
> I would say, if you really want a hybrid, then get one. The expense of trailer, generators, invertor/electronics to charge or power on the fly are going to be substantial, and I dunno about laws regulating engines in trailers RUNNING as you drive along the highway.


To keep the cost down, I thought about picking up a couple non runner generators, match it up to a decent bike engine. As for electrics. I would use 2x ng3 chargers and an ng5 for about 11kw's. The chargers would be situated in the car so they can be also used for fast charging from the grid. As for the law of running engines on a trailer, I dont know for the UK! ???


----------



## lou-ace (Jul 21, 2009)

I guess I'm pretty much with BikerA, I consistently pull heavy 200 amps throughout 1st and 2nd gears, and even 200-250 in 3rd on the freeway at 55 mph, in the small truck configuration, curtis 1231c, ADC,fb4001, 120volt ( #20 6v crown batts) est. weight 3800lbs. I too have put in premium low visc. fluids, checked brake drag. although I am considering lowering the rear end to increase torque at highway speeds.


----------



## Guest (Feb 1, 2011)

lou-ace said:


> I guess I'm pretty much with BikerA, I consistently pull heavy 200 amps throughout 1st and 2nd gears, and even 200-250 in 3rd on the freeway at 55 mph, in the small truck configuration, curtis 1231c, ADC,fb4001, 120volt ( #20 6v crown batts) est. weight 3800lbs. I too have put in premium low visc. fluids, checked brake drag. although I am considering lowering the rear end to increase torque at highway speeds.


Battery or controller amps?


----------



## lou-ace (Jul 21, 2009)

I thought I already posted here, I guess not. My small truck, 9" motor, curtis 1231c, 120 volt pack sukkkks 200-300 amps to maintain highway speeds. I changed the ampmeter from motor side to batt. side and really didn't see much difference.There was a little less notable spike in amps as i started out but the reading is still pretty much the same...... too much!!! I'm looking for an amp/hour guage as i think this might lead to more usefull info, I also plan on switching to lipo's as soon as my lead dies....... some years yet I hope.


----------



## ElectriCar (Jun 15, 2008)

TX_Dj said:


> What about for a heavier vehicle, lets say around 4000-4500 lbs fully converted S-10?
> 
> I was guessing somewhere around 125a or so @ 60 mph on a 144v system.


That's my setup. Mine weighs 4147 with 24 US XC2200. I get about 30-35 miles in my area which has lots of hills. On level ground my PakTrakr reads about 6-9kw. On the amps side I've frequently seen 45-55A battery amps with a voltage around 140. The above is just going by memory. 

For wiring I have parallel 1/0 throughout the pack. The one time I checked the top speed it hit 85. Shortly afterward I learned I had a bad connection and as I was doing the run I had a terminal melting down. It finally broke the connection after I had gotten off the interstate and started coasting.

Some people will say you don't need that much wire but I do get better performance than a lot of people. Larger wire = more voltage to the motor due to less losses. It's not a great amount of voltage unless you're pulling a lot of amps though.


----------

