# Electric goKart top speed.



## EE1010101 (Oct 27, 2014)

I'm working on a EV goKart with a motenergy ME1115 motor. The top speed while the wheels are off the ground is 51.8 the top speed in about a 1/4 mile straight away on the ground is 31.5 
Is this normal? Even if the straight away was 2 miles I don't think the kart would reach upper 40mph so is it just an acceleration issue or power issue?

I am using a sevcon gen4 motor controller and I have the can-usb connection. Currently the motor controller is configured by thunderstuck for the motenery ME1115


----------



## dcb (Dec 5, 2009)

Can you give some more information? what type of battery, and volts/amp hours? which specific gen4 (size and voltage rating)? gear ratio? How heavy is the cart with driver? Anything useful you can divulge?

According to this, it only makes about 8 horsepower, so it isn't gonna go real fast, and you might have some sticky tires too.

http://www.thunderstruck-ev.com/images/ME1115Dyno69V.pdf


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> Can you give some more information? what type of battery, and volts/amp hours? which specific gen4 (size and voltage rating)? gear ratio? How heavy is the cart with driver? Anything useful you can divulge?
> 
> According to this, it only makes about 8 horsepower, so it isn't gonna go real fast, and you might have some sticky tires too.
> 
> http://www.thunderstruck-ev.com/images/ME1115Dyno69V.pdf


72 volt Sevcon Gen4 size 8 
I think they are lithium batteries 
The kart is around 300+ pounds with the driver.

These are the trip analyzer graphs for both trips.
This is with the kart wheels off the ground.








This is a test run around a parking lot









why is the mph almost half while on the ground. I understand weight and acceleration are factors. But is this something I can mess around with using the DVT software and CAN-USB connector?


----------



## dcb (Dec 5, 2009)

I'm no expert, but there is something very odd about your current graphs.


----------



## dcb (Dec 5, 2009)

I think I know what was bugging me, you should hold the speed steady with the wheels off the ground, that peak might be inertia, which doesn't count for sustained top speed (but explains why the current changed signs).


----------



## EE1010101 (Oct 27, 2014)

Here is another trip. Is the current not suppose to be negative? im confused


----------



## dcb (Dec 5, 2009)

see previous post, and I think %-110 regen might be a clue also, and other negative readings, dunno.


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> I think I know what was bugging me, you should hold the speed steady with the wheels off the ground, that peak might be inertia, which doesn't count for sustained top speed (but explains why the current changed signs).


Ohhh okay I understand what you mean. I wanted to see what the top speed was with the wheels off the ground. I noticed that as soon as it hit the top speed (if I slammed on the gas without slowly building up the speed.) the motor would cut off and I would have to reset the kart.

The graph with the 50+ mph top speed I had the wheels off the ground and slowly built up to 50 mph so the kart didn't cut off.

I was surprised that wheels off the ground the top speed was 51 mph and when there was a driver and wheels on the ground I barley got to 31 mph. With the help of the dvt software is it possible to tweak the acceleration or maybe power output?


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> see previous post, and I think %-110 regen might be a clue also, and other negative readings, dunno.


I new to the trip analyst and data analogger. is the %-110 regen refer to the regenerative braking?


----------



## dcb (Dec 5, 2009)

Also, I don't know that software or how it relates to the controller, but in the first graph it looks like it stopped accelerating at about 43mph. So rough guess that is the sustained top speed wheels off the ground, not twice as high. Though you are down in 2hp land still for some reason.


----------



## dcb (Dec 5, 2009)

EE1010101 said:


> .(if I slammed on the gas without slowly building up the speed.) the motor would cut off and I would have to reset the kart.


I don't know the software or controller, but hook it up and have a look and see if you have some current limits or rpm limits, sounds feasable. Do you know the motor rpm at 50mph (you probably should)?


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> I don't know the software or controller, but hook it up and have a look and see if you have some current limits or rpm limits, sounds feasable. Do you know the motor rpm at 50mph (you probably should)?


The RPM's are currently set at 5000. The motor controller was programmed for this motor so i'm not sure if I should change that setting. I know there is a page to make changes to the current limit and torque profile.


----------



## dcb (Dec 5, 2009)

It is acting like some sort of current limit maybe (that current graph is all over the place), so I don't think it is rpm related, but all the same, you should count the teeth on the sprockets and measure the wheel diameter and know the relationship between rpm and mph.


----------



## Karter2 (Nov 17, 2011)

It may really help to know what type, brand , and capacity of battery you are using.


----------



## EE1010101 (Oct 27, 2014)

Karter2 said:


> It may really help to know what type, brand , and capacity of battery you are using.


Lithium batteries. I'm not sure about the capacity but I'm using a litepower EMS so I can check the capacity tomorrow.
Here is a pic of the battery pack


----------



## major (Apr 4, 2008)

EE1010101 said:


> I'm working on a EV goKart with a motenergy ME1115 motor. The top speed while the wheels are off the ground is 51.8 the top speed in about a 1/4 mile straight away on the ground is 31.5
> Is this normal? Even if the straight away was 2 miles I don't think the kart would reach upper 40mph so is it just an acceleration issue or power issue?
> 
> I am using a sevcon gen4 motor controller and I have the can-usb connection. Currently the motor controller is configured by thunderstuck for the motenery ME1115


Hi EE,

It sounds normal to me. Information from other posts in this thread put your pack voltage at about 78V. That puts the base speed in the range of 3000 to 3300 RPM. Peak power will occur near base speed. Higher speed then comes at the expense of reduced torque and lower power. When the wheels are spinning freely off the ground, there is no load or very little power required and the system is able to accelerate and reach speeds near your maximum setting. However when the motor must accelerate against a load, you quickly run into the torque limitations of operation above base speed, or in field weakening as some would call it.

To increase the top speed you need to change the gear ratio. Decrease the numerical ratio or try to set 50mph near 3000RPM. This obviously has a negative affect on the acceleration (less wheel torque). You just have to try different combinations of sprockets to find the compromise which gives you the best lap times for a particular circuit.

Please go to the user CP and fill in your location. Also, tells us what you're doing with the cart. Just playing with it, club racing, or what?

Regards,

major


----------



## EE1010101 (Oct 27, 2014)

major said:


> Hi EE,
> 
> It sounds normal to me. Information from other posts in this thread put your pack voltage at about 78V. That puts the base speed in the range of 3000 to 3300 RPM. Peak power will occur near base speed. Higher speed then comes at the expense of reduced torque and lower power. When the wheels are spinning freely off the ground, there is no load or very little power required and the system is able to accelerate and reach speeds near your maximum setting. However when the motor must accelerate against a load, you quickly run into the torque limitations of operation above base speed, or in field weakening as some would call it.
> 
> ...


Thanks for the explanation major. The kart is for the EV Grand Prix at Purdue. I'm working with 1 mechanical engineer. The race track is pretty curvy and has very little straight sections so i'm not sure if the kart can accelerate fast enough to reach top speed on the track. 

I have the CAN-USB connector and some experience with the DVT software so I am going to hook it up today and create a couple configuration files with the RPMs set near 3000.


----------



## major (Apr 4, 2008)

EE1010101 said:


> I have the CAN-USB connector and some experience with the DVT software so I am going to hook it up today and create a couple configuration files with the RPMs set near 3000.


What do you hope to accomplish by doing that


----------



## EE1010101 (Oct 27, 2014)

major said:


> What do you hope to accomplish by doing that


What did you mean by "try to set 50mph near 3000RPM"
I'm not entirely sure what to change on the dvt software. I wont be able to test the kart until Friday, but I want to have another configuration file ready to test so I can compare the original data with the data I will get this Friday.


----------



## major (Apr 4, 2008)

EE1010101 said:


> What did you mean by "try to set 50mph near 3000RPM"


By changing the drive ratio with using different tooth count sprockets, make 50mph occur at 3000RPM.


----------



## dougingraham (Jul 26, 2011)

EE1010101 said:


> What did you mean by "try to set 50mph near 3000RPM"
> I'm not entirely sure what to change on the dvt software. I wont be able to test the kart until Friday, but I want to have another configuration file ready to test so I can compare the original data with the data I will get this Friday.


If your reduction ratio is off there is probably nothing you can change in the software that will make it better. You certainly don't want to limit the motor rpm to 3000 in any way. Motor controller programming is there only to protect itself, protect the motor, and protect the batteries. In all cases it will only serve to reduce your performance.

Assuming an 8" diameter tire, in order to get 3000 rpm to equal 50 mph you need a final drive ratio of 1.428 to 1.

How did I calculate this?

First convert to miles per minute. 50 mph / 60 minutes = 0.8333.

Multiply by 5280 to get feet per minute. 0.8333 *5280 = 4400 feet per minute.

Multiply by 12 to get inches per minute. 4400 * 12 = 52800 inches per minute.

Divide by the tire circumference in inches. With an 8 inch diameter tire that is 8 times pi or about 25.13 inches. 52800 / 25.13 = 2100.9 rpm.

Divide the desired motor RPM by the wheel RPM. 3000/2100.9 = 1.428

If this is a chain drive you would have 100 teeth on the motor sprocket and 143 teeth on the wheel sprocket or some ratio like that. I don't know much about what is available in sprockets or if those are reasonable tooth counts.

What is your current final drive ratio and what is the actual tire diameter?


----------



## EE1010101 (Oct 27, 2014)

This is the battery info







I'm still not sure, but is the 91.2 volts the max capacity of the pack?

rear sprocket 8" counted 65 teeth
front sprocket looks like 3" 22 teeth
wheel diameter is 10"

This ME working with me has the exact measurements. Shes not too interested in the project so I am left to figure it out myself. I was hoping to use the sprockets on the kart now since that is what she choose (for whatever reason). There are other size sprockets available, I just need to provide a valid reason they should be changed.

I calculated 1.7874 for the current final drive ratio with a 10" tire


----------



## EE1010101 (Oct 27, 2014)

This is whats programmed into the motor controller now.


----------



## dcb (Dec 5, 2009)

with that ratio and tire, you are going about 100 rpm/mph, so 3000 rpm is 30 mph. So you will need more teeth on the front gear, or less on the back.

Your battery voltage looks a little low also, I assume you found it with a charger?


----------



## EE1010101 (Oct 27, 2014)




----------



## dcb (Dec 5, 2009)

hmm, charge is listed as negative there. You aren't getting much more than 40A, and nowhere near 200A. Is something hooked up backwards?


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> with that ratio and tire, you are going about 100 rpm/mph, so 3000 rpm is 30 mph. So you will need more teeth on the front gear, or less on the back.
> 
> Your battery voltage looks a little low also, I assume you found it with a charger?


Yeah, I plugged in the battery to charge and view the capacity. I believe we have a smaller rear sprocket but it actually has more teeth 76. It seems like most of the sprockets we have are 76 or 65 teeth, but they range in size. I could always buy a new rear/front sprocket, but I need to confirm with the ME.

On the programming side is there any settings I can adjust so I can see a difference in the karts performance. I know its really a trial and error thing with tuning the motor controller. I just want to learn which setting make the biggest impact on acceleration/speed.


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> hmm, charge is listed as negative there. You aren't getting much more than 40A, and nowhere near 200A. Is something hooked up backwards?


hooked up backwards on the kart itself? It's unlikely since my professor helped with the installation of all the key components. 

On the graphs it looked like the highest or lowest the current got was around -60


----------



## dcb (Dec 5, 2009)

you can try changing -40 to -200 for troubleshooting  It doesn't look like it took a charge though.

Is there a "factory reset" in the software? Is the current sensor separate from the controller?


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> you can try changing -40 to -200 for troubleshooting  It doesn't look like it took a charge though.
> 
> Is there a "factory reset" in the software? Is the current sensor separate from the controller?


Yeah there is a factory reset on the controller. I believe these are the factory reset baseline settings 








This compared to the baseline profile setting I posted a s/s of above. It looks like the torque and RPM's were increased. This motor controller was purchased with the default programming for the ME1115 according to Thunderstruck.

I'm using a data analyst to record the speed/volts/current. It is hooked up to the motor controller though and only records the data into a CALog file. So I assume the current sensor is not separate from the motor controller.


----------



## EE1010101 (Oct 27, 2014)

here is the power limit table if that helps


----------



## dcb (Dec 5, 2009)

dcb said:


> you can try changing -40 to -200 for troubleshooting  It doesn't look like it took a charge though.


..........

Oh, and your batteries might need balancing. I couldn't quite make out the min and max values.


----------



## dcb (Dec 5, 2009)

and check battery undervoltage parameters too...


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> ..........
> 
> Oh, and your batteries might need balancing. I couldn't quite make out the min and max values.


I believe they do need balancing, but those are spares. The ones on the kart now are more balanced not fully charged though.
There are the parameters now for the UV


----------



## dcb (Dec 5, 2009)

UV looks good, let me know if you are going to experiment with that max battery charge parameter and test drive it. (change -40 to something higher, -200 and see if it drives better). I don't know what else to tell you, but if it stops cutting out then your current is sensing backwards, somehow.


----------



## EE1010101 (Oct 27, 2014)

dcb said:


> UV looks good, let me know if you are going to experiment with that max battery charge parameter and test drive it. (change -40 to something higher, -200 and see if it drives better). I don't know what else to tell you.


Yeah, I am going to change that value to see what if any effect it has on the kart. I have to wait until my partner and professor are available Friday morning to test the kart which is a real PITA when I am wanting to test drive the kart now. It will give me time to do some more research on the parameters and see if there is anything else that should or could be changed.


----------



## EE1010101 (Oct 27, 2014)

anyone know if there is a data sheet for the motenergy ME1115? I can only find the mechanical drawing and a brief description or RPMs and Max continuous current.


----------



## major (Apr 4, 2008)

EE1010101 said:


> rear sprocket 8" counted 65 teeth
> front sprocket looks like 3" 22 teeth
> 
> I calculated 1.7874 for the current final drive ratio ....


65/22 = 2.955. That is the drive ratio or _gear_ ratio.



> I'm still not sure, but is the 91.2 volts the max capacity of the pack?


Capacity of a battery pack typically refers to the Ampere hour rating (Ah).


----------



## major (Apr 4, 2008)

EE1010101 said:


> ... I believe we have a smaller rear sprocket but it actually has more teeth 76.


You don't see anything wrong with that statement? How could a smaller sprocket have more teeth, unless it had a different pitch and therefore would be irrelevant to this discussion? Or do you have front sprockets and chains with matching pitch?


----------



## EE1010101 (Oct 27, 2014)

major said:


> You don't see anything wrong with that statement? How could a smaller sprocket have more teeth, unless it had a different pitch and therefore would be irrelevant to this discussion? Or do you have front sprockets and chains with matching pitch?


The sprocket we have on now is 65 teeth about 8". The "spare sprockets" I found are 76 teeth each. one of them is definitely bigger then 8" and the other is clearly smaller but I counted the teeth on both and they both have 76 printed on them. The ME ordered the sprockets so I'm not sure if there is a chain with matching pitch.


----------



## dougingraham (Jul 26, 2011)

EE1010101 said:


> rear sprocket 8" counted 65 teeth
> front sprocket looks like 3" 22 teeth
> wheel diameter is 10"
> 
> ...


50mph on a 10" diameter tire is 1680.7 rpm. To get that with 3000 rpm on the motor means you need a final reduction ratio of 1.785 just as you assert.

What you have is a 65/22 = 2.95 reduction which pretty much explains everything. You have more torque but no top end. You want to change the 65 tooth to close to 39 tooth or change the 22 to something close to a 36 tooth.

The reason you need to change this is you will only go about half as fast as you need to if you don't. Of course there are other things at play in a race and just because the max speed you are allowed to go is 55 doesn't mean you have to go that fast. Having a lower top speed might not hurt you in a race with lots of corners. It might also turn out that if you have too high of a top speed you could consume all your energy and run out before the race is over. A lower top speed means more torque and that means faster acceleration.

Best Wishes!


----------



## EE1010101 (Oct 27, 2014)

dougingraham said:


> *50mph on a 10" diameter tire is 1680.7 rpm. To get that with 3000 rpm on the motor means you need a final reduction ratio of 1.785 just as you assert.*
> 
> What you have is a 65/22 = 2.95 reduction which pretty much explains everything. You have more torque but no top end. You want to change the 65 tooth to close to 39 tooth or change the 22 to something close to a 36 tooth.
> 
> ...




Thanks for the info! You guys have been a really big help. One thing I have a question about the part I put in bold. The ME1115 motor is recommended at 5000 RPM where is the 3000RPM coming from. The race is a ton of twist and turns so it is hard to get to top speed. Also the track is very narrow so there isn't much room to pass. Acceleration is key, but I do not want to sacrifice too much top speed. How would I figure out how much my acceleration will decrease if I increase my top speed by changing the gears?

Does anyone have experience with the ebikes trip analyzer? I noticed some users have the ability to graph Acceleration. I don't seem to have that option when I load my CAlog and GPSLog


----------



## Karter2 (Nov 17, 2011)

We ( you also ?) still dont know what batteries /cells you are using. !
All we can see is its likely a 72v or maybe a 91v nominal pack ?.. 
We dont know the state of charge, discharge ability, or Ahr capacity...
..all of which are pretty fundamental to making this thing work at all !
Until you can confirm some of these basic details, we are all just guessing.


----------



## major (Apr 4, 2008)

Karter2 said:


> .... All we can see is its likely a 72v or maybe a 91v nominal pack ?..
> We dont know the state of charge, discharge ability, or Ahr capacity...
> ..all of which are pretty fundamental to making this thing work at all !
> Until you can confirm some of these basic details, we are all just guessing.


He posted a couple of telltale graphs in post #3 which give the voltage. And that is what's needed to address the OP concerning top speed.



EE1010101 said:


> The ME1115 motor is recommended at 5000 RPM where is the 3000RPM coming from.


http://ep.yimg.com/ty/cdn/yhst-129399866319704/ME1115Dyno69V.pdf 

It is clear from this that the base speed is about 3000 RPM. Hence my post #16.



major said:


> Information from other posts in this thread put your pack voltage at about 78V. That puts the base speed in the range of 3000 to 3300 RPM. Peak power will occur near base speed. Higher speed then comes at the expense of reduced torque and lower power. When the wheels are spinning freely off the ground, there is no load or very little power required and the system is able to accelerate and reach speeds near your maximum setting. However when the motor must accelerate against a load, you quickly run into the torque limitations of operation above base speed, or in field weakening as some would call it.
> 
> To increase the top speed you need to change the gear ratio. Decrease the numerical ratio or try to set 50mph near 3000RPM. This obviously has a negative affect on the acceleration (less wheel torque). You just have to try different combinations of sprockets to find the compromise which gives you the best lap times for a particular circuit.


----------



## EE1010101 (Oct 27, 2014)

Karter2 said:


> We ( you also ?) still dont know what batteries /cells you are using. !
> All we can see is its likely a 72v or maybe a 91v nominal pack ?..
> We dont know the state of charge, discharge ability, or Ahr capacity...
> ..all of which are pretty fundamental to making this thing work at all !
> Until you can confirm some of these basic details, we are all just guessing.


I'm going to confirm the battery capacity with my professor this afternoon.


----------



## EE1010101 (Oct 27, 2014)

Hi Guys, My professor said the batteries are 61 A/Hr and can be 3cc. I wasn't clear about the 3cc, but he mentioned the batteries "can" go over 100A/Hr

I showed him the graph and he mentioned that the current was really low. The current in graphs is that the current to the batteries?


----------



## major (Apr 4, 2008)

EE1010101 said:


> Hi Guys, My professor said the batteries are 61 A/Hr and can be 3cc. I wasn't clear about the 3cc, but he mentioned the batteries "can" go over 100A/Hr


I'd get a different professor if he said 61 Amperes per hour. There is no such unit. Electric charge unit is Ampere hour (Ah). And hopefully he knew what he was talking about and referred to 3C rate, not 3 cubic centimeters (3cc). And he really said can go over 100A/Hr  Amazing  

I know this all may be new to you, but please make an effort to use proper engineering units.



EE1010101 said:


> I showed him the graph and he mentioned that the current was really low. The current in graphs is that the current to the batteries?


The first thing you need to do is read the manual for your instrumentation and verify the accuracy of the current data. Does the scaling factor parameter match the shunt specification?


----------



## EE1010101 (Oct 27, 2014)

major said:


> I'd get a different professor if he said 61 Amperes per hour. There is no such unit. Electric charge unit is Ampere hour (Ah). And hopefully he knew what he was talking about and referred to 3C rate, not 3 cubic centimeters (3cc). And he really said can go over 100A/Hr  Amazing
> 
> I know this all may be new to you, but please make an effort to use proper engineering units.
> 
> ...


Sorry I assumed ampere hour was written A/hr. He did say it could go over 100 amp hour. I will read the manual


----------



## Karter2 (Nov 17, 2011)

How about you just tell us what brand / type of cell, how many, and in what pack configuration...so we can figure out what your pack is capable of.


----------



## major (Apr 4, 2008)

EE1010101 said:


> Hi Guys, My professor said the batteries are 61 A/Hr and can be 3cc. I wasn't clear about the 3cc, but he mentioned the batteries "can" go over 100A/Hr





EE1010101 said:


> Sorry I assumed ampere hour was written A/hr. He did say it could go over 100 amp hour.


That is like saying "The professor told me it was a 61 gallon fuel tank but he said it could hold over 100 gallons of fuel." It doesn't make any sense, does it?


----------



## major (Apr 4, 2008)

Karter2 said:


> How about you just tell us what brand / type of cell, how many, and in what pack configuration...so we can figure out what your pack is capable of.


Did you see the photo in post #15?


----------



## EE1010101 (Oct 27, 2014)

Karter2 said:


> How about you just tell us what brand / type of cell, how many, and in what pack configuration...so we can figure out what your pack is capable of.


Lithium, 2 packs, 12 cells each, 24 cells all together.


----------



## EE1010101 (Oct 27, 2014)

major said:


> That is like saying "The professor told me it was a 61 gallon fuel tank but he said it could hold over 100 gallons of fuel." It doesn't make any sense, does it?


I'm an trying to communicate as much info as I can to an online forum. This kart has been put together with seniors just passing through. Some doing more then others and no one really leaving a paper trial. I definitely lack a lot of knowledge on this subject but I am trying to do the best I can.


----------



## Karter2 (Nov 17, 2011)

Ahh the photo again ! 
So !..you have BLUE cells...24 of them ! thats really helpful !
I deduce they are connected in series.. 24s and GUESS they are 61 Ahr Lifepo4..PROBABLY Thundersky /Calb..of some variety ????????????
As an EE student ( or am i guessing again ?) you really ought to know this detail before you launch into a problem solving exercise, and you certainly ought to understand and know how to write the basic units of battery capacity ( Ahr, kWhr etc,)
...and you most certainly will find it useful to learn to remember what your professor tells you when you ask him questions !


----------



## akseminole (Jan 5, 2014)

I thought I have seen those batteries before. The top posts are very distinct.

Here is what there is to read about these batteries.





Description

GBS is a high-tech manufacturer who specializes in developing and manufacturing of LiFeMnPO4 power battery packs. GBS owns a patented environmentaly friendly solvent binder (which replaces “PVDF”) and creates a unique scalable battery cell design. GBS has developed more than 10 battery products with single cell capacities ranging from 20AH to 400AH. They are the ideal energy sources not only for electric bikes, scooters, hybrid electric vehicles (HEVs) and electric vehicles (EVs), but also for energy storage devices used in solar and wind electricity generation applications and other multi-power systems, as well as military use.

GBS Features

- 10% higher energy density by weight and by volume than Thundersky batteries.
- Superior safety performance due to patented new safety valve and pressure cap designs.
- Batteries do not explode or catch fire when batteries are shorted or punctuated resulting in internal shorts.
- Robust connection due to new electrode terminal design using four rivets or four screws per terminal. This helps prevent loose connections caused by vibration.
- Reduced impedance due to improved electrode terminal design.
- Improved cycle life.
- New cell structure better facilitates BMS integration and battery pack formation, and improves air circulation.

Specifications 

- Nominal Voltage: 12.8V (4X 3.2 V)
- Nominal Capacity: 60 Ah
- LiFeMnPO4 chemistry
- Operation Voltage Range: 11.2 to 14.4V
- Weight: 9.2 kg or 20.3 lbs
- Dimension: 125X280X180 mm or 4.9X11X7.1 in
- Max Charging Current: 3C
- Max Discharge Current: 3C (continuous) / 10C (pulsed)
- Cycle Life : >1500 (80%DOD)
- Operating Temperature: -20 to 65 C or -4 to 149 F
- Self Discharge Rate: <3% monthly
- Accessories included: jumpers, bolts or rivets, washers, split washers and cell covers

Nominal Voltage (V)	Capacity (Ah)	Dimensions (mm)	Weight (kg)
12.8	60	125 x 280 x 180	9.2

http://www.electricmotorsport.com/ev-parts/batteries/lithium/gbs-12v-4-cell-60ah-lifemnpo4.html


----------



## akseminole (Jan 5, 2014)

Now, "knowing" the specs of the batteries, will this make the OP's quest any easier?


----------



## major (Apr 4, 2008)

akseminole said:


> Now, "knowing" the specs of the batteries, will this make the OP's quest any easier?


I addressed this in post #44:


major said:


> He posted a couple of telltale graphs in post #3 which give the voltage. And that is what's needed to address the OP concerning top speed.


I mean he should have known what cells he was using. I guess Karter2 was just pressing him. And I was giving him a hard time for not knowing much about engineering units. I told him his problem and he couldn't recognize it. Sometimes students come on this forum and seek easy answers instead of doing their own homework. He hasn't showed up here lately. Maybe he figured it out or just gave up.


----------



## akseminole (Jan 5, 2014)

I find it surprising that a student who was actively working on this project in college would be so clueless to the technical terminology.

I am not an engineer nor student to become one, yet I did not find the terminology that difficult to assimilate.

I hope that he has spent some time reading up on the subject so the jibes of the EV illuminati might abate.


----------



## EE1010101 (Oct 27, 2014)

major said:


> I addressed this in post #44:
> 
> I mean he should have known what cells he was using. I guess Karter2 was just pressing him. And I was giving him a hard time for not knowing much about engineering units. I told him his problem and he couldn't recognize it. Sometimes students come on this forum and seek easy answers instead of doing their own homework. He hasn't showed up here lately. Maybe he figured it out or just gave up.


I was looking for advice and ideas. Just something to lead me down the right path. This wasn't a homework assignment or something I needed an easy answer to. EE undergraduate is all theory so it has been difficult for me applying that theory to an electric vehicle.

This class could be passed with minimal effort. Literally turning in a couple papers on the EV kart and doing a presentation. Posting on this forum and asking questions was only because I was interested in learning more about electric vehicles. To be honest it does not seem like the most useful knowledge right now. I already accepted a job and decided to focus on my other classes. Electric vehicles are a hobby not a career.


----------



## major (Apr 4, 2008)

EE1010101 said:


> I was looking for advice and ideas. Just something to lead me down the right path. This wasn't a homework assignment or something I needed an easy answer to. EE undergraduate is all theory so it has been difficult for me applying that theory to an electric vehicle.


We were (or at least I was) attempting to help you without giving you the easy answer, which it appears you really did want. It is a pity universities such as your fine institution omit the practical application of theory. Projects such as that ekart can be a valuable learning experience for guys like you and a great resume point which future employers will notice. 



EE1010101 said:


> This class could be passed with minimal effort. Literally turning in a couple papers on the EV kart and doing a presentation. Posting on this forum and asking questions was only because I was interested in learning more about electric vehicles. To be honest it does not seem like the most useful knowledge right now. I already accepted a job and decided to focus on my other classes. Electric vehicles are a hobby not a career.


It takes some effort to be good at a hobby. It also takes some effort on our part the help guys who come to this board for problem solutions. Please understand that we are less than enthused about spending that effort when you're not willing to.

Good luck with your career and also with finding the easy solution to your throttle problem.


----------



## dcb (Dec 5, 2009)

good luck to your employer (mcdonalds assumed).


----------



## EE1010101 (Oct 27, 2014)

major said:


> We were (or at least I was) attempting to help you without giving you the easy answer, which it appears you really did want. It is a pity universities such as your fine institution omit the practical application of theory. Projects such as that ekart can be a valuable learning experience for guys like you and a great resume point which future employers will notice.
> 
> It takes some effort to be good at a hobby. It also takes some effort on our part the help guys who come to this board for problem solutions. Please understand that we are less than enthused about spending that effort when you're not willing to.
> 
> Good luck with your career and also with finding the easy solution to your throttle problem.


90% of the problems encountered with this EV Kart have had "easy" solutions (Usually a settings change). Your "pity" means nothing and your interest and education in electric vehicles is nothing more then a useless hobby. You consider yourself good at this hobby yet what have you done with it? what are you credentials? What breakthroughs in electric vehicles have you made? 

You probably spend more money on these projects then you make which is why you act like the little knowledge you have is equal in weight to gold. 

I can't wait to read about your great advancements in the field of electric vehicles Dr. Major ...lol 



dcb said:


> good luck to your employer (mcdonalds assumed).


You feeling threatened? Your comment just reflects on your own lack of work experience and education. Do any of you even have a BSEE?

Sounds like a bunch of techs upset that they're not engineers.


----------



## dcb (Dec 5, 2009)

EE1010101 said:


> Sounds like a bunch of techs upset that they're not engineers.


Lol, I don't believe you are an EE for a second, you have shown absolutely zero comprehension here. I imagine your paper for this class will be titled "how electrons make me feel".


----------



## major (Apr 4, 2008)

EE1010101 said:


> 90% of the problems encountered with this EV Kart have had "easy" solutions (Usually a settings change). Your "pity" means nothing and your interest and education in electric vehicles is nothing more then a useless hobby. You consider yourself good at this hobby yet what have you done with it? what are you credentials? What breakthroughs in electric vehicles have you made?
> 
> You probably spend more money on these projects then you make which is why you act like the little knowledge you have is equal in weight to gold.
> 
> I can't wait to read about your great advancements in the field of electric vehicles Dr. Major ...lol


If you were really interested in my achievements in the field you could find some in the archives. There are a number of items which I've shared with the members here. I don't feel the need to list my credentials for you.

It's the attitude of students like you which is a big reason I stopped teaching and left the university system. Fortunately there are some young people who I meet that still have a work ethic and respect. I now choose to spend my effort with those who appreciate it.


----------



## Woodsmith (Jun 5, 2008)

Can we calm down the personal digs please, people.

Regulars on the forum know an awful lot of stuff, either through training and education, experience, or both. And sometimes get fed up.

Newbies sometimes don't know what they don't know and may misinterpret info from other parties, and get terms wrong, and not understand everything.

It's why we are here, to learn and to help, if we want to.


Thank you.


----------

