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ev jr dragster

113K views 293 replies 14 participants last post by  tropes 
#1 · (Edited)
I am going to build an electric jr. dragster for my daughter who is 10 years old.Last year was her first year racing with a stock 5 hp Briggs with a best run of 15.77 at 40 mph in the 8 th mile.We would like to run in the 10's to 60 mph(she wants to go faster),the car weighs 285 lbs without the driver,I have not yet pulled out the Briggs -thinking it will weigh 240 with out the engine-we must stay under 400 lbs.There is more info at Nedra.com. Now for a newbie question-in knowing weight will be an issue can i get power out of a 24/36volt or 48 or do I need 72. There are some Mars motor on Ebay with controller for under $1000.00-good buy???Do I need a progammable controller? How many runs do you think we would get out of batteries before re-charge?I think I will use a DC motor.I would like to do this for around $1500-$2000 if possible.Will post some pics asap.Thanks for any advice.I own a bodyshop and have a friend who is a machinist and another who is an electrician so we can fabricate most of the parts if needed. Please give me your ideas on motor size,controller and battery.
Thank you!
 
#2 ·
I am going to build an electric jr. dragster for my daughter....... Please give me your ideas on motor size,controller and battery.
Hi jr dr,

You might be able to find some example systems and build info searching in the bikes forum here. It seems like a lot of kart builds end up there as well. Here is a parts list for a kart kit (just for example). http://store.kta-ev.com/Go Kart Package (Basic).pdf

I personally would not use a PM motor (like the Mars) (and please call the electric motor a motor, not an engine). The Mars motor may be a good product, but I have seen too many PM motor parts laying on the drag strip and race track to recommend them. Stick with a series wound DC motor for great starting torque and durability. I think you should look at the 6.6 inch diameter motor. A bit heavier, but commonly available, and can provide good performance at low voltage to start and take increased voltage system as you upgrade.

With that in mind, you may wish to find a controller which will accommodate a wide range in battery voltage. WRT the batteries, this application requires power more than a large energy stored. Small Ampere hour (Ah) AGM Pb-Acid 12V batteries will work and not cost an arm & leg. Hawkers or Genesis brand are good. Lithium would be best, high C rate jobs, like A123 or Headway. Maybe even rob some Dewalt tools. You can get into the info forum here and read about energy, watt hours and Ah and such and figure out the number of runs per charge. Most such racers charger inbetween passes. You get the most power from a freshly charged and warm battery.

I think you will benefit from starting modest and working your way up in performance, meaning system voltage and power. Your mistakes will be less costly and you'll get it on the track sooner :)

Good luck.

major
 
#4 ·
ev drives has a d&d es-10e-33 motor, 500 amp controller 36- 48 volt kit for$ 1091 its kit #5. Kit 9 has a d&d es-15-6 motor 450 amp controller 72 volt kit for $1293.with kit would you recommend to get the jr in the 10s in the 1/8 mile?? could you run the #5 kit at 48 volts then later run it at 72,or would it fry the controller?thanks for your ideas.
 
G
#7 ·
Convert your photos to .jpg format if they are not yet and be sure they are not huge. 100k or so should be just fine. Much larger the server balks. No need to clog up the server with photos that are too large. Use your camera to get nice photos then reduce them in size. Then try again.

Pete :)
 
#8 · (Edited)
#9 ·
does anyone know the weight of alltrax axe 7245 controller?? The d&d weighs 62 pounds,i found 12 volt 22amp hr batteries that weigh 13 pounds each about $60.00 each .car weighs 225 batteries 6 x 13= 78 d&d 62 ,so im at 365 pounds so far have to stay under 400. so will the controller,wiring ,solenoid weigh less than 35 pounds or do i have to lighten the car some how. thanks
 
#10 · (Edited)
Go to the Alltrax site. If the info you need is not on their pages go to to the "Contact Us" page. They answer promptly.

http://www.alltraxinc.com/

Depending on length and guage of cable you are going to be close on the weight.

I have been running a small pulling tractor. Weight was/is a problem for us as well. Finally went to Headway batteries. We now have a (Edit change this to 99 pound from 65) pound battery that can produce over 100 (EDIT change this to hp from kW) for over 30 seconds. Check with some of the others like Yabert that have gone this route. Slightly:eek: more expensive then the lead you are looking at, but you will probably end up there anyway.

Jim
 
#13 ·
Hi

Kw = hp x 0.746 or W = hp x 746

And HP = (Torque x RPM) / 5252.

So 75Kw = 100 hp and 100 hp @ 2500 rpm = (100 x 5252) / 2500 = 210 lbs-pi
If you start from other side, a big 11" motor give 300 lbs-pi of torque @ 3000 rpm, that give 171 hp ((300 x 3000) / 5252).


When you will got your cells please give the result... I'm interested to know the internal resistance difference between Headway 10Ah and 8Ah cells!
 
#14 ·
i will go with lead to start with to keep costs down.How would you recommend i buy my kit from ??? ev drives?? or from d&d ?? or any where else? i have read some horror stories on this forum and dont whant to get ripped off. im going to order one in the new year.i emailed alltrax for the weight of cont.
 
#16 · (Edited)
Lead is the easiest way to learn.... no complex charger and balancing. But it's a fact, many cheap batteries come more costly than few good Headway.

Pay attention to the real price.... that including shipping, custom and taxes!

Watch your PM.
 
#15 ·
jr dragster,

I bought my ES15-6 and Alltrax 7245 from D&D Motors.

D&D is an Alltrax dealer. They gave me a fair price and good service.

You might shop and get a motor or a Alltrax 7245 on eBay for a better price, but they don't come up often. I've also seen used, prices vary.

I want to mention that there are other equivalent name brand motors out there as well. ADC, Netgain, Warp and others

If you buy a new motor, plan on spending a lot of time running the motor on 12 volts to seat the brushes. I have run the motor I have for over 6 hours and it just keeps on getting better the more I run it.

Before you read below get used to the fact that good batteries cost a lot and cheap batteries cost more.

If you are going to go with lead I recommend 16 ah Hawker (Enersys) Oddsey batteries, you will probably pay over $100.00 each. They are not cheap but you get what you pay for. They weigh 13 pounds apiece and are about the size of a motorcycle battery. You won't find many, if any, other batteries that will give the kW they will. Look up the specs on the OEM site. you will be imppresed.

You can probably draw twice the amps from the Hawkers, while still maintaining good voltage, then you can from the cheaper lead batteries.

Last gasp on the Headways.

Yabert has had a set of Headways in service for a while in his bike. He might have a bit of info to throw in here as well. So might Frodus.

I went through 2 years of pulling with lead, and that experience tells me that high output lithiums are the way to go. At the Power range you need the price difference isn't that bad.

A 72 volt Headway system would be minimum of 20 batteries. You can pull 200 amps (25C) from a single string of 38120P batteries for around 30 seconds and expect it to sag to 50 or so volts at that load.

At the $19.00 each price that I paid (you might do better) thats $380.00 for a single string and a double string of 40 would be $760.00.

A 6 battery set of Hawkers would cost a minimum of $600.00.

A double string of 40 Headways weigh 12 kg 26.5 pounds. Six Hawkers weigh 78 pounds.

My 72 volt Hawker pack saged to around 40 volts when I pulled 400 amps. The double string of Headway's (According to Headway) should hold to about 50 volts at 400 amps. As soon as we get our batteries we will put them through some tests to see how they will hold up.

Hope he above helps you decide.

Jim
 
#17 ·
i found a d&d model 170-501-001a 48 v for 250 +shipping do you think it would have the power i need to move the 400 pound dragster fast enough? it rated at 13hp is that peak power? what controller would you recomend for this motor.also looking at an advaced dc motor lighter than than the 15-6 d&d by 25 pounds ,but more money. to many decions to make LOL
 
#18 ·
i found a d&d model 170-501-001a 48 v for 250 +shipping do you think it would have the power i need to move the 400 pound dragster fast enough? it rated at 13hp is that peak power? what controller would you recomend for this motor.also looking at an advaced dc motor lighter than than the 15-6 d&d by 25 pounds ,but more money. to many decions to make LOL
That motor is a made to be used on a golf cart axle and does not have a front bearing and DE cover and has a female output connection.

I'm afraid it is a very poor choice unless you have access to machine shop equipment.

Probably not a good first time, starting out motor (ask me about the door stop I bought).

I would need to look up the model number of the Advanced DC motor to tell you if it would be good. But a lighter weight then an ES 15 may mean a smaller diameter motor. Get pictures and specs and post them. Many people on the forum will help out.

D&D has a series of motors that start out with the ID code of ES. Like ES 15 and ES 31, those would be good.

Don't buy until you ask. I didn't and paid the price of an unusable motor for my task.

If price is important look for take out and reman lift truck (Hi-Lo) motors. Read through the the Sticky posts about chooseing a good Hi Lo motor in the Motor forum. It's a long read but invaluable.

Hope this helps.
Jim
 
#21 ·
jr dragster,

With an Alltrax controller, yes you can, you would add a parllel circuit to your throttle. You would need to find the proper resistor to give the rate of creep you need. Zero ohms is thriottle off, 5000 ohms is full throttle. Somewhere in there at the low end is what you need. A bit of trial and error.

I would operate it with a push button. To use it, foot off throttle and push the button for creep.

Jim
 
#22 ·
motor??????????????? amd a000-4009 at kta services for $605 ,50 pounds .or D&D es-15-6, $669 at ev drives 62 pounds with one would you guys recommend?????price is so close that ethier way, 12 pounds in weight is more important .give more your ideas thanks
In my opinion (we all know what opinions are worth) both are good motors. I don't know about power and torque differences. If weight is a consideration and power and torque are close go, with the lightest. Since you will only be stressing the motor for a few seconds heat won't be a big consideration.

Ask someone like major to offer an opinion, he knows bunches more then me about motors.

Jim
 
#23 ·
ADC a000-4009 vs D&D es-15-6!


Isn't exactly the same motor!
Both have same diameter, but the D&D is 12 lbs more heavy because it is 2" longer than the ADC.

This 2" longer = more torque!

And it's probably why the ADC is rated 6hp continuous/28hp peak and the D&D is rated 10hp continuous/40hp peak.

But don't forget, the 28 and 40 peak HP is only give by the manufacturer, and I'm not sure that will be easily reachable with the Alltrax 72v 450A and lead battery.

My ES-15-6 on my DRZ SM feel like around 35 hp at 83v nominal (62v sag) and 600A.

Well I think you need to forget the 12 lbs in more and appreciate the higher torque!
 
#24 ·
ADC a000-4009 vs D&D es-15-6!


Isn't exactly the same motor!
Both have same diameter, but the D&D is 12 lbs more heavy because it is 2" longer than the ADC.

This 2" longer = more torque!
Hi guys,

I recommend jr drag get the motor performance curves and brush size for these 2 motors, then he (we) could make an intelligent decision. Barring that, I'll side with Yabert here :)

major
 
#26 · (Edited)
Hi,

I just bumped into this motor while looking for something else..

http://cgi.ebay.com/4-HP-DC-Motor-4...643?pt=LH_DefaultDomain_0&hash=item45f8017d73

I AM NOT RECOMMENDING it. I just don't know enough. I'm hopeing major would comment on it. It seems reasonably priced and powerful. It might work for jr daragster if they can work with ccw rotation. The low rpm and high torque just means different gearing.

Jim
 
#27 · (Edited)
ok after 3 months of looking im ready to order my parts so i can get this done in time for racing,or dad will be in trouble. parts list missing ANYTHING??????????
d@d es 15-6 motor
axe 7245 72v 450 amp cont w fuse [should i get an extra fuse?]
JCA 400 solenoid
3amp diode [extra?]
1k ohm precharge resistor w 3/8 terminal [extra?]
pb6 throttle
wsb prog cable
deltec 250 amp shunt
10 amp fuse and holder x2
ed 250 emergecy stop x 2
20 feet 2 awg cable
18 wire lugs {some spares for learning lol}
crimper
cable cutters
heat shrink
front rear spockets and chain[wil have to figure gear ratio 4.1??]
lanyard shut off {may get one off a snowmachine}
will make all mounting and brakets.
sound good or will i need anything thanks for your ideas.
priced it all out will come in at $ 2,000 to 2,500 depending on battery prices.
thanks again
6 \12 batteries
 
#30 ·
Snow finally melted :) got car out of shed.Made some parts from cardboard, motor ,and batteries to see if they will all fit.NO!!!!!!!!!!!!!!! :mad: motor is to big at 6.6 .would have to cut frame and body to make it fit.So new plan will us a Mars 1003 with a alltrax 7245 at 72volts.It may not be the perfect set up, but we will see? :confused:Alot of people are using them on bikes and they are working.The weight should not be an issue anymore,car 225 motor 39, batteries 78 ,cont 8 , wires etc 20-30 =370-380.
 
#34 ·
the tear down day one ,removed rear axle,so i can change gear.Made all brackets for mounting mars & controller ,relays ect. Picked up batteries and more alum today,for battery box .Got 18amp hr batteries,will try see how they work. start welding soon first race may 28.
 

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#35 ·
need some advice on wiring ,went to all trax got wiring diagram,need to put some safety shut offs in, can i put them in where it has the key switch?? need to put lanyard in and one on roll cage.in the rule book it says must shut off all power to motor, will that work as key switch to shut off all power ? I have a ED 250 heavy duty emergeny stop for roll cage ,can it be wired in the same way ?.If you google jr rules it is on page 48.of rule book.Going to weld up battery box and motor plate tommorow,would like to wire it this weekend.worst case if the main contactor was to to arc would holding the brakes blow the battery fuse ? trying to make it as safe as possible.thanks for your help so far
 
#36 ·
I'll put together a copy of the wiring diagram of the system I use on the pulling tractor. You can copy anything you need or is useable. The total system, tether, emergency shut down precharge are all here. You just need to arrange them as you need. I'm having some health issues so it mght be slow.

Jim
 
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