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  #11  
Old 12-20-2010, 08:27 AM
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Default Re: ev jr dragster

Quote:
Originally Posted by Jimdear2 View Post
Finally went to Headway batteries. We now have a 65 pound battery that can produce over 100kW for over 30 seconds. Check with some of the others like Yabert that have gone this route.
The Headway are rated 909w/Kg (10 Ah) or 1500w/Kg (8 Ah).... so the max power you can produce with 65 lbs of cells will be : 65 / 2.2 = 29.5 x 1.5 = 44 Kw

But 44 Kw is 310 lbs-pi of torque at 1000 rpm or 62 lbs-po of torque at 5000 rpm.

To Jr, the D&D is a great motor, so start with 5 or 6 lead batteries and later if you decide to go with lithium your motor will be good enough...
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  #12  
Old 12-20-2010, 11:06 AM
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Default Re: ev jr dragster

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Originally Posted by Yabert View Post
The Headway are rated 909w/Kg (10 Ah) or 1500w/Kg (8 Ah).... so the max power you can produce with 65 lbs of cells will be : 65 / 2.2 = 29.5 x 1.5 = 44 Kw

But 44 Kw is 310 lbs-pi of torque at 1000 rpm or 62 lbs-po of torque at 5000 rpm.

To Jr, the D&D is a great motor, so start with 5 or 6 lead batteries and later if you decide to go with lithium your motor will be good enough...

I'm not all that good with math, and those of you out there that know this stuff better then me please point out where I'm wrong

The 38120P battery is rated at 8 ah and 25C for at least 30 seconds. That equals 200 amps. I'm hoping that voltage drop at 25 C in a 50S/3P battery will not exceed 2.75 to 2.5 volts per cell. (Still waiting for the batteries to arrive so I can test this volts per cell premise)

So here is what I came up with

2.5 VPC under 200 amp load times 50 batteries per series string equals 125 volts.
3 parallel strings at 200 amps per string equals 600 amps total.
600 amps times 125 volts equals 75 kW battery output for about 30 seconds.
75 kW equals approx 100 horse power.
150 batteries at 300 grams per cell (I goofed here) is 45 kg equals 99 pounds.

At approx 100 lbs of battery your math and mine are not too far apart.

Would you please post the formula that you are using to convert kW into torque. It would be a big help.

I also went back and edied my original post.

Thanks,
Jim
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Last edited by Jimdear2; 12-20-2010 at 11:12 AM.
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  #13  
Old 12-20-2010, 11:37 AM
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Default Re: ev jr dragster

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!
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  #14  
Old 12-21-2010, 12:38 AM
jr dragster jr dragster is offline
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Default Re: ev jr dragster

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.
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  #15  
Old 12-21-2010, 02:01 AM
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Default Re: ev jr dragster

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
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  #16  
Old 12-21-2010, 07:48 AM
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Default Re: ev jr dragster

Quote:
Originally Posted by jr dragster View Post
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.
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.

Last edited by Yabert; 12-21-2010 at 07:53 AM.
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  #17  
Old 12-22-2010, 09:40 PM
jr dragster jr dragster is offline
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Default Re: ev jr dragster

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
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  #18  
Old 12-23-2010, 02:15 AM
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Default Re: ev jr dragster

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Originally Posted by jr dragster View Post
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
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  #19  
Old 01-09-2011, 05:39 PM
jr dragster jr dragster is offline
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Default Re: ev jr dragster

can you set up the electric to creep to stage the car ?????
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  #20  
Old 01-09-2011, 05:49 PM
jr dragster jr dragster is offline
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Default Re: ev jr dragster

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
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