mars brushless vs brushed etek for an electric dirt bike

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kp647
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mars brushless vs brushed etek for an electric dirt bike

I have read here that the mars brushless motor has less torque than the etek brushed motor.
I am planning a dirt bike conversion (125cc) using 50 v lipo batteries (40ah) from my rc planes(very high power packs)

My plans now include a mars brushless motor ~ 24 lbs $450
and a kelly kbl 48301 controller run on 50 to 58v

I am looking for a low top speed bike with lots of torque, maybe gear it for 25/30mph tops.

Is there a compelling reason to choose the brushed etek over the mars brushless motor?

Kevin

racermike39
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Re: mars brushless vs brushed etek for an electric dirt bike

Hey Kevin.
I just thought I would suggest something about the controller you are planning to use. Based on my experience, when using a Kelly controller, you should purchase a higher amp rated unit. If you look at the break down of how Kelly rates the controller output, It only allows peak output for a few seconds. I have found with my 4 wheeler, geared the same as you are planning, when I get in a tight spot, the output is not enough to get it over a rock or tree etc from a dead stop. (Mine is a 200 Amp) I would recommend buying a 400 amp or higher if you can afford it. You will have reserve capacity when you need the extra power. You can always limit the output with the programing feature if you want to conserve battery power. I was told by someone who compared the performance of Kelly VS Altrax, and he said if you want the performance of an Altrax 300 amp, buy a Kelly 600 amp. I think EV of America sells Kelly controllers based on the continuous rating, not the peak rating.
If you want to do wheelies and climb steep hills, I would recommend a 400 Amp unit.
I have had great success with Kelly controllers, and I am very impressed with the delivery and customer service.
I can't help you on the motor stuff, but someone on the forum will help you out for sure.
Sounds like a great project!
BTW, have you check out www.evalbum.com ? Hundreds of examples you could gather data from. Use the search feature for motorcycles.

Racermike
5 years ago I met Jesus and he total ruined my life. I have never been happier.

andys
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Re: mars brushless vs brushed etek for an electric dirt bike

http://www.thunderstruck-ev.com/roadrunner.htm

I'd talk with these guys and go with their recommendation, since they have tested both of the motors in a situation like you want to use them. Also, check out their bike in the link above-you may not be able to build one for much less than you can buy a finished sorted out bike from them.

kp647
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Re: mars brushless vs brushed etek for an electric dirt bike

Well if I can get the gearing right , I will go with a 72v brushless mars and the kelly controller, I can reconfigure my packs to 75v by going 18s2p and stil have 20ah capacity.
Since I will be shooting for a really low top speed I hope to avoid the off the line sluggishness others have reported using the mars brushless motor

Kevin

frodus
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Re: mars brushless vs brushed etek for an electric dirt bike

20Ah at 72V? 1440wH won't get you more than 10-15 miles.... so keep that in mind... also, depending on the batteries, make sure their peak current rating is decent. If they only supply 2C at 20Ah (which would be 40A) it might not be enough.

Did kelly ever fix the problem they had with their brushless? Seems to me I remember lots of people saying the kelly was a ton more noisy than the sevcon controllers because of the waveform it sends to the motor on the AC power side.

____________

Travis Gintz
1986 Honda VFR Conversion
www.evfr.net

kp647
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Re: mars brushless vs brushed etek for an electric dirt bike

Thanks for your help and replies, keep in mind this is a dirt bike for riding around my property,,, that said i dont need tons of range, I would describe it in minutes not miles,, if I can blast around for 20-30 minutes tops that would be great.

on the batteries c rates, the packs I am using are super hi discharge lipos from my electric RC aircraft. I use enerland cells assembled by various companies into 6 cell packs (25.2v) in 5000ma to 10,000ma cell configs.

the 75v 20ah pack I described would weigh 12lbs and be made up of 6 packs (of 6 cells each 10,000ma cells)
they would be connected in a 18s2p setup so 18 in series is 75v, and 2 in paralel is 20ah

the cells are very high c rate and you can pull 200+ amps on them (400amps+ on a 2p)

here is a link to the suppliers website
http://www.maxamps.com/products.php?cat=24

I am also concerned about the performance of the kelly kbl controller with the mars brushless, and also just wondering if I should go with an etek-r and alltrax controller
to make things easier ....

anyone who has used the brushless mars and the kelly controller, I would value your advice.

Kevin

ruprek
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Re: mars brushless vs brushed etek for an electric dirt bike

I just bought a Kelly kbl 48301 controller and was planning on mating it up to one of Powerpacks BMC 1500 watt motor. But since I'm a fool for speed and my life insurance is paid up Iwas thinking of getting either an etek or the Mars brushless. Since i'm putting it on a fairly modified I-Zip 1000 scooter frame, I don't think I will have any problems or complaints against the Mars being sluggish, which is what I plan to get. My reasoning is simple. If I have problems, need parts, questions, I have a resource with Kelly who has proven to be outstanding, and I mean that sincerely. I don't know of any company who will e-mail you, not once, twice, but three times on a Saturday afternoon/ Sunday morning!!! No kidding! I hope I don't ruin his weekends letting that one out. You can't find that kind of service anywhere. So as someone who is still braking things trying to bottle lightning, that is a no brainer for me. Call me ignorant, but does Briggs and Stratton have a customer help line thats accessible to people who didn't buy from the factory? If so, then it clouds the water.

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