Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[cavi]

okay, I have never done a E-conversion, that said , I did alot of electric conversions of  RC airplanes so I do have a initial idea of what is needed.  I would like to do a dirt bike conversion.  I want a trail bike that.  I am not concerned about top speed, if I can get it to 25mph I am happy, torque is more important.  I would like to get a battery run time of 1/2 hour with normal trail use.  Where do I start?  Which motor do I choose, other reference materials for info?  Initially I am debating weather to go with a old style 125 prolink style frame or use a yz80/cr80 frame.  The 80 frame would be lighter to start, and the yz80 frame is pleanty large enough toa make a good trailbike even for a full size adult.
Ideas?
Also batteries?  Lead acid or lithium, what is the cost of eqivalent lithiums?
Sorry for the basic questions, but I want to learn it right and get it right, I am not afraid to read old articles, just direct me to them.
Thanks

[Bogan]

whats your budget? lithiums are more expensive but are a lot more powerful and lighter. Get the frame that best suits your size, no point having a slightly lighter frame if its too small for you. Etek-RT is probably the best value for money motor these days, and would easily provide great acceleration to 25mph.

[cavi]

As bad as this may sound the idea of a budget is debateable.  This project will be born as a project, I know there will be a learning curve, as it grows I am sure I will end up with lipos, but I will probably start with leak acid.  I am not allocating a real total budget.  I will buy the donar bike first, then the E-tek RT and  controller and throttle, and initial batteries.  By doing it in stages it will not hurt my pocket.  End result is Lipos are in the final budget, just not an initial buy.  As for the frame size, I was thinking the smaller frame initially as it serves well as a trail bike, but as of now I am considering a 125.  What it comes down to is priority of the project is.  If I was to build a streetbike it would be tough to get the performance I would want without major dollars.  Ideally I would like a electric trials bike, but as a first project I will probably not go there as a donor bike will be a large outlay of money, so I fall back on a dirtbike proper.  Is a dirtbike perfect?  Not really as a proper trailbike, as most of my current trailrides are 90 miles and up and last for 4 plus hours with no place to leave extra batteries.  But a dirtbike will still be a fun learning project and fun to use around camp, this is why I was initially thinking 80 size.  After the whole project is done and learning curve complete, I would consider a trials bike as project 2.  I hope this makes sense.  Now for my new question, BMS for Lipos, do I have to make one  or are they available?

[frodus]

Don't confuse Lipo with lithium iron phosphate.... Lipos are the dangerous ones that can burst into flames if overcharged/overdischarged...... part of the learning curve, but I'd make sure you don't get lipo....

BMS are available for lifepo4, but you gotta look around, they aren't abundant.

start with lead, get it working at like 48V and get things fabricated.

[cavi]

yes I do know the difference between the lithiums, I was just generalizing.  Another twist, I just saw the post on the Lifan 200 conversion.  Apparently you can get a brand new rolling chasis for 650, that is interesting.  I still think it might be a bit dissapointing speedwise, but I am considering it, again as a cool project, and it would be cool to show up to work on an electric bike, and that one does look pretty cool.....  What is the perfermance difference between the brushed motor they used and the etrex rt brushless.  I know that with the airplane the brushless were much better, less maintance and more power for the same input.

[Bogan]

first to answer your question from the other thread (should prolly keep it all in one place) i reckon the RT is the way to go, more torque at slower rpm, so you dont need a ginourmous rear sprocket. Im yet to see a brushless EV motor making more than bout 10hp, they require a different controller to run them of course. Is there a link to the brand new rolling chassis youre looking at, it does sound interesting. Also with the batterys i reckon price up both lead acid, and lifepo4 setups, as the better mbatteries may not add too much to your project cost.

[frodus]

for prices on lifepo4, try my company: www.evcomponents.com or email travis@evcomponents.com with questions.

As far as BLDC goes, there's one that I know of thats available, the Brushless Etek/Mars motor and sevcon or Kelly controller with it. Not as good performance, but its brushless. Not sealed.

The other option is go AC, but you'll drop more than $2k at the very least into that.

For your first, just used brushed, no reason really not to. You can ALWAYS upgrade later.

[cavi]

tell me more about the lithiums, i looked at your site, and it seems most come in a box like form, do I just wire them togeather, or do you make them into a pack for me/?  I ask as i also saw a premade pack, however it waas only 20A and I want at least 40A, preferably 60a.  But it did have a BMS built in.  tell me more please.  If i build a pack, can i use a onboard charger or am I bst not

[frodus]

email me with questions in the future, I'm trying to keep everything straight and organized for EVC.

Those packs have wires coming out for charge and wires coming out to go to the controller. Paralleling them should be fine, but has not been tested.

We don't build packs for free, we can build larger packs, but we don't do enclosures at the moment, and our consulting and fabrication services are normal engineering and manufacturing rates.


Another thing, use correct units. 20A should be 20Ah, there's a difference. One is capacity, one is ampacity.

if you want 40Ah or 60Ah then you'll have to build it. Either get Headway and some pack building hardware from us, or go with thundersky or Sky Energy cells and build a pack.

It'd be hard for us to build a pack remotely, as you're confined with a motorcycle.