Print

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

[enviro geek]

Alright so I want to build an electric motorcycle but i am in the phase of pricing and playing with stuff like that. Frankly i am not a mechanic i fail at changing oil. i understand basics of stuff and have done research into this before but i dont remember much. Im thinking i have at minimum 3000 dollars to spend not a whole lot of money but its just a guess. I have looked at two different motors one is a 48 volt and ones a 72 volt i understand 72 volt is faster and that jazz but im looking for both economy and speed. I need at least a decent speed somewhere around 60 mph and a decent amount of travel time. I dont want to go around the block id like to be able to go out and do errands or go to work something along those lines. Also chargers with a DC connector is that saying like a normal plug like that can be put in a wall or what? that was my logic if im wrong inform me if not sweet. I would like to be criticized because i have no idea really what im doing i have done minimal research. I have done most of the research before. i know i need a motor and controller and dc to dc converter batteries are where i get lost most of the time cuz i dont get the Ah thing at all. there are some kits put together by electricmotorsports.com which is cool and where i was basing a lot of things off of. I was thinking the regen braking system because regen braking helps recharge the battery... correct? i thought that was a economical idea and helpful. so here are a few links of random things i was thinking. I also dont have a vehicle in mind obviously a motorcycle but kind and stuff are negotiable if you have any ideas about where to look ive seached craigslist and ebay but neither of those really worked i was thinking of a local junk yard but idk how well that would work nor do i know if they would have anything like a full bike they have full cars so i figure a full bike wouldnt be such a farfetched thing. I also dont understand sprocket stuff? like size and things i got an excel thing that did the equation for me but i didnt get how to match the info in the chart to stuff on the internet so any help with that would be great.

here are some links i was looking at mostly from the same website:

http://www.electricmotorsport.com/store/ems_ev_parts_motors_etek-r.php

and then the chargers and batteries all link from there not hard to navigate pretty much everything but my bike research has been from here. What do you think?? thank you for any help.

[frodus]

60mph undoubtedly requires 72V in my opinion. Otherwise you'll be really sucking amps at low RPM which might be too much for those eteks.

I'd get some 50Ah lead batteries, an etek RT, an alltrax controller, and a compatible charger (or 6 individual chargers).

It won't do regen, but regen is very little on a lightweight motorcycle. On cars its useable.

what range do you need?

[enviro geek]

range is really negotiable average range like 40+ would be cool mostly just to get around town i dont forsee it taking me far distances

[enviro geek]

another curious thought on my mind was are there any like solar panel abilities for the bike itself so while riding/sitting it will charge the batteries? or would that be too complicated?

[enviro geek]

and final thought about batteries... you said lead acid is that because its the best bang for you buck? or is there a specific detail about them the makes them better for the motorcycle? also what about lithium or LiPo4 watever those are? i know they are expensive although i havent been able to find an actual price but i was still curious if theres much of a difference.

[frodus]

range is really negotiable average range like 40+ would be cool mostly just to get around town i dont forsee it taking me far distances

you're borderline for lead and lithium, i'd say maybe consider Lithium for your project. You'll need about 4-5kwh to get 40 miles.

say you have a 72V system, and need 4.3kwh, you'd need 60Ah batteries. To get 72V you'd need 24 of them. At $66 each through our website (www.evcomponents.com) it'd cost you $1584 USD plus shipping without charger or BMS.

[frodus]

another curious thought on my mind was are there any like solar panel abilities for the bike itself so while riding/sitting it will charge the batteries? or would that be too complicated?

Solar is completely seperate. That has to do with supplying your charger with the AC it needs to charge the bike. You could do it with a custom charge regulator, but its far easier to have several 300W solar panels charging a 48V Lead battery pack, hooked to an inverter to your house grid, and then plug into that.

They're not small, so onboard solar charging is pretty much gonna be impossible for now.

[frodus]

and final thought about batteries... you said lead acid is that because its the best bang for you buck? or is there a specific detail about them the makes them better for the motorcycle? also what about lithium or LiPo4 watever those are? i know they are expensive although i havent been able to find an actual price but i was still curious if theres much of a difference.

I said lead because of your budget. Overall, lithium is a better choice because of longer life and ligher weight.

Pros for lead:
less batteries to get 72V
cheaper
readily available locally
chargers are easy to get
easy to replace less batteries

cons:
lower life expectancy, which means replacing them more often
heavy
peukert effect lessens your useable capacity


lithium pros:
longer life
much lighter than lead
less of a peukert effect/more useable capacity

cons:
more batteries
requires BMS
chargers must be programmed for lifepo4
harder to source, but its getting better (we sell them)


boils down to budget. I said because you were new to this that lead would be good because its a very simple system. Once you go lifepo4, its very complicated with the BMS and connections between batteries.

[enviro geek]

alright so how do you figure out how many batteries you need. you came up with numbers but was that a guess or a calculation. like how many lead batteries would i need in comparison to lithium?

[enviro geek]

and if i were to consider the lithium how much on average does a BMS system cost??? i was looking at the specs for it on your website and it says it has a controller is that the same as a controller i would buy seperately so would it cut out the cost of that? or are they two different things... and about chargers is it better to get individual chargers or one that will i guess distribute the power? i dont really get how that works. and when looking for a charger what exactly am i looking for....

thank you for your help i know i am asking a lot of questions

[frodus]

Can you keep the questions in one post? Its much easier to answer questions inline from one reply.

alright so how do you figure out how many batteries you need. you came up with numbers but was that a guess or a calculation. like how many lead batteries would i need in comparison to lithium?

Lead = ~12V
Lifepo4 = ~3.2V

Take pack voltage you want, divide by the numbers above and you get a rough estimate on number of cells. Then there's BMS. Most BMS manage 8,12,16,24 cells at a time, so pick one that is the closest. If its higher than 24, you need a custom BMS.

and if i were to consider the lithium how much on average does a BMS system cost???

depends on your amperage requirements and budget. If you want a dumb shunt, its not that expensive.

i was looking at the specs for it on your website and it says it has a controller is that the same as a controller i would buy seperately so would it cut out the cost of that?

BMS controller is different than the motor controller. Two different things

and about chargers is it better to get individual chargers or one that will i guess distribute the power? i dont really get how that works. and when looking for a charger what exactly am i looking for....

For lead, 6 individual chargers for a 72V system is much cheaper, and you wouldn't need to balance the 12V batteries. For lifepo4, its very expensive and inefficient to get 24 single cell chargers. Its easier to get a larger bulk charger. It all depends. I like one larger charger for both types of systems, but thats just me.

they would be (i think) somewhere in the range of 600 dollars for 6 of them so if i remember correctly they last for like 400 cycles which i assumed was charges??

400 cycles at the 20hour rate. You'll be discharging them at a 1 hour or 30 minute rate and get less life out of them.

but even still with the 2000 cycles that apparently lithium gets i would never really need to get knew batteries even if i wanted to upgrade the motor and other stuff just would have to keep the same voltage right?

2000 cycles is on the high side for lithium, but it all depends on how much you abuse them (heavy current draw, often). As long as motor/controller voltage is the same as it is before, you can upgrade. They're completely different systems. Also, once you have a BMS, you never need another one unless it fails. In the long run, cost for ownership over 5 years can be close to the same with either one.

so they are worth like 5 sets of 6 lead acid? in a perfect world without any sort of self destruction that batteries get.

you could find yourself replacing lead 2-4 times in 5 years, and lithium, maybe once at the end of that 5 years? it all depends on how many COMPLETE discharges you do, and how you abuse the batteries. Its not a simple answer.

Now im mostly talking from what the internet tells me and you have actual experience in the field are these ratios near correct or anything cuz if not i want to be corrected i want to know exactly how all this will work so i can make sure i put get the right things and put it all correctly together.

This is not an exact science like math class or chemistry. It depends on many variables. Battery type, riding style, weight, terrain, rolling resistance, aerodynamics, efficiency of motor/controller/batteries/charger, density of air in different places in the world, acceleration, efficient use of coasting.......

I like my 5:1 ratio with a HUGE motor. 6:1 is better for an etek. It depends on motor and current.

[enviro geek]

ok im going to try and post everything i have questions on in this box :]

So first the BMS i would need 24 of the lithium batteries so it is a standard set up as you said depending on the price of that would probably change everything

now you kept saying about the cycles that it would depend on how harsh i was to them. now what would be considered harsh like would like "flooring it" hurt the batteries or is it just riding it too long that it gets past that recharge thresh hold?

finally battery charger are there any things to look for for wen i want to get one. I look at them and see so many things
http://www.electricmotorsport.com/store/ems_ev_parts_chargers_elcon.php
http://www.electricmotorsport.com/store/ems_ev_parts_chargers_zivan.php

those two are the ones i was looking at they are expensive so im assuming they are bulk chargers and they say stuff about 72 volts so i thought they would fit. if im missing something please make me aware because some have like 20A charger and im not exactly sure what that means amp? and then from there how to decide if thats what i need

o and you said the 72 volt e tek motor would be ok right? it would get the speed i wanted? just making sure

[frodus]

So first the BMS i would need 24 of the lithium batteries so it is a standard set up as you said depending on the price of that would probably change everything

a cheap one would cost you a few hundred dollars, a full featured one would cost much more.

now you kept saying about the cycles that it would depend on how harsh i was to them. now what would be considered harsh like would like "flooring it" hurt the batteries or is it just riding it too long that it gets past that recharge thresh hold?

more current draw = higher C rate discharge from the batteries, the higher the average C-rate, the less life you get out of the battery. If you floor it all the time, its going to make the average C-rate go up and life expectancy go down. this is with all batteries.

Overdischarging batteries also hurts their life. Overcharging batteries hurts their life. Its all three of these things.

A good BMS will protect from all three of these things, but you really only need to prevent overcharge/overdischarge with the BMS, and the controller can help keep the current (c-rate) low on the battery side.

finally battery charger are there any things to look for for wen i want to get one. I look at them and see so many things
http://www.electricmotorsport.com/store/ems_ev_parts_chargers_elcon.php
http://www.electricmotorsport.com/store/ems_ev_parts_chargers_zivan.php

get something waterproof if you can, it'l be exposed to the weather most likely. The zivan has a fan and it'l get crap inside, its not sealed. Basically you need to know if the charger can charge lithium, as it has a different charge profile. I've got a waterproof Delta-Q and it'l charge lifepo4 and lead depending on the charge profile you chose (there's 10 to chose from). You need to pay attention to voltage and current to make sure they're within range of the batteries.

those two are the ones i was looking at they are expensive so im assuming they are bulk chargers and they say stuff about 72 volts so i thought they would fit. if im missing something please make me aware because some have like 20A charger and im not exactly sure what that means amp? and then from there how to decide if thats what i need

Chargers are not cheap, not fast chargers. 72V would be the one you need for 24 cells of lifepo4, but you need to make sure it cuts off at the right voltage, ask electricmotorsport. 20A is the charge current. those thundersky cells will be able to charge at 72V 20A no problem.

o and you said the 72 volt e tek motor would be ok right? it would get the speed i wanted? just making sure

yup

[enviro geek]

ok well if its more than like 600 - 700 for a decent BMS i may have to start rethinking this(depending on how much more). im hoping to have about 4000 for wen i start doing this so that would bump up my bounds a bit. i want the best i can even tho im like a beginner because i wanna be proud of this and if im going to do it might as well go big and do it right. also i have a question about lithiums environmental impact i saw a lead acid battery with 98% recyclable materials. are lithiums like environmentally sound or are they like horrors for the environment? if you are unsure thats fine.

would this be a decent charger?
http://www.evcomponents.com/ProductDetails.asp?ProductCode=CHWP-7212

im not horribly worried about the weather element my bike/charger would end up staying in my shed till its time to be taken out. but this charger shuts off and everything wen the charge gets to 100% and has lights and jazz. its more expensive than the ELCon charger i posted before. however it doesnt say what batteries its compatible with.

thank you for practically teaching me everything haha i appreciate it greatly

[frodus]

Lithium is recyclable, not sure what percentage though, depends on the cell construction.

Thats a good charger, just got a few in. they're compatible with lithium, but we need to know the lithium battery type first.

my email is tgintz@evcomponents.com when you get ready to buy cells and charger. BMS shouldn't be much of a problem.