Newbie on the scrounge

hi all,my name is paul,i am thinking of a electric motorcycle,what would be the best set-up,i really dont know about outputs at all,ive seen bikes on you tube using what looks like four batteries,i am using a honda cb350 sg which has a ladder style frame,the bottom half of the frame is good for the conversion as the petrol engine hangs on the bottom rails which hopefully create enough room for the batteries,looking forward to chatting and swapping ideas:D.

The number of batteries basically determines the voltage of the system. As a general rule the higher the voltage the better the performance. i.e. acceleration and top speed.

Most homebuilt motorcycle conversions use DC motors in the 48 to 72 volt range.

If you have a line on a good used motor for free or cheep, build your bike around that. New motors with the required power run between $1,000-$2,000.

Keep in mind Electric motors produce nearly full power from 0 RPM. A gas engine builds power as RPM increases. For motorcycles the required horsepower needed to cruse at 70 MPH is between 7-9 HP and torque determines how quickly you get to cruising speed. Torque is achieved by converting volts to Amps.

The speed controller and batteries determine how many Amps can be delivered to the motor at any given moment. High Amp controllers suitable for motorcycles run between $400 to $800.

Hope this helps.

Some amp explination:
A higher voltage system will draw less amps. i.e. a 72v system with 6 hp pulls 125a continuous
A lower voltage system will draw more amps. i.e. a 36v system wil 6hp puls 400a continuous in the same vehicle

The numbers I uses are just to help you get the picture.

You can’t convert volts to amps, that makes no sense at all. They are two ways to measure electricity.

Metallover is right, I did not express that accurately. As a general rule to achieve high torque requires more amps. Sometimes Amps are compared to pressure and voltage is compared to volume. But comparing electrons to liquids is not really accurate either. I guess what I am really saying is faster/further uses more $$$$$.

[I]:D[/I]cheers for details,i do have some idea,but i am not the best,i have been thinking of the 72volt idea,i am thinking of the lithium brick batteries,my plans will probably involve me changing the idea of using my honda to my yamaha fz600 frame,this to has removable chassis rails,but there seems to be more room,once again thanks for the information guys:D

Excellent thread chaps ! I’m learning every time i log on and can’t thank you
enough.
One question , and it’s a big one ; would it be feasable to build a brushless DC pulsed
permanent magnet motor on a 96 volt battery set up , at the moment i’m just
collecting some background information as i would be trying to minimise weight by
charging an electrolytic capacitator when off throttle and using it’s charge to help
initial start up (the battery bank would not be lead acid due to weight)
This post may need to be moved elsewhere as i’ve gone off on a tangent !

I am new too and would like to add that the best bang for the buck motor sounds like the Chinese MARS ME0709 it is a 72 volt motor and costs only $500 dollars. I plan on using that in my 1989 Suzuki Katana which was a 600cc bike.

The second option is the PERM 132 German 72 volt motor which you can get for $1,000. It is lighter and a bit shorter.

I believe you can over volt the motors a little, so if you can find the room for a 7th battery you could run a 84 volt system, am I correct?

[QUOTE=polygonfla;4468]Metallover is right, I did not express that accurately. As a general rule to achieve high torque requires more amps. Sometimes Amps are compared to pressure and voltage is compared to volume. But comparing electrons to liquids is not really accurate either. I guess what I am really saying is faster/further uses more $$$$$.[/QUOTE]

Almost right. Amperes are the amount of electricity, volume. Voltage is the push behind the electricity, potential. Wattage is the overall work of the electricity, amps times volts. 750 watts = 1 HP. 10 amp hour times 12v = 120 watts. 10 ah times 24 v = 240 watts. available from the battery at 100 % efficiency. Lead acid has the lowest efficiency.

If you’re interested in LiFePO4 cells, I have some on my website that are perfect for motorcycle conversions and are at good prices. I use them myself in my bike! Check it out at Kennedy Alternative Energy - LiFePO4 and feel free to let me know if you have any questions.

If you’re selling these batteries can you post information on the
advantages of your batteries , (charge time/recharge capacity /amp hours / overall voltage , the nitty gritty ) over lead acid thanks
Oh and a price guide would be cool !

Hi sure, LiFePO4 offers many advantages over Lead Acid especially in terms of safety.
[ul]
[li]They do not contain toxic and caustic chemicals that lead-acid batteries do.
[/li][li]They do not catch fire and are very thermally stable even when exposed to an external short circuit, punctured or even crushed.
[/li][li]They have a cycle life of 2000 cycles or more (they last up to 10x longer than SLA’s!)
[/li][li]They can be charged at up to 2C - that’s a full charge in just 1/2 hour!
[/li][li]They do not suffer from “memory effect” like SLA’s and NiCd’s
[/li][li]They are much lighter and smaller in volume than lead acid for the same storage capacity (High energy density!)
[/li][li]They have a shelf life of up to 5 years or more!
[/li][/ul]

A 10Ah cell that has a nominal voltage of 3.2V is only $23 at Kennedy Alternative Energy - LiFePO4. Please visit the website for more details. All cells are on sale today and tomorrow only at $3 off each cell so do not delay!