MT44 project(ratbike 2)

^_^ I Need To See This Machine!! It SOUNDS AWESOME!!! ... Um... Krap.. I Just Thought Of Somthing... *Ahem* I Thought That A Qualifying EvPb 30+ club Bike Has To Go Under Than 2 HP D: And Of Course It Might Be The Fastest Bike In This Section... But Can We Allow It To Be An EVPB Bike? You See What I'm Saying?? I Donu =/ What I'm Typing May Not Make Sense But Just Trying To Say.... :s But Anyway... SCHWEET!!! I Would Deeply Consider Building This Bike!!! ^_^ I've Been A Fan Of Your Projects Since... Ratbike Mod.. lol I'm Even Trying To Copy It For Myself D: I Found That I Could Get Razor 10 For 100 Dollars Each... And Then I Thought "Hey... I Could Mod These Babys And Make A Local Pocketbike Gang" lol I Donu... My Friends Love My Pocketbike (Cuz I Show Off Allz The Time D So I Was Thinking Of Getting Some For Them (Family Is Loaded :S Just Bought 7 Superbikes For 1,200 Dollars Total [200 A Pop]) :S Anywayz.. I'm Typing Too Much... GOOD LUCK!

dave, exon is using1200watts on his project so it makes it ok... he could use 5 motors as long as the motors is under 1500 and under. he's still hasn't broken the rules..... exon you definitly will have the fastest evpb... i can see 45 but 60 i don't know bub.... guy's are having trouble hitting 60 with almost the same set up but they are using eteks...

OH! I'm So Sorry... Forgive Me... That Did Not Catch My Eye... Hnm... Ah Yes I Remember Now... As Long As The Motor Is Under 1500 (As You Just Said) You Could Have As Much As You Like In Your Bike!... If You Can Fit Them... Hnm... Then Great!! This Looks Like The Perfect Project For Exon To Tackle :P Oh And Again.. So Sorry Aproldan I'm Just A Kid... Kids Are Stupid... They Can't Read So Good D: And Plus... Your The Smart One ^_^

60mph?

ya i know but i do think if i got a 48-72volt controler i could mess around with higher voltage, first iwill use just 48volts then add a cell and take it up to 60volts, that should take any motor up to the rpm and torque needed, but it will for surly take the motors up to 1500w when i add the extra 12 volts though, but it should be a good show....i know about the amps that are needed to power any thing over 60 volts so that will be the only high amount i will try, couse most 400amp controlers only put out 1/3 of the max for long runs over 5 mins, i may be rong with that statment but the 400 amp controlers that i am looking at dont have prolonged amp out put couse the solid state tech inside gets hot and heat steals the amps a lot


love the pic dave, i can see the motor and it looks good!

i may do a couple capacitors for back up amps when the controler need them, couse the gell cells probly wont discharge as fst as a cap,

look exon is messing around agen with some new technology agen, lol

hope this end up helping us out more, but this is not somthing any one should attemp, a 48-72 volt cap is very poverfull, i will be using maby 2) 1ferrit caps, discharge should be a lot of amps enuff to kill, dont try this at home kids lol

here is the controler i found under 300 bucks, droolat those specs, realy read them and you will drool too, i want one as soon as i come back from the skatepark road trip next week(20 bike parts, 1 week, 2 of wich have 13ft Vt ramps with roll ins)


DCX 300 amp Controller

This motor controller is designed to work with various golf cars depending on
configuration and adapter harness used. Replaces E-Z-Go Models DCS and PDS (PDS requires PDS Adapter Wire Harness).

The DCX300 is intended to be a bolt in replacement to the standard controller found in E-Z-GO DCS cars. The DCX400 (See DCX400 Controller) bolts in too, and offers increased torque and acceleration. Both may be used in E-Z-GO PDS cars with an adapter harness that allows the existing wiring to simply plug in. Note that Tach speed limiting is disabled on PDS cars.

Programming:
This controller may be programmed to change operating characteristics such as throttle response rate, throttle type, top speed and braking force. Download the free software tool ControllerPRO. With a DB-9 serial cable and a notebook PC running Windows XP, you can customize the driving style of the car on the fly.

Model: DCX300
Type: Separately Excited DC motor controller
Battery Input Voltage: 24 – 48VDC Nominal, 60VDC max
Undervoltage cutback: adjustable, 16-30 VDC
Overvoltage shutdown: adjustable, 30-60 VDC
Armature Current Limit, 2 minutes: 300A
Armature Current, 5 minutes: 150A
Armature Current, 1 hour: 135 Amps
Field Current Limit: 30A
Operating Frequency: 18kHz
Contactor drive current: 2A max
Control voltage range:
Key, Throttle and Reverse inputs: 12 – 60 VDC, 15mA max
Reverse Horn Output: 50mA sink max
Standby Current: < 35mA
Throttle Input: ITS (inductive); 0-5K, 5K-0 Ohm +/-10%
Operating Temperature: -25C to 75C, 95C shutdown

Adjustments via software:
Throttle acceleration / deceleration rate and map profile
Armature current limit
Brake current limit
Under / Over voltage shutdown
Programmable Field Map
Top Speed & Turbo button


it is a tubo option, kickass

exon make sure this controller is for a permanent magnet motor(those are the motors we use) not a serie motor....

I DO belive it is a perm mag controler?

i will check befor i ordr it, though.....good point to make couse that would suck if i did not check and it was for a nother type of motor

WOW.... I let you guies for a week and what do I see... Exon are you planning on burning your a$$ on this rocket pocket ? It sounds awesome. Can't wait to see it working... I bet on 50Mph with the proper gearing Oh and guies sorry I was away in eastern Europe for shows jumping 8 days ago. Happy to see you again

hope you had a great time bro, sound fun

i have to find a nother place to get my frame now the place i was going to gte it from has no more in stock.....dang!

Hi, just to confirm what Armando said -
PM motors dont have a field coil...

Cheers
Phil

confirmed

ahhhhh, ya they do!
.....DAng!

"Field Current Limit: 30A"
FIELD CURENT, NOT FIELD COIL!!!!!!!!

READ BEFOR YOU POST......

ahhhh, no they dont.

And what, pray, do you think the field current flows through?

The field coil, energised by the field current, replaces the permanent magnet of a PM motor. Do you know anything at all about electric motors?

How about "Learn a bit about electric motors before you post"

Phil

Sorry didnt mean to be so patronising there. My apologies.
Basically a motor needs a magnetic field against which the armature windings can react. In a PM motor, these magnets are permanent magnets. In in a field wound motor however, they are electro magnets, in fact a coil called the field coil through which field current flows to create the electromagnetic effect. This coil can be wired either in series with the armature or in parallel, each configuration giving different torque/speed characteristics.
Permanent Magnet motors have no field coils, and therefore 'field current' simply doesnt apply.
Hope this clears it up, once again, sorry for my snappy reaction there!
Cheers
Phil

This looks like a bit of an old thread but I may have something to contribute to this. If you want all out speed, you will probably want to go with something better than lead acid. A 12 a/h rated 12 volt lead acid battery will in reality will only be 9 amp hour at a 1C discharge rate. Also at high amp draws, if you want 300 amps your battery voltage will sag considerably, probably down to 6-7 volts for a 12 volt rated lead acid battery. So that motor you are thinking of running at 60 volts will only be seeing maybe 35 volts at best.

If I were to make a pocket bike for all out speed, start with your power source, everything else is just used to convert that available power in the batteries to mechanical power ( motors, controllers, wire, etc. ). A better solution might be to look into the A123 cells that many people are using in the model aircraft world, and also in the new Dewalt 36 volt line of tools. Some problems arise when using these, such as battery balancing with multiple cells in a pack, but the benefits are worth it once these obstacles are taken care of. These cells also dont start on fire like other lithium based batteries do.

The weight advantage is also far better with these lithium cells as well as power density. With these gel cell lead acid batteries, you may see 600-800 watts per kilogram of weight for power density, maybe a slight bit more, but not much. With these A123 cells you can get 3500 watts per kilogram of weight.

Your range with the same amount of weight of batteries of lead acid will be about 5 times that with these a123 lithium cells. So if you go 15 miles now with lead acid, multiply that by 5 and thats what you would have with the same amount of weight in A123 batteries.

If you dont have the money for these cells, ( their about 9 dollars per 3.3v 2.3 amp hour cell) you can look into other chemistries like nicad, nimh, etc. this will also be better than these gel cell lead acid batteries, but will require balancing the cells from time to time, which isn't that big of a deal really.

We're thinking along similar lines it seems John, I've been looking into the A123 M1 cells. I just wish they were fatter & cheaper!
For a racebike application I was looking at 4x12v 7 AH SLAs, but under heavy discharge where the SLAs would give massively reduced voltage & A/H capacity, I suspect a 10s2p pack of A123's will hold their voltage better and would give much nearer their nominal A/H capacity. A123 Systems specify M1 cells at 30C (70A) continuous and over 50C (120A) for 10 seconds.
I think you would get most of the 4.6 A/H capacity of the M1s under heavy load, whereas the SLAs under heavy load might give only 3 or 4 out of their nominal 7A/H.
The cheapest way to buy A123s over here in the UK seems to be to buy DeWalt cordless 36v packs & split them, which is what many of the model aircraft boys are doing.
A 10s3p pack of M1s would be even better at nearly 7 A/H but at over 100 GBP per '10s' DeWalt powerpack, its getting beyond my budget. I wonder where you saw them at $9 per cell John? Thats a huge saving.
Of course as well as the performance gains you'd have all the advantages of size, weight and short charge times.
I just hope that mass-producion will bring the prices down soon.
Cheers & thanks for the comments
Phil

Phil, I usually see the dewalt packs on ebay go for about 9 dollars a cell if you win the auctions, or about 10 dollars per cell if you do the " buy it now " function. The graph that shows the A123 different discharge rates, really gives a clear indication of how exactly these batteries will perform under different amperage draws. An interesting note is that these batteries loose very little capacity at high draws and the voltage is very " flat " thoughout the discharge stage. No more declining performance as you ride your bike, once its about to die, it will happen very quickly. Also your cycle life will be dramatically improved over lead acid, 10C continous discharge rate cycles, and still 1000 cycles til 80% of initial capacity is left at 100% dod.

As far as actual power is concerned, that will depend on the length you need them to last, during a race i'd estimate it would be a good idea to plan on 10C and above discharge though.

The one matter i'm concerned about though, would be the motor performance at these rates and abuse, and the performance efficiency you would have. I haven't looked into the actual performance graphs of these pmdc scooter motors but its probably not much better than common pmdc's. I picked up a motor that I think may have some potential and if i ever get around to it would like to put maybe up to 3 of these on a bike. They are from a store called American Science and Surplus and are surplus 24 volt pmdc lawnmower blade motors. http://www.sciplus.com/category.cfm?...8&category=173

From their website :

The motor draws 4.5A no-load, and is rated at 1.5HP. Reversible. Spins approx 3200 rpm. Torque is 2150 in/oz. The motor measures 7" long x 4" dia with a 2" long x 7/8" dia keyed shaft with a 3/8"-24 bore at the top.

I am going to have to machine some end plates to make this motor usable and able to mount to a frame of some sort but it should be well worth it. For 50 dollars a motor and 50 dollars for the materials, its a 100 dollar motor, for that price its very competitive with any motor.

The plan is to run 3 of these at 48 volts or 60 volts of A123 cells, this would be peaks of 1000-1200 amps and at 60 volts, about 40 volts to the motor depending on what pack size i decide to go with. For gearing i might go with a CVT to take advantage of the variable ratios to get a higher top speed. This of course would be a drag bike, with wheelie bars on the back for safety and improved launch.