Puma/KMX trike at 82v A123

Jozzer

Jozzer

100 kW
Joined
Apr 19, 2007
Messages
1,069
Location
Swindon UK
Hi all, just got back from a very fun test drive on the newly rebuilt (4th time in 4 weeks!) KMX. It now sports 25 A123 cells in series, 3 paralell, giving 82.5v. Amazingly at 30A the pack voltage drops just 2.5v :D (6.6AH pack!)
No load speed is 52mph (24" wheel), and on the road it will pull past 40 nicely. it was still accelerating, but I lost my bottle and slowed down (windy day and I'm not as young as I used to be).
Motor held up well, and didn't seem to get very warm, though its hard to tell with these puma's, they dont transfer the heat out to the casing very quickly. (temp guage/cutout needed before I test too aggresivly).

I'm not endorsing use at these voltages you understand, just testing the limits of these new motors (i already smoked one....do I get a prize for being the first? :roll: )

Also, the modded 20A controller (4310 fets and adjustable current to 35A) held up well, getting slightly warm.

all in all.... YAY I like Puma's/A123s. :twisted:

I've just ordered a performance meter that is supposed to be able to measure acceleration (g-force) and 1/8 and 1/4 mile run times/speeds ( http://www.escortradar.com/gtimer-specifications.htm ) .. when it gets here I'll post some times. I'm looking forward to having a consistant way to measure performance, theres alot of guesswork going on ATM!
 
Most cool. 8)

Can we see pics of your pack and perhaps a build description (or did I miss it...?)?
 
Regrettably I didnt take any pics whilst building the pack, but I'll borrow the GF's camera to take a few snaps of the finished article later today.
You'll be pleased to know though Xyster that I soldered them much like your 18650 pack after reading your thread carefully :lol:
 
Jozzer said:
Regrettably I didnt take any pics whilst building the pack, but I'll borrow the GF's camera to take a few snaps of the finished article later today.
You'll be pleased to know though Xyster that I soldered them much like your 18650 pack after reading your thread carefully :lol:
Click to expand...

My heart throbs with joy and my ego bulges with pride. 8)
 
Lol, scary...you just keep your bulging EGO in your pocket! :lol:
 
Jozzer said:
Lol, scary...you just keep your bulging EGO in your pocket! :lol:
Click to expand...

Don't worry, I assure you there's no physical bulging -- probably because you haven't posted the pics yet. :lol:
 
Wonder if you have measured the battery current at no-load top speed for the 82.5V.
 
Current at top no load speed (54mph) is 3A. Seems alot, but then it is REALLY pushing that wheel around! Next time I gewt the chance I'll try a motor without the wheel attached (bare motor).
Heres some pics for the needy..
Theses a pic of the dead X'lyte 408 I murdered last month. For the puma you will have to wait, I need a new impact driver bit before I can take it apart for post mortem. Theres still the vague hope that the windings are OK, and only one of the phase wires parted company from the copper! (I'm not really an optomist!).
 

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Very embarrassed about the appearance of the battery pack, I had tried to build a perspex box for it last week, but it didn't survive the first road test. I'll try again soon with heavier perspex and more glue :lol:
 
Holy sweet-pieces of machine, Batman! :) Me so electrically frustrated now... :(
 
Jozzer said:
Current at top no load speed (54mph) is 3A. Seems alot, but then it is REALLY pushing that wheel around! Next time I gewt the chance I'll try a motor without the wheel attached (bare motor).
Click to expand...

82.5X3= 247.5 W at 54 mph at no-load.
Seems that it is on the high side.

Would suggest to mount the controller so that its heat-sink touching the metal frame. So the metal frame could also act an extra heat-sink.
 
Thought about that, decided that heat transfer would be minimul, and the breeze blowing direct on the controller does a better job. Doesnt get too hot in any case. @40mph the amps are a lot lower....I think its a "wind generator" at top speed....
 
See, at least he used black duct tape :wink:

I'm interested in how the performance changes when you switch the pack voltage in half.

I'm also interested in how much the controller heats up. You say it's not too bad? 4110's should work even better.
 
At half the voltage its still a nice ride. You can feel theres only half the power, but apart from a blip or two at startoff, it pulls smoothly all the way to top speed. At any voltage the motor works well, it begins to sound a bit funny at high voltages tho (humerous funny, not OMG whats wrong with that funny). the startoff "bliping" disapears at over 70v though, which is an added bonus (before you needed to be ready to help with pedals at least to 0.5 mph. Not a big deal, but noticeable)
I went with 4310's because I fancied experimenting with higher amps too, and put 4110's in the bigger controller (since it has more fets to spread the current). The big controller barely gets warm, but it cooks the puma nicely, and has since been banned from the KMX :evil: . At least the little controller has a temp cutoff! I had a small pc fan ready for the summer, but sadly since England forgot summer this year, it hasn't been needed. If I ever need to change a fet again I will go with 4110's, since I doubt I will put more current than they can manage. If I am tempted to do so I can use the 40A controller.
I picked up a couple of thermostat modules today, about the size of a mosfet. Hoping I can squeeze one in the Puma and connect it to the E-brake cuttoff so as to protect it from all the abuse. I'm a little concerned about long term reliability of this dream come true :lol:
I do have silver ductape, but was worried about being sued for copyright violation :lol:

PS...sorry guys, I seem to have verbal diahorea this week...cant stop typing.
 
Ypedal said:
I've used aluminum heat sinks from PC power supplies before.. the fins wedge into the controller's ridges perfectly.. does a good job..

Nice ride !!! I like it !!!

About the polycarb boxes.. have you seen my thread in progress ?
Click to expand...
You mean this thread? http://endless-sphere.com/forums/viewtopic.php?t=855&postdays=0&postorder=asc&highlight=battery+pack&start=45
Idd yes. (good work btw). I assumed that since my pack weighs just 5.5kg (or 4.3 if I go with just 66v) I could get away with just 3mm perspex. Seems I will have to go metal though. Thicker material makes the pack too big in that configuration (the pack is very close to being a pain in my bum on bumpy ground). I suppose aluminium would be the best bet.
Fibreglass is another option, but I've never worked with it before....
 
keep on typing jozzer, reading the thread with great interest!!!


cheers

D
 
Oh I see! How did I miss that!
That looks great, and would fix all the probs I had with box streghth. The worst part was I wanted to include the relay's and fuses in the box, which makes for strange shapes.
Beginning to wonder if I shouldn't make a box to fit the space in the trike first, then reconfigure pack to fit the box :(

TBH if it wasnt for the messy wiring I'd probably leave it like that. Its wrapped in coroplast atm, so its pretty well protected.
 
Nice Work

Where did you get the A123 from? hmm i like!! although I have my point-1 packs which are still working fantastically, no fires no smoke nothing but great performance, oh the naysayers that ripped in to me about them, 1 year later and loving them.

I make them better and fatter though! ha ha, still they are an amazing battery, A123 is rolls Royce! ha ha, glad you got your Puma rocking at 80V but amazed as well! my modified 20A controller blew really quickly at 72V, what phase connections are you using? the new Puma must get a good outing at 72V, it needs a really good test, both my modified Lipos should be able to handle it if it goes wrong, still may blow a fuse, can limp home on one pack!

Must try and meet up sometime? I have a feeling the BMX will be able to run well on 72V with the new controller, I can go video myself killing a few mopeds then!

Cheers

Knoxie
 
I picked up the A123 in dewalt packs on ebay. Theres a guy named "leatherman" selling them for £90 inc postage ATM that I got the last (fully packaged brand new) pack.
Absolutly fantastic batteries. You could easily run a 35A controller from a 4.4AH pack for a superlightweight machine, with just modest sag.
I'm using the same phase connections as maytag.
Had no trouble with the 20A controllers once I upgraded fets, currently i'm running 4310's in this controller.
A meet up would be cool, been dying to get the KMX out for a ride with another KMX :lol:
I went with NickF (who lives near) to the new forest electric bike rally, we met Mark (TH), Rich Papa, Steve Head, monster and more, real shame you couldn't make it.
 
Hi M8

Looks amazing, thanks for the heads up on the A123, by the time I need new cells they should be available to be single and I can ship them fom the states?

I run my KMX on 1 x 37V lipo, I took it out for a nice run in the week, I did 45 miles on it! amazing fun on long distances, no neck ache at all, I pumped the front tyres up to 60 psi and the rear at 50, it makes for a bumpy ride at times but the rolling resistance is so little, combine that with the reduced air resistance it rolls for ever!

I find you can put a considerable amount of force in to the pedals as you push against the seat, I am using the USPD at the moment on it, it works great and it easy to spin the rear wheel on gravel if you want to show off to spectators! :lol:

It will have a Puma in there one day I am sure, how did you hook up your A123 cells? are they still in the cases or have you split them? and is there a BMS in there? you must have to run a big chainring to keep up!

Yes must meet up with you before the bad weather hits, I have a car I can borrow and drop the BMX and KMX in and pop down, I need to get down and see Mark as well.

Cheers

Knoxie
 
My cells are all made up like xysters lithium pack. Doesnt seem to need abms at this size....so far! It seems to self balance to a fair extent. I'll do a complete cell checkover at the end of the month just to be safe tho.
Yes to the big chainring, took the smaller ones off too, just no need for them! :lol:

Your welcome down here anytime m8. Later this month I will be (slowly) opening an electric bike workshop too.....I'd value your advice on that.
 
Hi, I'm running a 48V 28A controller with 72V and a nine Continents Motor. Now I think about making a 3s2p Dewalt akkupack, whitch will be at ca. 105V. I thought about updating my controller with the 4110 mosfets and install new capacitors whitch will handle up to 100V(the actual ones are rated to 63V).

Is it all I have to do , or are there some Other things I have to consider and change?
Will the fets handle 105V?
I actually need only 28A max, thats enought for me, but what can I do to increase the max A in the controller. It would be possible with the 4110 fets. Right?

here is my bike: viewtopic.php?f=6&t=235&p=41610#p41610
 
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