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View Full Version : Upgrade and compare Kelly 72v 400 amp controller to Alltrax SMP72400



DRZ400
22 July 2015, 1029
So now that I have the 11 Leaf modules in its time to look at the motor controller. With all (3) battery types 6, 35 AH AGM', 25, 40AH Calb's and now the 11, Leaf modules I've never pulled more than 280 amps. I've tried different settings on the Kelly but I suspect they flat out over rate it. Physically the Alltrax dwarf's the Kelly....MUCH bigger, 2x size....and it has a cooling fan. The Kelly is VERY smooth and has been reliable as a hammer on the plus side. I know my motor and batteries a capable 400+. Going to have to move everything around to make room for the bulbous Alltrax.

Stevo
22 July 2015, 2132
I'm looking forward to reading your review on this controller because I'm leaning towards this one also. Keep us posted!

SplinterOz
23 July 2015, 0337
Just to remember Kelly rate their controllers on peak Phase Amps, not battery amps. So peak of 280 from your batteries is probably right.

DRZ400
23 July 2015, 0554
Kelly's torque curves seem to relate to motor RPM and not throttle position. When cranking in full throttle from a dead start, current builds from around 100 amps to a peak of ~260-280 at ~60 mph (with my 12/72 gearing). Alltrax controllers pull much harder off the line (I'm told). I got a great deal on a used SPM72400 over at the DIY car site. The SPM's allow full customization of the speed, throttle position and torque curves.

DRZ400
26 July 2015, 0753
Peak phase? Mine is a brushed controller.


Just to remember Kelly rate their controllers on peak Phase Amps, not battery amps. So peak of 280 from your batteries is probably right.

DRZ400
26 July 2015, 0800
WHOLLY CRAP! What a difference 200 more amps make during acceleration! First twist of the throttle and you better be hanging on! My Kelly would hit 260-280 amps, but only after 45mph or so.....the SPM gives you 450amps right away! NIGHT and DAY difference! Now I gott'a figure out their torque, speed and throttle curves to match the range of my 0-5K pot. I bought the controller used an it seems the PO and my range are quite different.

SplinterOz
26 July 2015, 1941
Peak phase? Mine is a brushed controller.

So motor current then... From the Kelly site for the Brushed controller
• Motor Current Limit, 1 minute: 400A.
• Motor Current Limit, continuous: 160A.

SplinterOz
26 July 2015, 1942
Nothing beats more amps :)

DRZ400
27 July 2015, 0559
At full throttle, (no FET switching, 100% duty cycle) motor & battery current are equal....could never get more than 280 amps from it. On the plus side, its a very smooth reliable controller. ALLTRAX put in the ability to regulate current as a function of speed in the SPM which I don't think they had in the AXE.


So motor current then... From the Kelly site for the Brushed controller
• Motor Current Limit, 1 minute: 400A.
• Motor Current Limit, continuous: 160A.

Stevo
27 July 2015, 0855
I have a 0-5K pot Magura throttle, so I'm hoping you will post how you program the interface adjustment.:confused:

DRZ400
27 July 2015, 0912
No brainer....select 0-5K on throttle options page. They have an adaptive throttle feature that monitors your throttle range (so if yours goes from 200 ohm to 4900 ohms) it automatically sets these as 0 and 100%.

Nuts & Volts
27 July 2015, 0919
At full throttle, (no FET switching, 100% duty cycle) motor & battery current are equal....could never get more than 280 amps from it. On the plus side, its a very smooth reliable controller. ALLTRAX put in the ability to regulate current as a function of speed in the SPM which I don't think they had in the AXE.

Keep in mind that full throttle does not mean 100% duty cycle. Unless you're above base speed then the controller still needs to use the duty cycle to control current (ie limit current). And thus motor current does not equal battery current.

Above base speed the controller will be at 100% duty cycle at full throttle. The battery voltage and motor voltage will be equal and its this principle that will limit current.


Sent from my iPhone using Tapatalk

DRZ400
27 July 2015, 1022
Sure....like I said no FET switching. Dead stop full throttle on, no PWM. Full power limited by fets RDSon.

podolefsky
27 July 2015, 1023
To add to what Kyle said ^^^^^

You have to have switching at full stop. Otherwise the motor would see full voltage at 0 RPM, no BEMF or PWM to limit current and the motor would receive 1000s of amps (until either the motor or the controller blew up).

Here's the thread I reference whenever this comes up:

http://elmoto.net/other-parts/1301-pwm-controllers.html?highlight=controllers+work

DRZ400
27 July 2015, 1103
Getting unnecessarily complicated...nobody really cares much about motor current anyway. What is useful is what your CA reads from the battery during acceleration (both in V sag & current). In my case my motor is good (useful) for about 450 amps. My Batteries probably ~500. My old Kelly couldn't deliver more than about 280 battery amps so it was my weak link. The SPM hits 450amps off the line and PULLS MUCH harder (violent in comparison, and much more fun!) than the Kelly.

podolefsky
27 July 2015, 1226
It is as simple as it needs to be, and no simpler. The current that your CA reads will not tell you how hard you will accelerate. If you want to know why the Alltrax is doing better, you have to think about motor current. No point in arguing, it's just a fact.

DRZ400
27 July 2015, 1246
Agreed...the motor current its getting from the battery now that the controller is capable of delivering it. Like you said...no point or desire in arguing. How's it going with your Leaf cells?

podolefsky
27 July 2015, 1359
The Leaf cells are beautiful. I admire them every time I walk by the shelf they are still sitting on. Sigh...

DRZ400
27 July 2015, 1413
Well....you have my thanks for evaluating them early on! I choose the Leaf cells over the 60ah calbs after viewing your test results. I only have 6 cycles on them, no BMS, however I only charge to 88.5 volts and my deepest discharge has been 35 Ah so far. At full charge they all read 4.02 volts +-.003v. It seems like the discharge curve isn't as flat as my Lifepo4 were. I can only go to 90 volts because of my controller....if they stay balanced I'm going to go up to 89v which according to the graphs I've seen may give me 5 more ah.

DRZ400
28 July 2015, 0821
It is as simple as it needs to be, and no simpler. The current that your CA reads will not tell you how hard you will accelerate. If you want to know why the Alltrax is doing better, you have to think about motor current. No point in arguing, it's just a fact.

So your point is the motor current isn't influenced by the battery current during initial acceleration? Interesting....easy to prove. As a test, if I limit my battery current to 250amps and leave the motor current limit at 450amps my initial acceleration shouldn't change since my motor current/torque will be the same as your graph suggests?

podolefsky
28 July 2015, 0853
So your point is the motor current isn't influenced by the battery current during initial acceleration? Interesting....easy to prove. As a test, if I limit my battery current to 250amps and leave the motor current limit at 450amps my initial acceleration shouldn't change since my motor current/torque will be the same as your graph suggests?
Basically right. I'll be interested to see the results of your test.

Sent from my SAMSUNG-SM-G850A using Tapatalk

podolefsky
28 July 2015, 0904
It seems like the discharge curve isn't as flat as my Lifepo4 were.

Yup. Lifepo4 are flat(ish), and they come to rest around 3.3V regardless of SOC. Other chemistries are more "slopey". Their rest voltage changes with SOC and it drops very little after you stop charging. Which means you can't do the trick where you charge over 90V and then let the cells rest to below 90.

DRZ400
28 July 2015, 1042
Just what I'm seeing. I charge to 88.5 volts.....next day its at 88.4 volts. I thought this was due to me not fully charging to 92.4 so as to purposely avoid the steep up slope of charge curve.

podolefsky
28 July 2015, 1652
Yeah, if you charged to 92.4, it would end up sitting there (or maybe 92.3). You should be able to charge to 89.9V and the Alltrax will turn on.

Lunchbag
29 July 2015, 1746
Immediately after I charge my 11 modules to 91.2V they indicate 91.2 on the CA. 24 hrs later they indicate 90.7. The good news is that the AXE7245 operates at all of those voltages including 91.2. I don't know if the SPM will do the same.

I'm wondering if the drop from 91.2 to 90.7 is characteristic of the batteries, or due to draw from my system. I believe the only draw I have is the 0.7W load to sustain the unswitched 12V. But when I left the bike for a couple weeks it was down another volt or more. So I'm wondering if I have another draw - perhaps current flows through the precharge resistor? I thought once the capacitors are charged, the current would stop flowing. Does anyone know? Diagram attached:

https://electriccycle.files.wordpress.com/2015/02/drive-system-wiring-diagram.jpg

DRZ400
30 July 2015, 0630
You certainly will have some current thru the pre-charge as well as the DC/DC idle draw. Should be easy to measure from you B+ output. I only charge to 88.5 volts because I NOT using a BMS....I'm purposely staying away from the steeper side of the charge slope that occurs ~4.1v per cell.