Difference between AXE and SR Alltrax controllers

DaveTM

Ok....so.."Learn me something here."...:

My existing AXE-4865 will put out a sustained 250 amps when I keep the pedal to the floor.

The new SR-48600 will put out a sustained 380 amps when I keep the pedal to the floor.

Is this right?

Now..assuming the above is correct, if I were to keep the "pedal to the medal" in a given situation,....say keep it floored for a time period of 45 seconds, I should "consume" more power (more stored battery power) using the new 48600 than I would using the existing 4865 controller. Yes?

Now, if my assumption(s) are correct, and I use my cart for 99% of hunting applications where I travers paths, hills, gas well roads and the like, and speed is not a primary factor for me, then what would the benefits of the new SR controller be?

BGW

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BobBoyce

Faster hill climbs is pretty much the only positive. Might shorten battery charge a bit faster due to higher power consumption at times. I say, if it isn't broke, don't try to fix it

JohnnieB

I concur with the "If it ain't broke, don't try to fix it," school of thought, as mitigated by the "There is always room for improvement." school of thought.

I'm not sure how much improvement, if any, going from an AXE-4865 to a SR48600 will make, or if it would be noticeable on the trails.

The trick is that your motor is electrically incapable of drawing the max amps either controller will pass when it is spinning faster than a specific RPM and how fast the motor spins is determined by the tire height, the differential gear ratio and how fast the cart is traveling.

During dynamometer testing, motors are loaded (physical drag) to a target torque value and then the the actual Torque, RPM, applied Volts and Amp flow are recorded. HP-Input (electrical), HP-Output (mechanical) and Efficiency (Out vs In %) are calculated from those actual measurements. Also, the applied voltage starts at 48V and is reduced by 15mV for each amp of current being drawn.

On the attached chart, the max amps the motor being tested with a 48V power source will draw at 1002RPM is 526.2A, so it doesn't matter (very much) is the controller is capable of passing 600A, or 650A, or 3,000A, the motor is only going to draw about 526A at 1002RPM, and it will draw progressively less as the RPM increases. However, at some point below 1002RPM, the higher ampacity controllers will have better performance than the lower ampacity controllers.

This may not apply to you since you probably don't climb hills anywhere near your cart's max speed on level ground, but using a controller with a higher sustained throughput might keep the cart from slowing as much from its top speed while going uphill.

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If you connect a laptop to your AXE controller while driving to your favorite hunting spot and save a datalog, you can see what your battery pack drops to under load and how many amps are drawn. No RPM data is recorded for series motors, but you can get a pretty good overview of how hard you are working your motor and controller.

Attached Images

ES-5-9 48v - SS.jpg (142.4 KB, 0 views)

DaveTM

Yeah. OK. Your confirming what my tiny grey matter was thinking. I'm quite happy with the current performance of the cart. Going up hill faster.....and faster couldn't be much faster than what I do now....would not be worth it. Besides, speed is not the need here. Getting up a hill....or frankly down a hill here is a matter of traction. For both the rear tires going up....and traction for all 4 tires coming down. The brakes can lock up the tires.....but iffin there is no traction.....spooky can go from 0 to 100 darn fast!! So...none of that has to do with the current controller....nor one that will make it go faster up hill. Or I should say.....make it noticeable.

Thanks guys.