How can I be sure I have a Smart Pie 3 not 4?

[Davidmnz]

I just bought what I believe is a Smart Pie 3. I was a bit surprised to receive the 3 and not a 4 as I bought new from the local NZ dealer. The only indications that it is a 3 are on the invoice and I can connect to it with the older software as shown in the pic (which might not show in the post - didn't show in preview). Is there any chance a Smart Pie 4 would talk to the old software? The reason I ask is that I'm not sure I'm getting full power (20 A continuous, 35 A peak, 36 V). Maybe I'm expecting too much from the Smart Pie? I expected more of a push up hills but it really needs a lot of help with pedalling to make it up the slightest slope.

[Bikemad]

Hi David andto the forum.

I would say you definitely have the Smart Pie 3 as the Smart pie 4 has the vector controller which needs both the later software and the later USB lead with a 5 pin connector for programming:



The Smart Pie 3 uses the earlier software via a USB lead with either an 8 or 10 pin connector (dependant upon its age):



The easy way to tell is to ride it, if you can hear a difference in the motor sound when you quickly open and close the throttle it will be a Smart Pie 3.
The Smart Pie 4 with the vector controller is virtually silent in comparison and the emitted sound only changes in direct relation to the wheel speed and is not affected by the amount of power being provided.

If your motor becomes discernibly noisy when you open the throttle, then it must be a Smart Pie 3.

Just out of curiosity, what size wheels do you have?

Alan
 

[Davidmnz]

Thanks Alan. It is a 3. Confirmed it "growls" under heavy load and it does have the 10 pin connector. I guess it was wishful thinking that I might have a 4. It's in an old Giant MTB with 26 inch wheels. I know I could get more hill climbing torque with smaller wheels but I'm starting to get used to the performance. I think my initial expectations were too high.

One thing puzzles me a bit. I read your thread about putting a Smart Pie in an old MTB. In the thread I think you mention setting the current to 30/70 A continuous/peak. Can the Smart Pie actually draw 30 A continuous and 70 A peak? Seems like it should be much stronger if it can. I had a look at the performance data for both 36 V and 48 V and both tables showed 15 A max. Not sure if this was externally limited by the test equipment or by the controller.

[Davidmnz]

I think I figured it out. I have a 36 V 10 AH bottle battery and assuming it uses cells rated for 2C discharge current the BMS is probably limiting the current to 20 A or less. So setting my controller for more than 20 A is a waste of time.

[Bikemad]

So setting my controller for more than 20 A is a waste of time.

I would say it's much more likely to waste battery power rather than time.

I have my "Battery drawn current" set to 18 Amps for the Smart Pie as shown on the sticker on the controller. If I put it too high, there seems to be very little additional power at the wheel in comparison to the extra power being consumed.

The Smart Pie is very inefficient under high load with high current settings, therefore more of the consumed power is basically being used to heat up the motor windings instead of being converted into useful torque.

Alan