Hi Everyone. I have recently converted a 2021 Polaris Sportsman 570 Quad to electric using a ME1304 motor driving a toothed belt to the original gearbox.
The problem i have is, as i don't have an engine flywheel, i don't have a pickup coil sending an AC signal to the ECU so the ECU knows what speed the engine is rotating.
With no AC signal, the digital speedo remains at zero regardless of vehicle speed.
I have overcome this by using an AC transformer to mimic the AC signal so the ECU thinks the engine is running at 4800rpm all the time, the speedo now works fine.
This has thrown up another problem because the AWD will not engage above 3100rpm.
I have been trying to find a way of fooling the ECU into thinking the engine is running between 2000 and 3000rpm but haven't found a solution yet.
If i could get the speedo to work without having to mimic the AC signal or the AWD to engage above 3100rpm, then all would work ok.
Does anyone have an idea of how to overcome these issues???

 

We have the information you seek on the ATV Connection homepage, here:

https://atvconnection.com/articles/a...speedo-issues/

 

Hi, thanks for the reply and some great advice.
I measured the pickup coil voltage from an engined quad and at 1200rpm voltage was 7vac @ 780Hz and 2000rpm voltage was 12vac @ 1200Hz.
I found on amazon a small transformer which converts 12vdc to 220vac @ 50Hz, then used a step down transformer to reduce to 20vac.
The small transformer actually output 180vac @ 2800Hz and the stepdown transformer reduced to 15vac @ 2800Hz which was connected to the cable which the pulse coil would usually plug into.
The resulting display of 4800rpm correlates with the 2800Hz applied frequency.
I have tried a sine wave generator so i could adjust the wave frequency to around 2000Hz but the maximum voltage was 0.7vac, not enough to function the bike ECU.
I don't need rpm to be displayed on the cluster as it doesn't really mean anything in the electric vehicle.
Could the brown/white wire on the plug be used to engage AWD when the thumb switch is functioned regardless of ECU/pulse coil voltage or rpm?

Thank You

 

That is a very creative workaround you devised. In truth, had you not begun with an RPM actuated AWD machine, it would have worked perfectly! It's unfortunate that the transformer converts 2800Hz to 4800 RPM. Had been a bit less, you would be good to go with your solution.

We wondered if a sine wave generator would let you tweak it just enough but feared exactly what you encountered.

Yes, bypassing the safety AWD engage circuit as we described will still allow you to engage AWD at the thumb switch regardless of RPM reading. It's a decent fix to your dilemma, just unfortunate that your speedometer reading goes with it.

Best of luck!