GEM eL XD Truck - Upgrades - Lithium, R4F Motor, On-Board Solar Charging, 72v to 110v Inverter, Lights

This thread mentions the same motor but with no indication of actually installing one. Other than “the guy in Florida” I may be kind of the Guinea pig here.

Based on comments from @Old_Houseboater it looks like it may be a good thing I opted for a D&D performance motor because of the higher potential RPMs at around 30 MPH. Remember, my eL XD has the 14.76:1 gears and bigger stock tires.

One question: Are higher RPMs only an issue under load on flats or uphill vs. coasting downhill @ 35 mph for example?

I also found some discussion about the motor here:
http://www.buggiesgonewild.com/electric-ezgo/95868-sepex-series-rookie-question.html
They talk about 8hp and 16.5 (at 48v) peak and typically higher torque in a longer motor. How does voltage affect HP? The motor label says it can operate at 36, 48, 72 volts but does not show HP.

Elsewhere on this site they discuss heat of this motor @ 48v.
http://www.buggiesgonewild.com/electric-ezgo/102983-high-torque-motor-getting-hot-will-bigger-controller-2.html
A couple of positive takeaways from this as it applies to my setup…

Just a technical expansion on the highlighted comments.
The Ohm’s Law formula for power that is usually seen is I x E = W. (Amps times Volts equals Watts)
However the Ohm’s Law formula that tells the tale best is: I² x R = W. (Amps Squared times Ohms equals Watts ---- or Amps times Amps times Ohm equals Watts)

*Basically, by increasing the pack voltage from 36V to 48V (a 33.3% increase) you reduce the amps by 33.3%, but reduce the heat by 66.7% (times the efficiency of the motor at the same RPM and under the same mechanical load) *

In other words the relationship between Amps and Volts is linear while the relationship between Amps and heat is exponential.

  • Good because my ~80v should run much cooler. I’ll get a heat gun just because it would be good data to have.

*What gear ratio is your differential? *
If you have stock gears (12.44:1) going to 14.96:1 will almost offset the heat problems caused by the 23" tires.

  • I have 14.76 with similar tire size, so good also.