Rxv gear vs tire size questions

[bizle]

Thanks Bob that makes a lot better sense to me.
What is your thoughts or opinions on the new navitas controllers?
Obviously I'm not going to run out and purchase a high-dollar controller if there's nothing wrong with the cart but I do want to be prepared just in case this controller fails.
Do you think I would be okay with the cart as it is only installing a set of 14 inch rims with low profile tires and adding a rear seat?

[JohnnieB]

Originally Posted by bizle

1. Maybe the whole reason I made the post on here is because I'm looking for some advice?
2. I'm just simply asking why I see all different years of RXV that have high-speed gears and I don't see any follow-up reviews or long-term reports?
3. I just can't see how changing the gear ratio a little bit is going to be any different than lifting it up and putting 23 inch tall tires on the same cart?

1. The AC drive system used in the RXV is Final Drive Ratio critical. Changing either the transaxle gear ratio or tire height can transition the cart out of the safe operating range.

2. Perhaps those that have done so are too embarrassed to admit their mistakes.

3. With 16.99:1 gears and 18" tall tires, the final drive ratio of an RXV is 22.65:1. If you maintain that final drive ration by selecting a gear ratio that compliments the tire height, the motor and controller won't know the difference, and neither will the regen braking, but the cart's top speed won't change.

To get the cart to go faster, the only viable option is to spin the motor faster, but with a stock final drive ratio, the motor is spinning almost 6,200RPM at 19.5MPH. To get 30.0MPH, it will have to spin a bit over 9,500RPM, which might be over the max recommended RPM for the motor.

I'm not familiar with the max recommended RPM of the AC motors used in AC drive carts, so 9.5k may be well within the operational realm. Max RPM could even be higher. I don't know.

[BobBoyce]

Originally Posted by bizle

Thanks Bob that makes a lot better sense to me.
What is your thoughts or opinions on the new navitas controllers?
Obviously I'm not going to run out and purchase a high-dollar controller if there's nothing wrong with the cart but I do want to be prepared just in case this controller fails.
Do you think I would be okay with the cart as it is only installing a set of 14 inch rims with low profile tires and adding a rear seat?

Yes, just be sure to add heavy duty rear springs if you intend on carring a heavy passenger load.

I have contacts that are not happy with the Navitas controllers, and have heard from a few here on the forum that are. I'm trying to reserve judgement on the Navitas controllers until they get some bugs worked out. The Danaher controllers were obsoleted for good reason. The Curtis controllers are much better than the Danaher, but Curtis had locked them down pretty tightly to keep us from exceeding the E-Z-GO VCL safety limits. That has since been hacked... We can turn up the stock Curtis 235 Amp controller to it's full 235 Amp per phase design limit, bypassing the 115 to 150 Amps per phase limit that E-Z-GO had set in its VCL. The Navitas has an upper limit of 600 Amps we're told. A stock Curtis controller can actually be tuned to deliver 705 Amps combined (rated power). The Navitas has the advantage of an operating system that delivers that power without having to hack the controller. We're waiting to see just how open they go with the architecture to allow us to tune it like we now can with the Curtis controllers.

[BobBoyce]

Originally Posted by JohnnieB

1. The AC drive system used in the RXV is Final Drive Ratio critical. Changing either the transaxle gear ratio or tire height can transition the cart out of the safe operating range.

2. Perhaps those that have done so are too embarrassed to admit their mistakes.

3. With 16.99:1 gears and 18" tall tires, the final drive ratio of an RXV is 22.65:1. If you maintain that final drive ration by selecting a gear ratio that compliments the tire height, the motor and controller won't know the difference, and neither will the regen braking, but the cart's top speed won't change.

To get the cart to go faster, the only viable option is to spin the motor faster, but with a stock final drive ratio, the motor is spinning almost 6,200RPM at 19.5MPH. To get 30.0MPH, it will have to spin a bit over 9,500RPM, which might be over the max recommended RPM for the motor.

I'm not familiar with the max recommended RPM of the AC motors used in AC drive carts, so 9.5k may be well within the operational realm. Max RPM could even be higher. I don't know.

Very well put JohnnieB!

Max RPM of the RXV motor is conservatively rated at 9500 RPM in the VCL. The drive maximum is 12,000 RPM, but we don't know where it will actually grenade at. When my 2012 RXV locked up in WOT runaway, VCL RPM and current limits were exceeded, and it hit that drive maximum. Thank goodness I was running the 350 Amp controller at the time, otherwise it would have blown a stock controller. I never overrode the VCL limit on RPM or current, it just happened to lock up in a mode that ignored the feedback loops for current and RPM.

[bizle]

Is this about a going rate for the Curtis speed controller conversion kit?
Would you guys go ahead and purchase a Curtis controller if you were me or should I wait and see how the Dahmer controller holds out?
I will be adding 14 inch rims with low profile tires and rear seat mainly use for a campground and to run back and forth into town lots of Street use

[bizle]

One more quick question?
What is a fair price to ask for this seat?
It is brand new and has only been sit on a couple times
It's made my ultimate buggy seating and it's over $1,300 on their website.
I'm looking for cash and a stock seat how much do you think would be fair?

[JohnnieB]

Originally Posted by BobBoyce

Very well put JohnnieB!

Max RPM of the RXV motor is conservatively rated at 9500 RPM in the VCL. The drive maximum is 12,000 RPM, but we don't know where it will actually grenade at. When my 2012 RXV locked up in WOT runaway, VCL RPM and current limits were exceeded, and it hit that drive maximum. Thank goodness I was running the 350 Amp controller at the time, otherwise it would have blown a stock controller. I never overrode the VCL limit on RPM or current, it just happened to lock up in a mode that ignored the feedback loops for current and RPM.

Wow! Anybody marketing scatter shields for RXV motors?

My stock PDS motor was only spinning a little over 8k when the armature exploded, but it wasn't the RPM that killed it. I was going downhill WOT (DCX controller - no RPM limiting) and everything was happy until I lifted my foot and the regen braking kicked in. Took out both motor and controller.

[Rooster59]

This conversation is why I have an old gas TXT with a Vegas 625. You sparky guys are ambitious.

[BobBoyce]

Originally Posted by Rooster59

This conversation is why I have an old gas TXT with a Vegas 625. You sparky guys are ambitious.

You have to have ambition when the cart and controller manufacturers want to keep owners in the dark

[BobBoyce]

Originally Posted by JohnnieB

Wow! Anybody marketing scatter shields for RXV motors?

My stock PDS motor was only spinning a little over 8k when the armature exploded, but it wasn't the RPM that killed it. I was going downhill WOT (DCX controller - no RPM limiting) and everything was happy until I lifted my foot and the regen braking kicked in. Took out both motor and controller.

I made my own scatter shield out of 3/16" 6061 T6 for the Bandolero. I'll be taking that one to 45-47 MPH on the highway. The rotor in the RXV motor has no windings or laminations. It just has NIB magnets mounted in the rotor, so it's a lot easier to build for higher RPM.