RXV Lithium conversion gets controller over current error

[gojira]

Much appreciated. Pack is sporting 2 gauge, upgraded when the 350 amp controller went on.

[BobBoyce]

Oversized tires really can cause unseen issues with these RXVs.

OK, there is no workaround to lower the low voltage cutoff threshold that is available to an OEM level programmer. Of course, I would go in and fix the problem at the master settings level to accept the wider voltage range for the Lithium pack chosen. 2 guage should be large enough. Is your Lithium pack a single pack, or 2 in parallel?

Beyond that, the only option that I can see OEM programming-wise would be to limit accelleration and current draw. Use a less aggressive Accell option for your chosen profile, or go in and adjust the values in Parameters/Current Limits/Power Limiting Map...

In that menu, lowering the PL Nominal Speed from 1800 to 1200 and the Delta Speed from 550 to 400 should further compensate for the 22" tires, by putting the current limiting map in play at lower RPMs

In that menu, advance to Drive Limiting Map...

If you lower the percentages so that power applied to the motor is reduced at Nominal, Plus Delta, Plus 2xDelta, Plus 4xDelta, Plus 8xDelta, your voltage drop will be lowered under accelleration.

I know, that partially defeats the reason for the 350 Amp controller upgrade, but the master limits are kicking in here and the only way to get at them is with an advanced Curtis programming station, such as the one that I have...

I'm normally tweaking values the other way, to increase performance of the Curtis controllers, while leavng the stock current limits in place. I just don't like the really lame limits that E-Z-GO put in place in their VCL!

[gojira]

Tremendous sigh. I found a manufacturer in NV who who sells 12v lithium drop-ins. When my lead pack started showing signs of age I undid my 6-8 volt conversion, put the old 12 volt tray back in and dropped in 4 new lithium 12 volts. Goodbye maintenance & sluggish performance. Hello....average performance? Darn. Decision time, advanced programming station or the Navitas controller?

This is going to become an issue for EZGO in the future as Lithium replacements start getting cheaper. Lots of RXVs out there on 12 & 14 in rims!

I cannot thank you enough for you assistance here. Local dealer simply doesn't have the experience on this front. I'll give your suggested parameters a try and let you know.

Again, thank you.

[BobBoyce]

Originally Posted by gojira

Tremendous sigh. I found a manufacturer in NV who who sells 12v lithium drop-ins. When my lead pack started showing signs of age I undid my 6-8 volt conversion, put the old 12 volt tray back in and dropped in 4 new lithium 12 volts. Goodbye maintenance & sluggish performance. Hello....average performance? Darn. Decision time, advanced programming station or the Navitas controller?

This is going to become an issue for EZGO in the future as Lithium replacements start getting cheaper. Lots of RXVs out there on 12 & 14 in rims!

I cannot thank you enough for you assistance here. Local dealer simply doesn't have the experience on this front. I'll give your suggested parameters a try and let you know.

Again, thank you.

You have another option...

You can ship your RXV controller here in a Priority Mail medium flat rate box. I can put it on the bench, set the undervolt cutout setting to whatever value you want it set to, and I can send it back to you in the same box. I can also enable Freedom Mode on it for you. I don't charge members here to do RXV controller programming. All I ask is that you pay for the return shipping. We can chat on the phone during the programming session so I can get your input on how you want your advanced settings set.

You would find that a Navitas controller cannot perform as good as or better than even a stock Advanced programmed Curtis controller.

A few of the RXV guys here are running at up to 35 MPH with their stock 235 Amp Curtis controllers that I reprogrammed.

Bob

[gojira]

Your offer is beyond generous, greatly appreciated and eagerly accepted. Drop me your contact info at gojira_lj@yahoo.com & I'll follow up with you directly.

[BobBoyce]

Originally Posted by gojira

Your offer is beyond generous, greatly appreciated and eagerly accepted. Drop me your contact info at gojira_lj@yahoo.com & I'll follow up with you directly.

email sent

[Riso]

Originally Posted by BobBoyce

You have another option...

You can ship your RXV controller here in a Priority Mail medium flat rate box. I can put it on the bench, set the undervolt cutout setting to whatever value you want it set to, and I can send it back to you in the same box. I can also enable Freedom Mode on it for you. I don't charge members here to do RXV controller programming. All I ask is that you pay for the return shipping. We can chat on the phone during the programming session so I can get your input on how you want your advanced settings set.

You would find that a Navitas controller cannot perform as good as or better than even a stock Advanced programmed Curtis controller.

A few of the RXV guys here are running at up to 35 MPH with their stock 235 Amp Curtis controllers that I reprogrammed.

Bob

[Steve390Gold]

Originally Posted by BobBoyce

You have another option...

You can ship your RXV controller here in a Priority Mail medium flat rate box. I can put it on the bench, set the undervolt cutout setting to whatever value you want it set to, and I can send it back to you in the same box. I can also enable Freedom Mode on it for you. I don't charge members here to do RXV controller programming. All I ask is that you pay for the return shipping. We can chat on the phone during the programming session so I can get your input on how you want your advanced settings set.

You would find that a Navitas controller cannot perform as good as or better than even a stock Advanced programmed Curtis controller.

A few of the RXV guys here are running at up to 35 MPH with their stock 235 Amp Curtis controllers that I reprogrammed.

Bob

Quick question - are those individuals pushing 35mph spinning the motor to 9,500rpm or higher or are they accomplishing this with larger tires/gears? I thought the stock curtis programming didnt allow any motor speeds above 6000ish rpm thereby limiting one to 19.5mph with stock tires ala freedom II?

Also this overcurrent/undervoltage thing, im a little confused about. Is there a way the curtis 235/350 controllers can manipulate all the current a lithium pack can supply without having to govern down things? Because the main reason i went with a navitas was to allow usage of 72v to reduce current consumption and to have much more user control.

Can a curtis be programmed to allow use of 72v or even 72v from a lithium pack?

[BobBoyce]

Originally Posted by Steve390Gold

Quick question - are those individuals pushing 35mph spinning the motor to 9,500rpm or higher or are they accomplishing this with larger tires/gears? I thought the stock curtis programming didnt allow any motor speeds above 6000ish rpm thereby limiting one to 19.5mph with stock tires ala freedom II?

Also this overcurrent/undervoltage thing, im a little confused about. Is there a way the curtis 235/350 controllers can manipulate all the current a lithium pack can supply without having to govern down things? Because the main reason i went with a navitas was to allow usage of 72v to reduce current consumption and to have much more user control.

Can a curtis be programmed to allow use of 72v or even 72v from a lithium pack?

35+ MPH is best achieved with tires of 20.5" diameter. When one goes larger, it takes more current to achieve the same speed, and you top out early in the current vs speed curve with the 235 Amp controller. We never take it over 9500 RPM, even though the motor and controller OS are technically capable of 12,000 RPM. The 9500 RPM is a VCL limit, not an OS limit. Basically, the controller, as designed by Curtis, is capable of 100% duty cycle at its rated current, but E-Z-GO chose to throttle them back, likely for warranty purposes. When a Passkey is used to enable Freedom Mode, the program in the passkey reads the profile set and the max MPH settings, does a bit of calculating, and cuts back on the max current setting that the RXV is allowed to draw. The more aggressive the profile and the higher the speed it is set for, the more the max current is dialed back. These settings are in the top 2 master menus, one assignable by a Factory level programmer, and the highest level one, only by a Development level programmer. Both of these are checked by the VCL, and lower level programmers cannot even see that they exist. When you set your current curve, you are seeing what you assume is 100%, but that 100% is 100% of the locked current level. So say it was in Profile 4 and the max speed set to 14 MPH, as I've seen, 100% max current is actually about 60% It will trigger an overcurrent error if you try to exceed that!

What I do is go in there and set those limits to 100% of the controllers rating, all the way down the line. That means that a 235 Amp controller can deliver 235 Amps per phase, ie X 3 = 705 Amps of total 3 phase power! Of course, it's not the same as 705 Amps of DC, but it is still quite impressive. You have to be careful of how you set your profiles and accel rates, because you can end up pulling wheelies or snapping axles. Not only do I take bottlenecks out of the accell side of things, I give a corresponding boost to the decell and braking side of things. With more Go, you want the capability of more Woah!

Now, as for the max voltage, default energy burn-off resistor cut-in is set to 67 volts. Max setting is 80 volts. Without the resistor, you are liable to overvolt the controller and damage it. Both of the Undervolt and Overvolt values are settable, ie the values required to trip those error codes. I have not tried pushing an RXV controller to 72 volts. You must remember, 72 is a nominal number... Full charge would be higher.

I'm thinking his pack is dropping in voltage under the heavy demand that a 350 Amp RXV controller is capable of. If I lower his LVCO setting, his issues might resolve. Going oversize on tires does have negative impacts on performance. At least he's resolved the overcurrent error. If I take those limits out of the way, that might resolve his overcurrent error at such a low value as it seems to be. I won't know until I go live on the controller and check what the settings are. Worst case is if Freedom Mode was turned on with a Passkey. Easy enough to fix though.

[Steve390Gold]

So a curtis 350 with a good lithium pack can be programmed to use the full potential of the controller, you just need to have a high enough level programmer to do so? Btw - wheelies sound AWESOME!! lol!!


So am i to understand that an rxv should run just fine without the resistor, resistor control module, and heat sink however there could be over voltage issues with regeneration braking?