[Old Goat]

Just finished my project, a 95 Acura Integra with 36 LiFEPO4 cells, a Curtis 1238 Controller and AC-50 motor. Very, very sluggish performance. No error messages. Cannot draw more than about 24 Amps. Can't get RPM above 1785. I have no idea how to troubleshoot this. Curtis documentation is slim to none and I have no reference material. It almost seems as if a governor or limiter (software generated) is kicking in. When the RPM slowly (I mean REALLY slowly) increases, it almost seems like the motor speed actually starts to back off at about 1700 RPM, doesn't matter what gear the transmission is in. The throttle pot is not perfect; it is a two wire Curtis look-alike and the range of resistance is only 45 Ohms to about 3.9K ohms but I'm quite sure this is not the only problem here. I'm going to order another (3 wire) pot soon but I want to find out what else is amiss. Is there a setup code or parameter that I need to change in the Curtis controller?

[Zak650]

Hi,

I don't know if you are familiar with EVTV but Jack has talked in previous episodes that if the cutback voltage is set too high as the pack voltage sags it sends the controller into cutback mode and limits the power output in order to protect the battery pack.

[Old Goat]

Thanks very much for the very quick response. No, sorry, I'm new to this and am unfamiliar with EVTV and don't know Jack. How can I either contact him or view his episodes on EVTV?

[Old Goat]

Thanks very much for the very quick response. No, sorry, I'm new to this and am unfamiliar with EVTV and don't know Jack. How can I either contact him or view his episodes on EVTV?

[Ziggythewiz]

Use google. EVTV

Do you know what the cutback is on the AC-50, or if it is adjustable? Check with your vendor.

[major]

Originally Posted by Old Goat

.... a Curtis 1238 Controller and AC-50 motor. Very, very sluggish performance. No error messages. Cannot draw more than about 24 Amps. Can't get RPM above 1785.....

Always double check the encoder. Secure to shaft and wires correct?

Can you view parameters? If not, how can you be sure you have the motor wired for the correct direction of rotation? Either switch motor phases with parameter setting or if you don't have the programmer, swap 2 of the 3 motor leads.

[Zak650]

EVTV is at EVTV.ME watch the original episode A Conveinient Response and then progress as much a you wish. The second Speedster, duh as it is called is Jack's first car using the Curtis controller and AC-50 motor.

[frodus]

Have you contacted the company you bought it from?

I bet it's going into limit mode, 36 cells is higher than the "stock" programming. You will likely need a handheld or PC programmer to change those parameters.

[JRoque]

Hi. Putting out only 24A and rising speed so slowly is one odd way of handling an over voltage limit. Thirty six cells @ 3.4V each is 122V. Jack has one running with 38 cells.

I would look into the suggestions already mentioned here: 1. encoder and it's connections 2. check with a programmer or PC terminal for current limit

JR

[frodus]

Actually that's exactly how it works, JRoque. Overvoltage or undervoltage both cause the car to go into limp mode. I've had direct experience with this same issue. I helped a customer with this locally and they had higher voltage pack than the normal 72V. It took us a while, but we figured out it was in limp mode. We reprogrammed the battery voltages and it immediately came out of limp mode and drove just fine. It had very slow/sluggish performance before that change and only got to about 2500RPM or so. We changed the limp mode max RPM and the motor max RPM followed. Unfortunately, one needs a programmer to change this value. I usually ask customers and change it for them before they get it, or rent the programmer to them for a couple weeks. Jack has a programmer and I'm pretty sure he needed to program a new higher voltage cutout (or he ordered it for that voltage).