Seeing a strange loss of power at intermediate speeds, almost as if a gas motor was missfiring. Ramps up to speed very fast, at about 20mph or so, if I take my foot off to coast then put it back down to regain speed it starts sputtering. It will catch up but, it sputters all the way.
Lithium cells settle to 92.8v
Programmed T2 (Controlled Acceleration is now set to 16)
Do you still have the BMS in the car or are you just running the balance boards now? Wondering if it could be the BMS cutting power.
Running both the BMS and the Balance boards. BMS is setup to charge only, meaning it is not controlling the discharge through the car. Im leaning towards the settings in the controller, they were copied from IMS and I think they are too aggressive with the Lithium Conversion. When controlled acceleration is set to 12, it will spin the tires from a stand still!
Gotcha, I asked because I’m running the same BMS as you and similarly only have it setup to manage the charger however when I took it out for the inaugural test run the car went five feet and died. A few seconds later I drove another five feet and it died again. I had my tablet connected to the BMS via bluetooth and could see that I had one cell that was tripping the low cell voltage power cut due to voltage sag while driving. I lowered the cutoff voltage setting on the BMS and was able to run up and down the street just fine. I was surprised that the BMS could cut power to the motor as I thought it would only cut the charger.
I have seen that as well in testing, but mine has never died most likely because it is set up as charge only. If you drop past the low voltage allowance it will cut the remaining capacity and the alarm will go off. I keep mine at 2.5v lowest voltage and low voltage alarm at 2.6v. With voltage sag, it will hit it sometimes but very very rarely. I am seeing my problem more when the car is completely topped off, I fully charge at 20amps, then almost trickle it at 2.5amps.
What year is your car? We are doing my friends 2014 with the same setup minus the balance boards. At slow acceleration he gets a code 45. Turn the key off then on it clears it. But only at a slow creep does he get the code.
Code 45 may be from a weak transistor in controller. Made worse at high voltage.
I had the stutter problem with super high voltage. 72v on my 48v Tomberlin. I could not figure out how to tune it out, so I reduced the voltage to stock.
Only a matter of time till someone loses a control running high voltage.
Hey Dave, code 45 is on a 2014…Not ready to cross that bridge yet. The stuttering is on my 2002 with a T2 controller. I am not getting any codes, Im guessing it has something to do with IMS programming being to hot. Im going to dial everything back to stock programming except for MPH overspeed and see if it is still happening.
Could the accelerator pedal be an issue? I have noted it seems more sensitive since I did conversion and also maybe a flat area on acceleration that I can sometimes feel at partial throttle.
Thought about that as well…I tested the pot and its working accurately. Ive tried rolling onto the throttle as well but its no help either.
I have a similar experience after installing the blue D&D motor. My suspicion is that its ramping current faster than the old motor and so the field current reduction is kicking in and out causing an oscillation. I need to play with those settings but haven’t had time so I just don’t hold it to the floor when accelerating. If you figure it out please be sure to post back and I’ll do the same.
That’s what I was thinking on mine, but I could not tune it out.
Set all programming back to a stock T2 with the exception of controlled acceleration at 18 and mph over speed at 255.
Had 28 of Dave’s green cells at 94ish volts and headed out. I still had some stuttering at about 12-13 mph, primarily while slowing to that speed and trying to accelerate. Only had a few incidents qand it pulled out of the lag much quicker than before I changed from the IMS settings.
Not sure if this mean anything but with my LED headlights on I had the lag, when I ran my LED fog lights with the head lights it ran perfect. As the miles racked up, no lag at all, even with lights off.
Mine was stuttering at 30 mph or so. I am not home now, but seem to remember changing the error compensation and that fixed my stuttering. I still have a code 45 issue that I have learned to deal with. I can put it in turf mode, stomp the pedal, and switch to high once I reach 15 mph. Or, I can just do a gradual start. I am running at 96 volts.
Setting my T2 controller to all the stock settings seemed to help, but its still happening, seems to be only at top charge. Decelerating to around 17mph or so then hitting it to speed up. Motor bogs and sputters but will slowly gain speed.
Im getting a 45 error on my friends 2014 when accelerating from a full stop very slowly. If you mash the accelerator, it doesnt happen.
The best “fix” might be to cut back a cell. We are pushing these higher than is prudent.
22s is where I like to be. That’s only 6v higher than a stock setup might see.
Would this be for the T2 controller or for the 2014 with the code 45? Or both?
As we are pushing the limits some respond better than others nearing 100v. If it works fine, if not, a little less voltage should fix it.
Might be a programming work around. No one has taken the time to work on it.
Now that I have a bunch of miles on your green cells they are holding a higher charge. I may back the chargery charger off some and see what happens.
Mine does it less when not at full charge and only with the blue motor. I’m pretty sure I can tune it out but need to get motivated to try. I read something somewhere on here about the Error Correction adjustment. I think its a matter of finding the right balance between the Min Field Current, Error Correction, Field Weakening Start and maybe the Armature Acceleration Rate. Error Correction says its to reduce ripple in field current… which is exactly how I would describe what I’m feeling. Must get ambitious soon!
@Mr.Vern My error compensation is set to 10, which I believe is stock. Reading the GL2 Tech for a T2 controller, it says it should be set to 0. IMS settings are 32 as well as a few others that I have seen. Im going to set mine up to 32 and see what happens.
My other settings for reference…
Min Field Current: 85
Error Compensation: 10
Field Weakening Start: 43
Controlled Acceleration: 18