Help Please - Curtis 1268 - MAIN DROPOUT and AUX RELAY DNC

[snsrider717]

2009 Tomberlin Emerge 48V DC with Curtis 1268 & New Lithium Batteries
Purchased from a dealer that "didn't have time to trouble shoot the problem".
He thought it may be a wiring harness issue. There is no specific evidence I have found pointing to a wiring issue, but I don't know.

So, I read this forum regularly, I have a bunch of experience with all types of golf carts but don't post on here much. Any help with this problem will be appreciated. I think I have read every post on this subject on this forum and have tried everything reasonable. I am on the verge of ordering a rebuilt controller, but don't want to waste money on something that is fixable. I have the Curtis 1315 software on my computer and have connected to the controller and made a bunch of minor changes to see if anything would make a difference. The ONLY thing I can tell, is the issue seems to happen when the cart is transitioning from accel to decel (regen), but that assessment could be completely wrong. It seems like it happens more when I am running it harder (full throttle to full decel), but that also may not be 100% the case.
Sometimes I can run a half mile at medium throttle (15 mph) with no issues at all. Sometimes the MAIN DROPOUT happens at 6 mph.

No matter what I do, I cannot get these *Intermittent* MAIN DROPOUT and AUX RELAY DNC errors to go away.

I have been generally ignoring the AUX RELAY DNC and just focusing on the MAIN DROPOUT for the time being.

New Solenoid - No change.
New Batteries (fully charged) - No change.
Checked and cleaned all connections - No change.
Removed old charger (to install new lithium charger) - No change.

I have considered disengaging regen completely to see if that would make a difference.

Should I investigate switches, connections, or something else?
Has anyone else had issues like this with a 1268?

[snsrider717]

UPDATE: Just completed more testing.
I set the AUX WALKAWAY to Zero, which removes that as a variable.
The AUX RELAY DNC error did not return.

MAIN DROPOUT occurred while cruising at 20 MPH.
Generally it will immediately reset once the throttle is returned to 0.

It occurred again while backing into my driveway going less than 5 MPH.

Thanks again for any advice.

[Carryone]

hi it looks you missing throttle switch some times ?
can you do a test direct connect on switch ?
but you can only drive forward at that test

[TheCartBoy]

MAIN DROPOUT = The main contactor has opened while you are driving.

Now why did that happen?

1) Likely cause is the contactor is defective or not compatible.
Make sure the contactor coil is rated for 48V, this controller does not allow voltage adjustment for the main contactor.

2) Battery voltage dropped suddenly and the contactor ended up releasing. Check your battery voltage under load.

[snsrider717]

Thank you both for the advice.
I haven't been able to replicate a switching error, because it has been raining too much to actually run a bunch of tests. I will try a few more times when it dries up a bit.

The main solenoid is new. Same issue with both the new and old solenoid. The evidence points to it being something else.
The batteries are new. As in 2 weeks old, lithium, and incredibly strong. There is no voltage drop during testing. Also, has the same error with both the old lead acid and the new lithium batteries.