Mamba Monster has delay with throttle input

[snellemin]

I installed my backup Mamba Monster that I had purchased a while back, but never used until yesterday. I'm am running it on 2s with a B50-5S Hacker motor. kV is about 7400. Batteries are 2s GensAce 5000mah. Gearing 46/13 in the RCM CRT.5 with 3" tires.

Problem is that when I give it throttle there are a few seconds delay for the ESC to ramp up to full speed. I have reflashed the ESC to the latest firmware, just in case and same results. I've even tried the default settings with the same results. I've swapped RX's and same thing. Rebound the ESC to the RX a bunch of times and nothing. My Radio settings are stock as well.

Suggestions anyone? Just send the ESC back?

[suicideneil]

The latest/later firmware is the problem- you need to downgrade it to an earlier version ( v1.24 is the last known 100% stable and reliable firmware ).

[snellemin]

coolbeans. I'll try it today.

[snellemin]

It's a no go. ESC is no good. Verified against MMpro. Bummer that I can't run that B50 yet.

[suicideneil]

Hmm, have you tried the MMM with a different motor, checked for any cold solder joints on any of the connectors?

[snellemin]

I've tried 4 motors and checked out everything. The connectors with the motor wires came off the RSpro, which worked fine. I'll try again today on higher voltage and see what's up.

The MMpro limits my gearing options on 2s, whereas the MMM doesn't. The RX8 is powerful and smooth, but the MMM is still king on high amp 2s setups without breaking a sweat.

I had the same problem wit a new MMM ESC.
I had to send back for the replacement.

[snellemin]

Good to know.

[fastbaja5b]

Just bought a new Flux XS for my son last night, went to power it up, same deal, hesitates on initial accelleration, battery is a Turnigy Nanotech Hardcase Lipo 65c/130c 6000mah..... and you people wonder why I am castle critical???

[Pdelcast]

Originally Posted by snellemin

I installed my backup Mamba Monster that I had purchased a while back, but never used until yesterday. I'm am running it on 2s with a B50-5S Hacker motor. kV is about 7400. Batteries are 2s GensAce 5000mah. Gearing 46/13 in the RCM CRT.5 with 3" tires.

Problem is that when I give it throttle there are a few seconds delay for the ESC to ramp up to full speed. I have reflashed the ESC to the latest firmware, just in case and same results. I've even tried the default settings with the same results. I've swapped RX's and same thing. Rebound the ESC to the RX a bunch of times and nothing. My Radio settings are stock as well.

Suggestions anyone? Just send the ESC back?

Hi Snell,

Well, the issue is this:

The controller gives throttle to the motor, the battery voltage drops quickly below 5.8V (cutoff...)
The controller sees the battery voltage drop, and throttles down to protect the battery.
The battery voltage rises again, so the controller throttles up
The battery voltage then drops again,
and so on...

until the speed rises enough that the controller can give throttle without the battery voltage dropping significantly.

Usually caused by:

Insufficient battery
and
mismatched pinion

We see this a LOT -- and the issue is easy enough to fix.

Thanx!

Patrick

[snellemin]

Originally Posted by Pdelcast

Hi Snell,

Well, the issue is this:

The controller gives throttle to the motor, the battery voltage drops quickly below 5.8V (cutoff...)
The controller sees the battery voltage drop, and throttles down to protect the battery.
The battery voltage rises again, so the controller throttles up
The battery voltage then drops again,
and so on...

until the speed rises enough that the controller can give throttle without the battery voltage dropping significantly.

Usually caused by:

Insufficient battery
and
mismatched pinion

We see this a LOT -- and the issue is easy enough to fix.

Thanx!

Patrick

Hey Patrick,

I tried several 2s packs and some behaved better with the V-cutoff disabled. Tried a 4s pack and it got better. Basically you are right about me having sucky 2s batteries for what I'm trying to achieve. I'll get a better 2s pack and try again.

Thanks for the reply.

[Pdelcast]

Originally Posted by snellemin

Hey Patrick,

I tried several 2s packs and some behaved better with the V-cutoff disabled. Tried a 4s pack and it got better. Basically you are right about me having sucky 2s batteries for what I'm trying to achieve. I'll get a better 2s pack and try again.

Thanks for the reply.

Snell,

You can try dialing in some punch control, or some torque control. Both will limit the current into the motor at startup and may relieve the problem somewhat.

I'd suggest trying a torque limit of 1.5 or so.

Thanx!

Patrick

[snellemin]

Patrick,

I tried the 1.5 torque limit setting and it just was sloooowww. I then went ahead and set the punch on 20% and all was well with the 1506 Neu motor w/19T pinion. Speed was in the 60's mph.
I then swapped in the B50 5s 7400kv Hacker motor with a 20T and did a single run with the truck dead. I blew the copper traces off my lipo. I soldered on some copper braid wires and the monster within came out. I'll reduce the punch to 30% and call it a day. Speed was nearing 70 mph. Mike RCM CRT.5 chassis stayed planted to the ground.

Thanks for the support Patrick!

[Pdelcast]

Hey Snell:

Instead of doing the punch control, try dialing up the torque control.

The main difference is torque control controls current at the motor, and punch control controls the throttle change rate.


Just keep pushing up the torque control until it feels good. I think it works significantly better than punch control -- and it will help the components survive better.

Thanx!

Patrick

[E-Revonut]

Achieving those speeds in a 5+lb 4wd truck on 2s is impressive. I wouldn't want to be your lipos though, thats putting some serious draw on them