New Savage is cutting out durring accleration.
 

Hi,
My new brushless Savage is cutting out when I try to apply fast throttle. It's almost as if the ESC is cogging but I don't think that's the problem. My set-up is as follows:
MambaMax ESC w/ UBEC
2-2S2P Lipo (2-8000mAh MaxAMPS)
Feigao 540C 8XL
13T/47T gearing (started with a 15T pinion)
Weight: 13lbs
Temps have been below 120F.

If I slowly give throttle the truck will continue to response proportionally without suturing or stopping. But if I give quick trigger pulls the truck will usually jump forward a few times and stop or if I get it going by starting off slowly it'll sometime studiers when it hits 2nd gear.

What could be the problem? These 8000mAh MaxAmps should be able to keep up with the high amp draw and I've seen a lot of other brushless Savages with a similar set-up as mine. :002:
Any ideas?

Thanks,
Tom

It can be the batteries dropping too far in voltage. Try it once with the cut-off disabled.. If that's it, please report back..

I disabled the cut-off voltage today. Same problem. I'm puzzled.

Tom

Have you tried to change punch control and timing?

Hi,
No, I have not. I just update my ESC I see that this is now an option. But I wanted to figure out why this is happening 1st. I will try punch control and hope that it'll fix the problem....it should. But I don't think I should be having the problem to begin with.

Thanks,
Tom

I have heard of other having such a problem. They changed a few settings and it helped out alot. Hope it works for you.

I've changed the punch setting from 0% to 30% and didn't notice much of a difference. I then moved it up to 60% and noticed some improvment but it's still not great. I still have to baby the trottle to keep it smooth and once it hits 2nd gear, it starts gittering again.

This testing has been done on very short dry grass or concrete, i.e., high traction. When I test it out on my slippery basement floor there is no hesitation, no studuring at all.....the wheels start slipping and start ballooning right up :)

So is this strictly my 8000mah MaxAmps and/or my connection/wires not supply the current the motor/esc is calling for?.....or could it be my ESC. Would moving up to a different ESC fix the problem???

Thanks for the help,
Tom

Did you try moving the timing to a lower setting to?

Well setting the timing to the lowest value help tremendously! It's 70% better. Now I just need to find that other 30% to make it perfect.

Thanks,
Tom

What about punch control to 100%?

I tried 100% this morning. It's not any better than the 60% setting, if not worse as it doesn't cut out any less but has even less punch then before.

Do you think the cause is my ESC or my battery/cable set-up? I'll move up to a beefier ESC if it'll fix the problem. I still can't beleive that 8000mah MaxAmp batteries couldn't keep up with the amp draw and I think my gearing is low enough.

Thanks,
Tom

Well the lvc cut off it wouldn't matter if batts did.
It could be the esc. It could be a bad joint in connectors to.

I have one thats acting similar. Mine is pulsing power (very similar to a glitch), I think its motor related on mine. Fresh charged packs work best on mine. Thought it was a glitch so I put my nomadio in it and it still did it. Everything looks perfect, but motor wires could possibly be the culprit...not sure though.

Move the start power to the lowest setting.

I'm still not happy with it. Setting timing to the lowest setting helped out a lot but it still not right. The last thing I tried was directly soldering the ESC and motor wires together.....didn't help.

I have a 2nd new mamba max I have for a crawler project and I'm going to see if there's any difference using this one. If not, I guess I need a different ESC.

......I'll look into what I have the start power set at also.

Thanks,
Tom

What connectors are on the battery? You might try changing them/resoldering them and even shortening the wires while you are at it. Sure sounds like a bad connection/battery issue.

But it could be anything really.

You have a fat truck but still the MM should be ok... my CRT is almost 12lbs and I have never seen this.. and others have a similar setup to yours wihtout a problem.

Is it cold where you are? Is the battery at least at room temp?

This is how I have the batterys wired. Tell me this is my problem ;)
http://www.baltimoreboyz.us/images/misc/bat.JPG

I also ment to add that I've my latest gear ratio was 9/49. Didn't help. Before I was at 13/47 but my motor and ESC never get hot.

Thanks,
Tom

Nope.. The deans are good plugs.
Have you got some NIMH cells you can test? the batteries should be up the task though.

have you got a loose receiver pack to test? (not with poor 1.5V alkaline cells, but with nimh cells)

you did remove the red wire going from the speedo to the receiver?

It would be nice if you could test it with an Eagletree Datalogger!

If you can, try different batteries.

Do your lipos get warm?

I do have good NIMH's. A few pairs. It was one of the next things to try. My LIPOs only get slightly warm but only after extended use (< 90 F). The LIPOs have been at room temp when I use them.

I do have the red wire cut on the ESC....using a 5amp ubec but I'll try a rx pack. Any chance the rx has anthing to do it it? I'm using the stock AM rx that comes with the savage. I have a Spektrum rx for it but havn't installed it yet?

Thanks for the help!
Tom

Sounds like a lot of good options to try!

I found the problem!!!!!! I was still using a on/off switch between the ESC and rx and as I was going over all the wires while installing the Spektrum rx I noticed a very small cut in the switch wire. It was a deep enough cut that at least half the wire was severed. I pulled the switched out.....never really needed it anyway....and all my problems are gone!!!!!!

Thanks for the help and ideas!

Tom

Terrific!

Good to hear you fount the solution!!

now go out and have fun!

Atleast it wasn't noting major.