Worth upgrading from a 9920 to a Quark 125?

[Serum]

The quark should be smooth, but your warrior shouldn't stutter when you go from 0 to WOT.

perhaps faulty cells?

[Rtsbasic]

Does it with all my packs, I don't think its the cells, they're matched 3700's, only had them since May, and have looked after them correctly with a balancing tray etc. Does it with my 3300's as well.

[Serum]

No leaking caps or a failing bec/receiver pack?

[Rtsbasic]

Using a 6v UBEC, which works fine - no stuttering on servo's. It only stutters going to WOT immediately, if I ease it in over the space of a second or so its fine. Its also fine pulling away to a medium speed, although it does cog for that split sec.

Caps aren't leaking, although there are only two on my model. 650uF 50v ones I think, not 100% though. One is easier to move around than the other, perhaps its become disconnected.

Btw do you know if the 9920 has thermal cut off? I've never encountered it so I presume it doesn't?

[Serum]

It still could be the ubec. did you tried reprogramming it, or do you have your epa set higher than it was with programming?

yes, it has got a thermal cut-off.

[Rtsbasic]

EPA's set to 100%, never saw the point in going over that with an electric. I tried reprogramming it a few days ago and haven't changed the EPA since then.

I don't have a reciever pack to hand to test with, nor any other ubec :( I'm going to order a new one with my Quark anyway so I'll swap them over and test then.

Suprised to hear it has a thermal cut-off, any idea what sorta temp it cuts off at? I've felt it get pretty hot before but its never cut-off. Mind you I'm not 100% sure what 180F feels like.

[Serum]

you need to realize that 50-53 degree C is too hot to hold. it feels like burning.

i would try a seperate receiverpack. or if you got the ability, hook up 2P of your 3700 cells.

[Rtsbasic]

True enough..think I'm going to go order a temp gun today. To my thumb theres 3 temps - cold, hot and burning.

What do you mean by 2P of the cells? You mean hook both up in parallel as a test?

[Serum]

Yeah, i doubt if they deliver the punch needed for the launch.

Running them in parallel makes them more than twice as powerfull.

[Rtsbasic]

I could run the car two batts in parallel with 5 mins of soldering.

To be honest its never been too big a problem so I've never given it much thought. But I'll run them in parallel this evening if the rain stops for 5 mins. Its probably just my batteries being a bit weak like you say.

[Serum]

That or another receiver pack. Please report back if you know more.

[neweuser]

My girls truck stutter on 14 cells running the 9xl. but i think it too is trying to draw too much juice. i need like an 7 or 8 xl...it too runs on the 9920. Anywho, i think IMO, the quarks run way hotter than my 9920 with a fan. i have run the 9920 with 16cells and my 10xl geared 18/51 and no probs. But i can't run the same gearing with my Quark...i have to go down to 16/51...

[Serum]

my 7XL doesn't stutter at all, on 12, 14, 16 or 18 cells. it's just takes off without a fuzz.

you do use a fan on your 9920 but not on your quark?

I know Daniels quarks stays very, very cool on 5S lipo (set to 70 or 75 percent) it stays quite cold, even with his 'direct drive' centerdiff.

[Rtsbasic]

Hmm, if the Quarks going to run hotter, I may not bother. With the quark because it has a solid case, I could thermal epoxy it to the roll handle on my Savage to use that as a heatsink? I'm not running any fans in my truck at the mo, and would like to keep it that way if possible, so if I put a fan on and it fails, the system isn't going to thermal..

[Serum]

a heatsink needs to have a large surface, adding a flat piece of aluminum helps a bit, but it's not the purpose of a actual heatsink.

a fan helps removing the heat.. as long as the air is moving.