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i think i may have finished it off

Old 03-26-2009, 09:15 AM
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Default i think i may have finished it off

so last night i plugged 2 venom 5000 2s 20c lipo's into my novak 4.5hv

my truck was like lightning when compared to nimh batteries

now for the bad news, i charged the lipo's for the first time at 1 amp to make sure they took a good first charge.
i ran my blinky on each as they charged
i stopped the charge at 4.1 volts per cell
i proceeded to run the truck on the grass in my front yard
i only got about 3 minutes of run time before it seemed like i stripped my plastic spur gear
well upon futher inspection i found that all three screws that hold the end bell of the motor on were now missing
even worse 2 of the 3 wires soldered to the motor had become "un-soldered" all by themselves


so whats the deal? i mean what the hell happened to cause all this?
my novaks instruction sheet says its rated for up to 4s lipo and i was using a lipo voltage cut to protect the batteries.

i checked the batteries after i discovered my motor in pieces, temps were more than perfect and voltage was 7.92 and 7.91 on the two packs.

im just gonna take a stab in the dark and say these batteries have WAY to high of a discharge rate for my motor/esc haha

i did find three new screws for the end bell and i resoldered the wires to the motor and all is well, it still works fine but i dont think im gonna try to run it with anything more than a pair of 7 cell nimh packs from now on.
Old 03-26-2009, 10:06 AM
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Default RE: i think i may have finished it off

How many rpm's would that motor be doing on 4s?
Old 03-26-2009, 10:12 AM
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Default RE: i think i may have finished it off

The batteries only supply what the ESC requires; the batteries don't push current into the ESC; The current from the batteries is limited by what the ESC pulls. I wouldn't give up in the Lipos, that wasn't it. I think it was a motor malfunction in its own and not tied to the batteries at all.
Old 03-26-2009, 10:12 AM
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Default RE: i think i may have finished it off

Did you change the gearing? I know for instance in my old E-maxx, I run a 14-tooth pinion on that setup. You can't run the stock gearing with the Novak HV system.
Old 03-26-2009, 10:22 AM
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Default RE: i think i may have finished it off


ORIGINAL: Access

Did you change the gearing? I know for instance in my old E-maxx, I run a 14-tooth pinion on that setup. You can't run the stock gearing with the Novak HV system.



i was running 18/68
Old 03-26-2009, 10:23 AM
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Default RE: i think i may have finished it off

ORIGINAL: redfisher1974

How many rpm's would that motor be doing on 4s?


i dont know how to calculate that. lol sorry im still really new to the whole brushless/lipo scene
Old 03-26-2009, 12:30 PM
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Default RE: i think i may have finished it off

ORIGINAL: cat samich
i was running 18/68
I remember in the package I got the motor, ESC, etc. in, there was a piece of paper from Novak saying to start with a 13 or 14 pinion, watch your temperature, move up from there at your option if the temps allow for it.
Old 03-26-2009, 02:08 PM
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Default RE: i think i may have finished it off


ORIGINAL: Access

ORIGINAL: cat samich
i was running 18/68
I remember in the package I got the motor, ESC, etc. in, there was a piece of paper from Novak saying to start with a 13 or 14 pinion, watch your temperature, move up from there at your option if the temps allow for it.


thats the funny thing, this truck is a beast with 18/68 on 2 7 cells.

and running the 7 cell packs i got the motor way way way hotter, like fry eggs and bacon on the heat sink hotter.

i definitely didnt see higher than 120/130 degrees F

why would all the screws dump out of the end bell like that too?




oh and btw i said screw it and ordered the mamba monster 2200. im just gonna throw 6s at that and see how much abuse this truck will take.
Old 03-26-2009, 02:21 PM
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Default RE: i think i may have finished it off

Are you going with the Mamba Monster in the 3905 or 3906 Maxx? I shudder at the thought of 6S and a Mamba Monster vs. stock 3906 Emaxx drivetrain.
Old 03-26-2009, 02:27 PM
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Default RE: i think i may have finished it off


ORIGINAL: Dale Gribble

Are you going with the Mamba Monster in the 3905 or 3906 Maxx? I shudder at the thought of 6S and a Mamba Monster vs. stock 3906 Emaxx drivetrain.
That should last less then one set of packs.....[X(]
Old 03-26-2009, 03:01 PM
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Default RE: i think i may have finished it off

I would contact Novak and explain to them what you were doing and what the outcome was. Their customer service is top notch and they won't hesitate to have you send it back and get it replaced/repaired if the motor or ESC(or both) were defective. I have no idea why the screws would come out of the endbell unless their was some serious vibration. I would assume the motor wires came unsoldered because the motor was way too hot, but you said it was in operating temp range. Sounds like a mystery caused by a possibly defective product. Like I said, contact Novak and they'll have you fixed up in one to two weeks. They're really quick at repairing and shipping out warrantied parts!
Old 03-26-2009, 03:34 PM
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Default RE: i think i may have finished it off


ORIGINAL: Dale Gribble

Are you going with the Mamba Monster in the 3905 or 3906 Maxx? I shudder at the thought of 6S and a Mamba Monster vs. stock 3906 Emaxx drivetrain.


my 3906 shudders when i threaten it with 6s and a monster 2200 lol

but in all seriousness im going to put it into the 3905 haha i think the 3906 is getting retired here shortly in favor of something else. perhaps an e-revo or a axial ax-10
Old 03-26-2009, 03:37 PM
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Default RE: i think i may have finished it off

Solder does not just "unsolder" unless it gets very hot. A solder connection can break fairly easily though. Vibration, a cold (poor) solder joint, a poor physical connection or getting hit with something are all things that could cause a solder joint to fail.

As for the screws, I'd chalk that up to coincidence. When one screw becomes loose then I find that the one loose screw causes more to become loose. Once screws start to back out it doesn't take long for them to work all the way out. How often do you do a maintaince check for loose screws/parts?
Old 03-26-2009, 03:42 PM
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Default RE: i think i may have finished it off


ORIGINAL: DaveG55

Solder does not just "unsolder" unless it gets very hot. A solder connection can break fairly easily though. Vibration, a cold (poor) solder joint, a poor physical connection or getting hit with something are all things that could cause a solder joint to fail.

As for the screws, I'd chalk that up to coincidence. When one screw becomes loose then I find that the one loose screw causes more to become loose. Once screws start to back out it doesn't take long for them to work all the way out. How often do you do a maintenance check for loose screws/parts?

well the solder joints were the ones from novak, and as i already stated this run did not see temps out of normal range. i have had this set up hot enough to melt your skin when using nimh packs and the solder never came loose

as far as maintenance im a stickler for it. i check my trucks after every run
Old 03-26-2009, 05:18 PM
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Default RE: i think i may have finished it off

ORIGINAL: cat samich
well the solder joints were the ones from novak, and as i already stated this run did not see temps out of normal range. i have had this set up hot enough to melt your skin when using nimh packs and the solder never came loose

as far as maintenance im a stickler for it. i check my trucks after every run
Your motor should never get that hot.
Old 03-26-2009, 05:28 PM
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Default RE: i think i may have finished it off


ORIGINAL: cat samich

well the solder joints were the ones from novak, and as i already stated this run did not see temps out of normal range. i have had this set up hot enough to melt your skin when using nimh packs and the solder never came loose

as far as maintenance im a stickler for it. i check my trucks after every run

That would certainly seem hot enough to weaken solder joints, if not cause immeadiate failure. Also, a weak or flawed solder joint will pose a point of increased resistance. Increased resistance will equal increased heat so it may have been that hot at the joint and not in the whole system.
When you looked at the failed joints did they appear broken or melted or could you tell?

Just throwing out ideas and thoughts as you asked what could have happened...
Old 03-28-2009, 01:08 AM
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Default RE: i think i may have finished it off


ORIGINAL: Dale Gribble

The batteries only supply what the ESC requires; the batteries don't push current into the ESC; The current from the batteries is limited by what the ESC pulls. I wouldn't give up in the Lipos, that wasn't it. I think it was a motor malfunction in its own and not tied to the batteries at all.
But if you had a battery that was capable of 80 amps, and an ESC that was capable of handling 100 amps, you are only gonna max out at 80 amps. A battery that can handle a higher dischage rate can create more heat in the ESC/Motor.
Old 03-28-2009, 03:51 AM
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Default RE: i think i may have finished it off

ORIGINAL: Budget Monty
But if you had a battery that was capable of 80 amps, and an ESC that was capable of handling 100 amps, you are only gonna max out at 80 amps. A battery that can handle a higher dischage rate can create more heat in the ESC/Motor.
No, in reality batteries can provide 3-4 times their actual rating in terms of current, they just end up ruining themselves in doing so. The battery doesn't magically stop or current limit once it hits the maximum. Ie. a battery capable of 40A hooked to a system that draws 100A will actually provide 100A for a period, heating up and ruining itself in the process. The reason a LiPo can run hotter than NIMH is b'cos of the voltage loss from internal resistance, it's less in the LiPo.

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