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Old 05-09-2009, 04:52 AM   #271
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Originally Posted by over gear View Post
Does the spx have polarity protection? if i plug the battery in the wrong direction, will it fly the fets?
No top end ESC's have reverse voltage protection.

This was asked a while ago on a UK site.
Anything put into an ESC to prevent that would increase the resistance and therefor reduce it's performance.

Fit Deans or Core connectors etc that stop you from ever doing that.

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Old 05-11-2009, 12:08 PM   #272
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Originally Posted by gameover View Post
Some comparative dyno runs.

LRP SPX Stock Spec ESC
LRP X11 10.5t (ceramic bearings, extra cooling front plate)
SMC 5000mAh 28c

The current curves are very interesting (keep in mind the current reading on the Sentry is clamping above ~110A). You can clearly see the punch levels, the profile 1,2,3,4 increase in punch and it looks like (1,2,3) & (4,5,6) & (7,8) have similar timing profiles. You can also see the new Stock Spec profiles 5,6,7,8 increasing in punch, with 5,6 having a similar timing profile as profile 4 and profile 7&8 having large amounts of timing past the power peak. Any wonder you need to be careful on 7&8 with the motor pulling 30A at almost no load.

You can hopefully see why gearing down is good thing on profile 7 & 8.
Does that mean there might be even more difference in the profiles if the current wasn't limited on your test equipment?
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Old 05-11-2009, 01:26 PM   #273
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Originally Posted by stitchy View Post
Does anyone use the SPX with a DX3R or Spektrum? At first, I heard there were some compatibility issues, but not as much lately...
I run the SPX with a DX3R and have had no problems at all.
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Old 05-11-2009, 02:00 PM   #274
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Originally Posted by Skiddins View Post
No top end ESC's have reverse voltage protection.

This was asked a while ago on a UK site.
Anything put into an ESC to prevent that would increase the resistance and therefor reduce it's performance.

Fit Deans or Core connectors etc that stop you from ever doing that.

Skiddins
Or make one battery lead shorter than the other, that way you can't plug in the wrong lead to the wrong terminal
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Old 05-11-2009, 04:56 PM   #275
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Originally Posted by Skiddins View Post
Does that mean there might be even more difference in the profiles if the current wasn't limited on your test equipment?
the current wasn't limited, just the measurement of the current was limited by the Sentry. It can read to around 105A, but it doesn't restrict the current into the motor/ESC above that. It means that the current charts may not have detected the actual peak current (it may have been a little higher than 100A) and an efficiency curve wouldn't be accurate at that point.
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Old 05-11-2009, 07:18 PM   #276
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Hey all,
here's a bit of a technical question... with the coming of 1C lipo in 12th & wgt... is there a voltage threshold that is activating the radio priority in the SPX somewhere mid run?

I have been initially testing on asphalt with a SMC 4000 1C lipo, 150mah rx pack, in the nimh mode, punch at #6, motor timed roughly at 15-20* on a Novak 10.5. The car seems quite capable and then starts to get slightly soft out of the hole or lacks punch. Recharging the battery shows that about 2200ma goes back in, so it's far from discharged.

I did run a test on positive wire removed from the esc harness using both switches vs positive wire installed with the esc switch off. I found that the positive installed/esc off maintained better punch. Still, it would be nice to have a 3.2v lipo cut off for safety & consistent punch throughout the run.

Any comments? Help?

Thanks!
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Old 05-11-2009, 09:11 PM   #277
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Originally Posted by linger View Post
Max, I need to respond to this or Hebiki won't stop pestering me.

It's never a good idea to store a lipo battery (or NIMH either) fully charged. The degredation rate goes through the roof when stored that way. Anywhere between 20%-80% is good - it does not need to be that precise.

I've done testing where storing a battery fully charged can kill it in a matter of weeks/months depending on temp while just backing it off to 90% charged keeps them good for years.

High temp is never a good thing for a battery. The general rule of thumb is that for every 10 deg C, the degredation rate of the battery doubles. So storing the battery for 1 year at 20 deg C is the same as storing the battery for 6 months at 30 deg C. When the temps hit over 90 deg F in my garage - I bring my packs indoors. The practice to heat up batteries during charge is to increase performance not for longevity. The combination of high temp and long time is never good.

Lipos do not increase in voltage while being stored...umm...ever. There is something wrong with your charger or multimeter.

Sorry about the off-topic. Back to the SPX thread.
Thanks Ling for the reply! Your the LIPO-MAN!
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Old 05-12-2009, 04:35 AM   #278
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Originally Posted by Slapmaster6000 View Post
Hey all,
here's a bit of a technical question... with the coming of 1C lipo in 12th & wgt... is there a voltage threshold that is activating the radio priority in the SPX somewhere mid run?

I have been initially testing on asphalt with a SMC 4000 1C lipo, 150mah rx pack, in the nimh mode, punch at #6, motor timed roughly at 15-20* on a Novak 10.5. The car seems quite capable and then starts to get slightly soft out of the hole or lacks punch. Recharging the battery shows that about 2200ma goes back in, so it's far from discharged.

I did run a test on positive wire removed from the esc harness using both switches vs positive wire installed with the esc switch off. I found that the positive installed/esc off maintained better punch. Still, it would be nice to have a 3.2v lipo cut off for safety & consistent punch throughout the run.

Any comments? Help?

Thanks!
I would have thought that if there was a radio priority then the motor would cut completely, at least for a second or so.

What about the ESC and controller temps?

Might be better if you put the timing back to 0 and use profile setting 7 or 8, then put some negative throttle expo in to get rid of any wheelspin.

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Old 05-12-2009, 09:58 AM   #279
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Quote:
Originally Posted by Skiddins View Post
I would have thought that if there was a radio priority then the motor would cut completely, at least for a second or so.

What about the ESC and controller temps?

Might be better if you put the timing back to 0 and use profile setting 7 or 8, then put some negative throttle expo in to get rid of any wheelspin.

Skiddins
I believe that is exactly what was taking place in the lipo mode.... the car would run on the bench, but would stutter on the track. It would appear that the "lipo" mode is for 2C only, which is obviously to high of a threshold for 1C. It would be pretty slick of LRP to have yet a 3rd option when selecting power types: 1C, 2C and nimh.

Another odd situation I stumbled on; in profile #7, on the bench with no axle load, full trigger... everything heats up rapidly. Both motor and esc became quite warm in roughly 20 seconds. I put together another SPX and another motor set up the same way to repeat the test and the results were the same; got hot quick. I have to think that because it's under no load, the rev's go through the roof (even on 3.7v) and must be causing an artificial timing that creates heat. I can not imagine this happens on the track or people would be screaming about burned up equipment.

I will get to test some more on this Wed, but time is very limited and I want to make the most of it. Any tips to sort cut the process of 1C racing is much appreciated. I will set the motor at 0* on #7 with a 13.5 Duo.

Brian
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Old 05-12-2009, 12:08 PM   #280
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Set the ESC to NIMH mode, I never bother with the lipo mode as I only ever do one run on the lipo and their 'lipo cut-off' doesn't always work!

You're also correct that Lipo mode is for 2C only.

If you look at the graphs that were posted in post #249? you'll see that even off load at the top end of the rev's the 10.5 motor was drawing nearly 30A, no wonder things get hot.
You can see how close to shutdown the ESC got by using the temp readout thingy.
The closest mine has come to shutdown was 14 flashes of the blue LED (at 5 you're about to shutdown).

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Old 05-12-2009, 02:31 PM   #281
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Originally Posted by Slapmaster6000 View Post
Another odd situation I stumbled on; in profile #7, on the bench with no axle load, full trigger... everything heats up rapidly. Both motor and esc became quite warm in roughly 20 seconds. I put together another SPX and another motor set up the same way to repeat the test and the results were the same; got hot quick. I have to think that because it's under no load, the rev's go through the roof (even on 3.7v) and must be causing an artificial timing that creates heat. I can not imagine this happens on the track or people would be screaming about burned up equipment.
Brian
Brian, we've done quite a bit of testing with the SPX and profiles 7 and 8. It seems to work well in TC (and your observations are what we've found on the track) but in 12th it seems not to work so well.

The car comes out of the turn, doesn't pick up immediately, but then launches itself down the next chute. Even coming off the throttle to reduce speed doesn't seem to have a linear effect once the timing kicks in. That doesn't fit with those running in TC. Our conclusion at this point is that the timing is dynamic relating to load (current draw) and revs. No draw, no timing would explain the reluctance to pick up quickly, and more revs more timing would explain the ability to scream off down the straight! On open tracks it works well, on tight 12th tracks we've had less success.

We've found setting 6, with some motor timing, works very well indeed. Most of us are there now. HTH
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Old 05-12-2009, 05:12 PM   #282
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I hate to speculate and head scratch without real data from trackside to back facts with. What you guys are saying matches my feelings as well. I think that the SPX is wonderful in TC for 17.5-13.5. I have yet to utilize it correctly or in the same manor in 12th with 17.5-13.5... even with 4 cell. To date, it would seem that #6 is ideal, but then that does not seem any different then a Sphere Comp at #6. The brakes are way better with the SPX then a Comp.

My two planned tests are #7 with no timing rolled about 85mm on a 13.5 Duo vs a #6, 10* time rolled about 90mm. Track size is 40x80' and fairly flowing.

The other thing that is bugging me is the 25C rating of the 1C lipo pack. I am hearing of 40C packs becoming available. If that provides more "kick" without the voltage drop when the trigger is squeezed, it may also sidestep the punch issue. If the pack voltage dips below... say 3.5v.... every time the trigger is squeezed, the esc is likely not letting the motor pull any more current. I know that the 5000 mah pack I have for TC is a 40C rating and it feels pretty stout out of the hole. I know that is apples to oranges.

Anyway, that's enough. I will go hit the rug and find out and I will be back.

Brian
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Old 05-12-2009, 05:24 PM   #283
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SLOWERONE:

it sounds like you are getting to grips with the spx comp, i will run mine for the first time on saturday at cotwolds (large track)..my FDR ratio with sphere tc was 4.65, full timing,profile 6..last time there, what would you suggest for ratio for the spx comp?

4.65 was 96 spur with 43 pinion..

why do you feel profile 6 with a little motor timing works well, rather than putting it on profile 8 with no timing on motor?

from what i have seen from other people using this esc in tc's i havnt been too impressed, they look guttless and i cant help wondering if i have purchased the wrong esc... i hope im wrong and it is fantastic

if anyone else wants to also answer this post please do as i want as much info as possible before i run the car..at the moment i have geared it with 96 spur and 36 pinion with is FDR of 5.5
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Old 05-12-2009, 06:29 PM   #284
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Originally Posted by mark williams View Post
SLOWERONE:

it sounds like you are getting to grips with the spx comp, i will run mine for the first time on saturday at cotwolds (large track)..my FDR ratio with sphere tc was 4.65, full timing,profile 6..last time there, what would you suggest for ratio for the spx comp?

4.65 was 96 spur with 43 pinion..

why do you feel profile 6 with a little motor timing works well, rather than putting it on profile 8 with no timing on motor?

from what i have seen from other people using this esc in tc's i havnt been too impressed, they look guttless and i cant help wondering if i have purchased the wrong esc... i hope im wrong and it is fantastic

if anyone else wants to also answer this post please do as i want as much info as possible before i run the car..at the moment i have geared it with 96 spur and 36 pinion with is FDR of 5.5
If you are using profile 6 with SPX Stock Spec, then you are not taking advantage of its dynamic timing feature. Profile 6 on SPX is equivalent to profile 8 on Sphere TC.
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Old 05-12-2009, 06:32 PM   #285
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Have anyone tested SPX Stock Spec with Hacker E40 13.5T and 17.5T? Can you share your experience?
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