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Old 08-04-2006, 03:12 PM   #1
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Default LRP Sphere combo battery dump

Hi guys, just fitted a LRP sphere combo 3 to my mission, using new batterys 3300 nmh run time is found to be only 5.25 seconds before cut out

Spur gear 89 tooth, pinion 22 tooth, running in limited sportsman mode 24,00 rpm (within recommended roll out I think)

I have fiited a LRP cooling fan kit, speedo temp is 60 degrees, motor is about the same.

I have just discharged the remainder of the battery & got out 1000 mah before charger cut out!

Is this the norm? our club races for 7.5 mins, even with 4,300 nmh it will probably dump @ about 7mins

regards,

Chris.
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Old 08-04-2006, 03:42 PM   #2
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Make sure you are in racing mode not Lipo mode.
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Old 08-05-2006, 01:57 AM   #3
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Quote:
Originally Posted by walterhenderson
Make sure you are in racing mode not Lipo mode.
I've run with my NIMH's in Lipo mode, thats not a problem at all.


My Sphere comp isn't even that hot after 6 minutes.
I think there is something wrong with the timing/gearing.

Rob Janssen
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Old 08-05-2006, 03:05 AM   #4
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hope you get sorted soon.from our tel conversations it sounds like you should ring lrp and send it back,as it is not over heating now at 60 deg with the fan and cap and it should not dump batts as quick as that! you got a lot longer on the brushed motor ?

Last edited by yokomo ezz; 08-05-2006 at 01:52 PM.
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Old 08-05-2006, 04:57 AM   #5
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This isn't a Competition Sphere, so it doesn't have a LiPo mode setting.
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Old 08-05-2006, 08:32 AM   #6
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Just tried the same test running in modified mode & I only got 3.45 mins before battery dumps, prety grim I guess, speedo temp 45 degrees & motor 72 degrees.

I have checked set up for lipos & I belive this system has auto regognition between nmh & lipo.

On my first test in sportsmans mode, I removed the battery & discharged the cells, the charger had to remove 1000 mah before it cut out.

Regards,

Chris
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Old 08-05-2006, 08:52 AM   #7
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What is your rollout or FDR? Also, do you equalize your batteries at all? Also what are your charge settings?
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Old 08-05-2006, 04:11 PM   #8
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Quote:
Originally Posted by XrayFK
What is your rollout or FDR? Also, do you equalize your batteries at all? Also what are your charge settings?
1.8:1 Internal ratio = 7.28, I do not equalize my cells & I charge them at 3.0 amps.

I have since lowered my gearing & fitted a 20 tooth pulley = 8.01 & my run time lept upto 8.13 mins on my 3300 nmh battery pack the only thing is, it runs out of legs I guess its a compromise, might have to invest in some 4300 nmh batterys so I can run slightly higher gearing to remian competative!

The instructions guide states for touring cars with small tight tracks 10.0:1 & our track is a big fluent track with some tight bends it recommends for this type of track 8.0:1 as a starting point

I'm thinking of changing my internal ratio to 2.12:1 keeping my 89 spur, fitting a 23 tooth pinion which should = 8.19 or fitting a 24 tooth pinion which should equal 7.85

My only thoughts on that is I may not be competative against a 27 turn stock motor due to my limited 24,000 rpm in sportsmans mode! any other sugestions guys, some of our club members are running Novak SS4300 & appear to have no issues regarding battery dumping, I'm quite sure they have not changed there gearing from there original brushed set up.

Regards

Chris.
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Old 08-06-2006, 08:45 AM   #9
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Blue , My experience with using the Sportsmans limiter has taught me to not use it...
It does not quite perform as it should ..

Sometime it will stall, other times its can overheat the ESC and cus it crash, requiring it to be reprogram..

The limiter has to take power away , which mean it converts what it takes and turns it into heat for the ESC....

Use the normal modified mode , its has no issues.....

or

Try the low traction mode instead...


This mode performs rather well ...

If you limit the EPA so you can`t reach full throttle you can swear you are driving a normal brush stock motor...

It also does not have the stall problems off the line, that the Sportsman mode has....

also

Don`t think having only 24,000 rpm is a disadvatage , You still can gear the motor so that has way more speed than a normal stock motor , however it will generate a lot of heat...(bad)
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Old 08-06-2006, 09:43 AM   #10
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Quote:
Originally Posted by BlueisBetter
1.8:1 Internal ratio = 7.28, I do not equalize my cells & I charge them at 3.0 amps.

I have since lowered my gearing & fitted a 20 tooth pulley = 8.01 & my run time lept upto 8.13 mins on my 3300 nmh battery pack the only thing is, it runs out of legs I guess its a compromise, might have to invest in some 4300 nmh batterys so I can run slightly higher gearing to remian competative!

The instructions guide states for touring cars with small tight tracks 10.0:1 & our track is a big fluent track with some tight bends it recommends for this type of track 8.0:1 as a starting point

I'm thinking of changing my internal ratio to 2.12:1 keeping my 89 spur, fitting a 23 tooth pinion which should = 8.19 or fitting a 24 tooth pinion which should equal 7.85

My only thoughts on that is I may not be competative against a 27 turn stock motor due to my limited 24,000 rpm in sportsmans mode! any other sugestions guys, some of our club members are running Novak SS4300 & appear to have no issues regarding battery dumping, I'm quite sure they have not changed there gearing from there original brushed set up.

Regards

Chris.
Equalize your packs and charge at 5-6A .03v peak detect. Are you running rubbers or foams? How big is the track? 7.28 is a pretty low gearing for stock. Monsters gear around 6-6.5
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Old 08-06-2006, 10:12 AM   #11
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Quote:
Originally Posted by XrayFK
Equalize your packs and charge at 5-6A .03v peak detect. Are you running rubbers or foams? How big is the track? 7.28 is a pretty low gearing for stock. Monsters gear around 6-6.5
The track is very big not sure of its actual size, we are indoors in a massive sports hall, the track has one long straight & quite afew tight twists etc, I have played around with gearing on the brushed motor & found 7.28 to be optimum for our track, any higher gearing results in severe heat build up on motor, the sports hall has very low traction which adds to the problem, the tyres we use are rubber mini-pins.

Regards,

Chris.
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Old 08-06-2006, 10:15 AM   #12
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Quote:
Originally Posted by Wild Cherry
Blue , My experience with using the Sportsmans limiter has taught me to not use it...
It does not quite perform as it should ..

Sometime it will stall, other times its can overheat the ESC and cus it crash, requiring it to be reprogram..

The limiter has to take power away , which mean it converts what it takes and turns it into heat for the ESC....

Use the normal modified mode , its has no issues.....

or

Try the low traction mode instead...


This mode performs rather well ...

If you limit the EPA so you can`t reach full throttle you can swear you are driving a normal brush stock motor...

It also does not have the stall problems off the line, that the Sportsman mode has....

also

Don`t think having only 24,000 rpm is a disadvatage , You still can gear the motor so that has way more speed than a normal stock motor , however it will generate a lot of heat...(bad)
Hi, I take on board your comments on this one, but our club will only let members race with the brushed boys in sportsmans mode, perhaps I should of bought the Novak SS4300 system instead, but I like the different modes that the sphere has.

Regards,

Chris.
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Old 08-06-2006, 10:48 AM   #13
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Blue


Still, try the low traction mode as I said ...
They will agree its the closest you can get to a stock motor in feel and power...

Runs cooler & less rev bounce from limiter kicking in..

Reminder, the sportsman mode has issues like stutter, and can stall when the car is not moving or when staging for the start of race...
Not to mention a lot more heat for the Esc....

BDW

The sportsman mode was`nt design to be a stock motor , its just a limiter design to take away full power & rpm .....

Your bottom end power will remain a lot faster than a stock motor !
And if gear up a extra pinion or two in "sportsman",you will easily out run a similar car with a stock motor...

But .... when you use the low traction mode you get a lot less bottom or torque,which is more inline with a stock motor performance.

Then limiting the EPA keeps Rpm or top speed in check.....

Just a suggestion ,hope it helps...

I`v raced the Sphere in either mode, the low traction mode is the ticket for best performance like a stock motor...
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Old 08-07-2006, 01:31 AM   #14
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Hi Wild Cherry, can you expand on this:
Quote:
The limiter has to take power away , which mean it converts what it takes and turns it into heat for the ESC....
My understanding is that limiting the rpm of a sensored brushless esc is just a timing issue, I don't see where power is removed or why the FETs have to dissipate more heat?

Quote:
and can stall when the car is not moving
Surely this should never ever happen with a sensored brushless controller?

Any help understanding appreciated.



The tyres used in this kind of racing are 66mm diameter so the FDR may be missleading...
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Old 08-07-2006, 11:10 AM   #15
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Author
1st question
Each time the limiter has to trim power it cut off, or bounces at full throttle ..
A lot like a real rev limiter...


Each time the limiter kick`s on, it has to get rid of the power ...
The power has to go somewhere , resulting in more heat for the ESC....


Not sure how the power is really channel thought the Esc , but for sure the Esc gets a lot hotter when limiting the voltage...


2nd question

I`v race in sportsman mode , it can stall on the start line when staging for the a race...

I would say it can stall 1 out 6 times, sometime more , sometime less...
It is not predictable....

I think what is happening is the when the race starts you go to full throttle off the line , the limiter try`s to control the power, resulting in a stall....

A bit more refinement on the sportsman mode is in order from lrp....
Its never stalls in the other modes, just the sportsman mode...

I love racing with my Sphere , it the best thing to happen for racing in years...
So please understand I support the lrp....

I just would like other racer`s out there to realize the "sportsman" mode is not a "stock" motor mode , its a "limiter" for full power ....
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