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Old 05-07-2009, 10:20 AM   #1
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Default Number of Amperes in Brushless ESC

Bigger Amp is better ?

What ESC has the highest Amps on the market now ?
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Old 05-07-2009, 10:29 AM   #2
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Originally Posted by asw7576 View Post
Bigger Amp is better ?

What ESC has the highest Amps on the market now ?
The better ESC's tend to have better Amp ratings as their FET's are a higher specification. These numbers are theorhetical and are based on what the FET manufacturer say's.

But your better off looking at their 'voltage drop' or resistance, this will tell you that ESC's specification.

What ESC's is best for you depends on what class you run etc.

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Old 05-07-2009, 11:20 AM   #3
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What about if I'm looking the best esc out there for LRP X12 2.5T with 13mm sintered rotor, hot tropical climate around 37C, and 7.4V lipo batt ??

I race modified.

Bigger amp also means less cut off ? .... assuming I want to go ultrasonic with 2.5T and 13mm sintered rotor ?
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Old 05-07-2009, 03:23 PM   #4
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What about if I'm looking the best esc out there for LRP X12 2.5T with 13mm sintered rotor, hot tropical climate around 37C, and 7.4V lipo batt ??

I race modified.

Bigger amp also means less cut off ? .... assuming I want to go ultrasonic with 2.5T and 13mm sintered rotor ?
You need one with a rating for a 2.5T motor at 7.4V, that will mean a top end expensive ESC no matter what;

LRP's SXX will only go down to 2.5t @6V

Possibly Orion's latest as well.

If your running a 2.5t with lipo then your probably just going to crash!

Just get one with the settings you want to change etc.
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Old 05-07-2009, 11:19 PM   #5
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Thanks for your insights skiddings.


I did some math. Assuming 2.5T motor with 13mm rotor can generate 780 watts of power. 780 watts divide by 7.4 volts = 105 amperes.

LRP SXX FET ratings : 768 Ampere / phase.

KO PROPO VFS BMC FET ratings : 780 Ampere / phase

NOVAK GTB FET ratings : 540 Ampere / phase

I guess even Novak GTB should be capable to carry the load huh ? .....
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Old 05-07-2009, 11:46 PM   #6
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I would still take note of what the manufacturers recommend and none of them say that you can run anything lower than a 3.5 on more than 6.0 volts. There must be good reasoning behind this, however if you're intent on blowing up a perfectly good ESC then go ahead.
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Old 05-08-2009, 05:42 AM   #7
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No one runs the Novak GTB anymore, it's spec's and real world performance just can't keep up with the latest stuff.

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Old 05-08-2009, 07:21 AM   #8
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a 2.5 on 7.4V has far more real power than 780W

we rather talk about 1.4kw!

not even with 5 cells a 2.5 makes sense ... and it sure does not with 6cells/lipo
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Old 05-08-2009, 07:49 AM   #9
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Quote:
Originally Posted by asw7576 View Post
Thanks for your insights skiddings.


I did some math. Assuming 2.5T motor with 13mm rotor can generate 780 watts of power. 780 watts divide by 7.4 volts = 105 amperes.

LRP SXX FET ratings : 768 Ampere / phase.

KO PROPO VFS BMC FET ratings : 780 Ampere / phase

NOVAK GTB FET ratings : 540 Ampere / phase

I guess even Novak GTB should be capable to carry the load huh ? .....
The new speed passion 2.0 GT output rated @ 800 amp i dont think GTB can even handle VORTEX 3.0 with 7.4v Lipo it will melt your GTB for sure
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Old 05-08-2009, 08:42 AM   #10
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Don't fall for all those super over rated numbers. All these manufacturers should start posting realistic numbers instead of going with only the maximum burst rating of a MOSFET.

Just get a ESC that you feel will be the best for your application. Choose a company with good customer service.
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Old 05-08-2009, 11:36 AM   #11
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Quote:
Originally Posted by Martin Hofer View Post
a 2.5 on 7.4V has far more real power than 780W

we rather talk about 1.4kw!

not even with 5 cells a 2.5 makes sense ... and it sure does not with 6cells/lipo
Sorry, how do you come up 2.5T motor and 7.4V will equal to 1400 watts ? ..... r u just guessing ?


This is from LRP website :

LRP X12 3.5T motor generates 698 watts

LRP X12 3.0T motor generates 797 watts

I should have type 3.0T instead of 2.5T ..... ( sorry, I didn't check lrp website ). There is no X12 2.5T motor in LRP's website.

Can you imagine a 797 watts bulb is ON for 5 minutes ?? The heat must be amazingly hot.
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Old 05-08-2009, 12:02 PM   #12
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Quote:
Originally Posted by asw7576 View Post
Sorry, how do you come up 2.5T motor and 7.4V will equal to 1400 watts ? ..... r u just guessing ?


This is from LRP website :

LRP X12 3.5T motor generates 698 watts

LRP X12 3.0T motor generates 797 watts

I should have type 3.0T instead of 2.5T ..... ( sorry, I didn't check lrp website ). There is no X12 2.5T motor in LRP's website.

Can you imagine a 797 watts bulb is ON for 5 minutes ?? The heat must be amazingly hot.
but light bulbs are 10% efficient, while brushless motors are over 90% efficient
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Old 05-08-2009, 01:13 PM   #13
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but light bulbs are 10% efficient, while brushless motors are over 90% efficient
yes..... you are right, sorry my mistake...... I check it on wikipedia they are not compareable.

Anyways.... thanks for all inputs. I will go ahead to test my GTB with 3.0T X12 motor. If it broke.... I'll buy KO Propo BMC. If it doesn't broke, good on me...... I save some dollars.
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Old 05-08-2009, 02:07 PM   #14
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no it'S not just guessing ... it's a pretty realistic value ... even if its only 1300 or 1200 it is still far too much
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Old 05-09-2009, 04:30 AM   #15
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Thanks for your insights skiddings.


I did some math. Assuming 2.5T motor with 13mm rotor can generate 780 watts of power. 780 watts divide by 7.4 volts = 105 amperes.

LRP SXX FET ratings : 768 Ampere / phase.

KO PROPO VFS BMC FET ratings : 780 Ampere / phase

NOVAK GTB FET ratings : 540 Ampere / phase

I guess even Novak GTB should be capable to carry the load huh ? .....
I have no idea why anyone thinks the speedo's can handle these currents..... Maybe for an extremely short millisecond but even your 2.5qmm wires to the motor cant handle 540A long, let alone PCB tracks, thats absolutely no way to see if the esc can handle the current.
Just check the manufacturer specs, if it says it can handle a 2.5 then rely on the fact it really can handle it.
And I'm with Martin, why do you really need a 2.5 anyway?? I know only a handfull of people that can handle it, you'd prolly be better of with a 4.5 or maybe a 3.5 on Lipo.
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