justyjuice

I have been looking into how to match my motor, with my ESC with my servo and battery so they will all run well! how are you doing the match to make sure everything works together.. I have read in some articles to start with your motor but it calls for what the kv value is but im finding that certain info to make the calculations are missing.. for instance I have the following:

MOTOR:
540-M4 REEDY 7.5T

Cells: 1-2S LiPoDiameter (mm): 35.9

Length (mm): 50.3

Shaft Diameter (mm): 3.15

Weight (g): 160-170

There is no information on the KV value or the Voltage of the motor so how do I figure out the esc to use or if the battery is safe?? the battery I order is:ORION
Charge Rate: 5C

Chemistry: LiPo

Capacity: 5000 mAh

Voltage: 7.4V

C-Rates: 110C

Connector: Gold Tubes 4mm

Balancer: Tubes

Length: 94mm

Width: 45mm

Height: 22mm

Weight: 217g


Hope someone who knows what they are doing can help with this so I don't ruin my electronics.. lol

justyjuice

what is my motor kv value or what is my motor watts for a reedy 540-m4 is the 540 the watts?

DirkW

iTrader: (1)

No, 540 is the size.

Backyard RC

Here's some basic info on brushless motors.

Understanding R/C Brushless Motor Ratings

the rc guy

I dont see how this site will help op.since your site is reference a 4600 to 12 volts we all know thats a NO NO...

the rc guy

Ok it clearly tells you its a 2cell motor or 1 cell.. So we will go with 2 cells. thats 8.4v full charge. wont stay that high long.. motor kv is not listed correct you can guess go with others as a comparison(I think best so 6100+).more like 6500 kv . so 52,000 rpm ..now you need to power motor with a esc. Id like to see 100 amps or more(me I go the highest I can afford. servo)what this going in?) that will determine how much Torque 1 wants or needs.Gotta power servo at peak times holding a line in a 180 switch back with rollers at end of turn.so if it says it will draw 3.2 amp it can draw wat more close to 7..so I run a Ubec(20amp) always (after I remove center rx plug wire from esc).

justyjuice

haha thanks buddy !

justyjuice

Thank you Backyard RC... but the motor I bought doesn't say the KV value on the motor, or in the spec sheet ... nowhere to be found... so im having trouble figuring out how to do my setup... no kv no rpm ... maybe im missing it somewhere?

justyjuice

Thanks buddy... but I thought 2 cells is 7.4V ....? I guess the actual is 8.4v? ... so you just use 6100 kv as a base line if you don't know...doesnt this throw off all your numbers? my battery says 110c discharge rate does this mean my esc has to be be a certain number to handle in term of Continous Current so I don't fry it? .. the esc im considering is a 150A? below are the specs:Reedy Specifications:

Voltage input: 2S LiPo

On resistance (mOhm): 0.105

Continuous current (A): 150

Dimensions (mm): 38.5 x 36.9 x 19.5

Weight w/o wires and fan (g): 44

Motor limit: 3.5T

BEC: 6.0-7.4V/5A

Fan: Optional

the rc guy

I used 6100 as what I could find with the lowest 7.5T I could find...

Alexv2024

iTrader: (2)

7.4v is the average voltage of a 2s lipo. All rechargeable batteries are listed like that.

An ESC max amp rating is just that, the max not what it'll pull out of the battery all the time. Most modern esc's have a built in BEC thats fine for two servos typically used in 1/10 cars and is more powerful than older stuff.

Quality motors like the Reedy m4 or similar are only rated in turns as you can change the KV and characteristics of the motor a lot with timing and rotor changes.

What are you putting all these parts in? It'd make it a lot easier for specific recomendations

Backyard RC

My apologies

the rc guy

if you are concerned about exact # then you have your motor dynode y a known company or you get a motor analyzer that will give you all the Numbers you need..Ive purchased up to 5 motors all the same make model and had a wide variance in kv from 1875 to 2300 at about 15 degrees timing...take same motor 5 years later they fall way behind in kv
a 7.4 volt lipo is for users to know its a 2 cell lipo and will have a max voltage of 8.4 and lvc should be at 7.80 volts I run mine to 7.60 no issue.. a High voltage lipo will be A 7.6v 8.65 max voltage a A123 cell is 3.6volts max but can be abused a lot more Have many 12 + years sit there then use n they are great...then the Lion not applicable.

justyjuice

Thanks so much!! that makes a lot of sense..... I am putting the reedy into a 2wd Associated B6.6 D .... I am planning on buying all the good stuff but I just feel uneasy about spending all this money without really understanding what im doing.. im kinda guessing and its making me feel uncontrollable .... this stuff is not cheap and there are sooooo many variations/options that im kinda throwing a dart at the wall.... so I had to pull the trigger on something and as per suggested buy the Team associated manual the M4 is a great racing motor ... so I bought that and a suggested brushless servo... so im trying to build from there...I sure I can keep buying what the manual suggests but I I really want to understand why.... and what ESC I need and what is the right battery to get so it all runs bad ass without overheating and destroying everything...... so I can make a calculated decision..... thanks guys for all the support !! I hope my questions help other rookies out there!! lol

justyjuice

I guess Im more concerned about burning out and destroying my motor and sending too much power to my ESC and making my battery swell... I keep hearing about all these people destroying their expensive electronics because of a bad setup.. I will buy a temp analyzer.. but going from volts to amps to rpm to C's and Milliamp hours to timing and variable kv values and variable battery voltage.... this is really really confusing for a rookie I must say.. I don't even know what a A123 cell is or an lvc? They used to put the kv value on a motor and now they don't which makes it even more confusing... a lot of reading I guess ... is there an easier method to understand all this? what is the process everyone is using? I guess they say to start with the motor... at least that's what im reading ... but when there is no KV value or rpm value what the heck ...lol ... now I gotta buy a motor dynode or motor analyzer?