Using 2S Lipo with 7.4v servo

[Mattmatt]

Hi,
I have an Arrma Nero Big Rock and i upgraded the servo. My new servo is a compatible with 6v and 7.4v but i would like to use a 2S lipo to reach 7.4v.
I plug in the servo on this 2S lipo but it didn't work and i don't know why.
Do you have any idea ?

Thanks

 

[Sledgehog]

Servo voltages are referring to the BEC on your ESC, not your battery voltage. Most Arrma ESCs come with a 6v BEC stock.

 

[Mattmatt]

Servo voltages are referring to the BEC on your ESC, not your battery voltage. Most Arrma ESCs come with a 6v BEC stock.

View attachment 32028

yes i know, i use 2x3s lipo battery, but 6v with the stock bec is not enough, i need 7.4v, that's why a connected only my servo on a 2s battery, but it didn't work, and i don't know why

 

[Toiletpimp]

yes i know, i use 2x3s lipo battery, but 6v with the stock bec is not enough, i need 7.4v, that's why a connected only my servo on a 2s battery, but it didn't work, and i don't know why

Your don't need 7.4 v. Your servo will work just fine on 6v.

 

[Mattmatt]

Your don't need 7.4 v. Your servo will work just fine on 6v.

Yes, i know, but i would like to compare the difference between 6v and 7.4v

 

[Sledgehog]

Your servo runs off the BEC voltage of your ESC. Your servo stock BEC only puts out a max of 6v. In order to put out the required 7.4v for the higher servo performance, you need to do one of two things:

1) Install an additional BEC that supports 7.4v output such as this: https://www.amazon.com/Castle-Creations-Bec-Switching-Regulator/dp/B000MXAR12

2) Buy a whole new ESC that has a built in BEC higher than 6v.

Also as Toiletpimp just stated, you really don't need to make your servo 7.4v, 6v is most likely fine as is. You really won't see much improvement or massive difference unless you were in a serious racing environment.

 

[Cheapbastard]

Your servo can operate up to 7.4v a fully charged 2s lipo is 8.4v. You need a BEC (by esc or stand alone) to regulate voltage to 7.4v.

 

[Michael2]

Your servo runs off the BEC voltage of your ESC. Your servo stock BEC only puts out a max of 6v. In order to put out the required 7.4v for the higher servo performance, you need to do one of two things:

1) Install an additional BEC that supports 7.4v output such as this: https://www.amazon.com/Castle-Creations-Bec-Switching-Regulator/dp/B000MXAR12

2) Buy a whole new ESC that has a built in BEC higher than 6v.

Also as Toiletpimp just stated, you really don't need to make your servo 7.4v, 6v is most likely fine as is. You really won't see much improvement or massive difference unless you were in a serious racing environment.

Question for you, I have one of those cheapo servos a lot of people talk about, the 20kg one. I also have an Max10 SCT combo which has the built in bec option of 6v or 7.4. My cheapo servo is rated at 6.8v. The speed of the servo is slow, slower then the factory 3s servo currently. Would I fry the servo if I changed the BEC to 7.4 or is it close enough to the 6.8v that the servo is rated, where it would be fine? I do take the Senton to the track so the additional speed would definitely be nice.

 

[Mattmatt]

Your servo runs off the BEC voltage of your ESC. Your servo stock BEC only puts out a max of 6v. In order to put out the required 7.4v for the higher servo performance, you need to do one of two things:

1) Install an additional BEC that supports 7.4v output such as this: https://www.amazon.com/Castle-Creations-Bec-Switching-Regulator/dp/B000MXAR12

2) Buy a whole new ESC that has a built in BEC higher than 6v.

Also as Toiletpimp just stated, you really don't need to make your servo 7.4v, 6v is most likely fine as is. You really won't see much improvement or massive difference unless you were in a serious racing environment.

I will try the BEC, i found one cheap BEC. The problem with a new ESC is : the diff lock motor will support more than 6v ??

 

[tjf]

You can hook the servo power and ground to the 2s lipo but yo still need to hook the signal wire to ch. 1 on the receiver, it should work and the servo will perform better.

 

[cootertwo]

Interesting thought. I guess you could run a separate battery just for the steering servo, kinda like some do for the fans, though I've never heard of it. You'd probably have to keep a common ground between the add on battery, and the receiver, and disconnect the red, power wire from the lead going to the servo, and connect it to the positive on the add on battery. But like said above, a fully charged 2S lipo is likely to be more than 7.4 volts. Might work ???? I'm late to the show.... yes, like above....

 

[Mattmatt]

Interesting thought. I guess you could run a separate battery just for the steering servo, kinda like some do for the fans, though I've never heard of it. You'd probably have to keep a common ground between the add on battery, and the receiver, and disconnect the red, power wire from the lead going to the servo, and connect it to the positive on the add on battery. But like said above, a fully charged 2S lipo is likely to be more than 7.4 volts. Might work ???? I'm late to the show.... yes, like above....

i think that it didn't work because of the 8.4v in the 2s lipo battery, and my servo is made only for 6 to 7.4v, there is maybe a security and lock the servo when an high voltage is detected, i don't really know. I will try the BEC. I should try to discharge my 2s battery to reach 7.4v and try again.

 

[Mattmatt]

You can hook the servo power and ground to the 2s lipo but yo still need to hook the signal wire to ch. 1 on the receiver, it should work and the servo will perform better.

Yes, but it didn't work, maybe because of the 2s lipo battery voltage ? (8.4v)

 

[slick2500]

You can hook the servo power and ground to the 2s lipo but yo still need to hook the signal wire to ch. 1 on the receiver, it should work and the servo will perform better.

Channel 2 is for the esc not channel 1, remember 1 to turn 2 to burn.

 

[Toiletpimp]

Correct. I switch out my stock motor and esc for a tekin setup for racing. It makes a difference but I can only tell on the track in tight corners...

 

[tjf]

Yeah, steering servo signal wire to ch. 1

 

[rockclimber]

most high end servos can be ran on 8.4v even though it says 7.4, but always best to check servo description to make sure.
newer generation HV servos should be fine