go_away

Author Topic: bigger batteries = more power?  (Read 3096 times)

0 Members and 1 Guest are viewing this topic.

Offline cooldogTopic starter

  • Supreme Robot
  • *****
  • Posts: 751
  • Helpful? 4
  • be nice to nerds, one day they will be your boss
bigger batteries = more power?
« on: November 08, 2007, 11:20:18 AM »
i am useing 4AA batteries to control my servos but if i use more volts will the servos be  stronger/faster ??? :'( ???
« Last Edit: November 08, 2007, 11:29:34 AM by cooldog »
robot will rule the world and i will be building them
-admin

favorite web sites
http://www.societyofrobots.com/
http://www.instructables.com/

Offline bukowski

  • Robot Overlord
  • ****
  • Posts: 219
  • Helpful? 0
Re: bigger batteries = more power?
« Reply #1 on: November 08, 2007, 01:20:57 PM »
Yes and no. Faster, yes, but weaker.
 It is OK to drive a motor at over-voltage (as long as it's not too much). You gain the benefit of greater motor speed, but you get less torque out of the motor (EG if you doubled the voltage thus doubling the motor speed, you half the torque) The stall current increases propotionally with the motor speed.
Also, when you double the voltage, you are at risk of quadrupling the heat generated in the motor and circuit, leading to a meltdown of your system.

-Buk

Offline cooldogTopic starter

  • Supreme Robot
  • *****
  • Posts: 751
  • Helpful? 4
  • be nice to nerds, one day they will be your boss
Re: bigger batteries = more power?
« Reply #2 on: November 08, 2007, 09:20:55 PM »
okay but does my reciver contol current to my servos
 
robot will rule the world and i will be building them
-admin

favorite web sites
http://www.societyofrobots.com/
http://www.instructables.com/

Offline ed1380

  • Supreme Robot
  • *****
  • Posts: 1,478
  • Helpful? 3
Re: bigger batteries = more power?
« Reply #3 on: November 08, 2007, 11:25:55 PM »
servos have little circuitry inside, so doing over voltage will fry them
Problems making the $50 robot circuit board?
click here. http://www.societyofrobots.com/robotforum/index.php?topic=3292.msg25198#msg25198

Offline frank26080115

  • Supreme Robot
  • *****
  • Posts: 322
  • Helpful? 2
Re: bigger batteries = more power?
« Reply #4 on: November 09, 2007, 12:08:43 AM »
Yes and no. Faster, yes, but weaker.
 It is OK to drive a motor at over-voltage (as long as it's not too much). You gain the benefit of greater motor speed, but you get less torque out of the motor (EG if you doubled the voltage thus doubling the motor speed, you half the torque) The stall current increases propotionally with the motor speed.
Also, when you double the voltage, you are at risk of quadrupling the heat generated in the motor and circuit, leading to a meltdown of your system.

-Buk

Hey are you sure that's right? I could swear torque have never decreased in any of my motors before when I upped the voltage.

Offline nottoooily

  • Full Member
  • ***
  • Posts: 91
  • Helpful? 3
Re: bigger batteries = more power?
« Reply #5 on: November 09, 2007, 01:09:25 AM »
Yes and no. Faster, yes, but weaker.
 It is OK to drive a motor at over-voltage (as long as it's not too much). You gain the benefit of greater motor speed, but you get less torque out of the motor (EG if you doubled the voltage thus doubling the motor speed, you half the torque) The stall current increases propotionally with the motor speed.
Also, when you double the voltage, you are at risk of quadrupling the heat generated in the motor and circuit, leading to a meltdown of your system.

-Buk

No offence, but that's a load of bollocks.

Except the last sentence about overheating. That's usually the limiting factor which prevents you overvoltaging a motor in the first place. You're right that the voltage itself isn't a problem (insulation won't break down until it's much higher), rather it's the extra heating caused by the extra current caused by the extra voltage.

But to the OP, yes you can increase performance but you'll have to worry about both the motor and the electronics, either of which could fail. If you don't care about reliability and destroying them, the best way is crank it up and see what happens, if you do care, that's what data sheets are for :P


Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,660
  • Helpful? 169
    • Society of Robots
Re: bigger batteries = more power?
« Reply #6 on: November 09, 2007, 07:57:45 AM »
4AA is about 4.8V

You can use 5AA to get 6V without any problem. Above that and you will get overheating problems.

Increasing voltage increases both torque and rpm.

bukowski, you got confused with gearing, which trades torque for rpm :P

Offline ed1380

  • Supreme Robot
  • *****
  • Posts: 1,478
  • Helpful? 3
Re: bigger batteries = more power?
« Reply #7 on: November 09, 2007, 06:05:12 PM »
if you add more voltage rpm and torque will increase

if voltage stays the same, but you use gearing to increase rpm 2x then torque is 2x weaker
Problems making the $50 robot circuit board?
click here. http://www.societyofrobots.com/robotforum/index.php?topic=3292.msg25198#msg25198

Offline bukowski

  • Robot Overlord
  • ****
  • Posts: 219
  • Helpful? 0
Re: bigger batteries = more power?
« Reply #8 on: November 14, 2007, 11:18:46 AM »
whoops, i went back and reread that chapter. Im an idiot, disregard everything i've said.

Offline Jdog

  • Robot Overlord
  • ****
  • Posts: 259
  • Helpful? 3
Re: bigger batteries = more power?
« Reply #9 on: March 29, 2009, 11:28:07 AM »
4AA is about 4.8V

You can use 5AA to get 6V without any problem. Above that and you will get overheating problems.

Increasing voltage increases both torque and rpm.

bukowski, you got confused with gearing, which trades torque for rpm :P
Isn't 4 AA 6 volts unless they are rechargeable? I use 4 AA and I get 6 volts.

Offline offy

  • Supreme Robot
  • *****
  • Posts: 340
  • Helpful? 1
Re: bigger batteries = more power?
« Reply #10 on: March 29, 2009, 11:40:55 AM »
4AA is about 4.8V

You can use 5AA to get 6V without any problem. Above that and you will get overheating problems.

Increasing voltage increases both torque and rpm.

bukowski, you got confused with gearing, which trades torque for rpm :P

4AA normal batteries are 6v
4 cells are 4.8 volts (Thats why 6v rechargeable batteries have 5 cells)

Offline superchiku

  • Supreme Robot
  • *****
  • Posts: 953
  • Helpful? 5
  • cooll
Re: bigger batteries = more power?
« Reply #11 on: March 29, 2009, 01:38:30 PM »
dnt give more than 7.2v they willfry.. . .
JAYDEEP ...

IT AND ROBOTICS ENGINEER

"IN THE END IT DOESNT EVEN MATTER"

Offline SmAsH

  • Supreme Robot
  • *****
  • Posts: 3,959
  • Helpful? 75
  • SoR's Locale Electronics Nut.
Re: bigger batteries = more power?
« Reply #12 on: March 29, 2009, 02:26:57 PM »
yup, servos cant take more than 7.2 normally. and is there a reason this was resurrected?
Howdy

Offline Jdog

  • Robot Overlord
  • ****
  • Posts: 259
  • Helpful? 3
Re: bigger batteries = more power?
« Reply #13 on: March 29, 2009, 07:38:20 PM »
yup, servos cant take more than 7.2 normally. and is there a reason this was resurrected?
I'm stupid :D

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,660
  • Helpful? 169
    • Society of Robots
Re: bigger batteries = more power?
« Reply #14 on: April 08, 2009, 12:53:10 AM »
4AA is about 4.8V

You can use 5AA to get 6V without any problem. Above that and you will get overheating problems.

Increasing voltage increases both torque and rpm.

bukowski, you got confused with gearing, which trades torque for rpm :P
Isn't 4 AA 6 volts unless they are rechargeable? I use 4 AA and I get 6 volts.
1.2 volt for NiMH cells, 1.5 volt for alkaline cells

 


Get Your Ad Here