My Creation! His name is DR-6

Discussions regarding building a walking robot at home. Most of the robots participating at Robo-One competitions are custom fabricated.
38 postsPage 3 of 31, 2, 3
38 postsPage 3 of 31, 2, 3

Post by bonmot » Tue Mar 09, 2010 4:58 pm

Post by bonmot
Tue Mar 09, 2010 4:58 pm

billyzelsnack wrote:Why do you say.. drop down to somewhere near 8.2v? To take in account the voltage of the battery under load? From my understanding Lipo's should easily hold above 3.2v/cell under load, especially in robotics applications which require much less continuous and surge current compared to typical RC applications.


I agree with Billyzelsnack. I use LIPO's for my helicopters. Current is 10A to 30A for my small size chopper. 3.2v/cell is already heavily heavily loaded.

If talking about 10A for the robot walking, we should be able to easily see >3.5v/cell before using up to 70% capacity of the batteries.
billyzelsnack wrote:Why do you say.. drop down to somewhere near 8.2v? To take in account the voltage of the battery under load? From my understanding Lipo's should easily hold above 3.2v/cell under load, especially in robotics applications which require much less continuous and surge current compared to typical RC applications.


I agree with Billyzelsnack. I use LIPO's for my helicopters. Current is 10A to 30A for my small size chopper. 3.2v/cell is already heavily heavily loaded.

If talking about 10A for the robot walking, we should be able to easily see >3.5v/cell before using up to 70% capacity of the batteries.
bonmot offline
Robot Builder
Robot Builder
Posts: 18
Joined: Wed Mar 21, 2007 11:00 pm

Post by mic2 » Tue Mar 09, 2010 5:41 pm

Post by mic2
Tue Mar 09, 2010 5:41 pm

bonmot wrote:
billyzelsnack wrote:Why do you say.. drop down to somewhere near 8.2v? To take in account the voltage of the battery under load? From my understanding Lipo's should easily hold above 3.2v/cell under load, especially in robotics applications which require much less continuous and surge current compared to typical RC applications.


I agree with Billyzelsnack. I use LIPO's for my helicopters. Current is 10A to 30A for my small size chopper. 3.2v/cell is already heavily heavily loaded.

If talking about 10A for the robot walking, we should be able to easily see >3.5v/cell before using up to 70% capacity of the batteries.


Guys,
8.2v is the power cut-off voltage NOT the load voltage! 3cell li-po is 11.1v when fully charged you will get a bit more. When using li-po battery you’ll have to use a battery monitor board to prevent it over discharging, I would recommend not to setting the threshold too low and damage the battery.

For a safety zone each cell shouldn’t drop more than 1v to be trigger the power cut-off point e.g. 3 cell =3v 11.1-3= 8.1v however you can set the voltage higher to achieve a longer battery life.

Anyway I have corrected my bad English. :wink:
bonmot wrote:
billyzelsnack wrote:Why do you say.. drop down to somewhere near 8.2v? To take in account the voltage of the battery under load? From my understanding Lipo's should easily hold above 3.2v/cell under load, especially in robotics applications which require much less continuous and surge current compared to typical RC applications.


I agree with Billyzelsnack. I use LIPO's for my helicopters. Current is 10A to 30A for my small size chopper. 3.2v/cell is already heavily heavily loaded.

If talking about 10A for the robot walking, we should be able to easily see >3.5v/cell before using up to 70% capacity of the batteries.


Guys,
8.2v is the power cut-off voltage NOT the load voltage! 3cell li-po is 11.1v when fully charged you will get a bit more. When using li-po battery you’ll have to use a battery monitor board to prevent it over discharging, I would recommend not to setting the threshold too low and damage the battery.

For a safety zone each cell shouldn’t drop more than 1v to be trigger the power cut-off point e.g. 3 cell =3v 11.1-3= 8.1v however you can set the voltage higher to achieve a longer battery life.

Anyway I have corrected my bad English. :wink:
mic2 offline
Savvy Roboteer
Savvy Roboteer
User avatar
Posts: 85
Joined: Thu Mar 01, 2007 6:52 pm

Post by bonmot » Tue Mar 09, 2010 5:50 pm

Post by bonmot
Tue Mar 09, 2010 5:50 pm

Hi MIC2

You are right about the over discharging issue. Yes, all my airplanes, helis and cars has a low voltage monitor to monitor each cell, and stop it going below 3.2V. Basically it has 2 stage of warning: warning and cut off.
Of course I don't do cut off on my airplanes and helicopters for the obvious reasons :-D

But to be clear to other people reading this thread, 3s LIPO WILL at least give you 10.8V power when running a robot when current is less than 10C.
Hi MIC2

You are right about the over discharging issue. Yes, all my airplanes, helis and cars has a low voltage monitor to monitor each cell, and stop it going below 3.2V. Basically it has 2 stage of warning: warning and cut off.
Of course I don't do cut off on my airplanes and helicopters for the obvious reasons :-D

But to be clear to other people reading this thread, 3s LIPO WILL at least give you 10.8V power when running a robot when current is less than 10C.
bonmot offline
Robot Builder
Robot Builder
Posts: 18
Joined: Wed Mar 21, 2007 11:00 pm

Post by mic2 » Tue Mar 09, 2010 6:07 pm

Post by mic2
Tue Mar 09, 2010 6:07 pm

bonmot wrote:
But to be clear to other people reading this thread, 3s LIPO WILL at least give you 10.8V power when running a robot when current is less than 10C.


This looks OK to me.

By the way what kind of controller board you're planning to use for the HV300 servo?
bonmot wrote:
But to be clear to other people reading this thread, 3s LIPO WILL at least give you 10.8V power when running a robot when current is less than 10C.


This looks OK to me.

By the way what kind of controller board you're planning to use for the HV300 servo?
mic2 offline
Savvy Roboteer
Savvy Roboteer
User avatar
Posts: 85
Joined: Thu Mar 01, 2007 6:52 pm

Post by bonmot » Tue Mar 09, 2010 6:16 pm

Post by bonmot
Tue Mar 09, 2010 6:16 pm

Hi Mic2

I am going to use whatever is avaible for me in my lab.
I do microcontrollers for living.:-D
Hi Mic2

I am going to use whatever is avaible for me in my lab.
I do microcontrollers for living.:-D
bonmot offline
Robot Builder
Robot Builder
Posts: 18
Joined: Wed Mar 21, 2007 11:00 pm

Post by Rick_swarty » Wed May 18, 2011 6:14 pm

Post by Rick_swarty
Wed May 18, 2011 6:14 pm

hi i'm back, after long time, last i can return to join robosavvy again. this is my simple work.
this is robot where i create. thr robot used intel atom, controlled uses modified atmega 8535. intel atom with OS windows XP for detection colour and instruction to controller with serial communication. thanks for the mic2 for any advice
http://imageshack.us/photo/my-images/196/photo382q.jpg
hi i'm back, after long time, last i can return to join robosavvy again. this is my simple work.
this is robot where i create. thr robot used intel atom, controlled uses modified atmega 8535. intel atom with OS windows XP for detection colour and instruction to controller with serial communication. thanks for the mic2 for any advice
http://imageshack.us/photo/my-images/196/photo382q.jpg
Rick_swarty offline
Newbie
Newbie
Posts: 6
Joined: Fri Jan 01, 2010 7:05 pm

Post by billyzelsnack » Thu May 19, 2011 3:33 pm

Post by billyzelsnack
Thu May 19, 2011 3:33 pm

Very cool. Vids please!
Very cool. Vids please!
billyzelsnack offline
Savvy Roboteer
Savvy Roboteer
User avatar
Posts: 618
Joined: Sat Dec 30, 2006 1:00 am

Post by Rick_swarty » Mon May 23, 2011 3:14 pm

Post by Rick_swarty
Mon May 23, 2011 3:14 pm

Very cool. Vids p

Sorry i don't have vids. But anytime i will post vids. because i'm busy right now.... :D :D :D :D
Very cool. Vids p

Sorry i don't have vids. But anytime i will post vids. because i'm busy right now.... :D :D :D :D
Rick_swarty offline
Newbie
Newbie
Posts: 6
Joined: Fri Jan 01, 2010 7:05 pm

Previous
Previous
38 postsPage 3 of 31, 2, 3
38 postsPage 3 of 31, 2, 3