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Topic: WIll this Battery work with my 4 servos and my Arduino UNO board? (Read 4 times) previous topic - next topic

Bajdi




Also, does anyone know the type of convertor this guy is using on the end of his battery? I think I will need something like this.



(this is the battery used in the above pic, but I thought it was kind of on the low side power wise, http://www.ebay.com/itm/battery-lipo-KingMax-500mAh-7-4v-25C-RC-mini-model-new-Free-Shipping-/230782766368?pt=Radio_Control_Parts_Accessories&hash=item35bbb98d20)

Thanks, Mike


Ha, that's my picture :) I got the connector from Tayda electronics -> http://www.taydaelectronics.com/hardware/dc-power/dc-power-plug-2-1mm-x-5-5mm-x-9-5mm-right-angle.html I use the 500mAh battery to power my "Arduino remote control" -> http://www.bajdi.com/arduino-remote-control/remote-control/

mpick67

#6
May 14, 2012, 02:22 am Last Edit: May 14, 2012, 02:43 am by mpick67 Reason: 1

Hi,
  You seem to be mixing and matching your battery technologies, some are LIFE and some are LIPO, you need to make sure that your charger can handle both types, mine can only do LIPO so thats what I use.

A 2S 8.4 volt LIPO will power your Arduino through the power jack as in your picture. The same type of battery with a higher capacity will also power your servos no problem.

I am not convinced that using a 2 cell LIFE battery at 6.6 volts is a good idea. Most servo specifications warn that running them at 6 volts as opposed to 5 volts will shorten their life, you are pushing this further and can expect subsequently shorter servo life, the standard approach in RC is to run servos from a 8.4 volt LIPO connected to a 5 or 6 volt high current regulator.

Heres an example (not a recommendation - seen cheaper) - http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXSWL3&P=ML

Duane B

rcarduino.blogspot.com


I'm a complete noob when it comes to batteries so I really appreciate your help. I'm a little confused on what voltage will harm my servo. If I got a battery that produced 6.6v and my servos operating voltage is between: 4.8-7.2V how will 6.6v harm my servos? Is it better to always stay on the lower voltage recommendations? (I'm not challenging you, I'm just trying to understand this better.)

When my final build is complete I will be powering the 2 servos (Operating voltage: 4.8-7.2V)

9805BB      
Weight: 160g
Dimension: 66*30.2*64.4mm
Stall torque: 20kg/cm(4.8V )C25kg/cm(6V)
Operating speed: 0.20sec/60degree(4.8v), 0.16sec/60degree(6v)
Operating voltage: 4.8-7.2V
Temperature range: 0~55 Celcius
Dead band width: 5us

1 UNO board requires: Input Voltage (recommended) 7-12V


Microcontroller   ATmega328
Operating Voltage   5V
Input Voltage (recommended) 7-12V
Input Voltage (limits)   6-20V

I'll be using 6 - 4 PIN LED
http://www.radioshack.com/product/index.jsp?productId=3097460&CAWELAID=174884615

and about 15-20 standard LEDs

I would really like to use one high capacity battery pack.


I wasn't able to find the battery you recommended but I did find this LIPO battery. Do you think this would power everything, or should I try finding one that's closer to 8.4 volts.


Would this battery be ideal at 7.4 volts or should I go up 11 volts and use a bunch of voltage regulators? http://www.hobbyking.com/hobbyking/store/__20680__Turnigy_nano_tech_6000mah_2S_25_50C_Lipo_Pack_USA_Warehouse_.html

I selected a battery with a Constant Discharge of 25C because that's what I saw Bajdi use. Let me know if you recommend something different! Thanks Again! Mike

mpick67

#7
May 14, 2012, 02:28 am Last Edit: May 14, 2012, 02:30 am by mpick67 Reason: 1





(this is the battery used in the above pic, but I thought it was kind of on the low side power wise, http://www.ebay.com/itm/battery-lipo-KingMax-500mAh-7-4v-25C-RC-mini-model-new-Free-Shipping-/230782766368?pt=Radio_Control_Parts_Accessories&hash=item35bbb98d20)

Thanks, Mike


Ha, that's my picture :) I got the connector from Tayda electronics -> http://www.taydaelectronics.com/hardware/dc-power/dc-power-plug-2-1mm-x-5-5mm-x-9-5mm-right-angle.html I use the 500mAh battery to power my "Arduino remote control" -> http://www.bajdi.com/arduino-remote-control/remote-control/


Thanks for the link! How long did the battery last you? Also, do you remember where you got the battery plug receiver that you used to make your DC power-plug? Thanks, Mike

DuaneB

Hi, regarding the servo voltage, if the specs say 7.2 then that's fine, most say 5 to 6 volts, but the servos you have selected are clearly designed for more. A fully charged lipo puts out 8.4 volts, dropping to 7.2 as it discarges. When LIPOs first came out a lot of RC car guys damaged servos because they had been getting away with connecting 6 volt servos directly to 7.2 volt nimh batteries, but the step up to 8.4 was a step too far. Running you 7.2 volt servos at 8.4 might be ok, but is outside the stated limits I suggest you weigh up the cost of replacing two servos against the cost of a 6 volt regulator.

You can run the Arduino from the same battery as the rest of the project, I usually connect mine into the balance plug on my LIPOs.

Duane B

rcarduino.blogspot.com



mpick67

#9
May 14, 2012, 04:30 pm Last Edit: May 14, 2012, 04:33 pm by mpick67 Reason: 1

Hi, regarding the servo voltage, if the specs say 7.2 then that's fine, most say 5 to 6 volts, but the servos you have selected are clearly designed for more. A fully charged lipo puts out 8.4 volts, dropping to 7.2 as it discarges. When LIPOs first came out a lot of RC car guys damaged servos because they had been getting away with connecting 6 volt servos directly to 7.2 volt nimh batteries, but the step up to 8.4 was a step too far. Running you 7.2 volt servos at 8.4 might be ok, but is outside the stated limits I suggest you weigh up the cost of replacing two servos against the cost of a 6 volt regulator.

You can run the Arduino from the same battery as the rest of the project, I usually connect mine into the balance plug on my LIPOs.

Duane B

rcarduino.blogspot.com



Thanks for the clearing that up! So a 7.4 LIPO will output 8.4 volts when fully charged? That's strange! lol

I think I found the battery you recommended, it's a 6000mAh 2S2P 7.4v 25C. There is a similar model that outputs 30C also. Which one would you recommend for this project?

25C: http://www.hobbyking.com/hobbyking/store/__19169__Turnigy_6000mAh_2S2P_7_4v_25C_hardcase_pack_USA_Warehouse_.html

30C: http://www.hobbyking.com/hobbyking/store/__17272__Turnigy_nano_tech_5800mah_2S2P_30_60C_Hardcase_Lipo_Pack.html

Also, I found the 6 volt Voltage Regulator for the servos (http://www.amazon.com/Common-Sense-RC-VR-6-Regulator/dp/B004DEOW3U/ref=sr_1_1?ie=UTF8&qid=1337004115&sr=8-1)

So, I can hook the battery directly to my UNO by connecting a DC plug convertor to the battery, and run my servos by running a 6 volt voltage regulator from my battery to the servos. Do you think I could also power my LED's with this battery, or should I get a separate battery dedicated just to the lights? And do you have any idea on the type of voltage regulator I would need for my LEDs? Thanks again for your help! I really appreciate it! :-)



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