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rechargable batteries? — Parallax Forums

rechargable batteries?

jcrue451jcrue451 Posts: 4
edited 2006-09-26 20:58 in BASIC Stamp
i apologize if this question has been asked already... i just read in the "robotics with the boebot" manual that rechargable batteries (nimh etc.) can't be used with the boe, because they are 1.2v instead of 1.5v. is there any way around this? plugging the boebot into the wall seriously cramps it's style, yet i don't want to keep blowing through alkaline batteries...ideas?

thanks,
john

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"elementary chaos theory tells us that all robots will eventually turn against their masters and run amok in an orgy of blood and the kicking and the biting with the metal teeth and the hurting and shoving." —professor frink

Comments

  • dandreaedandreae Posts: 1,375
    edited 2006-09-18 21:30
    Radio Shack carries 9v rechargeable batteries that will work just fine.· However, I recommend purchasing at least two for back up.

    Dave

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    Dave Andreae

    Tech Support
    dandreae@parallax.com
    Http://www.parallax.com

    ·
  • jcrue451jcrue451 Posts: 4
    edited 2006-09-18 21:48
    thanks dave!

    john

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    "elementary chaos theory tells us that all robots will eventually turn against their masters and run amok in an orgy of blood and the kicking and the biting with the metal teeth and the hurting and shoving." —professor frink
  • Mike GreenMike Green Posts: 23,101
    edited 2006-09-18 21:50
    You can use 5 x AA rechargables which should work fine (but harder to charge - chargers usually take 4). You could use a 6V R/C battery pack and charger (Radio Shack #23-338 - NiMH pack and #23-433 - Universal charger). I don't know about the size of the pack vs. the BOE-BOT, but it's probably 5 x AA cells in a pack. 6V is much better for the servos than 7.2V. Don't use the 9V batteries with servos, they're not made for that voltage. 7.2V is a little more than their rating, but they will run on it. The higher voltage shortens their life a little (arcing in the motor, wear on brushes, etc.).
  • dandreaedandreae Posts: 1,375
    edited 2006-09-18 22:00
    Mike Green said...
    You can use 5 x AA rechargables which should work fine (but harder to charge - chargers usually take 4). You could use a 6V R/C battery pack and charger (Radio Shack #23-338 - NiMH pack and #23-433 - Universal charger). I don't know about the size of the pack vs. the BOE-BOT, but it's probably 5 x AA cells in a pack. 6V is much better for the servos than 7.2V. Don't use the 9V batteries with servos, they're not made for that voltage. 7.2V is a little more than their rating, but they will run on it. The higher voltage shortens their life a little (arcing in the motor, wear on brushes, etc.).
    Hi Mike,

    There is a jumper on the Board of Education in between the two servo sockets that allow you to choose Vin or Vdd.· Therefore, you can use the 9v rechargeables as long as you make sure to put the jumper in the Vdd position.· It is true that the 9v batteries won't last as long as the AA's, but if you have a couple of them it should be okay.

    Dave

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    Dave Andreae

    Tech Support
    dandreae@parallax.com
    Http://www.parallax.com



    Post Edited (Dave Andreae (Parallax)) : 9/18/2006 10:08:54 PM GMT
  • Steve AndruesSteve Andrues Posts: 29
    edited 2006-09-25 02:59
    The Boe is not smart enough to know where the 6v is coming from; 4 alkaline or 5 NiCd (NiMh) is all the same. There are plenty of charging circuits around. If you need help or a custom battery, call Ni-Cad Systems in Hayward. They normally do aircraft stuff but are pretty good at the one-off.
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2006-09-25 20:44
    jcrue4S1

    ·They·make 1/4 size AA cells they are the same size long but not in dieamter They are 110 miamp hr·nicads·batterys

    You could put two packs together which would give you 220 miamp hr and would not be much bigger then 4 AA batterys you would have
    room·as the·5 1/4 size AA battery

    I do not know if this will help you any but if you are using the battery holder that come with the bot then this might work

    What you would have to do to use them·is cut the plastic that hold the cell in place and hot glue them in place

    ·If so let me know and i will let you how to get them i just order 5 of them for a project that i am working on

    Sam
    ·
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2006-09-25 21:51
    Sam -

    I suspect you are speaking about "N" cells like those in this picture:
    http://www.robotroom.com/NCell.html

    Regards,

    Bruce Bates

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  • ArtBroArtBro Posts: 3
    edited 2006-09-25 21:59
    5 AA NiMH cells will fit in the same place as the supplied 4 cell battery case. Get 2600 Mah cells and modify a 6 cell battery case, to hold five cells.. Look up R/C chargers and find one so that you can charge the 6V pack, in place, in about 15 minutes to one hour. I velcroed the new case in place, instead of using the original mountng screws.
  • sam_sam_samsam_sam_sam Posts: 2,286
    edited 2006-09-26 20:58
    Bruce Bates

    Sorry·Bruce· these are·Quad A·the·size
    The lenght is about·the same size as the reg AA batteries
    These are not N cells these are longer

    I just found these batteries at this battery store where i live

    I had to order them because they only had one left they are making·7.25 volt pack

    If you like i·can give you info
    If you like just PM me and i will let you know

    Sam······· ·idea.gif

    Post Edited (sam_sam_sam) : 9/27/2006 12:49:26 AM GMT
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