Page 3 of 7 FirstFirst 12345 ... LastLast
Results 41 to 60 of 124

Thread: How to make an external battery pack?

  1. #41
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Quote Originally Posted by enghong17
    Erm did i show you one with 5V 1A?




    Not necessary, it may powerup but it may die real fast. These circuits are built with latency of sometimes up to 25% so depending on the components.

    Just read the 7805's datasheet. Its max output current only 0.5A so maybe you need to buy a readymade circuit, thses circuits make use of OP-Amps to amplify the current output. The circuit diagrams can actually be found online but its a headache to read.

    If you are still not sure, you can go to some of the shops at Sim Lim tower. Some of the shop owners do do circuits for people, just let them know whta you need and bring along what you have.

    Eng Hong
    Any shop to recommend?

  2. #42

    Default Re: How to make an external battery pack?

    Quote Originally Posted by eawtan
    7805 has many variants, the standard is 1A, 78M05 is 0.5A, there is also a 78H05 that can supply 5A and a 78T05 for 3A.
    OOps......i was looking at the datasheet of the 78M05.......

    True, the setup may get hot......thus the need for a heat sink, u know the ones which look like the ones on your PC.........

    Shop ah? i know there's one at the basement when you walk down the stairs nearest the traffic junction from bugis closer facing the row of shophouses. The people there do do such circuits.

  3. #43
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    ok...great, thanks enghong, ewatan and the rest. Will post it up when done.

  4. #44

    Default Re: How to make an external battery pack?

    ting there is such thing called DC-DC converter that steps down/up the input voltage into any required voltage....

  5. #45
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Quote Originally Posted by user12343
    ting there is such thing called DC-DC converter that steps down/up the input voltage into any required voltage....
    Really? where can find?

  6. #46
    Member eawtan's Avatar
    Join Date
    Feb 2004
    Location
    Tampines
    Posts
    1,370

    Default Re: How to make an external battery pack?

    Quote Originally Posted by user12343
    ting there is such thing called DC-DC converter that steps down/up the input voltage into any required voltage....
    Like these : http://www.powerstream.com/ADC.htm ??

  7. #47
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Dun look like I want to carry it around....Its quite a hassle with all the boxes and wires.

  8. #48
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Was at SL Tower today....dun have any shop that do the board for you leh?

  9. #49
    Senior Member
    Join Date
    Mar 2002
    Location
    Astin Studio
    Posts
    4,736

    Default Re: How to make an external battery pack?

    Quote Originally Posted by Max 2.8
    Was at SL Tower today....dun have any shop that do the board for you leh?
    The shops will not do it for u, u got to do it yrself, or if u bump into any electronics students (they also buy their components there for their school projects) u can ask them to help u, or u pay them to do for u.

  10. #50
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Thanks Astin....I think I just stick to your 4 AAs case lah.... easier. Should be able to get extra 2hrs+ of power

  11. #51

    Default Re: How to make an external battery pack?

    have leh, i was just there at the shop and the uncle was telling someone else that he does circuits for them at 30% additional of the cost orice of the materials.

    B1-25 Continental

    Or you can try 03-24 Kaichin

  12. #52

    Default Re: How to make an external battery pack?

    its a rather small package without heavy transformers....

    http://www.rohm.com/products/shortfo...bd_index1.html

    Quote Originally Posted by Max 2.8
    Dun look like I want to carry it around....Its quite a hassle with all the boxes and wires.

  13. #53
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Quote Originally Posted by enghong17
    have leh, i was just there at the shop and the uncle was telling someone else that he does circuits for them at 30% additional of the cost orice of the materials.

    B1-25 Continental

    Or you can try 03-24 Kaichin

    Thanks again! EngHong, will go to the specific shop you say.

  14. #54
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Hi EngHong, Eawtan and the rest,

    Went to KaiChin, found a 0-30V regulator but the Uncle say they dun make for me leh, so in the end bought 2 4AAs case and a multiple DC plug kit that fit my X-drive, iriver and digimate to try to do a parallel thing.

    Just wondering, any of you be interested to help me do that regulator thing? I pay you a little kopi money?
    Last edited by TrailsofLife; 20th October 2005 at 04:52 PM.

  15. #55
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Ok, if I do the parallel input..

    Parallel means two 4.8V(4 X 1.2V - Sanyo rechargeables) powering together right? so I just have to join the wires together to a DC plug, thats all, right?

    The multiple plug kit, how to determine polarity since all are seal up with just two wires sticking out? If polarity wrong, what will happen? My device will spoil?

    Anyone knows?

  16. #56

    Default Re: How to make an external battery pack?

    borrow a digital voltmeter and test out the polarity...

    if connected wrong, most devices won't work, but dun take my word for it. always make sure and doublecheck the polarity before hardwiring.

    you might wanna put a 2A fuse series with the +ve to protect against accidental short-circuits...
    Quote Originally Posted by Max 2.8
    Ok, if I do the parallel input..

    Parallel means two 4.8V(4 X 1.2V - Sanyo rechargeables) powering together right? so I just have to join the wires together to a DC plug, thats all, right?

    The multiple plug kit, how to determine polarity since all are seal up with just two wires sticking out? If polarity wrong, what will happen? My device will spoil?

    Anyone knows?
    Last edited by user12343; 20th October 2005 at 08:15 PM.

  17. #57

    Default Re: How to make an external battery pack?

    Quote Originally Posted by Max 2.8
    Ok, if I do the parallel input..

    Parallel means two 4.8V(4 X 1.2V - Sanyo rechargeables) powering together right? so I just have to join the wires together to a DC plug, thats all, right?

    The multiple plug kit, how to determine polarity since all are seal up with just two wires sticking out? If polarity wrong, what will happen? My device will spoil?

    Anyone knows?
    Parellel means Voltage same, current split. If you connected wrong polarity, the device will not work but the battery may heat up.......and fast too......And if your device has no protection measures then you may burn your device.

    How to determine?........voltmeter......or usually we use the continuity meter on it, it beeps when touches parts connected to each other so we can tell which wire is connected where.

    As long as you don't short the wires, meaning putting the +ve terminal to the -ve terminal of your battery you will not see sparks............like what i have seen in labs.........dangerous work........

    If you are scared of getting shocks......even minor ones, either lift your legs off the ground when doing such circuits(so no connection thru your body to the ground) or wear shoes with thick soles or touch bare wires/metal parts with only one hand and keep the other hand always on insulated parts.

  18. #58
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    I have none of those you guys mentioned...

    Ok, What I will do is, join the 2 red wires of the 2 4XAA battery cases together, and the 2 black wires of the 2 same 4XAA battery cases together. Then I join the joined black wires to 1 of the wires of the DC plug and the joined red wires to the other wire of the DC plug.

    Is this called parallel? Is it correct?

    Ok, really know nuts about all this electronic things, need help in layman terms.

    Kum Sia

  19. #59
    Senior Member
    Join Date
    Mar 2002
    Location
    Astin Studio
    Posts
    4,736

    Default Re: How to make an external battery pack?

    Traditionally, the red wire is +ve, the black wire is -ve, btw, I am not sure why u want it in parallel, u just need 1 set of 4x AA battery right?

  20. #60
    Senior Member
    Join Date
    Jul 2004
    Location
    Singapore
    Posts
    8,884

    Default Re: How to make an external battery pack?

    Astin, its a sickness, the Hokkien called it "itchy fingers
    I thought this will make the battery pack later 2X longer, am I right?

    Made a diagram to back up my bad explaination earlier.

Page 3 of 7 FirstFirst 12345 ... LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •