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Thread: How to make an external battery pack?

  1. #61

    Default Re: How to make an external battery pack?

    In this config you'll get 2X current but still 4.8V. be putting in series you get 9.6V. Thot they had the 8xAA packs? those are already in series.

  2. #62
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    Default Re: How to make an external battery pack?

    Quote Originally Posted by Max 2.8
    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.
    I am very curious.
    U should have 1 battery case that hold 4x AA battery, that will give u 4.8V, and 2300mAh x4, enough to drive yr little gadget. Then u keep the 2nd set of 4x AA battery as backup.
    Yr diagram setup does not give u anything extra, electronically speaking.

  3. #63
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    Default Re: How to make an external battery pack?

    Quote Originally Posted by enghong17
    In this config you'll get 2X current but still 4.8V. be putting in series you get 9.6V. Thot they had the 8xAA packs? those are already in series.
    I saw, but I'll need that 5v regulator to give me 5v for my 5v device. So I thought this is easier. Does this means I can use 4 sets of batteries?

    The current...if my device only needs 2.5A, will my configuration blow my device with too much current?
    Last edited by TrailsofLife; 21st October 2005 at 01:30 AM.

  4. #64
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    Default Re: How to make an external battery pack?

    Quote Originally Posted by Astin
    I am very curious.
    U should have 1 battery case that hold 4x AA battery, that will give u 4.8V, and 2300mAh x4, enough to drive yr little gadget. Then u keep the 2nd set of 4x AA battery as backup.
    Yr diagram setup does not give u anything extra, electronically speaking.
    But Astin the 2 set of batteries will last longer. That is if the device draw the power constantly.

    Also, I think this will lessen the hassle of changing batteries, right?

  5. #65
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    Default Re: How to make an external battery pack?

    upsss this thread abit

  6. #66
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    Default Re: How to make an external battery pack?

    Astin & EngHong,

    I already did up the 1 set of 4XAAs already, was at SL Tower to get a soldering iron(mine spoilt years ago and I forgot about it!), saw a 4XAA case with switch, so thought just buy and try no harm and it works. Just a 3mins job, pretty easy

    I realised that the external batts only charge the existing battery for 2 out of 4 of my device, my Archos AV420 & iRIver iHp140 take the ext. batts as ext power supply, the digimate and X-drive super only use the ext batts charge the internal batts.

    But still going to do the 8XAAs parallel circuit, since on my first trip to SL Tower, already bought 2 cases, a switch and a DC plug. Now just need to find a right size plastic box.

    Thanks again for the advice.

  7. #67

    Default Re: How to make an external battery pack?

    Quote Originally Posted by Max 2.8
    I saw, but I'll need that 5v regulator to give me 5v for my 5v device. So I thought this is easier. Does this means I can use 4 sets of batteries?

    The current...if my device only needs 2.5A, will my configuration blow my device with too much current?
    May not be true that it lasts longer. Your device will most likely dissipate the extra current at power loss thru heat.......meaning a hot setup.

    Its better to like what Astin said, keep it as a spare batt pack.

    How the device works when an external source is attached really depends on the internal circuitary of the device. If it were made that once a power source is available then it charges its internal batteries then it does that, then its better you keep your home made batt pack as a backup emergency charger rather than charging the device indefinately by plugging in your external pack cos there may be battery refresh issues.

    The shops at SL towers sell plastic boxes ready for circuits and they come with screws for you to screw whatever circuitary you have to the box for stability.

  8. #68
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    Default Re: How to make an external battery pack?

    Max, I like your style of never-give-up and keep-trying, (and obviously u are not an electronic engineer but trying to understand the electronic stuffs), we need more of your type to rebuild Singapore!

  9. #69
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    Default Re: How to make an external battery pack?

    Quote Originally Posted by enghong17
    May not be true that it lasts longer. Your device will most likely dissipate the extra current at power loss thru heat.......meaning a hot setup.

    Its better to like what Astin said, keep it as a spare batt pack.

    How the device works when an external source is attached really depends on the internal circuitary of the device. If it were made that once a power source is available then it charges its internal batteries then it does that, then its better you keep your home made batt pack as a backup emergency charger rather than charging the device indefinately by plugging in your external pack cos there may be battery refresh issues.

    The shops at SL towers sell plastic boxes ready for circuits and they come with screws for you to screw whatever circuitary you have to the box for stability.

    So you mean the device won't draw the power from the 2 battery pack at the same time? I thought so too about those devices that don't recognise the battery pack as external power source. Will check out the boxes... Now I have 2 battery cases, a switch, rubber tubing, and a multiple DC plug kit...Have to use them up lah or else, wasted.

  10. #70
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    Default Re: How to make an external battery pack?

    Quote Originally Posted by Astin
    Max, I like your style of never-give-up and keep-trying, (and obviously u are not an electronic engineer but trying to understand the electronic stuffs), we need more of your type to rebuild Singapore!
    No lah, dun say that, I unemployed mah, free to do this kind of thing Thanks to all the help I got from this forum.

    Next, I am going to try those hobby kit and build a small ampliflier for my ipod...One of my friend already did it, quite good leh, the sound quality
    Last edited by TrailsofLife; 21st October 2005 at 06:48 PM.

  11. #71
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    Default Re: How to make an external battery pack?

    Last question, is there a circuit like a relay so when let say the first battery pack used up the power, then the 2nd battery pack will provide the power? I thought this will cut down the heat....am I right?

  12. #72

    Default Re: How to make an external battery pack?

    erm, to builf a replay circuit you need another power source........which i think is not too economical here...prob you can try another type of switch, the 3 way kind, meaning when switched to the right, it connects the circuit on the right, centre means neutral and to the left turns on the left circuit.......more economical

    A website on electronical relays.......
    http://www.kpsec.freeuk.com/components/relay.htm

    For the switch i meant, look at the Single Pole, Double Throw Switch here....
    http://www.kpsec.freeuk.com/components/switch.htm

    BTW the site above is a very good read on basic electronics......

  13. #73
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    Default Re: How to make an external battery pack?

    I think I'll just add 1 more switch to the 2nd battery pack so I can on it when the first one is drained. Still can change battery while the second one is on.

    Learnt alot from you, Eng Hong, thanks!

    Cheers
    Max 2.8

  14. #74

    Default Re: How to make an external battery pack?

    erm.......lots to learn from me?.......i still student leh, lotsa experts out there keeping quiet........

    Aniwae am doing a project module now which requires us to build a remote controlled amphibious vehicle.......just throw us a transmitter and receiver and motors and batts and expect us to come out with state of the art design........

    How?.........GOOGLE.......one thing NUS teaches........

    Prob can take a pic and show those who wanna mod their own backup batt pack.........too bad i too busy with work now, if not can build the regulator for you........and make eastgear's batt pack biz go flat..........

  15. #75
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    Default Re: How to make an external battery pack?

    Will do when the 2 pack one is done.(Dun think will put EG out of biz lah). Now thinking of how to put a USB socket on it so can charge my ipod. Anyone know the polarity of a USB plug?

    Good luck for that project you are doing
    Last edited by TrailsofLife; 22nd October 2005 at 12:39 AM.

  16. #76

    Default Re: How to make an external battery pack?

    enghong u are in third year eee in nus?

  17. #77

    Default Re: How to make an external battery pack?

    Quote Originally Posted by cosycatus
    enghong u are in third year eee in nus?
    Do i know u?.........

  18. #78

    Default Re: How to make an external battery pack?

    Quote Originally Posted by Max 2.8
    I think I'll just add 1 more switch to the 2nd battery pack so I can on it when the first one is drained. Still can change battery while the second one is on.

    Learnt alot from you, Eng Hong, thanks!

    Cheers
    Max 2.8

    Hi Max,

    I think adding a switch to the second battery pack will not do any different. When your first battery pack is drained, and when you switch on the second pack, the second pack will charge the first. If I am not wrong, they will be connected in parallel. As long as you connected the two battery packs in parallel without a protection circuit, the higher capacity or fresh battery pack will charge the lower capacity or drained battery pack until their capacity become equal.

    For USB cable polarity, please visit this link.

    Regards,

  19. #79
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    Default Re: How to make an external battery pack?

    Actually if the circuit for battery pack A is open, the circuit is broken, so I dun think battery pack B will charge battery pack A.

    thanks for the info,...although I dun understand it at all, can you tell me where's the positive and where's the negative of the USB thing I should solder to?
    Last edited by TrailsofLife; 22nd October 2005 at 06:52 PM.

  20. #80

    Default Re: How to make an external battery pack?

    Quote Originally Posted by Max 2.8
    Actually if the circuit for battery pack A is open, the circuit is broken, so I dun think battery pack B will charge battery pack A.

    thanks for the info,...although I dun understand it at all, can you tell me where's the positive and where's the negative of the USB thing I should solder to?
    True......that's what i meant.

    For switch thrown to left, circuit A's batteries are being used

    Code:
                   Circuit A             Switch          Circuit B
                       (batt set A)         |          (batt set B)
                               |            |                 |
                               |            |                 |
                               \            /                 /
                                 \ _____/               Open
    
    
    For switch thrown to right, circuit B's batteries are being used
    
                       Circuit A         Switch       Circuit B
                    (batt set A)           |          (batt set B)
                               |            |                 |
                               |            |                 |
                               \             \                /
                                 \ Open       \________/
    Last edited by enghong17; 22nd October 2005 at 07:15 PM.

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