electronic question

Discussion in 'Off Topic' started by REX, Mar 13, 2008.

  1. REX

    REX Member

    Messages:
    945
    Likes Received:
    0
    Trophy Points:
    0
    I have an old RC car and the battery have gone bad since it haven't been used for 8 years.

    I cant find another battery of the same type of output. Its a 6 volt 600 mah Nicd.

    Now my question is this. What will happen if I modify it to accept a more powerfull battery ?.

    I have only found one pack that gives 6 volts, but its a 2000 mah. I am guessing that it is capable of delivering a higher effect, but I am unsure of what will happen. Does that mean that It will last far longer than the old one, or will I get a smoke cloud ?.
     
  2. Mr. Weedy

    Mr. Weedy I will report bugs on the bug tracker

    Messages:
    2,291
    Likes Received:
    0
    Trophy Points:
    0
    If you give too much volts, the thing most likely burns right away or burns out eventually.

    If you give too much amperes the thing does work quite well and it does actually last longer but it also may slowly but surely fry the components because they aren't designed for that kind of ampere amounts.

    I experienced this with my 120x120 fan. It melt down eventually.
     
  3. [KM] The Corpse

    [KM] The Corpse Member

    Messages:
    160
    Likes Received:
    0
    Trophy Points:
    0
    You'll have a job getting another NiCAD pack as the cadmium means that they've been banned from sale for most uses.

    You can up the mAh no problem, you'll just get a longer run time thanks to the greater capacity. Voltage can be increased if you know what you're doing (motor rating/speed controller rating/battery rating need to be considered) but it's risky if you don't know what you're doing.
     
  4. REX

    REX Member

    Messages:
    945
    Likes Received:
    0
    Trophy Points:
    0
    Thank you

    I figured that upping the voltage probably would be bad.
    maybe I should not have chosen process technology instead of electronics in school.

    I also found a cheap recharger that seems to fit the 6 volt battery pack:) .
    Edit: The pack I found is actually a 5 cell NiCD pack. Im guessing they are illegal because they can explode ?

    I was so disappointed when my old battery didnt work. I got a free video camera with a mail order, but it turned out that my digital camera shoots far better videos. It didnt take long before I started considering what I would never do with my camera^^.

    The video camera is perfect. It doesnt have a screen or anything. It is super small and light weight:) pretty much just a mobile webcam that records. I hope to get some fun footage. I also got one of those powerful LED key chain things so I might have some fun in the dark.

    I have also lately considered making a crash cage and hook it up to a kite and a few hundred meters of line to see my neighborhood from above..... yes im a bit bored, trying to get a job but I cant find anywhere that will hire me, so I got way too much time on my hands.
     
    Last edited: Mar 13, 2008
  5. [KM] The Corpse

    [KM] The Corpse Member

    Messages:
    160
    Likes Received:
    0
    Trophy Points:
    0
    I can't claim my knowledge from formal qualification on this one, rather a lifetime of playing with everything remote controlled.

    There are a number of different types of chargers, in particular depending on how fast they charge the battery. If you've got a name/link for it I may be able to help more.

    Strangely enough it's not the explosive tendency that's lead to them being phased out, just the fact that Cadmium is nasty stuff.

    They've been widely replaced by li-ions and li-polys which have a far higher energy density and if treated badly are far more likely to explode. (This: http://www.youtube.com/watch?v=4OsBc8RqSKU gives you an idea, if you ever get a li-poly battery don't try this at home...)


    You may find that it's just very flat. I would probably trickle charge it (like 50mA) for a little while then once some voltage is showing put it on a delta peak charger at maybe 500mA to see what it's still got going for it. Completely discharging a NiCAD will not help it but it may not be terminal.


    This may interest you: http://www.rcgroups.com/aerial-photography-128/
     
  6. rampantandroid

    rampantandroid Member

    Messages:
    2,664
    Likes Received:
    0
    Trophy Points:
    0
    AFAIK, at least in the US, NiCads are still quite legal, sadly. I wouldn't mess with the voltage..just increase the capacity (or ampere hours, AH)

    Yeah, cadmium is nearly impossible to dispose of in a safe fashion. Worse than mercury...NiMH (Nickel Metal Hydride) is so safe you can pretty much toss it in a garbage can and be safe (but don't do it that way, send it off in one of those little bags meant for batteries). Lithium is OK for disposing of, as there is some amount of Lithium in the human body, it is safer.

    Regarding chargers for NiMH vs Lithium or NiCd, NiMH is usually charged MUCH slower. Lithium takes a faster charge, but even so, its best to charge betteries slower, and don't charge them continuously (don't plug your phone or MP3 player in every night, irregardless of battery type).

    I'd just crack open the battery and replace the cells with NiMH cells...that would turn out pretty well, given that you buy a matching charger, or open the battery pack and charge the cells separately...or just get a more versatile charger and gator clips.
     
  7. [KM] The Corpse

    [KM] The Corpse Member

    Messages:
    160
    Likes Received:
    0
    Trophy Points:
    0
    mmm. still in the states eh? Banned in Europe already.

    I agree that both NiCad and NiMH work well after a good cycle. However, for Lithium this is not the case. What takes life off a lithium battery is deep discharge. If you flatten one totally it is scrap and unrecoverable.

    Generally if you discharge them to the safe minimum every time before recharging they will last less time than a Lithium battery charged every time it gets a little low. Hence cycling the packs is a waste of time.

    Another rule of thumb is to never charge lithium cells at more than their stated capacity (ie 500mAh pack at 500mA).
     
  8. REX

    REX Member

    Messages:
    945
    Likes Received:
    0
    Trophy Points:
    0
    Interesting stuff.

    The old battery is a bit special its a Tyco I didnt get a response from it in the beginning and I have recharged it several times and I only get a very weak response.and I actually found a place that have these, but they only ship in the UK.
    http://www.batteries.com/productprofile.asp?appid=360463

    It does have enough power to run one side somewhat fast. I guess it has 2 engines and it is a 2 stick control like a tank. I remember that it could spin like a top without moving and the wheel are big so it can flip over and just keep going ^^.

    Much cooler than the ones I saw when I looked in a toy store the other day and also cooler than most cars I looked at in a hobby shop I went into.

    This is the one im considering to force into the system
    http://www.batteribyen.dk/ni_cd_rac...39_66&osCsid=7e2a6ee3c603c5c6d26e1129f76e89d7

    And heres is the charger
    http://www.batterilageret.dk/product.asp?product=1622
     
  9. Solokiller

    Solokiller Member

    Messages:
    4,861
    Likes Received:
    7
    Trophy Points:
    0
    If the new pack has more Amperes, it could melt the isolation if left on for a long amount of time, so you'll have to either add a cooling unit, or replace the wires with thicker ones, and with more resistive isolation.
     
  10. REX

    REX Member

    Messages:
    945
    Likes Received:
    0
    Trophy Points:
    0
    hmm maybe I should have a look inside it. Maybe I should just save the money and trouble of making it work again.

    Not even sure if I can get any fun videos out of it... maybe down a hill, highspeed forest or bugging the cats.
     
  11. REX

    REX Member

    Messages:
    945
    Likes Received:
    0
    Trophy Points:
    0
    Forgot to post it back then, but i actually did it. I hooked a 9volt battery to it and it worked just fine.

    I didn't come up with anything super interesting to do with it but here a video from it. Its a bit long and laud.
    http://www.liveleak.com/view?i=83e_1216321020
     

Share This Page