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Which switch?

Discussion in 'General Electronics Discussion' started by notTHEfoggiest, Jan 14, 2017.

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  1. notTHEfoggiest

    notTHEfoggiest

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    Jan 14, 2017
    [​IMG]

    Hey guys I'm new to electronics and a bit stuck designing a 6S battery pack. I need to have a 6S balance cable output to send to my Turnigy Accucell 6 charger and another going to my lipo alarm. The problem is that I don't want the lipo alarm constantly on, draining the batteries down. I have been looking into switches but am having trouble getting my head around which one I will need.

    I want the switch to simaltaneously open or close the 6 wires going to the lipo alarm to control when the alarm is in use. The 6 cells will be 18650 batteries with nominal voltage of 3.6V each. I'm thinking a 10A switch as I plan to charge and discharge thecells at 1.2A each max. I would be very appreciative of ideas as to which switch I need and the correct terminology I need to look for as the variations of switches on ebay are bewildering!

    PS: I'm open to better ideas as to how to operate the lipo alarm via a switch...

    Thanks!
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    The current through those connections should be quite small. Look for a 6 pole switch.

    Unless it's actively doing any balancing, the inputs will be high impedance and draw very little current.
     
  3. notTHEfoggiest

    notTHEfoggiest

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    Jan 14, 2017
    Hey thanks for the response. Can you be really specific as to what I should search on ebay please? I want to find the correct switch and there are so many variations of switch.
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    6 pole switch.
     
  5. notTHEfoggiest

    notTHEfoggiest

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    Jan 14, 2017
    Sarcastic, just what I was looking for... 6 pole comes back with "rotary, rocker, piano dip, changeover latching, normally open" and the endless variations continue on from there. If I were looking for obtuse, passive aggressive remarks trolling me for not knowing very much, I would post this question on a school forum. Seeming as I am looking for helpful, specific support I was hoping this was the right place to find it...
     
  6. Harald Kapp

    Harald Kapp Moderator Moderator

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    That's not sarcastic, it's sound advice. Any 6 pole swtch will work as long as it is rated for the voltages and currents you want to switch.
    What specific kind of switch is up to you, how should we know? More specifically you may want to search for '6 pole single throw switch' which means 6 contacts operated at the same tome by one operating mechanism (lever, rotary, you name it.
     
  7. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Sorry about that @notTHEfoggiest I followed up my post by doing that exact search. I noted that many of the switches shown on eBay with this search are NOT 6 pole switches. You need to be careful to check that the description actually states those words in that order. Perhaps including then in quotes would make eBay a little more specific in its results.

    Alas, before replying to you I rested for a moment and woke up very early this morning with the phone on my chest and my glasses still on. At that point I decided to take my glasses off, put my phone away and sleep.

    Having checked again (I've been awake for about 10 minutes) I find that the are also many other suitable switches having more than 6 poles.

    Going back to my initial comment, it is important to know if your device actually actively balances the cells or if it simply monitors them. In the latter case these cheap eBay switches may be fine, and nothing too bad will happen if they fail. However if the charger actively balances the cells, you need to be able to switch an appropriate amount of current and in the couple on instances I checked, this is not mentioned (and if it was, could I trust it?).

    If you want a switch off known quality an specifications you need to find a dealer which links you to the specifications of the switch and that you trust to do this honestly. For that you might try digikey, mouser, RS, etc.

    One example (probably of little use to you) could be:

    http://www.digikey.com/product-detail/en/copal-electronics-inc/ET610N13-Z/563-1928-ND/5086832

    Please don't mention to my wife that you were the last person I thought about before falling asleep and the first person I thought about after waking.

    Edit: it is also important to note that DIP switches are often (mis)described as having some number of poles when they are all controlled by different actuators. There are typically n x single pole switches.
     
  8. notTHEfoggiest

    notTHEfoggiest

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    Jan 14, 2017
    [
    I don't like to start off on the wrong foot but my post laid everything out clear as day that i plan to do and to my mind I couldn't have expressed it more precisely without the very knowledge I am posting here to receive. It's not like I'm lassie barking and you have to try and guess what I'm saying! I have said what I want to build and how I would like it to work. I would have happily ordered a switch and this thread would be benign. Anyhow, Steve has kindly given a thoughtful response for which I appreciate.

    Bloody electronics, it has that effect on me too, I woke up at 5am today thinking about it. It's really getting on my wick that i can't solve simple problems, I'm usually more adept at DIY stuff. I've spent so many hours on this that I'm determined to see it through. On your advice I made an uneducated guess and went ahead and purchased two of these switches for the lipo alarm (I have two packs I'm building, one test pack with 6 beat up 18650's and the other 6 good quality that I plan to use for this build):

    http://www.ebay.co.uk/itm/301724584834?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

    and was in the process of looking for a bulky 12V 20A switch for the main 21.6V output. The lipo alarm and the balance cable will be on separate circuits running directly from the batteries so shouldn't should avoid problems stemming from the balance charger right? I could install a resistor on each cable before it makes it's way to the switch?

    This is probably for another thread but I tested some wiring of my light this morning for a couple of seconds at a time at 25-26V and when I powered the light, a little smoke emanated from the step-up V regulator leading me to believe that maybe the regulator is pulling more current than it can handle? I'm waiting on two batches of 30 types of 1/4 and 1/2 resistors from China so will put those between the battery and the regulator and see if that solves the problem:

    http://www.ebay.co.uk/itm/112218796285?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT
     
    Last edited: Jan 15, 2017
  9. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    That switch may be fine.

    This switches are probably capable of switching reasonable current, so you should be OK. I now understand that the balance charger and the alarm are different devices, so if it's only the alarm you're switching, you're probably in a good place.

    Smoke is generally a sign of something failing, it's not just a warning. Resistors between the battery and the regulator are very unlikely to be a solution.
     
  10. notTHEfoggiest

    notTHEfoggiest

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    Jan 14, 2017
    O shoot! I will post a new thread for this problem...
     
  11. davenn

    davenn Moderator

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    no, keep it here all in the one topic :)
     
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I was going to say that too, but it's already in another thread.

    This thread will just be a side note on what will be a somewhat longer thread I think :)
     
    davenn likes this.
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