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Schematic suggestions???

Discussion in 'General Electronics Discussion' started by LectricCircuit, May 5, 2017.

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  1. LectricCircuit

    LectricCircuit

    33
    2
    Apr 7, 2017
    anyone know of a schematic to build a quad battery charger for 4 18650 Lithium Ion batteries. I'm trying to find one that will charge them independently and not split the charge rate in parallel. So if I charge 1 battery I want it to charge at 1 amp and if I charge 4 batteries I want them to charge at 1 amp each as to not slow down the charge rate with the number of batteries increasing in parallel.
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,299
    2,737
    Jan 21, 2010
    You could just get 4 single cell chargers based on the TP4056 chip.

    You will require a 5V power supply capable of 4A or more (I'd recommend 5A minimum).

    Small boards based on this chip are available from eBay at a price less than you could make them.
     
  3. LectricCircuit

    LectricCircuit

    33
    2
    Apr 7, 2017
    I'd rather build it myself just for hobby reasons. I like to build all my stuff instead of buy it even if it's a little more expensive. So ya basically I just build 4 single cell circuits like u said. Isnt that going to get large in size as far as the quantity and placement of components? I'm sure heatsinks are going to be required for each regulator. I was hoping there would be some kind of IC like a quad op amp but a voltage regulator. If they made a quad LM317 that would be great lol. Who knows maybe they do and I just don't know about it. I'm just trying to use the least amount of components and keep it as small as possible. When you buy boards made by companies they can solder all those tiny tiny resistors and capacitors n all that. I can't I'm left soldering 1/2 watt resistors and normal sized capacitors. N I'm sure to limit the current I'm going to need like a 1.5 ohm 3 watt resistor or something in that area. id need 4 lm317s with heatsinks. That seem s like it will be pretty big. I'm not familiar with the tp4056 IC but I will look up the datasheet and check out the typical application and see what I could come up with based off of that. Thanks. N if u have any suggestions on minimizing size I would appreciate it. I'm fairly new to building electronics and still learning more everyday. I got curious one day how vape mod worked so I looked it up. Next thing ya know I built my own pulse width modulation vape mod and that made me want to build a charger for the two 18650 batteries inside the mod in series. So I successfully built an 8.4 volt charger that plugs straight into my mod. Now I'm using a bigger mod that uses four 18650s and charge time is becoming an issue because I can only charge two at a time so I figured why not build my own quad battery charger that can charge each battery at 1amp in parallel as to minimize charge time. Here's some pics of the mod I built and the charger for it. Pretty cool stuff n I'm glad I got into all this. Thanks. Oh n btw yes I know the voltage display on my mod is faulty and not reading correctly. Must have beef damaged at the factory or something. After I built the circuit and got an enclosure from RadioShack I added an led to the circuit for charge indication. Didn't have a pic of the circuit after I added the LED though.
     

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    bushtech likes this.
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,299
    2,737
    Jan 21, 2010
    Check out the datasheet for the TP4056.

    There are plenty of other chips out there to, but this handles all phases of charging (low voltage, constant current, top up and finally, low current shutoff). It also monitors cell temperature.

    Sure, it would be large if it wasn't a single 9 pin device and a few external components.

    And I did say 9 pin. 8 normal pins and a large pad underneath it to electrically and thermally connect it to a large area of copper. You have to use an oven for this chip.

    I have a couple of these chips around somewhere for something I planned to make. In the end I just connected a couple of these modules via stakes onto my board -- they're between 3 and 4 cm^2.

    I understand wanting to make it yourself, for one thing you'll know it's designed right.
     
    LectricCircuit likes this.
  5. LectricCircuit

    LectricCircuit

    33
    2
    Apr 7, 2017
    I'll definitely check into that chip and it sounds like it's going to be pretty useful with the protection benefits and all that. Thanks a lot.
     
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