It seems like the aftermarket phone battery is so flooded with terrible counterfeits it can't be too hard to trick a phone into thinking a battery is genuine. I'd really like to learn how to use an 18650 in my old phone instead of buying a new crappy fake off of Amazon every few months but it won't power up without the extra 2 pins connected to the extra circuit.

I hate the idea of not being able to use something just because the manufacturer stopped making quality batteries for it. Right to repair etc etc

Edit: Okay maybe I need to clarify more. I keep buying batteries for a phone I have on Amazon. Every single one won't hold a charge after around 3 months. These are terrible quality, and this is not a phone I keep in my pocket and 18650 cells are so ubiquitous it would be very practical to have the option of using an 18650 cell in any old phone in the future, but I need to learn how to get the phone to boot up with one. I don't want to be forced to use phone specific batteries so I'm trying to get some information on how to accomplish this goal.

  • \$\begingroup\$ So, you want to make your own counterfeit? \$\endgroup\$ – Marla Jan 21 '19 at 23:30
  • \$\begingroup\$ Is it really a counterfeit if it's an 18650 cell that I want to use for myself? I'd be happy just knowing how to get the phone to accept an 18650 cell but I don't see that happening without fooling the phone into powering up with it. \$\endgroup\$ – Johnny Derpp Jan 21 '19 at 23:34
  • \$\begingroup\$ What phone have you ever seen that uses an 18650? \$\endgroup\$ – Hearth Jan 22 '19 at 2:35
  • \$\begingroup\$ Presumably, connecting an 18650 in place of the cell in a poor "counterfeit" would meet your need. This could be an old/deadish/low capacity unit (probably). \$\endgroup\$ – Russell McMahon Jan 22 '19 at 10:40
  • \$\begingroup\$ Edited post for extra clarification \$\endgroup\$ – Johnny Derpp Jan 22 '19 at 12:36

The easy way to do this is to grab one of your existing batteries for the phone. Take it apart and remove the defective cell. Then connect your new (larger) cell in place of the old cell.

You will most likely have to use extension wires to allow the battery case to fit in the phone. Make sure those wires are decently beefy - 20 AWG or so should be good.

  • \$\begingroup\$ I think his phone is using a single pouch or prismatic cell so he won't be able to remove a single cell. Also the cell chemistry might be completely different which can result in problems and possible fire while charging! \$\endgroup\$ – A.R.C. Jan 23 '19 at 8:06
  • \$\begingroup\$ He mentions purchasing replacement batteries for his phone. Also: a standard 18650 cell is most likely similar / compatible with the original cell. If not, simply recharge the 18650 cell in one of the many compatible chargers. \$\endgroup\$ – Dwayne Reid Jan 23 '19 at 8:19
  • \$\begingroup\$ Is there any way the safety circuit could also stay functional or would that require opening the 18650 cell? \$\endgroup\$ – Johnny Derpp Jan 23 '19 at 12:44
  • \$\begingroup\$ The safety circuit is separate from the battery cell. Disconnect the old cell from the existing safety circuit in the battery pack and connect the new 18650 cell in place of the old cell. The safety circuit remains active at all times. \$\endgroup\$ – Dwayne Reid Jan 23 '19 at 13:04
  • \$\begingroup\$ I'm going to try this. I've got a ton of batteries that won't hold a charge but do power up the phone so I can try a few times. I'd still be interested in knowing how these 3rd party manufactures copy all of the oem security circuits but then can't put decent cells in with them. \$\endgroup\$ – Johnny Derpp Jan 23 '19 at 15:25

If your looking to solder an 18650 bank of cells or battery holder - You can always use your SD card slot or sim card as the battery ground and extremely carefully solder your positive lead directly to the existing battery (you would have to tape over other two other battery tabs to ensure isolation and prior to the + tab soldering).

I'm not saying this will always work (the wiring will have limited current carrying capacity) or could be perceived as a safe / conventional way of powering a phone. But it worked for my THL smartphone.

  • \$\begingroup\$ Thanks for the extra information! It would be great to use a battery holder where the 18650 could be swapped out easily for a fresh one. This is my preferred method of charging even with conventional removable batteries. \$\endgroup\$ – Johnny Derpp Jan 23 '19 at 15:22

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