this is my first time asked on stack exchange, please bear bare with me. Anyway, I created portable monitor using multiple TP4056 as battery charger & protection circuit. But I'm not sure it's safe or not.

this is the wiring diagram : enter image description here

enter image description here

why I wired this way? Apparently the monitor needs more than 5 Watt, and using 1 TP4056 can't give enough power. (the monitor needs 12 volt). So far my solution works, but I worried about the safety.

what I'm asking is this solution safe?

Thank you

edit 2: To power up 12 volt monitor, I stepped up the output from TP 4056 (from around 3-4 volt) using XL6009 module to 12 volt. As you can see, the module located under the batteries.

  • 3
    \$\begingroup\$ +1 for saying please bear with me .... most people say "bare with me" .... lol \$\endgroup\$
    – jsotola
    May 12, 2018 at 5:11
  • \$\begingroup\$ lol... my bad XD. I want to say English is not my native language, but it's just an excuse. \$\endgroup\$ May 12, 2018 at 7:03
  • \$\begingroup\$ I'm surprised it works if the monitor needs 12 V. In the absence of external power you'll only get about 4.3 V from the batteries. It looks perfectly safe though. \$\endgroup\$
    – Finbarr
    May 12, 2018 at 11:15
  • \$\begingroup\$ TP4056 has a cut-off at 2.5V, which is rather low. 3-3.3V is best. I’ve also observed TP4056 cutting power at too high load (don’t know the exact ampere value). A LVCO of 2.5V is not going to give you 1000-1200 charge cycles. 5W is a stretch for XL6009, mine can only go up to 4-5W. Does the XL6009 get hot? \$\endgroup\$
    – user2497
    May 14, 2018 at 15:01
  • 1
    \$\begingroup\$ how do you charge the batteries?, you plug a usb to each usb female inputs?, or do you wired them in parallel?, how? \$\endgroup\$ Mar 31, 2019 at 4:34

1 Answer 1


The cutoff voltage is a trade-off between maximum current capability and battery under-voltage protection, at high currents (which is your case) the battery voltage can drop down to 2.5V even the battery is not over-discharged but this wasn't your question

There is nothing that forbids you to use this configuration, I actually used-it for a two batteries / two TP4056 configuration.


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