I am using li ion single cell in one of the application where device will be in sleep mode when is not in use. Life time of which is nearly 30 days.

Cell I am using is Li-ion, 18650 package, 2600mah and comes with "1s 3.7v 2a Li Ion Bms Pcm 18650 Battery Protection Board Pcb". For charging I am using TP4056. It is set to charge battery at 500mA.

My concern is if because of some reasons cell goes below its rated and fall into deep discharge, would TP4056 be able to charge it again up to usable voltage ?

Is it should be happening ?

Any other ways to prevent this situation ?


1 Answer 1


The point of having battery protection is to prevent the battery from reaching a "deep discharge" state in the first place. The battery protection will disconnect the battery when the battery voltage gets too low (usually 2.7 V). For good battery life, you should not let the battery voltage drop this low. Re-charge the battery when the voltage is below 3.6 V.

Even if the cell ends up having a low voltage that is no issue for the TP4056 as it will go into "trickle charge" mode. It will do this when the battery voltage is below 2.9 V, then battery is trickle charged until the battery voltage is high enough for normal charging to start.


  1. deep charge should not happen due to battery protection

  2. the TP4056 will work even with a deeply discharged cell.

  • \$\begingroup\$ Thank you for reply. How much time TP4056 will take to come out from "trickle charge" ? few hours ? few days ? I have such cells that shows 0V and I have tried to charge it back. TP4056 is consuming current and heat up accordingly as normal charge but I dont see any voltage rise. Do I need to change my battery protector ? \$\endgroup\$
    – dharmikP
    Jul 20, 2021 at 12:27
  • \$\begingroup\$ trickle charge" ? few hours ? few days ? The TP4056 will trickle charge until the battery voltage become higher than 2.9 V. If that takes days then your battery might be broken. As said: you should not allow the battery voltage to get that low in the first place. \$\endgroup\$ Jul 20, 2021 at 12:30
  • \$\begingroup\$ I have such cells that shows 0V ANY Lithium cell which shows 0 V (less than 1 V) is dead. There is no point in trying to charge it. It needs to go to a recycling point. \$\endgroup\$ Jul 20, 2021 at 12:31
  • \$\begingroup\$ Ok got it . Thank you. \$\endgroup\$
    – dharmikP
    Jul 20, 2021 at 12:54

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