SIM800L reboot and stability issues including a solution 'review'

Dear Arduino-fellows,

I am afraid that this is around the 1000th SIM800L post but I still haven't managed to achieve a stable solution, which is why I am reaching out for your help :).....

I have bought this SIM800L breakout board:

I powered it using 3xNiMH batteries that give a voltage of 4.0V and used a 1000µF cap between GND and VCC to account for a possible current spike of 2A. That works but sometimes the module seems to reboot. I have also used a benchtop power supply with a range of 0-30V and 0-15A -> works but also not stable.

Can you recommend a fix? Below, I am sharing a summary with possible fixes with you. I haven't tried all of those. I am not sure what is the advantage of using different capacitors and multiple capacitors like a 1000µF and a 10µF.

Thank you!

Proposed solution:

  1. Hey guys,
    I had the same problem on sim800c
    and increasing voltage to 4.1 volts fixed the problem
    on 4.00 volts it power's down after about 10 seconds blinking of net led

  2. use 1000uF 6.3V cap and it helps. It is better to use .
    in gsm wants to 5v,1.5-2A .we place a cap b/w vcc,and gnd

  3. I had the same problem but I solved it by replacing the tantalum capacitor on the SIM800L EVB. On my board was 107, which is 100uF, I changed it to 108, which is 1000uF. I made the exchange on all five modules I've bought on aliexpress and have been working since then.

  4. Solution for bare module: The SIM800 Cellular Module and Arduino: A Powerful IoT Combo

  5. Problem SIM800L - Sonsivri (very technical and good comment):
    The power supply range of SIM800 is from 3.4V to 4.4V. Recommended voltage is 4.0V. The transmitting
    burst will cause voltage drop and the power supply must be able to provide sufficient current up to 2A. For the
    VBAT input, a bypass capacitor (low ESR) such as a 100 μF.(I use 100uF tantalum and 470uF elco)
    For the VBAT input, a 100uF Tantalum capacitor (CA low ESR) and a 1uF~10uF Ceramics capacitor
    and 33pF and 10pF capacitors can effectively eliminate the high frequency
    interference. A 5.1V/500mW Zener diode is strongly recommended, the diode can prevent chip from damaging
    by the voltage surge. These capacitors and Zener diode should be placed as close as possible to SIM800

I have no problems after adding this capacitors.

  1. unstable SIM800L EVB · Issue #26 · stanleyhuangyc/Freematics · GitHub (is a bit worrying)

  2. SIM800L GSM/GPRS Part II – Seeking Stability | Big Dan the Blogging Man

  3. arduino uno - SIM800L not registering to network - Arduino Stack Exchange
    I am 90% sure it's a power issue. Not sure on what board/module you're using but the SIM800L/SIM900 needs a burst of current of 2 A during 577 µS (See the manual). Try using 4700 µF and a 10 µF capacitor in parallel with the module. Powering it with a proper power source instead of the Arduino wouldn't hurt too.
    Might be some power issues, but I fixed mine by just trying some AT command
    AT+CBAND?
    Then, AT+CBAND="DCS_MODE"
    That works for me. Give it a try man.

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