How to power SIM800L chip?

I have a project i testing currently running a Arduino UNO. With the UNO I can power the SIM800L chip from the boards 5V pin. In the final project I want to use a smaller Nano instead. When trying this the SIM800L will not connect and I figure it is because of the lower current in the 5V pin on the nano.

With adding the least amount of new items, whats is the best way to power the SIM800L? It is the newer version that can handle 5V. The project will end up in my car and I have 12V.

I hope you realise that the SIM800L will soon be obsolete and useless in just about the whole world (in parts of the world all 2G networks have been switched off already).

I remember the SIM800L needs to be able to draw 2A peaks. If you power the Arduino over USB, this may just work (especially if there's sufficient decoupling capacitance).

When running from your car's 12V supply, use a sufficiently powerful buck converter to produce the 5V supply for both your SIM800L and Arduino (use the 5V pin). If you have a voltage adjustable converter, consider one at 5V for the Arduino, and a separate one set to ~3.7V to power the SIM800L.

As the sim800L requires I believe around 4.2v would it work to power it through a diode (or maybe two)?
i.e. using the voltage drop of the diode to reduce the 5v down to the required voltage

wvmarle:
I hope you realise that the SIM800L will soon be obsolete and useless in just about the whole world (in parts of the world all 2G networks have been switched off already).

I remember the SIM800L needs to be able to draw 2A peaks. If you power the Arduino over USB, this may just work (especially if there's sufficient decoupling capacitance).

When running from your car's 12V supply, use a sufficiently powerful buck converter to produce the 5V supply for both your SIM800L and Arduino (use the 5V pin). If you have a voltage adjustable converter, consider one at 5V for the Arduino, and a separate one set to ~3.7V to power the SIM800L.

Aah did not know that, seems like 2025 is the year it will start to shut down the 2G in Sweden, at least the operator I use. I guess a 4G chip is a better solution then. If I have built my project around the 800L is it then compatible with 800A without changing other than hardware?

Thanks fore the info regarding voltage and power!

A LiPo battery is nominal 3.7V, but gets to about 4.2V fully charged and fully empty at 3.0-3.2V (that's about where the protection circuit should cut it off).

Some of those SIM800L modules indeed have one or two diodes in series at the 5V in to drop the voltage to within allowed range. See datasheet on details on the voltage range.

When looking for 4G modules a few years ago (recently been discussed here again - the situation is unchanged) I found out that an Arduino compatible module costs more than a cheap smartphone. They're really expensive! Especially considering that for most Arduino related applications 2G speeds are more than enough, it's typically about transmitting a few bytes of sensor data.

Whether other modules are hardware compatible is hard to say. Chances are they accept the same AT commands, which would mean a drop in replacement or minor changes, but you have to do your research on that. A quick check told me that the SIM800A is also GPRS, not 3G or 4G.

Ive used both the 3G and 4G upgrades from the 800...
The code is identical - except the software power-on timing is a little different.

lastchancename:
Ive used both the 3G and 4G upgrades from the 800…
The code is identical - except the software power-on timing is a little different.

Cool, do you know which model of the 800 that support 4G?

800... none...
I’ve used the 5320x for 3G, and the 7600x for 4 G.
All work well, but make sure of your solid 5V supply.

lastchancename:
800... none...
I’ve used the 5320x for 3G, and the 7600x for 4 G.
All work well, but make sure of your solid 5V supply.

Great, do you have any info of the power consumption of the 4G version (7600). I have an alternative right now to use a 4G mobile router I have laying around and then attach a wifi module to the Arduino, a bit of a work around but I want the power to be as low as possible and not draining my extra battery in the car, a 100Ah 12v Lithium.

The Wifi Router consumes around 200mA at load and around 90-100mA in idle. The I need to add a Nano + wifi to that.
Compared to a Nano with a SIM 7600.

They’re all drawing 5V @ about 500mA when idle, and require peaks of 2A when initialising/connecting... and when actually transmitting.
(Depends on signal coverage after initialisation.)

lastchancename:
They’re all drawing 5V @ about 500mA when idle, and require peaks of 2A when initialising/connecting… and when actually transmitting.
(Depends on signal coverage after initialisation.)

That’s a lot of idle current! Wondering how my 4G capable phone survives for a day without charging on a 2.5 Ah battery.

It’s actually a lot less than that, but have 500ma available, because the short TX blips occur ‘randomly’
I’d guess the nomnal idle is < 100mA, because my boards have some other pullups, LEDs etc.

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