microcontroller with LTE and solar panel

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Gerald10
 
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Joined: Fri Mar 10, 2023 7:26 pm

microcontroller with LTE and solar panel

Post by Gerald10 »

hi guys and @adafruit,

Im looking at this board - which has a microcontroller and a LTE module (T-SIM7600G-H R2): https://www.lilygo.cc/products/t-sim760 ... 8717972661

I want to connect the following battery to the battery holder - which is on that board (i dont plan to use a 16850 battery - since they only are available with 3600mAh): https://www.adafruit.com/product/353

and also connect this solar panel: https://www.adafruit.com/product/3809

What will i need to to make it work with that battery and solar panel?

Any idea whats the power consumption of that board? - i only see: reaches 300uA when sleeping.

Any idea what sim card i could use - which also works for LTE and GSM - with that T-SIM7600G-H R2 board?

Thanks,
Gerald

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adafruit_support_mike
 
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Re: microcontroller with LTE and solar panel

Post by adafruit_support_mike »

You'll need a Solar Charger like one of these:

https://www.adafruit.com/product/390
https://www.adafruit.com/product/4755

Solar panels are very bad at producing useful power on their own. You can get a relatively high voltage with almost no current, or you can get relatively high current with almost no voltage. What you want is an operating point somewhere in the middle that gives you the best combination of current and voltage, known as the Maximum Power Point. Circuits that know how to find and follow a solar panel's MPP are called MPP Tracking (MPPT) circuits.

Our Solar Chargers aren't true MPPT circuits, but have performance reasonably close to an MPPT when connected to a 6V solar panel and putting out the kind of current necessary to charge a LiPo.
Gerald10 wrote: Fri Mar 10, 2023 7:36 pm Any idea whats the power consumption of that board? - i only see: reaches 300uA when sleeping.
Not a clue.. we don't make the LTE board and don't know anything about it.

From experience, the current a cell module uses changes dramatically from one millisecond to the next. You can't think about it in terms of DC current like simple resistors and LEDs. Current can be as low as a few microamps when the system is truly idle, then jump to a couple of amps when the radio transmits to the nearest cell tower. The average cellular module can run for about a day on a fully-charged 1200mAh LiPo.

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Gerald10
 
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Re: microcontroller with LTE and solar panel

Post by Gerald10 »

Hi @adafruit_support_mike,

Thanks for you reply.

That LTE board already has a battery adapter, battery management and a jumper to connect a solar panel - so I would not need that battery charger board (bq24074) as far i understand - here is the schematic (battery management): https://github.com/Xinyuan-LilyGO/T-SIM ... 201012.pdf

If i use a raspberry pi instead:
I could use the Adafruit solar panel with the Adafruit battery charger board (bq24074) and Adafruit battery - do you have a raspberry pi with LTE also available in the store or know the best LTE module to get for raspberry pi?
I would like to use it with the https://www.raspberrypi.com/products/camera-module-3/ - and live stream with a sleep cycle - since LTE boards consume a lot of energy as you said.
The raspberry pi does not have a sleep mode as far i know - so im unsure if you can run it off a battery with solar cell
- Raspberry Pi Zero W: draws around 260mA at idle and 370mA when stressed using Stressberry...
- Raspberry pi pico: The power consumption of the Raspberry Pi Pico amounts to 91mA - looks like a candidate

I see you have Raspberry Pi Pico W - Pico Wireless without Headers: https://www.adafruit.com/product/5526 - can you connect that one to https://www.raspberrypi.com/products/camera-module-3/ ?

Thanks,
Gerald

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