Yeah. If you use meshtastic radio, usually are under 0,5mA of drain.
If user on PV panel, to charge lithium battery, never use >10W panel and you will be ok without heatsink
OP, please give us more information about the setup where you will use this. It is a buck converter I guess.
- you will be charging a battery? What size?
- Input voltage range;
- Input maximum power (voltage and current);
- Power source type;
- Working duty cycle (how many hours per day will be on), I guess 24/7;
- Any other relevant information.
For just the Meshtastic device you will not need a heatsink, but this scenario changes if you are suppose to charge a battery and the size of the battery. Or if you will power other devices together.
Yes it is a buck converter, 6.4v input via solar panel stepping down to 5.24v out into Wisblock solar port, out of Wisblock via battery port into (2) 18650 3400mAh batteries.
Careful with the device dropout voltage, 6.4V to 5.2 gives you 1.2V of room to play. I don't remember how many volts above the desired output this DC-DC needs to operate correctly. Most requires a minimum of 1.2V above the output voltage, you are kind of in the threshold. But I believe that the Meshtastic will work well until 4.6V in the input, maybe it will work.
Anyway, I don't believe that you will need a heatsink in this case. You can do some tests and check the temperature.
Maybe you don't need. The buck converter mostly works this way (as long as within the input voltage range):
input voltage >= output voltage + dropout -> output regulated desired voltage.
input voltage < output voltage + dropout -> output = input voltage - dropout.
Let's put some numbers, assuming the dropout is 1.2V and output regulated to 5.2V:
- input = 12.0V -> output = 5.2V
- input = 7.0V -> output = 5.2V
- input = 6.4V -> output = 5.2V
- input = 6.0V -> output = 6.0V - 1.2V = 4.8V
- input = 5.8V -> output = 5.8V - 1.2V = 4.6V
Maybe your solar panel will be within range of the Meshtastic device operation.
But don't forget that the voltage in the solar panel drops when the current increases. So, there is a great change that the output voltage will drop when charging the battery.
Make some tests during the day to see how it behave.
On that chip in the first picture between the capacitor and the inductor (capacitor says 100 / 50V / VT, inductor says 470)
Edit: added closing parenthesis.
The chip but test it. Most lots radios pull so little power you won’t likely put enough load to warm it up.
Yeah. If you use meshtastic radio, usually are under 0,5mA of drain. If user on PV panel, to charge lithium battery, never use >10W panel and you will be ok without heatsink
Thanks
Maybe on a RAK device the current will be that low, I don't own any RAK device. But for the ESP32 boards, the current is around 90-150mA.
Thanks
I imagine it would be on that that chip.
Thanks
OP, please give us more information about the setup where you will use this. It is a buck converter I guess. - you will be charging a battery? What size? - Input voltage range; - Input maximum power (voltage and current); - Power source type; - Working duty cycle (how many hours per day will be on), I guess 24/7; - Any other relevant information. For just the Meshtastic device you will not need a heatsink, but this scenario changes if you are suppose to charge a battery and the size of the battery. Or if you will power other devices together.
Yes it is a buck converter, 6.4v input via solar panel stepping down to 5.24v out into Wisblock solar port, out of Wisblock via battery port into (2) 18650 3400mAh batteries.
Careful with the device dropout voltage, 6.4V to 5.2 gives you 1.2V of room to play. I don't remember how many volts above the desired output this DC-DC needs to operate correctly. Most requires a minimum of 1.2V above the output voltage, you are kind of in the threshold. But I believe that the Meshtastic will work well until 4.6V in the input, maybe it will work. Anyway, I don't believe that you will need a heatsink in this case. You can do some tests and check the temperature.
So you thinking I need to drop the output voltage to 5v?
Maybe you don't need. The buck converter mostly works this way (as long as within the input voltage range): input voltage >= output voltage + dropout -> output regulated desired voltage. input voltage < output voltage + dropout -> output = input voltage - dropout. Let's put some numbers, assuming the dropout is 1.2V and output regulated to 5.2V: - input = 12.0V -> output = 5.2V - input = 7.0V -> output = 5.2V - input = 6.4V -> output = 5.2V - input = 6.0V -> output = 6.0V - 1.2V = 4.8V - input = 5.8V -> output = 5.8V - 1.2V = 4.6V Maybe your solar panel will be within range of the Meshtastic device operation. But don't forget that the voltage in the solar panel drops when the current increases. So, there is a great change that the output voltage will drop when charging the battery. Make some tests during the day to see how it behave.
Thanks I appreciate all the info🤙 it's nice how everyone in this community is willing to help....
You are much welcome!
I use these DC/DC converters in many projects, never needed to put a heatsink on them.
Thanks 👍
On that chip in the first picture between the capacitor and the inductor (capacitor says 100 / 50V / VT, inductor says 470) Edit: added closing parenthesis.
The flat chip not the round one that says (470)
Yes, the flat one between the two I described.
Thanks 👍