OpenEnergyMonitor Community

Can we upgrade old emonTH nodes to extend battery life?

Tags: #<Tag:0x00007fc9af066230> #<Tag:0x00007fc9af0660f0>


I was just wondering if it is possible to upgrade the old emonTH with the new temperature/humidity sensor Si7021 ?
The main objective is to extend the battery life to the same level as the new emonTH V2.

If possible, what needs to be done ?


Hi Jan,

I’m afraid the new Si7021 sensor require different hardware (new PCB design) and new firmware. See emonTH V2 repo:

You could increase the time between readings to increase the battery life of emonTx V1. You should be experiencing about 6-10 months battery using DHT22 on emonTH V1. If you don’t require humidity readings using a DS18b20 temperature sensor instead of DHT22 will increase battery life. No firmware change is required to use DFS18B20 with emonTH V1 instead of DHT22

Hi Glyn,

Thanks for the fast response.
I like your suggestion about increasing the period.
Do you have any idea about the impact on the battery life if I would increase the period from 1 minute to 5 minutes ?


Battery life would probably more than double. Most of the power is consumed powering up the MCU and sensor to take a reading.

You could also look to swap the battery to a larger capacity - perhaps a Lithium ion or similar - just ensure its the same voltage!