I have read some posts about external power, and also looked operations manaual and datasheet, but I cannot find a definitive answer, so I will ask here. My Audiomoth is v1.2
I would like to augment the power, so I can increase the durations, and storage; leave unattended for longer.
What combinations of power sources will work? 1. 3 x AAA batteries in the intergral battery holder
2. power connected to the contacts on the PCB (between GPIO and Mic contacts, yes?)
3. USB
My experience with USB power banks is that they are unreliable, and will simply power off when the draw is low.
So I'm more interested in combining sources 1 and 2. If I add a 4xAA rechargable battery pack as an external (or multiple), will it use internal or external power first? What about if I use a large 6v antern battery as external, it would be a different voltage from the internal - issues?
Thanks
Hi Matt, USB power packs work okay, but many have poor-quality regulators that provide noisy power, and some will power off when the AudioMoth sleeps between recordings as the power consumption is too low. The AudioMoth will always favour USB power when available. So, if you have batteries fitted, as well as USB power, the batteries will not be used at all. The internal batteries are connected to the positive and negative battery terminals on the top face of the AudioMoth between the GPIO pins and the microphone pads. You can solder these onto additional battery packs, as long as you don't also fit the 3 x AA internal batteries (since you will be applying power to these batteries directly). The 3V voltage regulator that AudioMoth uses will accept voltages up to 20V but the regulator will become hot in use. The table in the AudioMoth Dev datasheets describes this in more detail. https://github.com/OpenAcousticDevices/Datasheets/blob/main/AudioMoth_Dev_1_0_1_Datasheet/AudioMoth_Dev_1_0_1_Datasheet.pdf In general, we recommend a limit of 6V for these batteries.
We've used lantern batteries in previous long-term deployments. They work well and can provide over 10AH of capacity. Internally, they are typically just 4 x D-cell batteries. You would probably get almost the same capacity from 3 x D-cell batteries. LiPo battery packs also work very well being fully charged at 4.2V and spending most of their capacity at about 3.7V. These can be bought in lots of different capacities but they are often subject to restrictions on transport and shipping. The AudioMoth Dev board makes it very easy to connect external battery packs through a JST header on the back of the PCB. Shortly we have a larger case coming for the AudioMoth Dev board which supports 3 x D-cell batteries.
Alex