Hi Kaspars – this is Will from Austin Mesh – thanks for mentioning us! We have a meeting tonight and I’m excited to keep building out the network. We’ve found that it’s better to over-spec both the batteries and solar panels. Our “version 5.0” solar repeater uses a 12 watt panel and a 6,400 mAh battery (parts list is on austinmesh.org). One of the main problems with the RAK chips is if the voltage falls to a certain level it will put it into a permanent fault state, so it’s best to have a battery that cleanly shuts off power if voltage falls below a certain level. The simpleest way we’ve found to do this is with the Voltaic Systems iot battery packs. The other way we’ve tried is to use a an 18650 battery and use a cutoff chip that shuts power if voltage drops below 4.25v: https://www.etsy.com/listing/1421193059/10-li-ion-battery-protection-modules-pcm