Solar node

Hi. Im building solar node based on heltec v3. Board lose settings when power is low, so what is the best alternative? Ive got 2000mah 18650cell with solar rwgulator board and 6v/1w solar cell.

Hi. Im building solar node based on heltec v3. Board lose settings when power is low, so what is the best alternative? Ive got 2000mah 18650cell with solar rwgulator board and 6v/1w solar cell.