ProGrow Update #2 – Battery Bank
I’ve upgraded the system to include a USB battery bank. I’m using a cheap 4400mAh battery at the moment, but intend to upgrade it to a better system. I have a bunch of spare 18650’s and a MacBook battery that I could use, and I’ve ordered some charging and voltage step-up/step-down modules from Aliexpress to build a custom charger. I’m also going to invest in some solar panels to make the system recharge during the day, but I will need to find out my current draw and other things before I buy them. Right now the system requires too much power to have a realistic solar panel recharging system.
I ran into some initial difficulties using the battery bank to power the Arduino. The bank is designed for charging phones, it has an automatic shutoff feature if the output current is very low. During normal operation of the ProGrow, the battery shuts off after approximately 10 seconds if current draw is under 50mA. I had to make the automatic sampling time ~5 seconds, so that the LED display would turn on and draw enough current to keep the battery active. From 1/4 charge, the battery bank was able to power the system in its current state for ~18 hours. Not bad for a first run I suppose, but future versions will be much better. I’ll have to make a better battery bank and find out my current draw before I continue.