paulusbrand:
I know its a late response but I have a solution when using the ht4928s chip.
I use a 50 Ohms resistor to generate some load the keep the "powerbank" chip enabled. But it is switched on and off by a transistor (PN2222). The transistor is controlled by the arduino. After some experimentation I found out the load only has to be enabled for 0.01 seconds every 3 seconds to keep the "powerbank" on. Effectively this will only 0.333 mAh.
Great! Can you please send a picture or schematic of how did you wire this? I´m having the same issue as Bringamosa did, with a Nano that keeps shutting down when powered by a T6845 step-up/charger.
Thanks!