There may be some inconsistencies in the manual now as we have had quite a few different supplies of components and some of them behave in a slightly different way from the previous ones. It used to flash when it was running low, now when battery almost runs out i can confirm it's the error 6 coming up which means under voltage. basically it's over so you can't get much more from it. What you can still try to do is to reduce the PAS level to 1 or 2 so it should still keep you going for a while with lower power output.
BTW Steve the USB in the battery is designed for charging the phone.
all the best
Andrew
BTW Steve the USB in the battery is designed for charging the phone.
all the best
Andrew