Default Red light flashing battery expended completely problem - batch is not helping

I foolishly let my battery on my HOX completely empty and now I'm having the common charging problem. I can get into bootloader if I have it connected to a mains charger, so I thought I'd give the batch script a go that is all over the net:

Code:
@echo off
:start
fastboot getvar battery-voltage

fastboot reboot-bootloader

ping /n 6 localhost >nul

goto start
How I can't seem to cycle the loop - the output is as follows:

Code:
C:\htc>charge.bat
< waiting for device >
battery-voltage: 884mV
finished. total time: 0.207s
rebooting into bootloader...
OKAY [  0.256s]
finished. total time: 0.257s
getvar:battery-voltage FAILED (command write failed (No such file or directory))

finished. total time: 0.000s
rebooting into bootloader...
FAILED (command write failed (No such file or directory))
finished. total time: 0.000s
getvar:battery-voltage FAILED (command write failed (No such file or directory))

finished. total time: 0.000s
rebooting into bootloader...
FAILED (command write failed (No such file or directory))
finished. total time: 0.001s
getvar:battery-voltage FAILED (command write failed (No such file or directory))

finished. total time: 0.000s
rebooting into bootloader...
FAILED (command write failed (No such file or directory))
finished. total time: 0.001s
getvar:battery-voltage FAILED (command write failed (No such file or directory))
Note I am using stock, not a custom ROM.

I suspect I have so little battery (884mV!!!) that it is completely buggered. But I'd welcome any suggestions people might have. I tried all the normal power/vol buttons combinations, I've tried recovery from bootloader, and I've tried just leaving it on mains charge overnight. No joy.