Crash

[OgelGames]

2020-10-10 01:45:40: ERROR[Main]: ServerError: AsyncErr: ServerThread::run Lua: Runtime error from mod 'powerbanks' in callback node_on_timer(): /data/world//worldmods/powerbanks/init.lua:67: attempt to perform arithmetic on local 'item_max_charge' (a nil value)
2020-10-10 01:45:40: ERROR[Main]: stack traceback:
2020-10-10 01:45:40: ERROR[Main]: 	/data/world//worldmods/powerbanks/init.lua:67: in function 'charge_item'
2020-10-10 01:45:40: ERROR[Main]: 	/data/world//worldmods/powerbanks/init.lua:88: in function 'old_action'
2020-10-10 01:45:40: ERROR[Main]: 	.../world//worldmods/monitoring/builtin/nodetimer_calls.lua:26: in function <.../world//worldmods/monitoring/builtin/nodetimer_calls.lua:17>

[OgelGames]

This is caused by a non-chargeable item being placed in a powerbank, this should not be possible due to checks on inventory move callbacks, but it is possible in Minetest 5.3.0 or earlier because of this engine bug: minetest/minetest#6534