I did not notice this on my 3 older non sealed non passthru leo batteries.
My newer leo battery if I run it dead.....flashes. When I put it on charger it flashes 3 times...then light goes out...5 seconds later it flashes again 3 times then light goes out...5 seconds later flashes again 3 times....and then one more time. Then it starts charging light stays on till fully charged.
My newer leo battery if I run it dead.....flashes. When I put it on charger it flashes 3 times...then light goes out...5 seconds later it flashes again 3 times then light goes out...5 seconds later flashes again 3 times....and then one more time. Then it starts charging light stays on till fully charged.