Has something changed with how the batteries charge? When I first purchased my P4 the battery lights would blink in sequence towards the button and now for the first few minutes of charging only the light next to the button lights up three pulses at a time. Then after a while it goes back to the lights in sequence pattern that it was when I first got them.

Does anyone know if this is just a change or does that signify some kind of a problem?

check the little booklet that came with the battery (the intelligent flight battery guide). It should have came with your P4, and it mentioned the LED's lighting up in sequence when charging, and i remember it saying it would do something different with the LEDs if there was some issue (I can't remember exactly what it said, I don't have it with me). If you don't have it anymore. I can post what it says later when I get to the aforementioned guide.

Thank you for the information. I just read through the little booklet from the box and there is nothing about the lights in it.

the led3 link 3 times every 2 seconds indicates that the charge temperature is too high, and it will resume to the normal state when the temperature is under 40℃

Sounds like a failed pack if it won't wake up, a word of advice, do not leave the packs at 10% for more than 24 hours, always store batteries at around 40-50 charge

That happens when the battery is too hot,  remember to let the batteries cool off after a flight.