Ok, I did a bit of research on the charger setup for the P3. The charger itself is just a 3,3amp power supply. The batteries actually contain the charging circuitry. I have been in the electronics hobby for 40 years and have a general understanding of they setup. The P3A has a 17.3v, 3.3a charger with a output of 57w. My plan is to connect a battery charging bank, capable of charging 4 P3 batteries at once. This will be supplied by a 17.3v, 7a small bench supply I just completed. This will give me 121w of charging power. Has anyone else did this sort of thing and what has been your experience with it.