Hey doods!
By using boost converters, I bypassed the inverter circuit altogether, thereby eliminating a lot of waste via thermal energy.
Worth noting:
1) Voltage and amperage parameters are user-programmable. Therefore, these units can be set up as quick chargers or slow chargers in any combination. I can use one to quick charge a
P4P battery, and set the other converter to slow charge a Mavic Pro battery. The third could be set as an Inspire 1 charger.
2) Banana plugs insure compatibility with ALL batteries, regardless of make, brand or voltage.
3) Because this connects directly to a car battery, I bypass the DC -> AC -> DC conversions. The net result is almost no heat generated. The boost converters stay very cool.
4) First charge; initially set to 5 Amps and then boosted to 6 Amps @ 16 minutes, I was able to charge 3 batteries in < hour. If I set the charger for 6 Amps from the get go, I bet I could get that down to < 50 minutes.
5) 6 Amps @ 17.5 Volts = 105 watts. According to the DJI spec sheet, these batteries can sink 160 watts. So a 105 watt "quick charge" (about 50 minutes from 30%) is well within spec.
6) The boost converters are rated @ 900 watts/each. So running them @ 105 watts is WELL within spec.
7) This build is version 1.0. Assuming all of this continues to work as well as the initial testing, I will probably repackage it into something a little easier to carry...perhaps a case of some kind.
8) The whole mess costs less than 1
P4P battery.
D