If we trust the numbers and go with that then you could do any job up to 200 watts and this includes any amount of multiple chargers using the same ps.

do i go by the watts, or amps? It is 300watts and it claims 17A on the +12v side. Even if that number is a bit inflated, it still has two more amps than needed. That's providing I am charging both charger at max. Am I correct, or way off?

When figuring the charge jobs or when adding them all up it always must be figured in watts. I have an idea though that your ps "watts" is a total of all rails added up. You'll only use the 12v+ rail so I figured it's power was 12x17 = 204 watts. The other part of the 300 is useless for charging.

You can't simply use the max current of the chargers, they also must be figured in watts.

An example might be the 10 amp charger with a 10 volt battery at 10 amps = 100 watts
An example might be the 5 amp charger with a 5 volt battery at 5 amps = 25 watts

Added together they can be easily powered from a ps that has 200 watts

So I will be using this at the track, and I run 2s lipos. So even at the max voltage of the lipo and max wattage of each charger I would be pulling 8.4v x 10a and 8.4v x 5a = 126watts. I should be good with this setup then.

You got it, you'll be fine as long as those power supply specs are for real. Fire them both up at full power and then read the input voltages at one of the chargers to see how much it sags below 12. I'd consider anything over 11 volts to be ok. You could also read the ps output voltage with a dvm. If not you'll just have to cut one of the chargers back a bit.

Ok so I have most of the soldering done and I have tested it on my 5A charger. Works great. I went with a 10ohm 10watt resistor on the 5.5v side. That gave me 12.84v on the 12v side (it was only 11.6v before the resistor). With the 5A charger charging at 5A, the voltage dropped to 11.8v. Hopefully when I get my 10A charger and fire it up, the voltage won't drop below 11v. Fingers crossed. I just ordered my charger so I wont know for a few days. In the mean time I will finish up my wiring on the PS and work on my field box.

A couple more quick questions. First, I am running 4 yellow and 4 black wires to the banana jacks for the 10a charger and 3 yellow and 3 black for the 5a charger. Is that enough, not enough, or more than I need? Could I get away with say 2 or 3 to the 10a charger and 1 to the 5a charger? Second, should I keep an eye on the resistor to make sure it doesn't get too hot? I have it zip tied to the vent holes in the case.

Ok I finished everything up. I discharged a few 3s 2200mah lipos with my 5A charger so i could charge them up to test the new PS. It wont discharge any faster than .4A even with it set at 1A discharge. After discharging them down to around 10.9v I recharged them. With the charger set at 4.4amps it was charging at 4.3amps. I jumped it up to a full 5amps and it was still charging at 4.3amps. I'm not sure why it doesnt charge at the full 5amps, but when I use the ac cord that came with it, it will charge at 5amps. My new Thunder 10amp charger will get here this week so I hope it charges at 10amps. O ya while charging, the voltage never dropped less than 11.85v.