What charger?

[bl-is-future]

according to my calcs this PSU (http://www3.towerhobbies.com/cgi-bin...&I=LXKLP2&P=ML) will run the charger at full tilt (full 250w at 17.86a) but the PSU will be at full tilt with only 14v and 18a output.
However the biggest batt i will charge is a 6s 5000mah (most likely).
So -
6s * 4.2v = 25.2v then 25.2v * 5a = 126w then 80% eff 126w / .8 = 157.5w
157.5w / 14v = 11.25a minimum input for charger so 12-13 amps headroom and that is well below the 18a max output of the PSU.

But if i want 2c charge rates than it is as follows.
6s * 4.2v = 25.2v then 25.2v * 10a = 252w then 80% eff 252w / .8 = 315w
315w / 14v = 22.5a minimum input for charger and that is well above the max 18a output of the PSU and the required 252w is above the charger limits (250w) as well, so 2c charging will not be possible on this battery at least. I would only be able to do about 1.5c max on a 6s 5000mah batt.
Does any one see a miscalculation?
I think i understand this all now. Amazing what some research can do! Does anyone know of a 14v or higher and 25a or higher PSU for around 100 or so?

[bl-is-future]

Sorry for the posting so much jsut trying to figure out the best scenario of a PSU.
this psu (http://cgi.ebay.com/PYRAMID-PS52KX-4...QQcmdZViewItem)
can out put a max of 552w at 80% eff. and the chargers require 500w for 2 610iNET. so this PSU will power both chargers but my only question is how good is this brand. I know how to figure out specs to see if the PSU will work or not but i do not know good brands. I have read good things about the pyramid PSU's but would like your guys' opinion as well.

Originally Posted by bl-is-future

Well thank you all for the input. I have decided that i will get the single version with more power for now and get a second later on. I realize i will have to get a second psu but down the line it will be ok. And a point was brought up if one fails i still have one at least and i like the idea of that. Oh and thanks for the B-P-P hint. I forgot all about them. Wish mike carried the 250w hyperion and the adapter. Now i imagine i could possibly run both chargers off of a 500w 2 x 20a 12v rails. One charger on each rail. Only bringing this up because i already have one of these laying around. If this will not work you guys suggest at least 15a for each charger???? Or could i go less or have to go higher. Not sure how to figure out what i need to look for in the PSU. A formula to figure out a min would be great. thanks again guys. As usual you were all very very helpful.

you take the voltage X capacity X 20% = wattage needed

example 6s 5000 pack

22.2 X 5 X 20% = 133.2

the 20% is for effiency

Originally Posted by bl-is-future

according to my calcs this PSU (http://www3.towerhobbies.com/cgi-bin...&I=LXKLP2&P=ML) will run the charger at full tilt (full 250w at 17.86a) but the PSU will be at full tilt with only 14v and 18a output.
However the biggest batt i will charge is a 6s 5000mah (most likely).
So -
6s * 4.2v = 25.2v then 25.2v * 5a = 126w then 80% eff 126w / .8 = 157.5w
157.5w / 14v = 11.25a minimum input for charger so 12-13 amps headroom and that is well below the 18a max output of the PSU.

But if i want 2c charge rates than it is as follows.
6s * 4.2v = 25.2v then 25.2v * 10a = 252w then 80% eff 252w / .8 = 315w
315w / 14v = 22.5a minimum input for charger and that is well above the max 18a output of the PSU and the required 252w is above the charger limits (250w) as well, so 2c charging will not be possible on this battery at least. I would only be able to do about 1.5c max on a 6s 5000mah batt.
Does any one see a miscalculation?
I think i understand this all now. Amazing what some research can do! Does anyone know of a 14v or higher and 25a or higher PSU for around 100 or so?

if you set the charger up to charge @ 2c it may not charge at a full 2c and if it doesnt it will charge as much amperage that is available.....and I think your calculations are more accurate than what I posted I was rounding off using the 3.7vpc of a 6s pack