OK, I know this must have been asked before, but I can't find what I'm looking for in the search function.

If I have a I306b charger, how many watts do I need in a power supply to charge 4 batteries at once? Figure 5S or 6S 2700 to 3000mah batteries at 25 or 35C.

Thanks

Though for Powerlab chargers, this calculator also is useful.

http://www.revolectrix.com/PL6_calculators_Main.htm

You can vary 12v or 24v input.  What power supply are you using?  If none yet, these are easy to convert

http://www.ebay.com/itm/Lot-of-2-HP-Proliant-DL580-G5-438202-002-DPS-1200FB-1200W-Power-Supply-/291285365649?pt=US_Server_Power_Supplies&hash=item43d1f5f391

For the DPS 1200 noted, here is step by step conversion.  Fairly easy to do.

http://www.rchelination.com/setting-hp-dps-1200fb-power-supply/

Can you link, or post a picture, to what power supply you are looking at? The DPS 600pb is rated at 47 amps 585 watts and also works great. I was able to run the PL 8 and the 306b up to full power together to charge 4 cell packs in a 24v configuration. Even though they were rated at 47 amps, I tried a few times to try to cause one to fail just to see the limits. I pushed it as high as 53 amps and never had a failure. Are you running a 12V power supply or 24v?  If you are running 12V you most likely will NOT be able to max the 306b out. Your wires will also get really hot. By the way, if this is a PC power supply most are WAY OVERATED and NEVER put out even close to what they claim they do. I've experimented with a few pulls and even at FREE they are not worth my time to make up. So I guess to specifically answer your question, I still need a little more info on exactly what power supply you are looking at. I need to know more than just the watts. Volts, and Amps rating need to be factored in.

Not as cheep as the computer supply but easy to use.  Pick your size and pay the price.  Low of $5 high of $100.

http://www.ebay.com/itm/Universal-12-24V-2-3-5-10-15-20-30A-Switching-Power-Supply-Driver-For-LED-Strip-/400766807980?pt=US_Lighting_Parts_and_Accessories&var=&hash=item5d4f902fac

12V or 24V models.  I am a low end user and one of the 12V models works for me.

I was looking at something like this:

http://www.hobbyking.com/hobbyking/store/__20611__Turnigy_1080W_100_120V_Power_Supply_13_8V_18V_60amp_.html

If I have a I306b charger, how many watts do I need in a power supply to charge 4 batteries at once? Figure 5S or 6S 2700 to 3000mah batteries at 25 or 35C.

Thanks

If I understand correctly you want to charge 4 battery packs in parallel.  If you mean that the listed discharge rate is 25C - 35C burst, that does not specify the charge rate. I have Zippy Compact 2700 mah, and IIRC, you had some of those. The site says 5c for charge, but I don't go over 2C for those. Some of the 60C discharge batteries might tolerate 5c charge.

If you use 80%, about 2000 mah, then at a 5 amp charge rate, 2C being 5400 mah or 5.4 amp, you can put in 2000 ma replacement in about 30 minutes allowing for slowing at the end. That means 20 amp output into 4 packs parallel, 5 amp or 2C/pack.

If that makes some sense, then your setup should work fine, i306 and 18V 60 amp charger. Perhaps more at limit if 6 packs and 30 amps output needed, or 4 packs at 7.5 amps or about 2.5C.  Also, you may get close to the limit with 4 packs of 6 cells.  The charger output and/or input limit can control that.  The reason for higher voltage is to get more watts into the charger below its amperage input limit.  I could not see an input amperage limit for the i306b.  I recently searched before getting a PL8.

Sorry if this is overly wordy and perhaps too simplistic at the same time.

This is a DPS 1200 that I recently made up for someone this puts out 24V 1800 watts which exceeds the capabilities of your charger and is way more powerful than that Hobby King Power Supply you linked to.

Just to follow up. I ended up getting a PRC600 power supply to go with the iCharger 306b. Seems to work OK.