Well, my Prophet Sport Duo has died, so I find myself charger shopping again.
Previously, I had said I was looking at the
Reaktor 2x300w 20a DC only charger from Hobbyking, and the
UP120AC Duo Dual 2 Port from Amazon. These two chargers are still on my list, but I am expanding my search a bit before I spend my $$$...
I am also looking at maybe getting 2 single channel chargers. Cost wise, it will be similar to a two port charger. Note - these are DC only, you will need a 12v PSU.
Turnigy Reaktor 250W 10A 1-6S Balance Charger I read this a rebrand of the popular iCharger, and has a very good reputation. It is also sold under a few different brands, like the Banggood.com Charsoon. This is an intresting charger to me because although it is 'only' 10 amps, it can handle 250W - What this means for us, is that it can push that 10 amps regardless of whether you are charging a small 2s pack, or a big 6s pack. At $50 for the Turnigy branded version, this seems like a great deal for a charger than can handle almost any battery you throw at it.
Turnigy Accucel-6 80W 10A Balancer/Charger LiHV Capable - Another Hobbyking charger that I have come across in my research - this one is cheaper $30, and still 10A, but only 80W. So you will still be able to charge your 4s, 5000mah pack at 1c, but anything bigger, and charge times will get long.
So those chargers I mentioned are DC only. And what is the point of trying to save a few bucks on a DC only, of you have to shell out a bunch of money for a 12v Power Supply Unit (PSU)?
I bet most of us have an old, outdated, or dead PC taking up space in our garage or elsewhere. The good news, you can pull the power supply, and easily 'convert' it for powering a hobby charger. For these pics, I am looking at a smallish, 300w PSU. (Forgive me, but I missed some pics at the start of this...)
In a nutshell, when you pull the PSU from a PC, you will have a small box, with a ton of colored wires, going to a dozen different sized plugs. Don't get overwhelmed, we will be removing most of those wires.
First, inspect it. There should be a label similar to this:
This is the Faceplate, and it shows all the info about the different voltages available, and how many amps are on each bus. For this PSU, there are 2 +12v bus's. We don't care about the rest. You might do some quick math to make sure your PSU has enough watts for your application. Remember Volts * Amps = Watts. So 12V*8a=96W, on bus +12v1. Not a lot. Bus +12V2 has 174w output. remember we cannot combine these bus's. We can use them to power two different chargers at the same time, though. Assuming the chargers can keep up, bus +12v1 can handle up to a 4s 5000mah at 1c, and bus +12v2 can power a charger pushing 2c to that same battery.
Ok, math over for now. Look at the mess of wires. Note that most all of them are yellow, black, or orange, with a few other colors scattered in the mix. Each color represents a different bus/voltage inside the PSU. All the yellow is +12v, connect to the same solder point inside the case. Same with all the black (Common/Ground), and all the orange(+5v).
Find the green wire. It will go to the big 20-pin plug. Note the position, and find a black wire on a pin near it. Get a paper-clip (or similar small bendy wire) and jumper between the green pin and a black pin. Now plug in the PSU. Did the fan come on? If yes, Great! Pull the jumper. Did the fan stop? Great! the green wire is the on/off switch for most PSU's. If you have a multimeter, set it to 0-20vdc, plug the jumper back in between green and black (this should turn the PSU back on). Now use the multimeter to measure between any black (common) and any yellow (should be +12v) If you got +12v, we are ready of move on. Feel free to check the voltage of some of the other colors. also, look for a square 4-pin plug by itself - it will have 2 yellow and 2 black. If your PSU has 2 +12v bus, these two yellow will most likely be the second bus. The yellow wires may be yellow with a stripe - mine were yellow/black.
Unplug the charger, and give it 1-24 hours to "rest" to self-discharge all the capacitors inside. You can leave the green wire jumpered during this process to help it bleed off the power...
Now the fun part.
Cut off all the plugs, but leave the wires long. Sort all the wires by color, and bundle them together. Open the case, and enjoy cutting that "Warranty void if Damaged" sticker. If needed to get good access to the buses, unscrew the main PSU board from the internal case. Once you get it open, sort out the wires again, and it is time to start cutting -
Clip most of the wires off - leave all the yellow and black for now. Also leave the green wire long.
sort out 5 black wires, and clip the rest off. Check out the yellow buses - if there is 2 (like on mine) save the two yellow/black from +12v2 and 2 wires from +12v1. Clip the extra yellow wires. Once I was done clipping wires, I coated the ends with liquid electrical tape. Put the case back together, and I added wire wrap to tidy up the bundles.
Tie the green wire to one of the black wires. You could put an on/off switch here, as the green wire tells the PSU to power on.
Divide the 4 black into 2 groups, and match them up with the two groups of yellow wires - 2 yellow and 2 black in each group. Add connectors on the yellow/black pairs and heat shrink if needed. done!
FYI, I used a pair of wires for each power lead, because the 14a this PSU can supply is more than one single 18g wire should take, safely. A pair of 18g is safe, though.
That is all there is to converting the PC power supply to power a hobby charger. Really, though, if you did not want to open the case, you could clip all the extra wires an inch or three outside the case, and tape them all together. Also, if you want to get fancy, you could drill the case to mount bullet connectors on the case - then you would have a clean box with no exposed wires. All depends on how much work you want to do.
