I have an Accucel 8150 charger that works nicely for my 8s LiFePO4 pack. It runs off an 11-18V power source and wants 150W. I'm currently using a couple of old 12V SLAs in parallel and a 6 amp charger. A friend has a 300W ATX power supply from an old computer. They normally get switched by the motherboard. Can I just jumper across a couple of the terminals in the 24 block to switch it on and then use that to power the charger? If so, which terminals? Thanks - jd
They are not isolated 12v lines but common ground and it will go poof.
The blue line in the ATX connector needs to go to ground to activate the power supply but in addition you need to put some form of load (even a resistor) on the 5v bus to get the 12v up to proper voltage...
There is tons of info out there but be careful because the new ATX 2 style power supplies (like yours) aren't as simple to mod as the old AT / ATX..
You can't run 2 of them in series either without isolating them, have a search on here for Meanwell power supplies... they are cheap and push 150-350w depending on the model.
While you indeed may be correct on the color (I am actually color blind) ... you are using those to power multiple chargers - RC style but each at 12v?
There are mods you can make to some of these to increase the voltage a tad - many higher power RC chargers want 14-18v to acheive their full output (iCharger 1010B+, 208B+, etc)
Laptop chargers work great for this. Make sure that they are indeed isolated - the dell one I used the negative is connected to ground (earth). Unless you fit a 2 pin plug - you could have issues.
Thanks for the replies and good advice. I looked around the web a bit and most seemed to say I should put a load on the 5V circuit, so I bought a small bulb and socket at RS and plugged it into 4 & 5 (red-black) on the main connector. I jumpered 14 to 15 (green to black) to power it up. It worked - the fan spins and there's voltage across different colored wires. So I shut it down and cut the connectors off 5 yellow and 6 black wires. I plugged it back in and tested all the wires. There was no voltage from any yellow to yellow or black to black, but there was 11.87 V between individual pairs of yellow and black. So I stripped the ends and bundled the yellows together and the blacks together and put connectors on them. It does power up the charger but I didn’t try to actually charge the battery pack yet. It’s a 300W supply - hopefully I will have enough juice to run the charger. You’ll probably hear back from me if it doesn’t work - jd
I use a 600W supply, and it works great until you try to pull too many amps. The voltage from the supply drops and faults the charger. Ok as long as you don't overload it.
I'm using it to power a charger, not charge the batteries directly. The charger (a Turnigy Accucel 8150) requires an 11-18V power supply, not 110V from the wall so that's why I cobbed the old computer power supply. It provides me with a steady 12 volts - jd
Do keep in mind that the power of an ATX power supply is spread across multiple positive leads for the CPU, pci express connectors, hard drive/CDROM connectors, ETC.
It seems like you'd have to parallel the big +12v outputs together in order to draw any appreciable voltage out of one of those, and i wonder if that is safe.
Seems like the best way to go about it is to modify the power supply and basically have two uber 12v wires hanging out of it rather than ~20 12v tiny gauge wires.
( pardon my fairly elementary knowledge of electronics )
