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Old 11-01-2007, 08:32 PM   #46
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if im am only requiring the 12v do i still need all 5 bindind posts? my ps @ 12v is 18a, and i only want to run one charger. is there a way around not setting up 3.3v and 5v?
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Old 11-01-2007, 08:46 PM   #47
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if im am only requiring the 12v do i still need all 5 bindind posts? my ps @ 12v is 18a, and i only want to run one charger. is there a way around not setting up 3.3v and 5v?
Just leave the cable out will do.
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Old 11-01-2007, 08:58 PM   #48
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so no need to connect the 5v's and 3.3v's at all?
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Old 11-01-2007, 09:04 PM   #49
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so no need to connect the 5v's and 3.3v's at all?
Yes. Just unsolder all the wires on the pcb level. Make sure there is no wire dangling some where.

For the 3.3v wire you will need to connect to brown sense wire as per instruction.

For the 5v wire you can snips them off at pcb level but leave 1 for connection to power resistor.

BTW, I just follow the instruction and managed to get 1 working for sometimes now.

Last edited by -KilleR-; 11-01-2007 at 09:14 PM.
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Old 11-01-2007, 09:11 PM   #50
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thank you for the help killer
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Old 11-01-2007, 09:15 PM   #51
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thank you for the help killer
I amended the post above. Pls check.
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Old 11-01-2007, 11:06 PM   #52
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from my perception i only need the ground and +12v to be connected to the binding posts, or do i need -12v as well? any input would be much appreciated
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Old 11-02-2007, 02:12 AM   #53
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from my perception i only need the ground and +12v to be connected to the binding posts, or do i need -12v as well? any input would be much appreciated
You don't need it either unless you need to run something which uses 24v.
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Old 11-02-2007, 02:22 AM   #54
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actual output was 11.6
That will happen if the load on the 5v lead is not big enough. I know most instructions recommend to use a 10 ohm resistor as the load but from my experience that is not enough if you want to run multiple chargers and keep the output above 12v.

On my unit I use a 50watt 0.5 ohm heatsink encased resistor. Allows me to run 2 chargers, tyre warmers, and various cooling fans without dipping below 12v.
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Old 11-02-2007, 02:30 AM   #55
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Hi, i have converted 3 Computer power supplies, and hooked optional fuses on both the 5v and 12v rails. It really doesn't matter what watts the PSU is, it is just going to get hot.

But when you are setting up your terminals, put at least 4 yellow/black wires each for the 12v terminal, and the same for 5v but with the red/black wires, this prevents the wires from melting from too much current. I ran 2 Chargers charging at 6 Amp each and a couple of fans, on a Old 300watt PSU. It is better to use globes for the load, As Adam said, you can tell when the PSU is on, and it doesn't get hot.

Also, be VERY VERY CAREFUL WHEN CONVERTING POWER SUPPLIES, Triple check what you have done, and make sure you ask someone if you are unsure, because the last thing you want to do is injure yourself, or others. But If you were going to buy a power supply, id recommend getting one that has been made for that specific use, just to be on the safe side of things, and i am sure a lot of people will back me on this as well.

Marc
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Old 11-02-2007, 02:31 AM   #56
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That will happen if the load on the 5v lead is not big enough. I know most instructions recommend to use a 10 ohm resistor as the load but from my experience that is not enough if you want to run multiple chargers and keep the output above 12v.

On my unit I use a 50watt 0.5 ohm heatsink encased resistor. Allows me to run 2 chargers, tyre warmers, and various cooling fans without dipping below 12v.
Is it something like the image shown? If yes, then I must get 1 to test it out.

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Old 11-02-2007, 03:45 AM   #57
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Yep, exactly like that

On the subject of using globes instead of resistors, IMO light globes get bloody hot too so I don't see much of a difference, plus a light globe is physically much more fragile than a resistor.

Finally, as MArc05 said, you really need to be very careful when making these - often people over-estimate their abilities with things like this so it is important not to attempt it unless you are sure you know what you're doing.

The safest way to make one is to have all the wires coming out of the PSU go into a separate box, which can then be attached to the PSU via velcro or double-sided tape. Inside this box is where you put the binding posts, resistors etc and where all the actual re-wiring takes place. That way you never have to open the PSU itself.
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Old 11-02-2007, 03:51 AM   #58
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Also, if you want to test the effects of various loads on the 5v rail it is quite easy.

Connect your multimeter to the 12v lines to measure the voltage.
Now with the PSU switched on, add a small load across the 5v line - it can be something as simple as plugging a 540 motor or another resistor or light globe into the 5v binding posts.

Now watch on the multimeter how the increased load on the 5v line raises the voltage on the 12v line
By doing this with resistors of varying value, you can soon determine what value is required to get the desired 12v voltage.
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Old 11-11-2007, 10:05 PM   #59
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So how do you wire a rocker switch for power and led to let you know that the power is on.
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Old 11-12-2007, 12:32 AM   #60
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So how do you wire a rocker switch for power and led to let you know that the power is on.
Connect the switch between the green wire and one of the black wires.

Connect the LED between any of the voltage output wires and a black wire, using a suitable resistor. The value of the resistor depends on what type of LED you are using, and what voltage. Check http://ledcalc.com/ to work out the resistor value.
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