Wiring PC Fans

Xeno420 said:

if you have an old pc power supply, I can show you how to get a lot of things going on in your grow room. Look @ my thread on page 6 I think --->https://www.rollitup.org/grow-journals/420260-organic-window-grow-michoacan-bagseed.html

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I looked into one of these when i first was deciding on a pc fan, these power supply units are bulky but could support timers, thermostats, heat pads and a few other things, in the end i thought it was too much hassle and cost so went with a pc fan and an adaptor. It is rated 12v but the ampage of the switchable adaptor was too high so i simply run it at 4.5v to 6v. I check the adaptor for excessive heat and i find it to be quite acceptable, about the same as a pc or phone charger.

I know ampage makes a big difference and also getting the wires the right way.

You have four wires on the fan and two on the adaptor, there will not be too many combinations so strip the wires, turn the adaptor on and keep trying till you get fan movement, if not try a different voltage, there is only one combination, try it at half voltage and lower again, the higher ampage will be lower with lower voltages i think. Peace

I've honestly been trying for about three hours. I've tried every combination imaginable on the 12v adapter, then again on another 12v adapter. I've tried a few times on 5v adapters, but no luck.

I am VERY discouraged, to say the least. I appreciate all your help tho.

I seen your type of fan and seen how i needed a pc control, i just bought a standard cheap pc fan with just two wires and it made the whole thing a lot easier, it spins fast at 6volts so i leave it round there. The adapter dose have a higher ampage but this is lower at lower voltages i think. I even had a choice from pc fans that just run off 240v or the mains directly but i didnt want to hang a 240v fan in my grow room for fear of fire. Buy a new fan and i wouldnt recomend it but to check the adaptors are working rub the two wires together from the adaptor, if they spark its good, if they dont its not supplying electricity. I do not recomend doing this as it goes against all electricity safety rules.

Buy a more simple fan, i am gona get a small solar paneled fan next as i have plenty of spare light and its only a small veg room. Peace

yeah when i put the two wires together they spark, that was the first thing i did. Honestly this fan was the cheapest and smallest i could get my greasy mitts on.

I actually noticed when I took the other fan out of the box, I could move the fan slightly, by touching the exposed adapter wires to the pins on the jack/clip on the pc fan. Does this mean that the fan is underpowered? I mean the adapters do look pretty old.

Under powered or overpowered, could be too high an ampage or too low an ampage, i think all will cause a problem, keep trying or get a different rated fan.

Kingrow1 said:

Under powered or overpowered, could be too high an ampage or too low an ampage, i think all will cause a problem, keep trying or get a different rated fan.

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You can have a million amps at 12 volts and the fan will only use what it needs to use and the rest is on reserve for when needed.

So how many volts should the adapter have for a 12 volt, 0.15 mA fan?

Xeno420 said:

You can have a million amps at 12 volts and the fan will only use what it needs to use and the rest is on reserve for when needed.

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I checked my fan and adaptor, fan is a 12v 0.2va and the adaptor is switchable from 12v at 500ma down to 3v. I run mine at 4.5/6volts depending on the heat requirements. I know the fan will only use the ampage required but i found my fan stopped at too low a voltage and went to quick at the 12v setting on the adaptor. Peace

Agreed, are they both DC or AC, i think mine is DC?