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| Thread ID: 89453 | 2008-05-01 00:35:00 | Easy 12v source | ubergeek85 (131) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 664521 | 2008-05-01 00:35:00 | I have a device which I would like to power (a small air compressor). It needs 12v @ 10 amps (:horrified I know). However, the closest I can get to this is 12v, 8.5 amps, from an old AT PSU. Can anyone suggest anything? I don't have a car either. How long would a car battery last at that load, and would a car charger do the job? Thanks. | ubergeek85 (131) | ||
| 664522 | 2008-05-01 00:52:00 | These: jaycar.co.nz jaycar.co.nz A bit expensive though, and not really intended for what you want to do with them. |
somebody (208) | ||
| 664523 | 2008-05-01 00:57:00 | Ouch. I see, thanks. | ubergeek85 (131) | ||
| 664524 | 2008-05-01 02:04:00 | Put the battery charger on the battery and use the battery itself as a reservoir for the voltage and current you need . It will last a while longer than just using a car battery alone . If you need CLEAN, straight, no-sine wave current (not very likely with a 12v compressor), you might have to create a choke/capacitor/filter device to remove the peaks and valleys of the AC-wave getting past the charger . To get a thumbnail on the time and capacity of the battery, take the rated amps/hours and divide it by the amps of the unit you want to run . . and take . . . say, about 70% of that value as the real working capacity . If you are taking this current out of a lead/calcium battery . . . be warned that they don't like to get below about 10 . 5 volts . They aren't dependable after a recharge from that low voltage condition . Now . . in a lead/acid battery . . it is almost bullet-proof for near-to-total discharge . They can recover a lot better than the newer "non-serviceable" types . Remember that the closer you get to high pressure, the higher the amps-draw will likely be too . Your factoring in of the time-capacity-values will depend on quite a few variables . Heat Time running Pressure demands Volume demands Wiring size Battery age and design Starting charge and rate of recharge . . . . . . . . . . . . . don't forget the temp of the battery too! You gonna run an air brush? Sounds like it . That should help or not . |
SurferJoe46 (51) | ||
| 664525 | 2008-05-01 02:08:00 | Just grab an ATX power supply and short the green wire to any of the black ones. Voila - one stable, high-current 12v power source. There should be more current available than your old AT one can provide, and PSUs are relatively cheap. | Erayd (23) | ||
| 664526 | 2008-05-01 02:12:00 | That sounds like a lot of work! As for what I'm actually using the compressor for... I don't know, I just want to get it working at the moment. Its rated up to 250psi, and not supposed to be run for more than 10 mins. I'll see if I can get ahold of a cat batt and charger. Thanks. BTW Bletch, I don't have a PSU that does 10 amps on the 12v line, and don't really want to buy one. | ubergeek85 (131) | ||
| 664527 | 2008-05-01 08:17:00 | How bout 10x 1 amp 12v psu's :D | pine-o-cleen (2955) | ||
| 664528 | 2008-05-01 12:56:00 | Have you tried the old AT power supply? It's likely to have less over-current etc protection than a newer one and might just work fine. Just because the compressor asks for a 10 amp power supply doesn't mean it will always draw 10 amps. Can't hurt, anyway. |
george12 (7) | ||
| 664529 | 2008-05-01 22:59:00 | Have you tried the old AT power supply? It's likely to have less over-current etc protection than a newer one and might just work fine. Just because the compressor asks for a 10 amp power supply doesn't mean it will always draw 10 amps. Can't hurt, anyway. But it can hurt. I use that PSU all the time (not for a computer, but for other things). It's quite useful, and I don't really want to break it. As for not always needing 10 amps, well, true, but again, I don't want to end up breaking something. Thanks all. |
ubergeek85 (131) | ||
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