DIY High output 13.8v power supply???

[Gadgeteer123 10+ year member]

I have already priced out and selected the parts I need, i just want to know if it will work. I want to build a 130amp power supply to run my car electronics in my home. I need at least a 120amps of power, so I was thinking I could take a 1.5HP AC motor and attach a 130amp alternator to it, would this work? I have friends who can weld and are good with cars. I just don't want to drop 400 bucks on a 150 amp power supply. The ac motor is 1700rpm, and in theory the motor uses 200 watts at 220v so it would be more efficient also.

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[boom24 10+ year member]

I have already priced out and selected the parts I need, i just want to know if it will work. I want to build a 130amp power supply to run my car electronics in my home. I need at least a 120amps of power, so I was thinking I could take a 1.5HP AC motor and attach a 130amp alternator to it, would this work? I have friends who can weld and are good with cars. I just don't want to drop 400 bucks on a 150 amp power supply. The ac motor is 1700rpm, and in theory the motor uses 200 watts at 220v so it would be more efficient also.

why do u wana do this????

 

[MakeshiftAudio 10+ year member]

Um. 1.5HP=1119W.

13.8*130=2070W.

Either way, even if everything was 100% efficient, you will not get it.

Generally, you need a HP rating of 2x the kW rating. If you want 30kW, you'll need at least a 60HP motor. That's a general rule of thumb for generators.

It would be better for you to build a switchmode power supply, or get a large transformer to step the voltage down from whatever to 12.5V, rectify and filter it, and you should get about 14V or so. Though when testing with this sort of supply, don't be surprised if you get a 120Hz hum. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Gadgeteer123 10+ year member]

a car alternator only uses 2-4Hp of the car engine why would that be any different on a ac motor. and this motor is 1.9amps at 220volts, and yes 1.5hp would be that many watts if it was 120v which it is actually 220v.

 

[Korn4Life 5,000+ posts]

just get a pyramid 50 amp power supply and a couple batteries and your good to go. Thats what I do

 

[JimJ 5,000+ posts]

When you say "run", do you mean for testing purposes? Because trying to do this permanently is ghetto-rigging it.

Think about what you're doing here. You're trying to convert electrical energy into mechanical energy, back to electrical. It's expensive enough trying to rectify AC without any losses due to conversion...you're simply asking for trouble in doing this.

For benchtop use, buy a real power supply that's made to do this. Good test equipment isn't cheap, but it's an investment in your hobby - and you can troubleshoot other people's amps to help defray the costs //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Plutoman 10+ year member]

a car alternator only uses 2-4Hp of the car engine why would that be any different on a ac motor. and this motor is 1.9amps at 220volts, and yes 1.5hp would be that many watts if it was 120v which it is actually 220v.

It doesn't matter the voltage - it is still using 1.5hp with the alternator.

You will not get enough power out of it. You will get a fair amount, but not nearly as much as you are looking for.

A car alternator only does use 2-4hp, and it produces the equivalent amount of power for that. Think on it.

It's a neat idea, but not feasible for the power you want. And it would be more than a tad ghetto rigged.

 

[Gadgeteer123 10+ year member]

well i don't mind ghetto rigged, i just want this to work for about 3-4 months, i want at least a 100amps power for under $100, the amount of electricity it uses isn't a big deal. I can get a bigger ac motor if need be. I don't care how cheap it is. and I do have a bench power supply that is 25 amps of clean good power. But it isn't enough to run a amplifier that uses 120-130 amps of power. I Just want the cheapest way possible to achieve a 100 amps at a voltage of at least 13.8v.

 

[k_schutte 10+ year member]

I am not too knowledgeable on this but couldn't you just buy a few power supplies and wire them in parallel...? the ones I was looking at where like 150A max on 220v so in theory couldn't you parallel them and have a max of around 300A? granted that is 12V not 13.8 but it would be easier, cheaper and it would work (i think)

 

[Gadgeteer123 10+ year member]

you can't put them in parallel, i was gonna do that with four 25 amp ones but they would trip each others circuit breakers. And i tried a 200amp jump starter battery charger and it wouldn't even turn the amp on.

 

[k_schutte 10+ year member]

nothing a diode isolator or "gate" couldn't fix I would think...

 

[dappa5 10+ year member]

http://www.caraudio.com/forum/showthread.php?t=427150&highlight=dappa5

i do not have any more but you get the idea

 

[Gadgeteer123 10+ year member]

ya i wish i could a hold of one of those.

 

[dappa5 10+ year member]

ok ok i have 60's available but they are expandable tho 120 but trust me they dont need it i run my whole board of 1 60