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Electronics gurus. Can I build a "capacitor" to take 12V to 15v? How?

y5mgisi

y5mgisi

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Ok, before i say what its for (im sure you could guess) i want to know if anyone thinks this is possible To set up some type of inverter/capacitor setup that would take 12ish volts and jump it up to 15 volts constantly. at around 10 amps or so. It would be wired momentary but thats neither here nor there. Basically like this,

 
sure why not. they have box`s that step the voltage up to 15 for ignition coils.

try speedway or one of the stock car or ignition manufacturers catalogs.
 
Interesting. With the speedway setup, I wonder how instant it would be with it wired momentary? I also wonder if 17v is a little too much for what im after. And i sure as hell aint gonna spend $140 on what can only be a few bucks worth of electronics.
 
Might find this link helpful:

http://www.edaboard.com/thread56734.html

To step up voltage in the AC would you would need a transformer with the appropriate loop ratio. DC doesn't have the same benefit though so it's a little more complicated. It would be a lot easier to run 24V with a second battery in series then step the voltage down using a correctly sized resistor but would depend on the load resistance of whatever it is you're driving with the circuit.

The alternative, and might be easier way would be to run it off an inverter, find a power supply that will provide 15VDC 10A and plug it in. Technically it's only 150W we're talking about so shouldn't need too big an inverter
 
Exactly. It would be called a step up transformer. That's what transformers do.

Sure you can build it. I can buy 12 to 24volt transformers for around $50. And I'm going to to run some 24volt lights on my truck.
 
Yep you can build it, any electronics store should have the proper wire and the little brackets to make your own transformer.

DC transformers have crappy efficiency, suppose it doesn't matter much in a truck though.
 
If this is what they look like, and what im after, i cant build it. And furthermore, this one looks like it will do what im after for only $8.70! Thats a gamble i can afford!
 
For definition sake. A capacitor stores energy in a circuit. Like an accumulator in a hydraulic circuit. It absorbs and supplies energy pulses to provide "clean" power. If you remove power from a circuit that has a capacitor in it, you have to wait for it to discharge itself before you touch anything, or it will bite you.
 
Thank you for mentioning that. I was aware but probably would have forgotten... But you did just bring up an interesting point that i will have to consider.

So since it would appear that this is something that im not interested in building myself, I had thought about wanting to use a device like this to step up the voltage at the window motors in our trucks. I figured that it would be similar in principle to the relay idea but with the added benefit of having peak voltage at all times. With yet another benefit of having the voltage stepped up to around 16 volts. I think that if you could keep the amps up high enough where the motor likes, it would really power the motor without frying it with something like 24 volts.

You would still need to run fresh power wires to the device to keep the supply of power fed to it. Then, you would need to somehow have your window switches interrupt the current. Anyway, for $8.70, i think i will order one and give it a try before i do the relay mod.
 
how about run a 16 volt battery and an external regulator on your alternator ?set it at a volt and a half over 17.5 volts.

even if you didn`t run a step down box to the rest of the system the life of light bulbs wouldn`t be shortened that much.

years ago like 30 when i worked at a shop that tested batteries and alternators,we used to get chrysler products in that would almost full field the alternator when the regulators went bad. bulbs and gauges wouldn`t be effected that much until 20 volts or so.
 
Interesting thought. But all I really want to affect is the window motors. And only at the motors.
 
blaznjon said:
how about run a 16 volt battery and an external regulator on your alternator ?set it at a volt and a half over 17.5 volts.

even if you didn`t run a step down box to the rest of the system the life of light bulbs wouldn`t be shortened that much.

years ago like 30 when i worked at a shop that tested batteries and alternators,we used to get chrysler products in that would almost full field the alternator when the regulators went bad. bulbs and gauges wouldn`t be effected that much until 20 volts or so.
Click to expand...

With bulbs I think the concern would be the extra heat over time melting plugs and such, but I guess the overall impact is negligible.
 
I've thought of doing this very thing before. You can not use a transformer on DC voltage. What you need is a DC-DC converter. (Sure, they use either a transformer or coil inside, but they have a bunch of other electronics to make the DC into AC, step it up and then turn it back into DC).

I think what you want is another battery somewhere. By the time you're done, you should have double the stock current to the window motor and that would require a big DC-DC converter. You might try a 2V Cyclon cell (or two) in series with your regular starting battery. These are quite good batteries with low ESR (you could probably use 6 of the large ones instead of an Optima). Or you could use a complete 14-16V gel cel. Then you just need a floating charger (i.e. DC-DC converter with isolated input-output) for the 2V or 4V cell and reroute the window circuit there. You might be able to use something as cheap as this: http://www.ebay.com/itm/NEW-DC-DC-600W-Step-Up-12V-60V-to-12V-80V-Power-Apply-Module-High-Power-/331043297078?pt=LH_DefaultDomain_0&hash=item4d13b7d736

Since the windows run on switched ignition, having a large DC-DC converter would have the advantage of running the windows as much as you want with the engine running. With small batteries, you might run them down and you'd have to run the engine for a while before the windows work again. Duty cycle on windows is normally pretty small, so unless you deliver mail in the rain or something...

I don't think the extra voltage will hurt the motors. A circuit breaker is a good idea, though, in case a relay sticks or somebody keeps holding the button...

The other advantage to either of these setups is that the window speed is going to be almost constant whether the engine is on or not. A big adjustable DC-DC would be the best, as you could just "dial-in" the speed you think is best. But that could be an inefficient unit that draws a lot of current whenever the key is on.
 
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