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HOW to build 12 volt DC doubler circuit?

Ian Rogers

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The only car battery I can think of that has a 110A capability is for a Hummer... Most vehicles only have 40 ~50 Amp hour batterries..

When they can deliver 200 ~ 300Amps for a short time whilst cranking, it is only for a very short time..


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Way cheaper just to get a second 12V battery and put two in series...


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What are you powering with 24V?
It probably only needs to be 20 amps. I am doing 12vdc 20a now on my car better it is a bit slower than 22vdc 20a from a transformer. I need battery power at a Black Smith group gathering in a State Park the area where they meet and demonstrate for 3 days has no electricity so it needs to be battery power. I raise my car hood put 2 alligator clamps on my car battery to run the induction heater to heat 1/2" solid steel rods red hot. Induction heater will not get as not as coal I need an extra 400 degrees F.

Nigel Goodwin

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As suggested, simply use two car batteries in series for your 24V - by far the cheapest, easiest, and most effective way.

Or if you're regularly doing outside stuff, then buy yourself a generator and provide your own mains supply.


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I have worked on 24 volt trucks. It is hard to get the two batteries to charge together when you have 12 and 24 volt loads and only a 24 V alternator.
It is possible to add a second 12V alternator to your car. Connect "ground" to +12. This way each battery will have a alternator.
I can get negative 12V alternators. That will give you + and - 12V. You then connect your heater from -12 to +12 and it will think it is running on 24V.
All that requires you adding an alternator/generator and rerouting the fan belt. But the project is then just a mechanacial project.


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Thread starter #8
We might be able to park 2 vehicles next to each other then connect batteries in series with jumper cables. Then connect negative alligator clip to 1 car battery and connect positive alligator clip to positive of the other car battery to power the induction heater. I can try this at home first it should work fine as long as someone does not open a door that bumps the other vehicle and shorts out.

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