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12 volt to 24 volt

11-12-2008, 11:48 AM
Is it possible to mount another battery into a auto and wire it in series with the stock one, in order to get 24volts out of it and then return the grnd to the chassis and not smoke the rest of the electronics.


11-12-2008, 12:47 PM
It depends, but not likely. Maybe the better approach would be to share with us what it is you're trying to do and what the donor vehicle will be so we can offer solutions.

Are you asking about putting a second battery in series with the stock battery, running most of the car off of the stock setup, but only powering one single, isolated, 24V device using the positive terminal of the added battery but the common chassis ground? If the device truly is isolated, you could probably get away with this, but you'd not be able to have the alternator charge the added battery, so you wouldn't really gain much over just using a couple of smaller sealed lead acid batteries to power the 24V device.

How much current does the 24V device draw? What are the charging requirements? What isolation will be provided (ie: does it interface with any other devices on the 12V system)? Could a DC-to-DC converter fill your needs (eliminates the charging concern)?


11-12-2008, 01:31 PM
In a word, no. You could do it one of two ways to get both voltages.

1) wire the batteries in series for 24v, then have a 12v converter/transformer step it down for the normal vehicle electronics. The problem with that is some of the components (like the starter, blower motor, AC clutch) require very large amounts of juice. The size of transformer you would need would make it very impractical. Plus, you would have to use a 24v alternator to charge the batteries.

2) Have a normal 12v system, but make a circuit with a 24v inverter to step up the voltage for the component you wish to operate. That leaves the stock electronics intact and isolates a 24v circuit.

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