Re: need reliable 12-13 volts from 24volt wheelchair

dpondoc@xxxxxxxxx wrote:
I have a 24 volt wheelchair that runs on 2 12 volt batteries in
series. I need output not to exceed 13 volts for my cpap machine.
There are many DC-DC converters that are labeled 24 to 12 but it seems
all of these put out 13.5 or 13.8 volts. The cpap manufacturer clearly
stated that any voltage above 13 may damage the equipment. Is there a
way to reliably shave a volt or so off of the converter output?
Perhaps by using a diode in series? The Cpap is rated at 40watts max
or 3 amps at 13 volts. Any suggestions are welcomed, the more specific
the better.
Thanks

The AM 1301-7R is rated 12 volts at up to 4 amps out with 8 to 35 volts in.

http://www.power-one.com/resources/products/data***/mdc.pdf

They run about $500, though.

Digikey shows lots of other choices, but most, including this one are not in stock. But their search choices can give you some part numbers to look for. If you want good reliability, pick a unit that is rated for a bit more than you need. 50 to 100 watts is possibly a good max rating for a 40 watt load.

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Regards,

John Popelish
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