12VDC Power for Bi-Pap or Ventilator from 24VDC Wheelchair Batteries

This drawing documents the system I have been using for about five years to power my Respironics S/T Bi-Pap, then my LTV-950 ventilator.  These 12 VDC devices plug into a cigarette lighter adapter mounted in the back of my power wheelchair battery box.   There is a 24 VDC to 12 VDC power converter mounted inside the battery box.  This system makes the ventilator extremely portable, and only requires one battery charger.  I charge the wheelchair batteries nightly, and in my case, the batteries provide more than enough power for a full day of wheelchair and ventilator use.  As with any power source, I always have backup power handy.  The drawing is in Adobe Acrobat PDF format, and will require you to rotate it counter-clockwise for proper viewing.

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