Energy

DC to DC converters

• 12 volts to -12 volts: TC7660CPA-ND, 97% efficient, available from digikey (1800 digikey = 1800 344 4539) for $1.58 each. These are useful for video (wearcam, switching between two cameras from the parallel port) since the sync pulses go negative, and a split supply (+-12v) is needed.
• 9-18VDC to 5VDC (though used with a 6V lead acid gel cell). 3A output capacity, minimum of ~80% efficiency. Computer Products WR12S05/3000XC. 2"x3"x<1". ~$100. Smaller versions available if less capacity needed. Currently using for powering low end wearable (1.5A @ 5V) with either 6V or 12V gel cell.
• 4.5-13.2VDC to 5VDC. Minimum efficiency ~80%. Datel. ~$100.
• 12v to 12v avail. from Datel in variety of voltage ranges such as 9-18v. Typical efficiency around .8; 5 side shielding but Datel claims RFI claimed lower than competitor's 6-sided shielded units. Datel provides schematic; it seems evident there's a pi filter on the input and 2nd order filter on the output. UWR-12/830-D12 looks pretty good for nominal 12v in use and costs $83. In quantities: 10-24, $81; 25-49, $76; 50-99, $73. 1-25pcs 1 week order time. UWR-12/1650-D12 more current carrying capacity and higher range (18-36v) of input voltages: 1-9 $95; 10-25, $93; 25-49, $87; 50-99 $84.
• shipping: they're right in MASS, so if you live in the area (e.g. MIT) it takes 1 day by UPS. payment options include PO, Visa, COD.
• Minimum $100 order.
• Datel contact info: DATEL, Inc. 11 CABOT BOULEVARD, MANSFIELD, MA 02048-1194 TEL. (508) 339-3000/FAX (508) 339-6356.

Battery Comparison

Courtesy CPSI

Power Belts from NRG (for the SERIOUS power consumer)

NRG research Inc.
840 Rogue River Hwy
Bldg #144
Grants Pass, OR 97527
1-800-753-0357

Batteries from Sony

Batteries from Panasonic