Hello,

I have a spare D-Link DIR-615 and hope to add a internal battery to allow me to use it as a router for a couple hours when I just have access to a Ethernet port or using it as a truly wireless repeater or bridge.  The router runs on 5 volts 2.5 amps at peak so to run it for 5 hours I would need about 50 watts. If anybody has any ideas they would be greatly appreciated.

That page covers aspects of the right choice of batteries for different projects: http://www.ladyada.net/library/batteries.html

Hi benfriesen12;

Here is a cheap temporary solution I have used.
It requires a bit to work and using a good volt meter and ampmeter (10 amp full scale).

While the startup or short inrush current is higher I have measured the average operating current of a DIR-615 c1 and found it to average closer to 500 milliamps by itself.
If you do any modifications for example a usb mod and source current to devices on it then this average current could
be much higher.

The wall adapter can supply 5.12 volts at 2 amps. I have measured this voltage and it varies a bit.

Using 4 each rechargeable nickel metal hydride batteries each at  1.2 volts @ 1.3 AH (for example Sony EZ Find cell phone batteries) for a total of about 4.8 volts can be placed across the 5 volt adapter.
I use the rechargeable nickel metal hydride batteries only due to their availability, price, and power delivery.

The voltage on the battery will drift up to the voltage the 5 volt wall adapter potential.
It is best to measure the static voltage on this of a fully charged set of batteries and also the inrush current
on a set of discharged batteries.

Keep an eye on overheating or any safety issues.

This provides up to two hours of standard operation.

Some cautions to note; If these batteries run down excessively then the inrush could blow the fusing in the 5 volt power adapter so a smaller fuse in line with the battery is recommended.

Hope this information helps but as they say if you make it then you can bake it (fry your device).

~john