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Power An AN/PAS-13 From a 5590

This solution connects the medium or heavy AN/PAS-13 Thermal Weapon Sight (TWS) to an x90 battery. While not an elegant solution, it has proved useful in both Iraq and Afghanistan at guard towers for base security. In Iraq, the AN/PAS-13 battery was in extremely short supply and sights were not being used until we gave them an alternative power source. Elsewhere, soldiers have complained about the short lifetime of the AN/PAS-13 batteries under heavy usage (~3 hours for the rechargeable [BB-2847] and 6 hours for the disposable [BA-5347]).

In contrast, the BB-390 (rechargeable x90) will run the AN/PAS-13 continuously for 12 hours, and the BA-5590 should last well over 18 hours of continuous use.

Note/Warning: The battery compartment of the AN/PAS-13 is sealed, so having it open a bit will not harm the rest of the unit. However, since the wire is coming out of the compartment, it is not waterproof and could be shorted if it gets wet.

Tools

Supplies

**Note: It is very important that you get the 2.5A "High Power" variable voltage plug; we have found no other plug that can deliver enough power to ensure that it will power the AN/PAS-13. The variable voltage is required as the AN/PAS-13 requires ~6V; the plug allows one to reduce the voltage from the x90 battery to the required 6V. This is the plug to keep in your geek kit, regardless of price.

Directions

1. - 4. Make/Wire a 5590 to Cig Socket Adapter

Steps 1-4 for wiring the 5590 connector can be found here. You can also purchase one, part number 500102, here.

5. Open The BA-5347 (AN/PAS-13 Battery)

Using the cutoff wheel on a Dremel tool (or a hacksaw), cut off the top of the battery. The top is the sealed surface where the battery has been sealed shut (you can see a bonding line).

6. Remove The Battery Cells

Using wire cutters and pliers, remove the battery cells and any EXCESS wires. Leave one (+) and one (-) wire attached, and ensure that the metal contacts on the outside of the battery stay attached. Depending upon the manufacturer of the BA-5347, the end result may vary. Images of two final stripped batteries are shown below.

7. Attach The Variable Voltage Cig Plug

Solder the positive (+) wire on the inside of the BA-5347 to the positive (+) wire of the cigarette plug. Repeat for the negative (-) wires. The polarity (+ or -) is labeled by the contacts on the BA-5347. For the cigarette plug, the center tip is + and the side contacts are -. NOTE: You may not be able to "ring" or check continuity of the center tip of the cigarette plug due to the internal electronics, thus you may have to just ring/check continuity with the two side contacts.

8. Close the Battery Box And Set The Voltage

Make a small hole/cut out in the cover at the end of the battery where the contacts are from which to run the cord. Seal the top of the battery back on using epoxy.

Set the voltage selector to 6V. From a BA-5590 or BB-390, this will deliver ~6.2V, well within the 4.5V to 7V range of the AN/PAS-13. DO NOT set the voltage above 6V. EPOXY THE SELECTOR SWITCH TO ENSURE IT DOESN'T GET CHANGED!!!

9. Test and Connect

The battery adapter can now be connected to an x90 battery with the x90 to Cig Socket Adapter (steps 1-4).

Using a voltmeter, ensure that once connected the polarity output is correct [(+) and (-) correspond to the correct contacts on the BA-5347] and that the voltage is ~6.2V.

The BA-5247 can now be inserted into the AN/PAS-13 and connected to an x90 battery.

Reminder: The battery compartment of the AN/PAS-13 is sealed, so having it open a bit will not harm the rest of the unit. However, since the wire is coming out of the compartment, it is not waterproof and could be shorted if it gets wet.