Desk Lamp on and Off the Grid

I wanted a desk lamp that would work on both grid power and from a 12-volt battery. I converted an $23 LED desk lamp so it could be plugged in either way. I now have a desk lamp that works

• when the power goes out in my neighborhood;
• when I go camping or RVing; or
• if I need to set up a staging area during a disaster or a drill.

Parts: An LED Desk Lamp, a 12-volt battery (see discussion in Step 5), 4 or 6 15-amp Anderson Powerpole contacts, 2 or 3 red Powerpole housings and 2 or 3 black housings. Tools: Wire cutter, wire stripper, Powerpole crimping tool.

Notes:

1. Make sure you purchase an LED lamp that has a 12-volt power supply because you need a lamp that is compatible with a 12-volt battery. The one I used is "MEIKEE LED Desk Lamp, 12W Aluminum Dimmable Table Lamp with 12V/2A Adapter"
2. Anderson Powerpole connectors have nothing to do with the poles that delivery power to neighborhoods. They are a trademarked name for a type of connector that are used to set up 12-volt devices so they can be connected in a variety of ways. They can also be used for other voltages. Each connector involves a red and a black plastic housing, each of which contains a metal contact. Assembling Powerpole connectors involves a special crimping tool and some skill at using the tool and inserting the resulting contacts into the red and black plastic housings. See https://youtu.be/QzLvdR6X81k

Use wire cutters to cut the cable leading from the power supply provided with the lamp. I recommend cutting it about six inches from the transformer/power supply that plugs into the wall. Some people refer to this as a "wall wart". Their purpose is to convert Alternating Current (AC) power in your home to Direct Current (DC) and lower the voltage to make it easier to use for many modern electronic devices. Because most automobiles, boats and RVs have 12-volt batteries, many but not not all DC devices use 12 volts and those that do often come with 12-volt wall warts so they can be used with grid power.

This photo also shows the crimping tool that will be used in a later step.

Anderson Powerpole connectors can be assembled with 15-amp, 30-amp or 45-amp contacts. You want the smallest contacts, which are 15-amp and compatible with 20, 18 or 16 AWG wire. (AWG is an abbreviation for American Wire Guage, a somewhat strange but standard way of measuring wire where the numbers get large as the wire diameter gets smaller.) Your desk lamp's cable may use even smaller 22 AWG wires but hey should work OK with 15-amp contacts.

Crimp 15-amp contacts on the red and black wires on the bare ends of the cable.

Start with one of the two pairs of wires. Insert the red wire into a red plastic housing and the black wire into a black housing. You will probably need a tool to push the contacts until they click into place in the housings. I used a small pair of needle-nose pliers. Slide the red housing so that it attaches to black housing. Repeat the process for the other pair of wires.

Connect the two pairs of connectors so the two red housing are together and the two black housings are together. Plug the wall wart into an AC receptacle (aka outlet) and turn on the lamp. If it lights up, you're nearly done. If it doesn't, take a close look at your work to find a loose connection, correct it and try again.

If you already have a 12-volt battery with Powerpole connectors on it, move it near your lamp. If you don't have one, buy or borrow a 12-volt battery and install a red/black pair of Powerpole connectors on it with the red connector wired to the positive terminal and the black connector to the negative terminal. Popular types of 12-volt batteries are small AGM batteries and Lithium Iron Phosphate (LiFePO4) batteries. The one shown in the photo is a LiFePO4 battery.

In either case, turn off the lamp, disconnect the pair of Powerpole connectors on the wall wart cable and connect the battery's Powerpole connectors to the cable leading to the lamp. Turn the lamp back on. If it lights up, you're done!

Notes:

1. AGM batteries are lead-acid batteries similar to automotive batteries but are designed to be used in applications where they are not immediately recharged. They are typically sealed so they don't give off gas and don't require that water be added.
2. An automotive battery could also be used but such batteries should not be used indoors unless they sealed and unvented.
3. The power cable that connects to the lamp may work with other 12-volt DC appliances that have the same power socket as your LED lamp. Be careful, however, because some appliances may assume positive on the inside of the barrel connector and others may assume negative.