Make Your Own Trade Show Battery Power Supply
(with 110VAC outlets and USB charging ports)
If you’ve rented a booth at a trade show exhibit, you may have discovered that electricity is often an expensive upcharge. If your power requirements are not heavy, investing in a battery-based power system is a smart choice, and will quickly pay for itself.
Many commercially available trade show battery systems are available, but the complete systems can be pricey – even the smaller ones can be over $200.
If you don’t mind a little DIY work, you can get everything you need to make your own trade show battery system at Amazon.com.
The system is actually very simple, with the following main components:
- 12V Rechargeable Battery
- Power Inverter (converts the battery’s power into 110VAC outlets and USB charging ports)
- Battery Recharger
The system I built is smaller because all of our electronic devices are portable and battery-powered (notebook PC, battery-powered portable printer, and cell phones for card reader transactions), and we do not have any lighting to operate. The purpose of our trade show power setup is to be able to plug in any of those devices if they lose power toward the end of the day, which they probably will. To house the components, you can use any number of things. I found an empty Rubbermaid bin with a lid that seemed like a good size. I attached the inverter to the side of the bin with rivets, and made a plastic tray to keep the batteries in place.
If your trade show exhibit has lighting, video screens, and other power-hungry devices, you may need to consider a deep cycle marine battery and a much more substantial power inverter with higher wattage. The principle is the same.
You can click the images below for complete details and pricing on each component at Amazon.com.
First, let’s start with the battery. I chose a small 12V battery (8AH) that might be found in an alarm system. Since they are small, I bought two of them, so I have the option of bringing both, or or I can just bring one if I need to travel light.
For the inverter, I chose something that will power our Macbook and/or portable printer if they run out of juice. You can spend a lot more for a more substantial inverter with a higher wattage, but that may require a larger battery.
For charging the system at night before each day of the trade show, I went with the Battery Tender Jr. This is an intelligent charger that you can plug in and forget about – it knows when your battery needs charging and when it doesn’t.
For powering our Macbook, we could simply plug the wall adapter into one of the the inverter’s 110VAC outlets. But that would mean converting DC into AC and back to DC again, which isn’t efficient and will waste battery power. Since we have the cigarette lighter power adapter for our Macbook, I decided to include a lighter socket adapter, so we can power the Macbook directly from the 12V battery. No conversion, no wasted battery power.
Connecting the system is very simple, because all of the wiring goes to the same two terminals on the inverter. The inverter has two large posts, red and black, that accept ring terminals. To make some of the connections, you will need a tool that cuts and strips wire, and crimps the crimp-on connectors to attach them to the stripped wire.
To connect the battery to the inverter:
The inverter comes with a pair of red and black wires, each with a ring terminal on one end, and an alligator clamp on the other. Unscrew the red and black caps on the inverter posts to connect the ring terminals to the inverter. If you’re using a big car battery, you may want to keep the alligator clamps, but if you’re using a small battery (like ours) with .187 push-on tab terminals, then you will want to cut off the alligator clamps, strip the ends of the wire, and attach push-on connectors using the crimping tool.
To connect the battery charger to the inverter:
If you use the Battery Tender Jr. charger, it has a quick-disconnect cable with ring terminals. Attach these to the inverter posts.
To connect the cigarette lighter adapter:
Attach ring terminals to the stripped ends of the red and black wires using the crimp tool, and connect to the inverter posts just like the previous two items. Note – you are really connecting it directly to the battery when you do this.
To charge the battery:
When charging the battery, turn the ON/OFF switch on the inverter to OFF. Connect the Battery Tender wall adapter to the cable going to the inverter, and plug the Battery Tender into an AC outlet. The light will eventually turn green, indicating the battery is at full charge. Disconnect the Battery Tender when the charging is complete.
To use the system:
With the battery fully charged, simply turn the inverter ON/OFF switch to ON, and now you can plug in your USB devices or 110VAC wall adapters to get power “for free” in your trade show booth.
Wire Stripper / Cutter / Crimp Tool: