We received a call the other day from a lady who wanted to be able to run her laptop and printer from her Horse trailer. I told her that Outside Supply carried a variety of power inverters that can convert her 12 volt DC battery bank into 120 Volts AC power. She was looking to be able to track vitals and stats on a couple of her horses. She already had a good sized battery bank in the horse trailer and had a nice secure dry place to install the power inverter.
Here is what I recommended for her Horse Trailer:

1500 Watt Sine Wave Inverter

Power Inverter Installation Kit
This will provide her plenty of power in her horse trailer. It will even allow for her to run a laser printer if she decides to upgrade later. She also may add a TV at some point and this 12 volt DC AC Power Inverter will provide clean sine wave power to make sure her picture is clear and line free. The install kit will also make her installation much easier. Especially since it includes high quality non ridgid cables. The cbles make going around corners or bends downright simple.

