My truck came with the batteries and it works well. Probably quieter also than a diesel fired heater.
Just keep in mind warranty. Read it to make sure it's still valid on a d.i.y. install. Now if you don't care about warranty, or if it's not an issue, sure save the money. Heck even me with my lack of mechanical skills I could install one in a few hours.
i was going to record servicing my last year but i got busy and just did it without recording it. mine is starting to take a couple trys to start again maybe ill get servicing it on video this year. iv got a couple service kits ordered. i installed mine myself a few years ago was before i started doing video's though, there not hard to install.
Yeah and the amazing thing is some people think it is all plug and play, there are a few things that I don't care to deal with like the fuel piping and pickup in the tank, the troubleshooting of these units when they won't start and the getting under the sleeper to do the mounting of the unit - it has to be secured to the floor of the sleeper some how. Having it not start right out of the box happens but then if you do it and it doesn't work, getting off of ebay means a return to the seller and a bunch of sellers won't honor the return if it is screwed up by the buyer,