tell me if this would work

[krazy_texan]

i have the idea of putting a second battery on my truck on an isolator switch to seperate it from the cranking battery then putting a power inverter on it to run my block heater while i am at work then once the truck is cranked flip the isolator switch to recharge the second battery. I started to do this on my another truck but never got to test it in the winter. I am just wondering if anyone thinks that i could make this work as i drive my truck daily and i get off work at 3am so it is usually butt cold at that time.

[Heater63]

I haven't tried it, but ...My concern would be that 1) the block heater might draw down the second battery so much that it could kill it or make it not take a charge good 2) just driving it home will not recharge the battery...so your probably going to have to put a charger on it every day.

It would be best to find a parking place to plug it in to shoreline power

[Ledslinger]

You need one of these:

http://www.espar.com/html/products/hydronic4.html

[aerotruk63]

My 64 GMC 960, an old fire truck, had two batteries on it. Each battery flanked the radiator . The left hand tray was a reverse of the original right hand tray. They had mounted the Horn Relay and Voltage regulator on the drivers side inner fender. They had simply connected the two batteries together.

With a small inverter attached to a single full charged battery, I used to power a small television for about 3 hrs. Your block heater would draw more than the TV and would more than likely drain both batteries in less time. On a Freightliner I drove, there was a sensor that would shut off the current draw to make sure there was enough power to start the truck. Those power inverters use a lot of power to invert from 12VDC to 110VAC then you have the device itself drawing power. Mock up a setup and test it before installing it in your truck.