2nd Battery Install
 

Hi,

Did a search could not find any information regarding this.

I would like to install a 2nd battery so that I can hook up a small portable heater. I plan on sleeping in car in the snow (Mammoth).

I just wanted to get a few information right before I attempt to move forward.

I would like to be able to charge the battery with the car so I'd assume I have to run the 2nd battery in parallel with the 1st one. But since I will be running the heater while engine is off... I should get some sort of relay or "switch" to disconnect the connection between 1st and 2nd battery (to avoid draining 1st).

Would this be something that will work out? Is a car battery good enough to power up a small portable heater (do you recommend any heaters?)

How long will I be able to run the heater for? It seems that small heaters on amazon.com are 750w to 1500w... my ac-dc converter is 1400w

Whelp... let me know guys. Would love to get this started :)

750 watts means 63 amps.
What's normal for a car battery, 150 or 200 amp-hours? So that's only a couple hours (maybe 3) before that battery is DEAD. Long before it's dead, the voltage will go low so the heater won't work well.

I'd probably use a good sleeping bag, the car is better shelter than a tent. Backpacking stores will have stuff that's good for winter camping. I've done that in North Dakota in February.

You might have good luck going to some of the RV websites, or google search "battery isolator"
http://www.powerstream.com/battery-isolator.htm