It depends on how it's configured. You're right in that it does act just like a regular switch.
If it's bridging both batteries taking the place of an isolator like how I'm planning on installing one, I don't want to have to switch it on/off every time I start/stop the van.
This is actually one of the more common uses of relays instead of isolators, and yes a non-latching relay will probably heat up pretty good, one model I saw dissipates about 12-watts in normal operation.
In theory, since the Intellitec latches, you shouldn't need to provide continuous power to it, just a brief pulse when you want the circuit closed or opened back up, and it shouldn't be consuming power itself while latched.
You can't wire directly to something that's Ignition accessory switched as that doesn't shut off on it's own.
Likewise any switch that isn't a momentary on will keep feeding power to the relay.
If you want to have manual control of the relay you probably need a double-pole/double-throw momentary toggle with your center pins going to the I/S terminals using top of one side and bottom of the other for ground and making the other two your hot leads.
The way this works with the dual polarity boils down to how the mechanical latch inside operates.
It uses the magnetic north/south of the coil to attract/repel a magnetized rod that wedges against the contact plate preventing the return spring from opening the circuit.
I've been looking at some circuit designs that should handle the momentary and polarity aspects of the problem making it more automated.
I'll update this if the system ends up working the way I expect it to.
Originally Posted by skcyclist
I've been wondering why there is a need for this solenoid at all. It appears to simply act as a switch. Marko uses a knife blade switch; simple enough. Why not run appropriate sized wires to appropriate sized main swich on the panel for off and on in lieu of knife blade switch? The solenoid is almost too hot to touch when it's on... a useless drain of power.