Is there a relay that will allow me to do this? Powering weboost from truck battery while driving and house battery while parked.

[dfinn]

I'll be adding a weboost cell adapter at some point soon and I've been thinking about how to install it. Ideally I'd like to be able to make use of this while driving and also while in the camper which serves as a mobile office where I tether through my phone for internet. Ideally it would be automatically switched on and off while driving and powered from the vehicle battery/alternator. Then while parked I'd like to be able to manually switch it on and off powered by my house battery.

Is this possible without ever having the 2 batteries connected to each other? I'd like them to be fully isolated.

The other option could be to just have it be powered by the house battery since the house battery is being charged by a Redarc DC to DC charger. Is there a way to trigger it on and off either by ignition or manually from a switch in the camper? I'm not sure but I think this can be done with a simple relay?

 

[DiploStrat]

Yes. Use a crossover relay. Energized it connects one way (e.g., engine running), engine off, it connects another way.

You will have to scratch yer head a bit. The terminal that is generally labeled as "power" will probably actually be your load. But it isn't hard once you get it.

All of that said, connect it to your camper battery and be happy.

 

[dfinn]

Weboost is a cell phone signal booster.

 

[DiploStrat]

I think the key element here is that a cell booster simply does not draw enough power to worry about unless your camper battery is REALLY small.

And, of course, when the engine is running, it should be charging the camper battery; there is no reason to switch to the engine directly unless your REDARC is too small to keep up with your loads. (In which case you have another problem.)

I had an older model of this when I had an aluminum camper and I simply ran it off the camper/house battery.

 

[dfinn]

I do think the simpler solution is to just power it from the camper battery which is a 100 AH lithium battery and will handle it just fine.

I still would like this to turn on and off with the vehicle ignition though as well as being able to be manually controlled through my switch pro switch in the camper. I'm not exactly sure what kind of relay I need to do that. It doesn't seem as simple as having triggers coming from both the vehicle and the camper switch both connected to the same trigger on the relay though, wouldn't that be creating a connection between the 2 batteries that I think I want to avoid?

edit: just realized I can do what I want using the triggeR input on the switch pro. I think I’m all set.

 

[DiploStrat]

You seem to be WAY over complicating this. Doesn't it have a power switch? I can't understand the problem you are trying to solve. (Sorry, I'm dense on occasion. )

When do you want it off and can't you simply turn it off with its own switch?

 

[dfinn]

I want it to turn on and off with the ignition so that while driving I 1) don’t have to remember to turn it on and more importantly 2) can’t forget to turn it off and have it kill my battery.

 

[mep1811]

You can just cut off the switch and wire the power to a ignition powered circuit.

 

[clydeps]

You could use two diodes, one from the ignition circuit to the device, the other from the house battery via a switch. Then it will come on if either the ignition is on or the switch is on.

This part is a dual-diode package that will do the job, though it's extreme overkill in terms of current handling capacity.

 

[DiploStrat]

If your goal is to assure that the WeBoost cuts out whenever the engine stops, then a simple, ignition-controlled relay will work perfectly. Wire the WeBoost to the camper battery which, as noted, will be charging whenever the engine is on.

If your worry is that the WeBoost will kill your camper battery, then you need a bigger camper battery.

 

[dfinn]

The switch pro has the ability to trigger off of another source. Basically a relay built in. I'll be using that to turn on and off the weboost with an ignition switched trigger. I had completely forgotten that it had this ability. Thanks for all the suggestions.