Low voltage disconnect switch?

Thanks, folks!

Yes, I want something to interrupt 12v power (or 120v, as the heat pad is 120).

No, the cat in the picture does not look happy ;).

I thought this was a standard item and I could just get one for $5. Guess not.

If I need to get a solar controller, I suppose I might as well get a decent one I can later use for actual solar panels!

Naio

i think maybe you could use a Solar controller
one with a "load" function , usually used for lighting etc.

some have a fixed disconnect voltage , and some have a programmable voltage setting

even cheap $20 controllers have a load output connection

maybe something like this
http://www.amazon.com/HQRP-Controller-Lighting-Control-Display/dp/B002WI379E

it disconnects at 11.1v, inverters usually shut down at 10.5
use it between the batteries and the inverter

you don't have to have a solar panel for this too work

Mex, did you install a thermal sensing circuit on that cat?:B

We need some clarification or a description or the main issues involved about how low power in the night effects the user. If low wattage continuous draw is the thief in the night, adding more battery capacity is usually the easiest solution.

westend wrote:
What do you want this switch to do, interrupt 12 V when power falls too low?

Must be then. Just totally ignore my above post. :(

Is this ever done on the 12V system? And only because of the cat? Is it one of those hairless Sphynx cats?

What do you want this switch to do, interrupt 12 V when power falls too low?

To clarify, I don't have an RV. This is for the rig in my sig. No AC. I pretty much only use electricity at night.

My concern right now is my cat's low wattage heating pad. It (and the inverter) is the kind of low wattage continuous draw that can sneak up on a sleeping human!

Naio wrote:
Can any of you folks recommend a good one for cheap? I dunno why my various ebay searches turn up nothing.

An alarm would be ok, but a switch would be better. So I don't have to get out of bed in the middle of the night :).

Low voltage gets much much worse during the daytime from people using AC units, kitchen appliances, hair dryers, etc. If it's okay late in the evening, it will be okay overnight, unless it's already REALLY borderline low. An EMS works, but they reset automatically. An EMS of course has a lot of other very useful features like open ground, open neutral, etc.

Not aware of a simple plug-in device but there might be. Do a google or ebay search for "voltage sensing relay 120 volts" and see what you find. I don't think they are cheap but have not looked. You may or may not need a 30 amp 120 volt relay as well (assuming you have 30 amp service). Even if this would work, by the time you've bought all the other bits and pieces like electrical box, cable clamps, etc. to mount it all in, an EMS may be cheaper. And you'd need to be electrically proficient to be doing this stuff.

If you don't have one, get one of those inexpensive plug-in power line monitors. I installed a permanent LED display on the wall so I can see at a glance what the voltage is doing and can be had for dirt cheap on ebay.