making power inverter work 2 ways.

Hello,

I currently have a power inverter installed in my truck.  The wiring goes directly to the battery so the inverter is always on if needed.  I want to wire in a switch, relay, and ignition wire so that I can make the inverter operate as follows:

 - If the switch is in the ON position, the inverter should work as it always has

 - If the switch is in the OFF position, the inverter should only operate if the ignition is on. 

Can somone help me with the wiring and parts needed to accomplish this??  I could do it if I was only concerned with it working only with the ignition, but adding the switch and having it work in either way is confusing to me.  Thanks

ED7

pull out the switch out of the power inverter. connect one to 87 and and the other to 30. connect 86 to ground and 85 to your igition or accessory or 12 volt switch. 

Thack79 -   Seems like that would only allow the inverter to work when the coil is charged by the acc wire?  Unless I am reading wrong?  I want to have it work using a switch to make it either always on, or only one when the accessory is on.

im sure you can connect to both.

Inverter neg side to switch.
Relay, ignition to 86, NOT ACC too much power drain unless engine is running.
Ground to 85 and 30

output side of above switch to 87.
The switch must be rated at at least 10amps.
I'm amazed you haven't had lots of flat battery problems with that set-up.


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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

naw i havent had any problems, although i dont have the inverter on without the car started very often at all.  the constant is still connected to the battery, im just controling the on/off swtich.

Thanks for all the comments. I understand (i think) both methods of wiring this, however from what I can tell, neither will address my original question.  The switch was supposed to only change the way the inverter operates.  If the switch is on, the inverter should only function with the accessory/ignition charged.  If the switch is off, the inverter should function all the time (ie, even when the car is off.)  In both cases it appears to me that the inverter will only operate if the switch is in the ON position and the accessory/ignition wire is charging the coil?

Perhaps I can just use a SPDT switch and then switch between relay ground and true ground.  That should work.  Would I then need a switch rated for 10A as well as a relay rated for 10A?

Inverter's power switch permanently on.

A relay to connect fused power to the inverter (eg, +12V to 30; 87 to inverter +12V).
Relay coil grounded (85).
IGN via diode (IN4004 etc) to coil +ve 86 (diode "line" = Kathode towards 86).
SPST "on" switch from +12V to 86 (could be from +12V on 30; though consider fusing issue (ie, use thin wire).

Summary - inverter is powered on if IGN is on OR if switch is on.


PS - BTW, relay & its power wiring and fuse rated for the inverter (eg, 10A for 100W inverter).
Switch and diode and relay "coil" wiring rated for the coil/solenoid - typically say 250mA or less for auto relays. IE - 1A or higher rated diodes etc should be more than enough.

Peter that's what I said though I was switching through the ground side. I still don't think you should leave any inverter permanently switched on. too much juice required to feed the inverter before even any loads are applied.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Ooops - my bad for repeating. Sorry!


I agree with not leaving inverters on (as opposed to having its on-switch permanently on because it is controlled via a relay) - many inverters draw several Watts even with no load.

But that is no different to any non-alarmed manual-only switch (viz. my audio, and - until I fitted the buzzer last week - my car's lighting).

And electricd7 seems to have no problems remembering to turn it off. (Just as I do with my audio and lights - until I don't!)

But if electricd7 did, then maybe a spare battery (as I have) else a low-voltage cutout.
In electricd7's case, I'd use a $20 MW728 to drive the relay using 2 push-buttons instead of the SPST on-off switch, ie, a push-button to turn the inverter on until the 2nd push-button is pressed OR the low-voltage sensor (MW728) switches off (and doesn't come back on until the ON push-button is pressed).
Then if electricd7 does forget to turn the inverter off, who cares?