I have a siren that according to the label draws 1.5Amps @ 220VAC. I also have an 12VDC to 220VAC inverter that is rated at 300Watts
1.5 times 220 = 330 watts. Can I safely power the siren with this inverter? Is that extra 30 watts going to kill it? Also note that the siren isn’t going to operate more than 3-4 minutes at a time.
It will probably blow the fuse on the inverter,so you likely won’t get the 3-4 minutes at all.
12 V DC and 300 Watts implies 25 Amps. Not through your cigarette lighter (power outlet), I wouldn’t think. ETA: and is that 300 Watts input, or 300 Watts output. They womn’t be 100% efficient.
Check the manual for the inverter carefully. I’ve seen them (in stores) where they’ll have a large Wattage in big letters, but in the small print will say it’s limited to a lower amount when used with a car’s power outlet socket.
From what I’ve seen re 12VDC to x inverters they usually don’t have a lot of “reserve” powerwise and will generally crap out right at (or often below) maximum specs. Plus, pushing them too hard can be dangerous re shorts, fires etc., which is not what you want in an enclosed vehicle.
You might get away with it, but I would not do it.
It would help if you gave the model. I was looking around, and this inverter, for example, is “300 Watts”, but that’s continuous, and it can handle 500 Watts peak. You might be OK with that one. Also, see the first review there, as the reviewer mentions the limit from your power outlet, but talks about how to connect it directly.
Today I tested said inverter with a 220VAC 25W lamp.
The light intensity was half the normal intensity when connected to mains. Note that I connected the inverter directly to a fully charged car battery. I guess I will use an old UPS that I have sitting around instead of this POS invereter.
Might your inverter have a switch to select between 110 and 220, and set to 110?
Is the siren an eletronic noisemaker plus amp & speaker or a mechanical motor & fan type?
If the latter, it’ll have a massive surge load at startup. Like 2 or 3x the running load, but just for a few milliseconds. When connectes to mains power the transient overload is no big deal. When connected to an electronic inverter, the transient will kill either its output fusing or its final output stage.
No, it doesn’t have a switch. I tested it with a multimeter and unloaded it reads 220V.
It is a motor and fan siren. More specifically it is this one: http://www.klaxonsignals.com/productDetails.asp?productID=52&categoryID=49
How about a computer UPS? These are usually rated for a lot more that 300watts. Also does it matter if I run the siren on modified sine wave?