UPS on cheap inverter = no

[Keith]

Well, I HAD a good idea. I got a little UPS to run my navigation computer off of, from a little 12V inverter. The idea was that I could turn on the computer THEN the engine without crapping out the computer. If I do that now, the voltage drop kills the computer because the inverter stops putting out the proper voltage.

Well, the UPS won't run off the inverter. It doesn't even recognize that it's plugged into anything. I'll find something to do with the UPS.

 

[rwidman]

Well, I HAD a good idea. I got a little UPS to run my navigation computer off of, from a little 12V inverter. The idea was that I could turn on the computer THEN the engine without crapping out the computer. If I do that now, the voltage drop kills the computer because the inverter stops putting out the proper voltage.

Well, the UPS won't run off the inverter. It doesn't even recognize that it's plugged into anything. I'll find something to do with the UPS.

What do you mean by "a little 12V inverter"? Your inverter needs to be able to supply whatever current the UPS requires.

If you have a house bank, power the computer from it. There should be no voltage drop when starting the engine.

 

[caltexflanc]

That sounds weird... a UPS has a little inverter already built in, so when the voltage drops or goes out, you have power for a few minutes. What was the other inverter for? had you charged your UPS? I take it your computer is 120v desktop, not a laptop?

 

[bobsyiruncle]

How little is little?
A standard desktop and screen needs more than 350 watts - ask me how I know!
A lap top does not

 

[Moonfish]

Interesting... When I'm running the inverter (new Magnum 2000W), my UPS will not stay "on". Buzzes and never completely comes online. I have to plug my computer directly into an outlet, and it runs fine. But I lose any battery backup capability, and that's not good...

 

[Keith]

It's a Maxx 400 W inverter. Usually, I plug the inverter into a 12V outlet, then into a surge strip, then the computer and peripherals plug into that, and it works fine. But the UPS plugged into the inverter doesn't even act like it's plugged into anything. Oh well, I'll find a home for it. The computer is a little "bookshelf" computer that's marinized from Big Bay.

 

[caltexflanc]

Interesting... When I'm running the inverter (new Magnum 2000W), my UPS will not stay "on". Buzzes and never completely comes online. I have to plug my computer directly into an outlet, and it runs fine. But I lose any battery backup capability, and that's not good...

I have never had that problem with my Magnum MS4024 and the Tripplite, APC or other surge/UPS devices and conditioners which are there for time on shore power or generator. After all, the inverter itself is a UPS, so it is a double dip. And my UPS devices have several outlets so no need for an intervening surge protector.

Keith, it sounds like you have quite a daisy chain going. If you have an inverter and a surge protector already, not much need for a UPS.

 

[rwidman]

It's a Maxx 400 W inverter. Usually, I plug the inverter into a 12V outlet, then into a surge strip, then the computer and peripherals plug into that, and it works fine. But the UPS plugged into the inverter doesn't even act like it's plugged into anything. Oh well, I'll find a home for it. The computer is a little "bookshelf" computer that's marinized from Big Bay.

My guess is that the inverter is a "modified sine wave" inverter, not a true sine wave inverter and the UPS is not compatible with it.

But why do you need a UPS when you're operating from your boat's 12 volt DC system? It's not like the power is going to go out.