Inverter wattage output.

...and they're switch-mode PSUs, not linear ones made from 7812 and 7805...

Steve

Hey is there some kind of linux-landrover analogy here? I've always believed that my interest in the linux-way-of-thinking (downloading source/compiling/fixing-without re-booting) was very similar to my reasons for running a land (sourcing from a variety of places/ building from chassis upwards etc) - though I have yet to try and see how much of the wagon I can fix without at least pulling over to the side of the road ;-)

Meanwhile ... back at the topic, Have a look at the quality of the sinewave output of the inverter. Many inverters use a very crude stepped quasi-sinewave which could freak out some PC power supplies (or at the very least cause some irritating whining and whistling from the supply). Also, since the voltage is being stepped up by a factor of 20 or so then the current going into the inverter will be huge. Huge currents mean huge magnetic fields mean huge data loss from magnetic media. Careful how close to the inverter, you fit the PC.

Hey, just had a thought (and too bone idle to see if anyone else in the thread has mentioned it)... Your peripherals will use 12V,5V and 0V and your mobo will use a variety of fixed value regulated dc voltages. Is there no project out there to turn the 13.6V car battery into all the voltages you need without ever going through the a.c. stage at all?

I'm sure a few 7812, 7809, 7805's and some zener diodes will give you all you want.

Hmm, maybe my first million is in the oven.

Oh Aye, maximum o/p current about 40mA, and dreadful regulation....

Steve

Tends to lead to RF noise, from ringing edges, fast changing mag. fields, high induced voltage transients ? That what you're after ?

Steve

I guess you'd need a few 7660, a luvly little 8pin chip. you provide the

+ve voltage, it inverts it for you... among other functions. gorgeous!

Buggar! you're right there, I was still thinking big transformers. :-( Perhaps fast switching of big currents?

OK ok, no more smug-mode.

On or around Thu, 28 Oct 2004 22:44:16 +0000, Andy Richardson enlightened us thusly:

should work, provided the current capacity of the 78xx are sufficient.

ISTR that some bits of PCs run -5 and -12V, but that should be possible. might not be quite so easy, but there may be a regulator which does it.

dunno how much current it all takes, mind.

A 7805 won't handle more than 3A - and that might need heroic heatsinking, or an extra radiator on the front. You can't GET -ve supplies from a +ve one with a linear method.

Steve

Probably too techy for me, I asked about it here but shied away. I ended up with an IBM laptop with 133Mhz pentium running some old navigator software and a 1:250000 OS licensed bitmap.I connect this to a Garmin 12xl which I carry when walking.

The 150W modified square wave inverter powers it all up but I cannot help thinking there must be a way of simply dumping the (extinct)

10.5V battery and using the 12V vehicle electrics, doing away the inverter. Wouldn't a couple of hefty diodes drop the voltage from 14.5V when running safely?

AJH

No.

Steve

Any relatively easy way around the problem? I think the mains adapter puts out 18V. So to take 14.5V dc, convert it to 230V ac and then to

18V ?? to replace a 10.5V dc Lion battery is a bit tortuous.

AJH