New install in ///M Roadster

**tags** · 10-05-2005, 04:11 AM

Hi,

I am planning a new install in my ///M Roadster and have a few questions regarding power and inverters. I plan to use a broken Sony VAIO (screen backlight is knackered, other than that, perfect) for the car PC project. This draws 19v @ 3.16amps. My limited knowledge of watts makes that 60watts (V x A = W). What about an XBOX (uk version)? Thats 240v @ 1.2amps, does that mean it will be 288watts? I was thinking about using a 300watt inverter, so not sure if it is enough to power PC and XBOX. Also, the inverter will be modified sine wave. Will the notebook be ok as the notebooks transformer/charger should smooth out the wave, correct me if i am wrong. What about the XBOX? The car has standard battery, will this cope? and will everything be ok when cranking the engine? The only other equiment i am using in the install will be a vga in dash monitor (probably the xenarc 700idt) and a kenwood head unit.

Thanks for any advice on any of the above questions.

tags

**Fusion-One** · 10-05-2005, 10:56 AM

Your calculations are good, but keep in mind this is peak power. Your devices will never ever go past this, I highly doubt an xbox ever gets close to 288watts of power usage. Something to check, however, is the RMS rating of your 300 watt inverter.. most often what is advertized on the packaging is the peak wattage, and that might put you in rough waters trying to squeeze so much from it... again, the actual usage of your devices might be low enough that it'll happily power them, only way to really find out is try them, or put each device on a bench and get an idea of the power they draw.

I'm 99% sure it will not survive crank, you could make a tank circuit to overcome this.. and the laptop should cope ok, but I urge you to look for a car adapter for the laptop.. this would take away some strain from your inverter, and would give the laptop much much cleaner power (DC to DC vs DC to AC to DC)

Hopefully this was of help.

-Jared

**tags** · 10-05-2005, 02:47 PM

Thaks for the reply.......so..errrr.....whats a tank circuit and how will it help overcome the crank.

The inverter i saw was only a cheap one, about £40 and a dedicated in car notebook adaptor is about £30 so i will consider this when i am buying. I understand what you mean about the peak power issues and especially with the notebook as this won't even have a screen (may as well take it off completely seeing as its broke). Just leaves the xbox question on power draw.

I was thinking? you can power devices on like amps from car stereos i.e. car stereo starts up on ignition and then remote turns on an amp...could this not also happen for inverters and such, but with a delay. So i start the car, head unit powers up as normal and inverter starts up say 10 seconds later on a delay? Would that make the cranking issue go away? IS this possible..or am i barking up the wrong tree?

Many thanks.

tags