Power strip calculation question

Genesisfactor · 02-16-2006, 01:30 PM

I need to know what the electrical calculations applied to a power strip are. I'm using a 2 port 400W (800W peak) inverter and have 5 devices that require regulated power. I'm just trying to figure out if i can connect all the power to one port or and how much do i have to spare, if its safe, and if i need more than one port, what is the maximum amount of ports i can use? Sounds like an electical engineering test question, doens't it? Sucsk for me, but i'm mechanical

I know DC-DC is great and all, but i'm using a laptop and would rather not mess with things right now as this is my first carputer. This may not be the most "integrated" way, and therefore not the best, but its a second best way and works for me for now.
Thanks!

DarquePervert · 02-16-2006, 01:48 PM

Have you considered a car adapter for your laptop? It's more efficient than an inverter and won't require you to modify the laptop in any way.

monger · 02-16-2006, 04:26 PM

Quote: Originally Posted by Genesisfactor

I need to know what the electrical calculations applied to a power strip are. I'm using a 2 port 400W (800W peak) inverter and have 5 devices that require regulated power.
Thanks!

The number of ports on the power strip dosent matter. Just so long as the total wattage of the combined devices dosent excede the rating of the power strip or the base load rating of the inverter.

Think of it this way, you could have a 100 port power strip full of devices each using 1 watt of power ( totaling 100 Watts draw) and be perfectly fine. Aside from the rats nest of wiring

Genesisfactor · 02-16-2006, 11:47 PM

hehe, i like rats...jk

Thanks. I remembered that there was an amperage concern though back in my highschool physcis class, where if you exceeded the amperage, you tripped the circuit breaker. I wanted to know those calcs. Thank you for yoru help. I know i'm pushing about 210 Watts and maybe about 15-17 amps.

nkotch · 02-16-2006, 11:55 PM

Check the manual for the inverter and see if it says anything about if each outlet is separately fused or not. I really doubt it and agree with monger....just worry about the total power draw....2nd outlet is really just for convenience.

But do a google search for "power calculator" or "wattage calculator" or just look up the specs (wattage, amp draw) for each piece of equipment you'll plug in and just compare it to what the inverter will handle....no real calculations involved.

Rocky388 · 02-17-2006, 05:24 AM

Well, your inverter is good for around 30 amps (400 watts / 13.8 volts)

So if all the devices added together that you wanna plug in are drawing 15-17 amps, you still have 13-15 amps to spare.

Genesisfactor · 02-18-2006, 09:38 PM

THe inverter syas 3.7 amps...go figure. I thought it woudl be like your calc, rocky.

DP, sorry, i didn't read your post ;ast time. I am powering quite a few items. Also, i want my cigarrette lighter free for some of my devices (air pump, cell phone charger, heat based torture device to keep my little brother in line). Beleive me, its going to good use

. Besides, i alread shelled out for the inverter...and an SDC. why not use it?

Seeign that there's no problems, i need to figure out what stri i shoudl get as some of these have thsoe annoyingly huge adatpers. Thanks guys, i'm happy. God bless and have a great one!

cMags · 02-19-2006, 09:23 AM

The calculation is WATTS = VOLTS x AMPS. So you're going to have different amounts of current on either side of the inverter in order to have the same amount of power. Your inverter is pulling around 30A into it from the battery (400W/13.8V), but is outputting ~110V, so is only putting out about 3.7A like it says (400W/110V).

Genesisfactor · 02-19-2006, 03:59 PM

so no go for the 15 amp thing?

Genesisfactor · 02-22-2006, 12:30 PM

Seriously though, are you saying i can't run more than 3 devices oon this hting becuase of the amperage requirments?
THese are the amps it pulls
2.4- axim
1.5- NX
4.5-laptop
2.4- DVD
1.4- usb multiport hub
maybe 1 or two for the NVD

Like i said, the wattage doesn't excced 200W. By what you're saying, i'm no where near the safe zone and won't even be able to power the laptop since it excceds the amperage of the inverter. AM i missing something or am i good to go?

MatrixPC · 02-22-2006, 03:58 PM

Something isn't correct here.
So you use a laptop, take a look at the power adapter/converter what does the label said? Output? Input?

The inverter you have said 3.7A which is about 440W. I havn't see any laptop that need that much of power yet.
10A at 12V (120W) is different than 10A at 19V (190W), and so 10A at 120V (1200W).

Genesisfactor · 02-22-2006, 04:26 PM

good point...see, that's probably what's confusing me. the laptop is 56/72 watts regulated. Thanks. i see my error in thinking and i'll take it from here

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