inverter power draw? - JKowners.com : Jeep Wrangler JK Forum
 
LinkBack Thread Tools Display Modes
post #1 of 4 Old 03-28-2010, 04:16 PM Thread Starter
Rock God
 
jeepersheart's Avatar
 
Join Date: May 2009
Location: South jersey
Age: 34
Posts: 1,121
Feedback: 0 reviews
inverter power draw?

I want to install a power inverter but I dont know how to figure out the power draw. The inverter I have on hand is a 350 watt inverter, but I have plans on getting a more powerful one. I am asking because I dont know what size relay, fuse, and wiring to use so as to not start a fire.

2008 Detonator 2Dr. 6 Sp.
Olympic double tube sliders I Rugged Ridge front XHD I Smittybilt XRC 8 I Ef's pod I Chopped flares I Rock krawler 2.5" stock mod with Bilstein 5100s I 35" Dick Cepek Crushers


Jersey

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Crew
jeepersheart is offline  
Sponsored Links
Advertisement
 
post #2 of 4 Old 03-28-2010, 05:18 PM
Rock God
 
Eugene's Avatar
 
Join Date: Oct 2007
Location: San Lorenzo CA
Posts: 1,167
Feedback: 0 reviews

Watts= volts X amps. So if you have a 350 Watt (max draw) inverter and you plug something in that is 120 volts, then the most that it should draw is 3 amps.
W=VxA
A=W/V----->350W/120V= approx 3 amps at the inverter.

Hope this helps.
edit: Did some research and found that AC watts /12 x 1.1= DC amps


http://www.donrowe.com/inverters/inv...aq.html#safety

Last edited by Eugene; 03-28-2010 at 05:28 PM.
Eugene is offline  
post #3 of 4 Old 03-28-2010, 10:55 PM
Rock God
 
RubiZealot's Avatar
 
Join Date: Sep 2009
Location: PRNJ
Age: 43
Posts: 1,250
Feedback: 0 reviews

Quote:
Originally Posted by Rednroll View Post
Actually, that's kind of backwards since you calculated the current draw on the output side. If you want to know how much current the inverter is drawing, then you need to calculate the current draw on the input side.

So assuming your battery voltage while the engine is running is at about 14volts and it's a 350W power inverter, then the current calculation is 350/14=25Amps. So the inverter is drawing up to 25 amps from the battery.
It also depends on how the rating of 350W is calculated. Is that the supported output load or gross power draw? If it actually supports a load of 350W, then it must actually draw more than that since it's not 100% efficient. I'd say something like an inverter is at best 85% efficient which would mean that your actual draw is .85 / 350W = 411W /14v = 29A

Mike 2010 Rubicon 2DR | RK 3.5 X FACTOR MID ARM | ΜΟΛΩΝ ΛΑΒΕ
RubiZealot is offline  
Sponsored Links
Advertisement
 
post #4 of 4 Old 03-29-2010, 12:35 AM
Rock God
 
WeGo4x4's Avatar
 
Join Date: Aug 2008
Location: Whittier
Posts: 915
Feedback: 2 reviews

The easy way is to look at the fuse the inverter has. For a 350w inverter is should have around a 30amp fuse. That would be your starting point. You need to decide what you will use the inverter for. If it's just a laptop or cell phone charger you don't need anything bigger. If your running an electric chain saw you need to rethink you electrical. For basic stuff a standard relay 30/40 will work.
WeGo4x4 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JKowners.com : Jeep Wrangler JK Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome