Power Inverter Wire Size

hey guys. I have purchased a 1000w /2000w peak power inverter for my truck. I wanted to mount it to the backside of my regular cab, under the rear window. So it should be a fairly long wire run from the rear of the interior to the engine compartment battery.

I was just curious how to determine what guage wire to run. Since its a long wire run, i wanna make sure i size it right. I also want to run an inline breaker near the battery and i wasnt sure how to size that either lol

Any help is much appreciated. Thanks guys!

 

BTW, here is the 1000w unit I purchased

ERAYAK 1000W Power Inverter DC 12V to 110V 3 AC Outlets with 3.1A Dual USB Ports Modified Sine Wave Converter for Home/Office/Car/Travel

https://www.amazon.com/gp/product/B019PXILXA/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

 

I'd go #4 on the wire and 120 breaker...

 

thanks man.. yeah I figured 2-4awg was about right.. ive read some charts that said I could run 8, but that didn't seem correct whatsoever..

And I had no idea on the breaker size..

 

Doesn't the paperwork in the box tell you gauge size for length of run?

 

No i didnt see anything like that

 

That's odd. My inverter came with a chart on the paperwork showing how far placement from battery was as to how big a wire needed to be run. Mine is a 700 watt and I want to say 6 ft run recommended 4 awg for it.

 

http://bfy.tw/7sjq

 

Yeah thanks for the help dude. Smh

 

In short, The main fuse/circuit breaker on a wire will always be sized to the total amount of amps the equipment will pull under normal operating loads.

 

Thank u sir. I guess what i meant to say was, being that it is an inverter, how can i be sure what kind of amps it will pull if it varies on the load? Thats why i included the 1000w/2000w peak. I will probably never use it for anything crazy but id rather play safe. Hehe

 

Modified sine wave=be careful what you plug into it, it may harm some equipment. Also I would be leary of installing it under a seat. At full capacity it is going to produce a significant amount of heat.
1000W/12V=83.33A
I would use #2 wire, good for 10.3' at 90A
I would use a 100A circuit breaker. 83.33A X 125%=104A
This is just my advice, you should consult a professional (stereo installer or auto electric tech) #2 cause of car fires are electrical issues.
Good luck

Personally I would not buy this unit because it uses a modified sine wave, and it is to large (more heat). Pure sine wave inverters are expensive but worth it IMO.

 

I appreciate your insight! All notes have been made hehe. I already purchased it. To be frank with u, its mostly an emergency thing. Id be lying if i said id use it regularly. If at all. Lol

 

Ohm's law. watts = volts * amps.

If you want to know amps, solve the above and you get

amps = watts / volts. Since voltage = 12.5, to provide 1000 watts of output, you would need 80 amps assuming the inverter is 100% efficient, which is impossible. That's why it has those heat fins on it, to get rid of the heat it produces. Figure 80% efficient, so you will need closer to 100 amps, and that assumes you stop at 1kw of power. If you surge to 2kw, you will need 200 amps. If the wire is too small, you will never get to 2kw of output peak.

Note that you are NOT going to run 1kw for very long, battery will die. That's why the Toyota inverter is much smaller and also further limits the output if the engine is not running. The stock hi-cap alternator will barely keep up. This is the problem with DC power, you can't step the voltage up with a transformer which reduces the wire size requirement dramatically.

 

It's been shown that AC power transmits more efficiently over long distances and that's the reason all power lines transmit AC. Most household components only require DC hence requires a conversion from AC to DC. However, anytime you convert (AC->DC) or invert (DC->AC) there is always loss and heat generated. Most equipment can make this conversion at 80% efficiency of power.

 

Agreed. The pure sine wave inverters are less likely to damage your components. I wouldn't use modified sine wave inverters for a $2k Apple laptop.

 

This is wrong. A/C works better because it is trivial to step the voltage way up, which steps the current way down (to maintain the same power level). Lower current = smaller wire sizes to transmit same amount of power. I don't know about you, but I don't have any DC motors in my house, except for those that run off of batteries.

A simple transformer can double the voltage and halve the current, trivially. With A/C. For DC it is a major pain to change the voltage / current. An inverter first converts DC to AC, whether it is a true sine wave or square wave doesn't matter much. Once you have A/C, you can run it through a transformer to step it up to any voltage you want. Simple A/C to A/C voltage-changing transformers still lose a lot of energy to heat. An inverter loses even more.

As far as damaging things with non pure sine wave power, I wouldn't worry about things with a power brick that step the power right back down in voltage and then rectify it to DC. I wouldn't want an oddball line voltage in significant electronics, but I have run my macbook many times on a cheap inverter without any hitches..