Power inverters

[Garage5.9]

I have a 400watt coleman inverter that id like to use in case of black outs etc just to run a few lights or tv possibly but my question is if i wanted to have the inverter in the house would it be possible to extend the 12v side wires (alligator clamps) to go from my truck out side to in the house so i wouldn't have to leave the inverter out side or would i have to much voltage drop in say 25 feet of wire ? Or does it make more sense to just use a extension cord ?

 

[mrb]

use an extension cord. to go 25ft on the 12v side youre going to need to use some pretty big wire probaby 1ga

 

[Garage5.9]

use an extension cord. to go 25ft on the 12v side youre going to need to use some pretty big wire probaby 1ga

Thats what i was thinking also

 

[StaggeringGoat]

use an extension cord. to go 25ft on the 12v side youre going to need to use some pretty big wire probaby 1ga

Agreed. Inverter manuals always tell you to mount the inverter closest to the DC source.

 

[Greatbear]

Put the inverter as close to the battery as possible, and use an extension cord to connect the ac. If you are drawing 1 amp of ac power from the inverter (120 watts), the inverter will draw more than 10 amps from the battery. Voltage drop upsets inverters if the leads are too small from the battery, or they are too long. Think of it this way, two volts drop is not a lot when there is 120 volts, but at only 12 volts, the inverter will most likely shut down thinking the battery has been deeply discharged.

 

[nehog]

OK, 400 watts, at a nominal 12 volts, is 33 amps (efficiency says that it won't be 100% efficient, so that 33 amps is likely to be about 40.) You will need a minimum of 8 AWG (and better yet, 6 AWG) for those battery cables. You're probably going to be better off mounting the inverter in the vehicle and using an extension cord on the 120 volt AC side instead, as you could get by with a 14 AWG or even a 16 AWG extension.

 

[mrb]

8ga isnt big enough, 25ft is going to drop around a volt and a half

 

[ddawg16]

Put the inverter as close to the battery as possible, and use an extension cord to connect the ac. If you are drawing 1 amp of ac power from the inverter (120 watts), the inverter will draw more than 10 amps from the battery. Voltage drop upsets inverters if the leads are too small from the battery, or they are too long. Think of it this way, two volts drop is not a lot when there is 120 volts, but at only 12 volts, the inverter will most likely shut down thinking the battery has been deeply discharged.

That is the way to go.....

Keep the inverter and battery outside....I'm sure you have plenty of extension cords...

Additionally....Lead acid batteries can give off hydrogen gas when discharging....it's not a lot...but better to leave it outside in a ventilated area.

 

[hmbemis]

The higher the voltage the smaller the wire for a given amount of power. So you'd definitely want the inverter as close as practical.

I bought a group 27 (or whatever the largest was) 125Ah marine battery from wally world and a plastic box to house it... I have it hooked to a Black & Decker VEC049DCB 1000W inverter... I did a test the other day, I was able run my TV and cable box (~280W) for a good 3-4 hours, when done I hooked it up (outside of course) to my batt. charger which has a feature that reports the %-charge, it thought the battery still had a 75% charge, IIRC I was still at something like 12.1V as well. Works like a giant manual UPS.

If I'm using this setup during a storm my plan is to charge the battery from a running generator during the day and have this to supply power at night when we just need a few lights (and some quiet)

 

[HOTFR8]

The higher the voltage the smaller the wire for a given amount of power. So you'd definitely want the inverter as close as practical.

I bought a group 27 (or whatever the largest was) 125Ah marine battery from wally world and a plastic box to house it... I have it hooked to a Black & Decker VEC049DCB 1000W inverter... I did a test the other day, I was able run my TV and cable box (~280W) for a good 3-4 hours, when done I hooked it up (outside of course) to my batt. charger which has a feature that reports the %-charge, it thought the battery still had a 75% charge, IIRC I was still at something like 12.1V as well. Works like a giant manual UPS.

If I'm using this setup during a storm my plan is to charge the battery from a running generator during the day and have this to supply power at night when we just need a few lights (and some quiet)

Good idea. A solar panel to charge it would help then you do not have to run your Gen Set so much.

All my acrivity here on the forum is solar powered.

 

[Garage5.9]

Thanks for the input everyone , Looking to upgrade my inverter to something bigger. any recomendations ?

 

[PrecisionTools]

The BEST

http://www.sma-america.com/en_US.html

 

[nehog]

Keep in mind that a larger inverter creates some serious loads on the battery! Even a dual battery system will discharge way faster than you realize, and that most vehicle alternators do not have enough capacity to keep up with more than a 400 to 600 watt inverter once other loads in the vehicle are taken into consideration (at idle, alternators typically put out about 20-30% of rated current!)

 

[hmbemis]

Keep in mind that a larger inverter creates some serious loads on the battery! Even a dual battery system will discharge way faster than you realize, and that most vehicle alternators do not have enough capacity to keep up with more than a 400 to 600 watt inverter once other loads in the vehicle are taken into consideration (at idle, alternators typically put out about 20-30% of rated current!)

Absolutely... think about this way... putting 800W on an inverter that is ~90% efficient will mean drawing 880W from the battery, 880W at 12.xV is over 70A.

Most car alternators are rated at about 100-150A these days, but as you say, you might only be getting 30-40A at idle, and that's before figuring the power needed for the fuel pump, injectors, computer, electric cooling fans, etc.

I remember seeing a "high idle" pin on the wiring diagrams for my old 90s Ford w/ an EEC-IV computer... it was used for the heated electric windshield I think, but I always thought that would also be a great for anyone trying to generate more power for an inverter... I have no idea if modern cars have a similar high-idle feature that can be tapped... I went old school on my Blazer and used a pair of vice grips on the cable, but that won't work if you have an electronic throttle...

 

[Mowerpan]

Wouldn't it be easier/better to just go get a cheapy small generator like the small ones from harbor freight and it would use less fuel then letting the vehicle run.

 

[787B]

Wouldn't it be easier/better to just go get a cheapy small generator like the small ones from harbor freight and it would use less fuel then letting the vehicle run.

Yup. If you are going to run an extension cord outside anyway, I think a generator makes sense. That little 800 Watt HF genny is on sale for $90 right now. Runs good.