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Old 01-26-2018, 10:22 PM   #1
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TV running off of inverter

Interested in running the 50 inch TV in my Crusader 315 off of my batteries. It's a Summit. How do I determine how big of an inverter I need, and what kind of current draw am I looking at. Is it even a consideration. Have 4 6 volt golf carts under the hood, and solar panels to keep up. Thanks for any help.
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Old 01-26-2018, 10:57 PM   #2
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On the back of the television it will say voltage and either watts or amps. Get an inverter with more capacity than the tv will use. Our tv is right above the factory 12 volt power port. We use a Peak 400 watt inverter that is limited to 150 watts if you use the Peak provided cigar lighter plug. Works fine on our 32 inch tv. Jay
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Old 01-26-2018, 11:04 PM   #3
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Electricity is like water:

Power (gallons) is total water volume, current is water flow (gallons/minute) and voltage is water pressure. The more water pressure the more total water volume, the more water flow gives you the same. Some people get discombobulated by 12 volts and 120 volts and a/c and dc. For battery capacity no need to worry about it.


Power(watts) = Current (amps) times Voltage (volts).


So, look at the TV back label to see how many watts it draws. If it doesn't say watts, then look for current. If the TV says 1.2 amp-hours and it is a 120 volt AC TV then the TV uses 144 watts/hour of electricity. I prefer to have about 25-50% extra inverter capacity then I actually need for future growth of electrical needs.

You will want a true sine wave inverter and mount it as close as possible to the battery.

Battery Capacity Determination for adequacy.

Each 6 volt battery has about 220 amp-hours of battery capacity. Because two batteries are wired in series for 12 volts, each bank of two batteries has 220 amp-hours of capacity. Your 4 golf cart batteries give you 440 amp-hours of capacity at 12 volts. You should never go below 50% of battery capacity so you actually have 220 amp-hours of usable capacity if you want your batteries to last a while.

Here is what that means in theory regarding your batteries.

You have with 50% battery usage: 220 amp-hours x 12 volts = 2640 watts capacity.

220 amp hours means in theory you can use 220 amps of current for one hour OR 110 amps of current for 2 hours, 55 amp hours of current for 4 hours.... 1 amp of power for 220 hours....you get the picture I hope.

It also means (220 x 12 as above) you have 2640 watts of power to use. If you use a 1500 watt/hour heater at 120 volts from an inverter, then it will last 1.76 hours before you hit the 50% max consumption.

If your TV uses 200 watts;hour then you can run it for 13.2 hours. 2640/200)

Hope this makes sense.

Here is where it gets tricky. Inverters are not 100% efficient. My 1,500 watt inverter uses about 1650 watts of power at full load of 1500 watts. The less load on an inverter, the LESS efficient it is. I'm lucky to have 80% efficiency when I'm only running my TV, DVD player, and other small draw electrical items.

Also, if you have a motor device, it will draw more power called a start up load and your inverter and batteries should be sized for this. Air compressors are notorious for needing a lot of start up current at first.

Hope this info helps.
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Old 01-27-2018, 09:18 AM   #4
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Originally Posted by Skyliner View Post
Electricity is like water:

Power (gallons) is total water volume, current is water flow (gallons/minute) and voltage is water pressure. The more water pressure the more total water volume, the more water flow gives you the same. Some people get discombobulated by 12 volts and 120 volts and a/c and dc. For battery capacity no need to worry about it.


Power(watts) = Current (amps) times Voltage (volts).


So, look at the TV back label to see how many watts it draws. If it doesn't say watts, then look for current. If the TV says 1.2 amp-hours and it is a 120 volt AC TV then the TV uses 144 watts/hour of electricity. I prefer to have about 25-50% extra inverter capacity then I actually need for future growth of electrical needs.

You will want a true sine wave inverter and mount it as close as possible to the battery.

Battery Capacity Determination for adequacy.

Each 6 volt battery has about 220 amp-hours of battery capacity. Because two batteries are wired in series for 12 volts, each bank of two batteries has 220 amp-hours of capacity. Your 4 golf cart batteries give you 440 amp-hours of capacity at 12 volts. You should never go below 50% of battery capacity so you actually have 220 amp-hours of usable capacity if you want your batteries to last a while.

Here is what that means in theory regarding your batteries.

You have with 50% battery usage: 220 amp-hours x 12 volts = 2640 watts capacity.

220 amp hours means in theory you can use 220 amps of current for one hour OR 110 amps of current for 2 hours, 55 amp hours of current for 4 hours.... 1 amp of power for 220 hours....you get the picture I hope.

It also means (220 x 12 as above) you have 2640 watts of power to use. If you use a 1500 watt/hour heater at 120 volts from an inverter, then it will last 1.76 hours before you hit the 50% max consumption.

If your TV uses 200 watts;hour then you can run it for 13.2 hours. 2640/200)

Hope this makes sense.

Here is where it gets tricky. Inverters are not 100% efficient. My 1,500 watt inverter uses about 1650 watts of power at full load of 1500 watts. The less load on an inverter, the LESS efficient it is. I'm lucky to have 80% efficiency when I'm only running my TV, DVD player, and other small draw electrical items.

Also, if you have a motor device, it will draw more power called a start up load and your inverter and batteries should be sized for this. Air compressors are notorious for needing a lot of start up current at first.

Hope this info helps.
Just the electrical wiz kid I was looking for. I'm printing this out and going to read the tags on my devices. First the TV, then my inverter. Not sure if my inverter is a sine wave inverter. I used to run a 19 inch TV in my old trailer on it without issue. I believe it's a 750 watt. Just don't want to mess up my TV or my inverter.
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Old 01-27-2018, 12:03 PM   #5
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If your inverter works, then use it. There are cheap inverters that sent out a modified sine-wave which can cause issues in some electronics.

A 750 watt inverter uses at least 62.5 amps (750 watts/12 volts but more due to inefficiency) of current from a 12 volt battery. If you use all 750 watts, you cannot simply wire it into a cigarette plug outlet which are typically fused for 10 to 15 amp of current.

Rule for inverters is to wire them as close to the battery as possible. Use a website calculator to determine desired wire so battery voltage drop is less then 3%. https://www.wholesalesolar.com/solar...n/voltage-drop

The longer the run of wire, the greater the voltage drop which is bad. However, the thicker the gauge of wire, the less the voltage drop. I personally wire my stuff so losses are much less then 1% but 3% is the norm in the solar/electrical industry.

Inverter Standby Power Usage Always check to see how much power an inverter consumes in standby mode (when on but not being used). My 1500 watt inverter burns about 0.8 amp-hours. A person I did a solar install on bought an inverter that consumed 2 amp/hour. He did not have a remote on/off switch and wanted to leave the inverter on the entire time he was camping in the boonies. He was consuming almost 50 amp/hours a day just in standby! That is a lot of usage. The larger the inverter, the larger the standby current draw. This is why it is so important to size your inverter for your usage.

I will probably be going to 2 inverters this year. All I need for my TV and DVD player is about 250 watt capacity. I will probably use a 300 watt inverter and not turn on my 1500 watt inverter just for the TV.

Another thing, get an inverter than has a thermostat controlled cooling fan. Some inverters run the fans on 100% of the time you time them on even on light electrical loads. These fans can burn quite a bit of electricity over 24 hours. I've actually had to wire thermo switches into inverters so their fans wouldn't run 24/7...a PITA because I couldn't return them to seller.
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Old 01-27-2018, 12:11 PM   #6
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Darn it, you are in Colorado too?

I live in Colorado Springs. If you ever want advice or help with or do a solar install, shoot me an instant message with your contact info. I do about 2 solar installs a year which pays for minor upgrades/toys/stuff for my RV. I rather show someone how to do it themselves so they understand how everything works and can do upgrades on their own without having to hire someone.

My solar install allows us to go generator free about 95% of the time in Colorado. The only time we use generator is if we need air conditioning or if we go crazy on 120 volt AC usage in the late afternoon when there isn't much sunlight left for solar to top off the batteries for night usage. Where we camp, we run heat every night all summer and that uses about 50 amp-hours of battery capacity alone. This year's upgrades will include more solar panels and another pair of golf cart batteries so even on overcast days we should get enough juice to not have to run our generator.
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Old 01-27-2018, 02:51 PM   #7
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Darn it, you are in Colorado too?

I live in Colorado Springs. If you ever want advice or help with or do a solar install, shoot me an instant message with your contact info. I do about 2 solar installs a year which pays for minor upgrades/toys/stuff for my RV. I rather show someone how to do it themselves so they understand how everything works and can do upgrades on their own without having to hire someone.

My solar install allows us to go generator free about 95% of the time in Colorado. The only time we use generator is if we need air conditioning or if we go crazy on 120 volt AC usage in the late afternoon when there isn't much sunlight left for solar to top off the batteries for night usage. Where we camp, we run heat every night all summer and that uses about 50 amp-hours of battery capacity alone. This year's upgrades will include more solar panels and another pair of golf cart batteries so even on overcast days we should get enough juice to not have to run our generator.
I live east of the springs near Elbert. I use the Harbor Freight setup with 3 panels for solar. Way I have it figured is each panel is 25 watts at 12 volts which should equal 6.75 amps (2.25 per panel) using the formula you gave me. I just set them outside the trailer and can take them out if we are using parks with electric. A little cumbersome to move in and out but they work and you can't beat the cost. Works fine with my GC Batt's.
So after getting my specs on the TV, it's 110 watts at 110 volts which would translate to 1 amp. Am I correct in that figure? My inverter is 750 watt, modified sine wave, inverter. It is fan cooled, and I don't have it on unless I'm using it so not overly concerned about parasitic draw when not on. I'm thinking this system will work OK. TV is LED 50 inch also. So what's you opinion, should I be able to run that stuff without doing damage to anything? Thanks for the info.
We spend a lot of time at Eleven Mile and I never get a site with electric. Solar works just OK because of mountains, trees and clouds. I also have a Yamaha 2000 inverter generator that I take just in case, but I rarely run it. That may change if I start using the TV.
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Old 01-27-2018, 03:00 PM   #8
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One other thing Skyliner, my inverter has alligator clips and less than a foot of (guessing) 8 gauge wire. Should I hard wire to the battery terminals, or will the clips work OK. They worked fine on my old setup with 19 inch TV and Satellite receiver. Whatyathink?
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Old 01-27-2018, 04:41 PM   #9
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If clips work, then go with what works.

1 amp draw at 120 volts means equals 120 watts

120 watts used from 12 volt battery means you are drawing 10 amps from the battery (actually a little more than 10 amps from efficiency losses).

Harbor Freight panels are better then none but they are not considered very efficient or good quality.

Don't except a panel to put out full wattage (current) all of the time. The panel output is under best conditions and that is very rare.
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Old 01-27-2018, 04:47 PM   #10
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Originally Posted by Comanchecreek View Post
Interested in running the 50 inch TV in my Crusader 315 off of my batteries. It's a Summit. How do I determine how big of an inverter I need, and what kind of current draw am I looking at. Is it even a consideration. Have 4 6 volt golf carts under the hood, and solar panels to keep up. Thanks for any help.
I run a 42" Samsung with a sound bar and subwoofer. Draws about 90 watts. So with our 240AH battery system and a 600 watt inverter, we can watch TV for weeks.

if that is all you will be running off the inverter then a 150w unit will surfice. BUT, typically though you will eventually run other stuff at various times so get as big an inverter as you can afford but nothing smaller than say 300w and I would suggest 600w. Anything bigger starts to cost big bucks. You can do without a microwave and electric radiator when you are camping, surely.

I saw a guy in a park one day who started with a 100w inverter to power some small device he had, (can't remember what it was). Later realizing that he now also wanted to power something that needed more watts, added a 300w unit, then later again, for similar reasons, a 600w unit. They all are connected to different GPO's to run these specific things. After time, two of the specialty devices were superceded and became redundant, so did the two smaller inverters, which were still mounted in his front locker, consuming space and the GPO's they fed were still on the walls at different places in his van, unused. A dumb way to go. Expensive, space consuming and annoying when you think that he can only run 100w off GPO #1, 300w off GPO #2, etc.
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