12 Volt of 120 Volt TV

[agallant80]

Should I go through the hassel of getting a 12Volt TV online for my boat or just get a 120 Volt tv from walmart and use an inverter? Will there be a significant battery drain on 12V vs 120V on an inverter?

 

[Don S]

Re: 12 Volt of 120 Volt TV

Battery drain depends on the size TV you get from Walmart, and the efficiency of your inverter.

 

[Silvertip]

Re: 12 Volt of 120 Volt TV

There is a 10:1 conversion factor involved in usin an I.verter. Deyermine what the curret draw is for the tv you intend to use. If 120 volt device draws 5 amps that same device will suck 50 amps from the battery. That is just the way this works.

 

[colbyt]

Re: 12 Volt of 120 Volt TV

I suppose that if I said learn to do without it for a few hours each week, that I would tick you off.

Seriously, why do you need one on a boat?

 

[agallant80]

Re: 12 Volt of 120 Volt TV

I suppose that if I said learn to do without it for a few hours each week, that I would tick you off.

Seriously, why do you need one on a boat?

pimp palace........

For real planning on taking week long cruises etc. Would like to watch CBS Sunday Morning on the water with my tea.

 

[NYBo]

Re: 12 Volt of 120 Volt TV

You will find that many new televisions run on 12V DC using a power brick. All you need is the proper connectors to rig up a DC power cable.

 

[beardeddone]

Re: 12 Volt of 120 Volt TV

It really depends on the charging system on your boat in which way to go, most inverters draw a lot of current to run something like a TV even tho they are usually low voltage TV's after the power supply in the TV, especially the newer flat screens, I've used a 300 watt inverter to run my laptop in my pickup, but after about 15 minutes I have to start the motor up as it starts to beep for the lack of juice.

There are several nice 12v TV's out there and I think that is the way I would go for a boat and put it on an extra battery and not your motor battery, it depends on how pimped you want to be..Do you plan on a DVD player or have a satellite service provider or both..

I saw some nice setups when I was driving bigtruck, don't know how a satellite setup would work on a boat even anchored..Unless you get TV programming through your laptop..

 

[generator12]

Re: 12 Volt of 120 Volt TV

Battery drain depends on the size TV you get from Walmart, and the efficiency of your inverter.

Don said it. If a 120 volt TV consumes 100 watts, it's pulling about .83 amps. Reducing that to 12 volts makes it 8.3 amps. Divide that by the efficiency of the converter and you have the actual current draw on the 12 volt system. If you're watching it for an hour, you've probably drawn about 10 amp-hours from the battery storage - shouldn't be a problem. That's with a 100 watt power usage...you can do the arithmetic for a different power requirement.

 

[bruceb58]

Re: 12 Volt of 120 Volt TV

I've used a 300 watt inverter to run my laptop in my pickup, but after about 15 minutes I have to start the motor up as it starts to beep for the lack of juice.

Most laptop chargers I see are around 50W max. What in the heck are you running?

 

[beardeddone]

Re: 12 Volt of 120 Volt TV

Most laptop chargers I see are around 50W max. What in the heck are you running?

Your question really doesn't compute, sorry just got up and read this, maybe I just need my coffee first and maybe this will help

and that's the small one, I also have a 1500w inverter I used in the bigtruck and it would kill a regular car battery in about 15 minutes, they use a lot of current..

 

[bruceb58]

Re: 12 Volt of 120 Volt TV

The size of the inverter has nothing to do with the current draw. If you only had a 50W load on it, a 100W inverter and a 300W inverter would be drawing the same current from the battery. Just because the inverter is 300W doesn't mean its drawing 300W when your load is lower.

 

[beardeddone]

Re: 12 Volt of 120 Volt TV

The size of the inverter has nothing to do with the current draw. If you only had a 50W load on it, a 100W inverter and a 300W inverter would be drawing the same current from the battery. Just because the inverter is 300W doesn't mean its drawing 300W when your load is lower.

I don't believe I did imply that it would, but it has to do with what it could be used for by the wattage rating of each.
For the OP use it wouldn't be feasible for the usage of an inverter.

It would be easier to just get a 12v TV for his/her use.

BTW, try using a 100w inverter on a laptop and see if it'll fire up and for how long
Then try a 300w inverter and see the difference, if you don't believe it matters, I have, it matters..
Along with the size of battery, wiring used and fuze rating required.

Most battery backup units for computers will only give about 20 minutes of power max with the small battery supplied with those units, they all use a form of an inverter to supply 110v of power.

It gets more complicated from there for inverters. And none are advisable for use on a boat for an add-on..

 

[bruceb58]

Re: 12 Volt of 120 Volt TV

A 19" Vizio LED TV takes 19.7W. The extra watts required for the inverter losses are maybe another 4W. Not sure what the big deal for using the inverter is. What am I missing?

http://store.vizio.com/led-lcd-hdtvs/e191va.html?___SID=U

If its 24W total, that's around 2A per hour.

 

[bruceb58]

Re: 12 Volt of 120 Volt TV

BTW, try using a 100w inverter on a laptop and see if it'll fire up and for how long

Depends on the inverter and how its rated. Some inverters are rated for peak watts and some are rated for average watts. A transformer will have a huge inrush current because its an inductive load and that may be your issue. Measure the current that your laptop uses once its running and you will see that the current really isn't that high. I have a 100W inverter and run a laptop easily on it for hours and hours.

 

[Silvertip]

Re: 12 Volt of 120 Volt TV

As Bruce and I both have pointed out, it isn't the size of the inverter that determines the TOTAL current draw. It is in fact a very small part of it. Obviously it takes power to run electronics, but that's not the issue here. In the picture below, a 75 watt trouble light is plugged into an 800 watt Cobra inverter which is getting 12 volt power from a small lawn tractor battery. As you can see, the DC ammeter in the input to the inverter is showing about 6.5 amps. If one divides the lamp wattage (75) by 117 (the nominal AC voltage) one comes up with a current draw of .64 amps AC. I indicated earlier that there is a roughly a 10:1 conversion factor which is born out by this test. To get .64 amps ac out of an 800 watt inverter you need to input 6.5 amps into it. That's about as close to 10:1 as one can get. It wouldn't make any difference if that inverter was a 1500 watt or a 100 watt unit. The only difference is the efficiency of the inverter and it's idle state current draw. The point in all of this as it relates to a 120 volt AC TV is that whatever current it draws at 120 volts, multiply that by 10 and that's what the system will suck from the battery. If you have a deep cycle (group size 27 for example) it will have a reserve minute capacity of about 175 minutes with a 25 amp draw. In this example, the draw is 6.5 amps. That number is about 4 times less than the battery spec so the 75 watt light in this example would run for 175 minutes x 4 = 700 and dividing that by 60 minutes = 11.5 hours. At that point the battery would fall out of spec. The work gong on in the inverter is no different than running an electric drill, toaster, microwave or whatever. That's the cost of making 115 volts AC from 12 volts DC. The amount of current required by the inverter to accomplish that conversion has little bearing on the "capacity" (wattage) of the inverter. You would not likely see the needle move on the inverter if it was powered but had no AC load on it. With a low current meter one would only measure the current drawn by the indicator LEDs, perhaps a fan and whatever the idle state current was. Inverters are typically 85% efficient and depending on how much money you spend, can be higher.

 

[beardeddone]

Re: 12 Volt of 120 Volt TV

Depends on the inverter and how its rated. Some inverters are rated for peak watts and some are rated for average watts. A transformer will have a huge inrush current because its an inductive load and that may be your issue. Measure the current that your laptop uses once its running and you will see that the current really isn't that high. I have a 100W inverter and run a laptop easily on it for hours and hours.

Is that with or without the motor running?
Either way, you might hang on to that inverter as most won't come near to to hours and hours unless you have an extremely low current draw or the motor running.

And one other thing, my laptop was an older model at that time so that might have played with the requirement.

 

[bruceb58]

Re: 12 Volt of 120 Volt TV

Is that with or without the motor running?

Of course without!

An older laptop may have a high power transformer. Lets say it was close to 100W. That would be a little over 8A from your battery. After 15 minutes, that would only be 2A. Hard to imagine having to start your vehicle after a 2A draw.

 

[Moody Blue]

Re: 12 Volt of 120 Volt TV

The whole inverter thing is so misleading and mysterious to most people. I see ads all the time for 1500 and 3000 watt inverters that say "power up your home electronics or appliances while on the road". There is no mention that you would need a bank of batteries that fill your trunk to accomplish that task. Not to mention the size of the supply cables from the battery to the inverter.

Imagine taking along your 1500W kettle to make tea while "on the road". Well within the capacity of the 3000W unit BUT it would draw somewhat over 100A from the battery. A "typical" automotive battery won't last but a minute or the supply cable will melt if your not running 2ga cable.

 

[beardeddone]

Re: 12 Volt of 120 Volt TV

The whole inverter thing is so misleading and mysterious to most people. I see ads all the time for 1500 and 3000 watt inverters that say "power up your home electronics or appliances while on the road". There is no mention that you would need a bank of batteries that fill your trunk to accomplish that task. Not to mention the size of the supply cables from the battery to the inverter.

Imagine taking along your 1500W kettle to make tea while "on the road". Well within the capacity of the 3000W unit BUT it would draw somewhat over 100A from the battery. A "typical" automotive battery won't last but a minute or the supply cable will melt if your not running 2ga cable.

I agree about the misleading and mysterious to most people and I feel most people don't have a need to use them, there may be other areas they may be used, I don't know, but the only place I have ever seen inverters used are in 18 wheelers, I used mine mainly for my TV, laptop and coffee pot as most 12v coffee pots are junk and don't last long, when I was driving an 18 wheeler.

They worked great in this environment as the battery supply was there as well as the charging system and most, not all trucks had the heavy duty wires already installed for the inverters under the bed.

I need to sell my 1500w inverter as I have never had a need to use it since I had to give up truck driving dew to my open heart surgery a few years ago..

 

[bruceb58]

Re: 12 Volt of 120 Volt TV

Large inverters are used in RVs all the time. My parents had a huge bank of batteries and large solar panels across the top of their 5th wheel. Very nice to have when you can't or not allowed to run a generator.