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Post by william on Sept 6, 2018 11:09:44 GMT -5
I had no idea where to post this. Mods--please move if this is the wrong place. I do know that members here have varied interests. So here goes. Last year a small hurricane passed just west of me (Nate) DURING AN ALABAMA GAME! Thankfully it did not result in tragedy since I did not lose power until a few hours after the game, but I found the experience somewhat unsettling.  It prompted me to buy an inverter that would convert the DC current from a 12 volt battery to alternating current, and a small 28" TV. The last tropical brush was a few days ago, but I knew I was safe since it was a Tuesday, and I did not risk the danger of missing a good football game, and I had a backup plan if I did decide I wanted to watch TV. My power stayed on during Nate. But I have decided to find a better way to power a television set during wind and rain (apologies to Thomas Hardy here). I have spent the last hour or so at RV sites without success. So here are my questions. 1. Here is the extent of my electrical knowledge: amps x voltage = watts. So is a DC watt the same as an AC watt? I have a 12 volt deep cycle marine battery that is rated at 110 amps. My small AC TV says it is rated at 48 watts. So my dismal math skills tell me that is a 4 amp draw on my 12 volt battery. (48/12=4). So if I run this TV for 10 hours, I have depleted 40% of its capacity. Is that right? (And actually the DC to AC converter I am using draws a fraction of an amp so that is even more drain not included in my calculation above.) Of course all this reasoning is assuming an alternating current watt is the same as a direct current watt. Is all this right so far? 2. It struck me that someone must make a direct current TV, and I found a few online. This would eliminate the elaborate setup of battery/converter/cords all over the place, and allow me to connect directly to the battery with one cable. Also, many of these TVs draw 24-36 watts, so my battery would last longer. The problem is they all get bad reviews. So does anyone have a recommendation for a small direct current TV? And is my math for calculating battery drain correct? Apparently it is not economically feasible to even make a small TV, especially one that runs off direct current. So any advice would be appreciated..... |
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Post by jeffd on Sept 6, 2018 11:22:14 GMT -5
First of all yes, an AC watt is the same as a DC watt.
Secondly, I heard there is an app for your cell phone that gives you television channels. I don't recall the details (I don't watch television myself), but apparently you can get broadcast and cable on this thing.
Hope that helps.
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Post by Ronv69 on Sept 6, 2018 11:32:10 GMT -5
A certain amount of power is lost in the inverter itself. They vary widely in efficiency. So you are unlikely to get 1320 amp/hours on the AC side. I have a small TV that runs on D cells and a 12 volt wall wart. I have a HDTV antenna and I keep it all in an old briefcase with the weather radio and similar items.
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Post by william on Sept 6, 2018 11:42:13 GMT -5
First of all yes, an AC watt is the same as a DC watt. Secondly, I heard there is an app for your cell phone that gives you television channels. I don't recall the details (I don't watch television myself), but apparently you can get broadcast and cable on this thing. Hope that helps. Thanks. Seriously, all I know about electricity is that I am immensely respectful of it thanks to an experience installing a ceiling fan some years ago. I have a small 2000 watt inverter generator that is safe for electronics, but since I have no place to keep the rain off of it while running it, that would be no help. I can imagine killing myself standing on wet ground fiddling with a generator. But knowing a watt is a watt is a watt is helpful. |
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Post by william on Sept 6, 2018 11:47:32 GMT -5
A certain amount of power is lost in the inverter itself. They vary widely in efficiency. So you are unlikely to get 1320 amp/hours on the AC side. I have a small TV that runs on D cells and a 12 volt wall wart. I have a HDTV antenna and I keep it all in an old briefcase with the weather radio and similar items. Thanks Willard Ronv69--you changed your name. Maybe this is the way to go--a battery operated TV (maybe lithium?) and an extra battery or two. I hadn't thought of that. Then I could use the 12 volt battery directly to keep the TV batteries charged. I will wander around on the internet a bit and see what I can find. Also, I did not know how inefficient inverters could be. |
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Post by jeffd on Sept 6, 2018 11:48:00 GMT -5
Healthy fear is the beginning of wisdom.
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Post by slowroll on Sept 6, 2018 11:54:31 GMT -5
First need a clarification. You say the battery is rated at 110 amps. Is that the rated max continuous current drain capable (that should be defined in the battery specs), or , is that the amp/hour rating? Since it's a marine battery, I assume it is not. Marine deep discharge batteries usually have a higher amp/hour rating than 110. Check the specs to be sure of what the rating actually is. In any case, dividing the amp/hour rating by 4 will be in the ballpark, for effective time to discharge, within 10% of actual, allowing for liberal amp/hour rating and efficiency.
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Post by william on Sept 6, 2018 12:18:10 GMT -5
First need a clarification. You say the battery is rated at 110 amps. Is that the rated max continuous current drain capable (that should be defined in the battery specs), or , is that the amp/hour rating? Since it's a marine battery, I assume it is not. Marine deep discharge batteries usually have a higher amp/hour rating than 110. Check the specs to be sure of what the rating actually is. In any case, dividing the amp/hour rating by 4 will be in the ballpark, for effective time to discharge, within 10% of actual, allowing for liberal amp/hour rating and efficiency. Thanks. I looked again. It is 100 amp. And I think this is an amp hour rating. It is a size 27 Exide battery. They only make one size larger and it is 105 amps. I copied this from the website: Specifications Manufacturer warranty - general: 1 year Volts: 12 Manufacturer warranty - parts: 1 year Product weight (lb.): 56 Product height (in.): 9.44 Product width (in.): 6.81 Product length (in.): 12 Amps: 730 marine cranking; 575 cold cranking Amp hours: 100 |
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Post by slowroll on Sept 6, 2018 12:27:11 GMT -5
Ok, then 100 is the number to use. That current draw ought to be low enough to actually make the numbers fairly close. Typically, the higher the draw, the less chance to actually get the rated amp/hours.
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Post by Deleted on Sept 6, 2018 13:01:07 GMT -5
TV’s of today all operate on DC power, even though you plug them into an AC outlet. internally goes though a power supply circuit, the alternating current runs through a circuit made up of 4 bridged diodes & electrolytic filter condenser’s, which convert AC current into DC current. It’s not the voltage you need to worry about, it’s the amperage that will knock you out of your shoes.
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Post by slowroll on Sept 6, 2018 13:30:12 GMT -5
Damn near all electronics work on DC and always have. The problem is getting to the DC side of the rectifier inside the unit.
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Post by Deleted on Sept 6, 2018 13:43:35 GMT -5
Damn near all electronics work on DC and always have. The problem is getting to the DC side of the rectifier inside the unit. That’s correct, you’d be surprised how many people don’t know that. Some older transitioned Zenith, RCA and more had live 75 to 77 volts to ground. That’s why work benches had to use isolated AC. It was known as a HOT chassis. |
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Post by Deleted on Sept 6, 2018 13:44:51 GMT -5
Damn near all electronics work on DC and always have. The problem is getting to the DC side of the rectifier inside the unit. That’s where the bridge rectifier circuit comes in. |
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Post by jeffd on Sept 6, 2018 17:51:57 GMT -5
Damn near all electronics work on DC and always have. The problem is getting to the DC side of the rectifier inside the unit. Please be careful people. If you don't know exactly what you are doing you can really hurt yourself and do some hobby changing damage. And even folks who know what they are doing get hurt and worse on a regular basis. Be careful. There are lots of great tobacco moments you really don't want to miss. |
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Post by slowroll on Sept 6, 2018 18:09:15 GMT -5
Damn near all electronics work on DC and always have. The problem is getting to the DC side of the rectifier inside the unit. Please be careful people. If you don't know exactly what you are doing you can really hurt yourself and do some hobby changing damage. And even folks who know what they are doing get hurt and worse on a regular basis. Be careful. There are lots of great tobacco moments you really don't want to miss. Well, I don't think anyone is advocating tearing into the guts of a TV in any event. They used to be a lot more dangerous when CRT tubes were used. Multi hundred volts to light that up.. My intro to electronics was TV repair in the 196os as a part time job.. |
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Post by smellthehatfirst on Sept 6, 2018 18:27:12 GMT -5
Hey just for the record, don't use a marine/deep-cycle battery in an unventilated area. They are usually un-sealed cells, which can emit fumes when charged or discharged quickly. (This is why the battery compartment on boats is ventilated.) Commercial systems for backup power use sealed batteries that don't have this problem, but they tend to be kind of expensive. For example, this guy is 15 or 20 amp-hours, and it's $200 for a refurb unit! www.refurbups.com/APC-DLA1500RM2U-Smart-UPS-1500-Slim-Line-Tower?sc=27&category=1573(Of course, being a complete UPS, it's a battery AND an inverter AND a system to switch power feeds on power loss.) |
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Post by Deleted on Sept 6, 2018 18:27:27 GMT -5
TV’s made years ago with Cathode Ray Tubes ( CRT ) were made under a vacuum method, therefore if dropped they did not explode....they would implode.....much more dangerous!! Not only glass would go flying, you’d have to deal with a phosphorus powder that covered the shadow mask of the CRT. ALSO....the filters used in the old TV’s held a high DC voltage that could seriously give anyone a shock of their life if not discharged properly. It’s known as kinetic energy. Information......just in case anyone was interested.
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Post by william on Sept 6, 2018 19:03:12 GMT -5
Please be careful people. If you don't know exactly what you are doing you can really hurt yourself and do some hobby changing damage. And even folks who know what they are doing get hurt and worse on a regular basis. Be careful. There are lots of great tobacco moments you really don't want to miss. Well, I don't think anyone is advocating tearing into the guts of a TV in any event. They used to be a lot more dangerous when CRT tubes were used. Multi hundred volts to light that up.. My intro to electronics was TV repair in the 196os as a part time job.. Exactly. All I wanted to know is if the standard formula for calculating electrical current is the same for AC as DC. Apparently is is. Then I wanted to know if my method of judging the duration of running a TV from my battery is valid. Apparently that is as well. And the last thing I wanted to know is if anyone knows of a good direct current TV so I can eliminate the DC to AC converter and connect the thing directly to the battery. No answer on this so far, but I have located a small TV that runs on direct current--it just gets lousy reviews--as they all do. I have discovered that TVs with lithium or other rechargeable batteries are not the answer since every one I have found has an battery that cannot be removed for recharging. Anyway--I thank you gentlemen for your input. |
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Post by Pistol Pete 1911 on Sept 6, 2018 19:12:35 GMT -5
Ok! don't mess with electricity! buy a generator and have it wired into your electrical box don't mess with the extension cord with 2 male plugs "you will burn your house down" this is an viable option but it may cost you a few dollars but it is the safest way to go and you won't lose all your food either. Craigs list is a good place to locate a used generator. buy diesel if you can and get as many watts as you can afford, I would start looking at 1500 at least. forgive me the Jamisons it starting to be nice to me.
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Post by william on Sept 6, 2018 19:33:54 GMT -5
Hey just for the record, don't use a marine/deep-cycle battery in an unventilated area. They are usually un-sealed cells, which can emit fumes when charged or discharged quickly. (This is why the battery compartment on boats is ventilated.) Commercial systems for backup power use sealed batteries that don't have this problem, but they tend to be kind of expensive. For example, this guy is 15 or 20 amp-hours, and it's $200 for a refurb unit! www.refurbups.com/APC-DLA1500RM2U-Smart-UPS-1500-Slim-Line-Tower?sc=27&category=1573(Of course, being a complete UPS, it's a battery AND an inverter AND a system to switch power feeds on power loss.) Thanks for the caution. I am a boat person and a firm believer in battery ventilation. I saw one explode once several years ago. Luckily I was about 10 feet away. I was planning on leaving the battery in a ventilated battery box just outside my back door and running the wiring inside (under the door) from there. |
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Post by Deleted on Sept 6, 2018 20:43:39 GMT -5
Well, I don't think anyone is advocating tearing into the guts of a TV in any event. They used to be a lot more dangerous when CRT tubes were used. Multi hundred volts to light that up.. My intro to electronics was TV repair in the 196os as a part time job.. Exactly. All I wanted to know is if the standard formula for calculating electrical current is the same for AC as DC. Apparently is is. Then I wanted to know if my method of judging the duration of running a TV from my battery is valid. Apparently that is as well. And the last thing I wanted to know is if anyone knows of a good direct current TV so I can eliminate the DC to AC converter and connect the thing directly to the battery. No answer on this so far, but I have located a small TV that runs on direct current--it just gets lousy reviews--as they all do. I have discovered that TVs with lithium or other rechargeable batteries are not the answer since every one I have found has an battery that cannot be removed for recharging. Anyway--I thank you gentlemen for your input. William, I just called a friend of mine from Long Island. I knew his brother was also looking for a good TV that operates on only DC voltage. He ended up purchasing this model over 6 months ago. My friend said “ he really is glad he bought it “! He sent me the link......... www.amazon.com/Jensen-JE3212LEDWM-32-Inch-1080p-Volt/dp/B0056GUB5W |
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Post by william on Sept 6, 2018 20:57:38 GMT -5
Exactly. All I wanted to know is if the standard formula for calculating electrical current is the same for AC as DC. Apparently is is. Then I wanted to know if my method of judging the duration of running a TV from my battery is valid. Apparently that is as well. And the last thing I wanted to know is if anyone knows of a good direct current TV so I can eliminate the DC to AC converter and connect the thing directly to the battery. No answer on this so far, but I have located a small TV that runs on direct current--it just gets lousy reviews--as they all do. I have discovered that TVs with lithium or other rechargeable batteries are not the answer since every one I have found has an battery that cannot be removed for recharging. Anyway--I thank you gentlemen for your input. William, I just called a friend of mine from Long Island. I knew his brother was also looking for a good TV that operates on only DC voltage. He ended up purchasing this model over 6 months ago. My friend said “ he really is glad he bought it “! He sent me the link......... www.amazon.com/Jensen-JE3212LEDWM-32-Inch-1080p-Volt/dp/B0056GUB5WThanks, Ted. I took a look and decided that is larger than I want, but they make smaller ones too. This gives me a new avenue to search and I will look at more of their models. Thanks for going to all the trouble to call your friend and post the link. |
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Post by Deleted on Sept 6, 2018 21:12:11 GMT -5
William, yes they make smaller 12 volt DC TV’s as well. Jensen has been around for a number of years....good luck👍
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Post by Deleted on Sept 6, 2018 22:32:34 GMT -5
In a storm it is hard to beat a little 3500 to 4000 watt generator. That's enough power to run a fridge, fan and a TV. A company called Firman makes generators for lots of folks who slap their names on them. A little 1150 watt is 200 shipped and a 3650 is around 400. CPO outlet or some source other than the big box stores. These are nice units and have a three year warranty. www.firmanpowerequipment.com/ So long story short for just a few more bucks that a good deep cell battery you can have a little generator. |
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It prompted me to buy an inverter that would convert the DC current from a 12 volt battery to alternating current, and a small 28" TV. The last tropical brush was a few days ago, but I knew I was safe since it was a Tuesday, and I did not risk the danger of missing a good football game, and I had a backup plan if I did decide I wanted to watch TV. My power stayed on during Nate. But I have decided to find a better way to power a television set during wind and rain (apologies to Thomas Hardy here). 
