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  • #16
    DOH I meant *divide*

    Take THAT measurement, and divide it by 12, which is basically the voltage of the battery. TADA - you can figure out the amps being drawn from the battery ALONG with the loss from the inverter if you you are interested.
    Too much coffee I guess.

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    • #17
      Originally posted by Svencool View Post
      Thanks, My goal is to power my tv with is pulling 275w and my xbox 1 and home reciever. Which they are all total pulling 436w. Right now I have 2 100ah batteries and 2 100w solar panels installed. My goal is to power that setup for about 5-6hrs a day through the week. Maybe more on weekends weather depending. I'm pretty sure I will need at least one more battery.

      From what I've read most suggest that you don't take your batteries below a 75% monthly average, does that sound right? I'm trying to get the most life out of the batteries. Can anyone shed a little more real life experience or knowledge on this for me?

      Mike
      What kind of TV do you have that pulls 275 watts? You may love it, but I have seen AC/DC TVs in about the 32" range that pull 28 watts (max 48w) -- see Samsung at Target.

      That would make a HUGE difference in how big you size your system, depending on how much you watch TV, of course.

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      • #18
        Originally posted by PNjunction View Post

        One way to conserve with your television, is with an Led-backlight tv, turn the backlight down as far as you can comfortably go. You may end up cutting your power draw in half by doing that.

        Right now I'm doing just that with nothing but a honking big Optima battery and a pure-sine-wave inverter powering my directv receiver and tv just for kicks. About 8 hours before I want to recharge it without killing the battery.
        Thanks for the idea! I came home and plugged in my Kill-a-meter and I turned on the energysaver mode on my tv and it went from 275w down to 109w Thanks for the idea!!! PNjunction

        Mike

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        • #19
          Originally posted by lkruper View Post
          What kind of TV do you have that pulls 275 watts? You may love it, but I have seen AC/DC TVs in about the 32" range that pull 28 watts (max 48w) -- see Samsung at Target.

          That would make a HUGE difference in how big you size your system, depending on how much you watch TV, of course.
          Thanks for the idea!!! I have a Samsung right now. I bought it around 2008 or so. But it would be interesting to look at a few AC/DC TV's more great ideas! My Tri Metric meter comes in tomorrow so that will help me better gauge whats going on with my system. I do appreciate you guys taking the time to give me some idea's and helping me out!

          Mike

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          • #20
            Awesome - I just did nearly the same for my 32" led-backlit tv that I run from a giant Optima and pure-sine-wave inverter. The main saver was turning down the backlight (NOT the brightness) to just above zero. Went from 120w down to 50w. Not really watchable in a bright room, and not something I use on a daily basis, but for emergency needs good enough without me doubling down on more panel and more battery capacity. About 7 hours usable total when reaching the 50% DOD point approximately.

            The calculations came close to what my cheap clamp-on ammeter was showing on the battery terminal leads:

            50 w / 12v = 4.1xx amps, which is of course the tv, directv box, and inverter together as a load. TV is still light enough to serve as a dim light during night ops so I don't stub my toes.

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            • #21
              Originally posted by PNjunction View Post
              Awesome - I just did nearly the same for my 32" led-backlit tv that I run from a giant Optima and pure-sine-wave inverter. The main saver was turning down the backlight (NOT the brightness) to just above zero. Went from 120w down to 50w. Not really watchable in a bright room, and not something I use on a daily basis, but for emergency needs good enough without me doubling down on more panel and more battery capacity. About 7 hours usable total when reaching the 50% DOD point approximately.

              The calculations came close to what my cheap clamp-on ammeter was showing on the battery terminal leads:

              50 w / 12v = 4.1xx amps, which is of course the tv, directv box, and inverter together as a load. TV is still light enough to serve as a dim light during night ops so I don't stub my toes.
              Is that all the load you run from your system? It sounds similar to what I am thinking of doing. I have good grid power at my cabin but would like to plan for an emergency where I would not need to run my generator at night if there is a natural disaster. My TV and DirectTV are load that I thought could be run from a battery stored in the TV cabinet/stand. My TV is on power saving mode (went down from about 100 to 60) , my DirectTV box is 11w and the power supply wall-wart that powers the dish is 9. I had not thought to see if there was another adjustment that could bring the TV down lower.

              Its also all what you get used to. My Sony 32" on normal was sometimes too bright for my tastes in the evening. I tried power saving mode and immediately my wife said she did not like it. A few weeks later I adjusted it down again without telling her and she has not noticed it or commented on it

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              • #22
                Originally posted by lkruper View Post
                A few weeks later I adjusted it down again without telling her and she has not noticed it or commented on it
                Back around 1980, my mom added yogurt to my dad's ice cream. Dad would never touch yogurt. We were eating dessert, and my mom said out loud "This is pretty good, huh hon?". My dad smirked, looked down at his dish, and said "Well, yes, it is. What's in it?" You could tell by the look on his face that he knew he had been swindled.

                Back on topic, I finally sold my cutting edge Sony Trinitron 27" last year, and got my first flat screen. 32". I think it consumes 35 watts, which is a far cry from the 130 of the Sony. The total mentioned here for tv, inverter, box seems excellent.

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                • #23
                  Originally posted by Living Large View Post
                  Back around 1980, my mom added yogurt to my dad's ice cream. Dad would never touch yogurt. We were eating dessert, and my mom said out loud "This is pretty good, huh hon?". My dad smirked, looked down at his dish, and said "Well, yes, it is. What's in it?" You could tell by the look on his face that he knew he had been swindled.

                  Back on topic, I finally sold my cutting edge Sony Trinitron 27" last year, and got my first flat screen. 32". I think it consumes 35 watts, which is a far cry from the 130 of the Sony. The total mentioned here for tv, inverter, box seems excellent.
                  Yes, it does sound good. I have found (but not seen) a 32" Samsung AC/DC commonly available at Target, etc which draws 28w. My Directv takes 20w. That is 48w. One thing I have not researched is how to calculate the inverter draw. I know that larger inverters take more power and have seen the specs in the 80-90% range. But the specs I saw qualified it with the load. So my question remains, and maybe you or someone else knows, when the inverter is on, is the loss a percent of the total capacity or the percent of what it is outputting?

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                  • #24
                    Originally posted by lkruper View Post
                    Yes, it does sound good. I have found (but not seen) a 32" Samsung AC/DC commonly available at Target, etc which draws 28w. My Directv takes 20w. That is 48w. One thing I have not researched is how to calculate the inverter draw. I know that larger inverters take more power and have seen the specs in the 80-90% range. But the specs I saw qualified it with the load. So my question remains, and maybe you or someone else knows, when the inverter is on, is the loss a percent of the total capacity or the percent of what it is outputting?
                    I think I saw power consumption of something like 45w with no load for the Xantrex I was looking at - which would hint that efficiency at a low load would be poor, and not be surprising. I am speaking off the cuff and from memory - so I could be way off. With a load, I have no idea. That's a good question - is efficiency an always increasing function of load? Have a maximum in the middle? I would guess the latter.

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                    • #25
                      Originally posted by Living Large View Post
                      I think I saw power consumption of something like 45w with no load for the Xantrex I was looking at - which would hint that efficiency at a low load would be poor, and not be surprising. I am speaking off the cuff and from memory - so I could be way off. With a load, I have no idea. That's a good question - is efficiency an always increasing function of load? Have a maximum in the middle? I would guess the latter.
                      That is one of the reasons I was considering an AC/DC TV because half the load of the entertainment center would come directly from DC. Even the power supply for the receiver is a wall-wart that converts AC to DC, and there are ways one can run those from DC as well if one is careful.

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                      • #26
                        Number of Batteries

                        If I have 3 batteries which method would you guys choose? See Link,

                        http://www.smartgauge.co.uk/batt_con.html

                        Would #3 make the most sence?

                        Mike

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                        • #27
                          Method 2 would work well.

                          quote:
                          Method 3

                          This looks more complicated.

                          It is actually quite simple to achieve but requires two extra interconnectng links and two terminal posts.

                          Note that it is important that all 4 links on each side are the same length otherwise one of the main benefits (that of equal resistance between each battery and the loads) is lost.

                          The difference in results between this and the 2nd example are much smaller than the differences between the 1st and 2nd (which are enormous) but with expensive batteries it might be worth the additional work. Most people (myself included) don't consider the expense and time to be worthwhile unless expensive batteries are being fitted or if the number of batteries exceeds 8.
                          Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                          || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                          || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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                          • #28
                            Originally posted by lkruper View Post
                            That is one of the reasons I was considering an AC/DC TV because half the load of the entertainment center would come directly from DC. Even the power supply for the receiver is a wall-wart that converts AC to DC, and there are ways one can run those from DC as well if one is careful.
                            Ah ha. Interesting idea. Got it.

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                            • #29
                              Originally posted by Living Large View Post
                              I think I saw power consumption of something like 45w with no load for the Xantrex I was looking at - which would hint that efficiency at a low load would be poor, and not be surprising. I am speaking off the cuff and from memory - so I could be way off. With a load, I have no idea. That's a good question - is efficiency an always increasing function of load? Have a maximum in the middle? I would guess the latter.


                              I was thinking the same thing , running dc loads directly but I have plenty of ac loads as well . Since my bank is a 48v I had to compare efficiency of dc/dc converters 85% tipical to a ac inverter efficiency. So I researched for a high end efficiency ac inverter to keep all my loads in one convention point loss. So I found that high frequency heavy thyroid transformer pcb controled are the most efficient. My inverter draws 4w on stand by ; 2w stand by search mode( if load detected turns on) and 94-98% efficiency under load . The higher the load the more efficient up to the rated power , after that efficiency drops.
                              I also have a smaller system 12v with a inverter of the same type manufacturer and efficiency is lower 92% . I gues for small systems this is negligible but the advantage I have that I can use dc loads directly and turn on the inverter only when needed.

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                              • #30
                                If you guys really need a comprehensive guide to inverters, look up the SAMLEX inverters and download their manual for nearly any of their inverter products.

                                They include information that goes WELL beyond the basic information that the typical consumer is interested in, but WE are! Along with a quality inverter, these are the absolute best documents I have seen regarding inverter use - no matter what brand you end up with. Might save some time.

                                MSW, PSW, power factor, wiring, operations, batteries you name it - in great detail - it is all in there that is probably ignored by many purchasers.

                                That is one of the reasons I use their inverters - most manufacturers wouldn't go to this trouble or expense explaining it all.

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