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  • #16
    Originally posted by Mike90250 View Post
    Just grind down that heavy steel and the cheap tin pieces fit fine.
    Metal from the bad old days was heavy because it had to be. Often it was inefficient and over engineered.
    But a few percent of the time, it was just right. Quality control was primitive back then. They were allowing for defects that would be unthinkable today.

    Somewhere around the net are Industrial X-rays of - Industrial equipment. Connecting rod's the size of your forearm with massive defects from day one that ran 24/7 for 50 years. Pullies, hoists etc.
    I think it was a university hosting a library of old engineering stuff. Can't remember which one but they would have a big name engineering program... It's eye opening. Older being better is not always the case, but realistically 80% of the time it is true.

    -----

    But anyway, you can match the voltage (or get it close) and parallel the panels and you still get X+Y=Z amps, right?

    The bigger the gap in voltage the more you loose - I get that. (For parallel anyway.)

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    • #17
      Alright Sunking,the test is complete.After disconnecting the batteries 5 hours ago,the voltage was reading 12.88V. 5 hours later the voltage reads 12.82V .So my batteries are actually fully charged.Which leads me to 2 questions. Firstly,Is the reason I would have not seen 14.5V charging because the charge controller is doing a float charge? Secondly,if this 102AH 12V deep cycle is really full surely I should see atleast 5 hours on a single 15W AC CFL bulb at about 20% DOD? Which is not the case funnily enough. I only get 3 hours and DOD is about 35%. Bad battery maybe? If it is,I am going to beat the supplier with a circus midget because I bought it new and only about 2 months ago!

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      • #18
        Many things can contribute to lower battery capacity. Old stock, not recharged on the shelf, sat idle too long....
        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

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

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        • #19
          hmm... ok so the only reason for the 15w cfl to only last 3 hours (35% DOD) would be a bad battery? Is there any other tests anyone knows or thinks I could do before I go back to the sales man? So far it seems to have passed the voltage test?

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          • #20
            Originally posted by Offgrid View Post
            hmm... ok so the only reason for the 15w cfl to only last 3 hours (35% DOD) would be a bad battery? Is there any other tests anyone knows or thinks I could do before I go back to the sales man? So far it seems to have passed the voltage test?
            Offgrid is this a DC 12 volt CFL? If so measure the DC current going in. I bet you will find by multiplying the current by input voltage comes out quite a bit more than 13 watts. Reason is the manufacture is using a chap ballast inside the CFL, and the ballast uses power in addition to the light tube.
            MSEE, PE

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            • #21
              No ,its AC but I think you are still right.These bulbs were on special so I grabbed one.I used your sizing guide from our other thread and it worked out to be about 5 hours.Can the ballast have the same affect on an AC bulb? I dont know if this is any indication or help but on this "Maintenance Free" Deep cycle it has a little transparent round "portal" that changes color shoing how the battery health is and its green indicating the battery is good.

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              • #22
                Originally posted by Offgrid View Post
                Can the ballast have the same affect on an AC bulb?.
                Absolutely yes Sir. Inexpensive CFL's have very inefficient ballast and poor power factors. Read up on Power Factor. It is one of those ghost DIY do not know about AC energy.

                Give you a clue. A AC device consuming 100 real watts with a PF of .6 uses 100 watts / .6 = 167 VARS. Happy hunting and figuring out what that means, it will be an eye opener for you. I would tell you, but it will be better for you to find it on your own, you will not forget it that way.

                One other point, the inverter itself consumes power as they are not 100% efficient. It is entirely possible if you have something like a 1000 watt inverter just running a 13 watt CFL will draw 50 or more watts off the battery.

                So back to my point, measure the DC current from the battery, not the listed load watts on a AC device as their are other things using power you are not accounting for like inverter power consumption, AC power factor, and ballast power. It adds up real quick. Measure th eactual DC current to eliminate guessing
                MSEE, PE

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                • #23
                  Ok Sunking

                  In a VERY basic explanation of power factor...

                  Its basically when or to what degree the waveform is out of sync.The Wave form is the V and A which produces the wave.In a pefect circuit the V and A waves are in sync which produces the power (P=VI) and thats positive power.In a circuit where the V A is out of sync the Power waveform has parts that dip below the negative Negative power is a waste as it does nothing useful and has a higher power factor.

                  I havnt had too much time to study this and still going through a info video.

                  Since we spoke last,I bought another AC 14w CFL bulb made by phillips and compared it to my 14w Osram and the amp draw measured using a clamp on amp meter (on the postive inverter cable coming from the battery) measured 1.30A both CFLs.So I guess the power factor on my cheap bulb and new expensive bulb are the same.

                  If we now look at the ACTUAL Amp draw with 1 of the 14w CFLs and multiply it by the batteries 12 volts we see this...

                  12v x 1.30 = 15.6watts

                  So just about 1.6 watt is being getting lost as innefiencies....You agree?

                  Ok so what we know so far....

                  1. Its not the battery thats causing the 3 hour max/35% DOD for the CFL...The batteries after 5 hours rest measured about 12.80
                  2.Its not the CFL power factor/Inverter inneficiency as 1.6 watts is really small

                  I dont see what else it could be except my calculations in that Thread we created for sizing a PV system

                  Your thoughts on this?

                  Comment


                  • #24
                    Originally posted by Offgrid View Post
                    Your thoughts on this?
                    You learned SOC voltage is meaningless unless you rest the battery. Only true real time measure is a temperature compensated hydrometer specific gravity reading with a Lab Quality hydrometer.
                    MSEE, PE

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                    • #25
                      Problem is it's a sealed battery :/. I'm missing something crucial to solve this. I did however drain the battery to just less than 50% DOD last night (yes I know i shouldn't but it was a test) and I found that charge volts were still in the 13v region.Shouldn't I be hitting bulk with 14.5v? I'm so confused at this point lol.

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                      • #26
                        Originally posted by Offgrid View Post
                        Shouldn't I be hitting bulk with 14.5v? I'm so confused at this point lol.
                        No sir not at all until the battery reaches the 80 to 90% state of charge.
                        MSEE, PE

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                        • #27
                          No sir not at all until the battery reaches the 80 to 90% state of charge.
                          Ok well then I am not entirely sure why Im not getting the time I should from the CFL.

                          I can only ask how long you would calculate a 15W CFL to last on a fully charged 102AH 12V deep cycle keeping in the 20% DOD?
                          Perhaps my calculations were off as I calculated more or less 5 hours yet only getting 3 hours.

                          Will have to buy you a beer for your assistance lol.

                          Thanks,really appreciated.

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                          • #28
                            You should be getting close to 16 hours.

                            12 volts x 102 AH = 1224 watt hours.
                            20% of 1224 wh = 245 watt hours.

                            245 watt hours / 15 watts = 16.32 hours.
                            MSEE, PE

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                            • #29
                              You missing something,the inverter and the AC 15w bulb...not dc?

                              Comment


                              • #30
                                Wait,your calculation may still work... Because WITH the inverter on and 14watt bulb on, I measured with the clamp amp meter 1.30 amp draw multiply by 12volts is 15.6watts...only 0.6 watts more than your calculation which is MASSIVELY different to what I am actually getting. So either the battery is stuffed or it's not actually fully charged...you agree?

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