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Post by rabird on Oct 4, 2016 7:18:03 GMT -8
spider, what 'reading' do ya get when you are 'making' 5A and using 5A?
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Post by rabird on Sept 30, 2016 5:35:48 GMT -8
an inverter charger is an inverter and a charger (converter).
The inverter does not charge, it DISCHARGES batteries!!!
Stand alone charger is all that is needed to charge a battery when 120v power (utility or generator) is available.
RVs generally have a converter that has charging capabilities. While towed the vehicle alternator can charge in combo with solar.
Dumb or smart, chargers connect directly to the batt and do not employ the charge controller. Multiple charging sources can be used at the same time.
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Post by rabird on Sept 29, 2016 11:11:05 GMT -8
you can certainly use multiple chargers at the same time.
just hook the charger to the battery and plug it into the generator leaving the charge controller/solar connected.
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Post by rabird on Sept 26, 2016 15:48:59 GMT -8
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Post by rabird on Sept 19, 2016 18:06:52 GMT -8
look at the IV/power curve in the manual Figure 1-2 Maximum Power Point Curve A 12v panel has a couple of volts overhead. the peak power changes with light and temp so to charge at 14.6v for a 12v battery the panel must have over head for voltage drop from the panel to controller and the changes in Vmp with panel heating. 12v cells are 36 cells and '24v' are generall 60 cells, note not double so you'd likely use 24v panels in series with MPPT to exceed 2 * 14.6v charging. I'm not comparing controllers. There are many brands, Morningstar has a nice string calculator string-calculator.morningstarcorp.com/ which incorporates temperature. nice read www.victronenergy.com/blog/2014/07/21/which-solar-charge-controller-pwm-or-mppt/then be sure and read the white paper linked at the end of the article.
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Post by rabird on Sept 19, 2016 4:45:28 GMT -8
first the manufacture's manual for the 60A www.epsolarpv.com/en/uploads/news/201512/1449042525937914.pdfpage 10-11 may be helpful. Note the 150v input limit for series panels is really 138v @ rated 25C temps panels are rated. At very cold temps the panel's Voc increases. 12v panels have a Voc of ~23 for a max of 6 panels (138/23) in each series string. can parallel multiple strings. Their chart suggest max of 4 for 12v system, I assume this is due to the 'bucking' efficiency from 138v down to 12v! charging 12v battery 800 watts is all the controller will 'produce' so going much above 800 watts of panels is not needed, the controller will limit input if you go over 800 watts, spec is up to 2400 watts input. Have more than 800 watts panel can allow for more power in poor light conditions. Consider 60 cell '24v' panels (Voc ~38). 138/38 yields 3 in series, 1600 watt charging max @ '24v'. same number of 60 cell panels in series for 48v with 3200 watt charging @'48v' (misprint of page 11!) 24v system, so for 60 cell say 240 watt panels, 3 in series, 2 or more strings of 3 in series in parallel. 720 watts per series string, 2 strings in parallel would be 1440 watts total. if you intend on a 24v system, there is no need to use '12v' panels, 60 cell '24v' panels are available at a better price/watt.
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Post by rabird on Sept 14, 2016 16:15:39 GMT -8
its not, its $80. ignore marketing! a decade or so ago it might well been that.
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Post by rabird on Sept 14, 2016 3:57:26 GMT -8
I don't think I can justify the price difference. how 'bout a 6A panel for $80how many amps do ya need?
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Post by rabird on Sept 13, 2016 11:16:21 GMT -8
so what? panels don't operate @ Vmp with a PWM controller. Folks are surprised when they don't get 100 watts out of a 100 watt panel. or they divide 100/12 and expect 8A! Many consider them constant current so the one with the highest current wins! watch this as one hooks up a 20 watt bulb to a 21 watt panel, a perfect match = 6v, 1A !! www.youtube.com/watch?v=JZQEJ33xblE
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Post by rabird on Sept 13, 2016 7:37:38 GMT -8
Each panel has a specific iv/power curve. Note the power at zero volts, 5, 10, 20! PWM @ battery voltage is less than rated power. @stc mppt might harvest rated watts then looses some bucking. Also, as panel temp increases so does Isc (PWM), mppt peak power sure drops off! Also note the temp coeff are identical for the 'Renogy' polly and mono
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Post by rabird on Sept 12, 2016 15:37:39 GMT -8
compare the 3 100 watt panels Renogy offers. Panel, Isc, Imp Eclipse, 6.1A, 5.7A Polly, 5.92A, 5.62A momo, 5.75A, 5.29A
if we assume @13v they all operate @ Isc amperage (IV curves unavailable).
eclipse 13v * 6.10A = 79.30 watts polly 13v * 5.92A = 76.96 mono 13v * 5.75A = 74.75
if all things were EQUAL (they are not), using PWM, get the highest Isc!
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Post by rabird on Sept 10, 2016 10:42:55 GMT -8
yes, 12v panel is 36 cell, Vmp 17-19 (x2 34-38) 24v 60 cell has Vmp of ~31v. they do make 72 cell panels.
As I understand it, say the 2X100 have a Vmp of 36v combined, 5.55A. If the mppt controller finds a Vmp of 31 then the 2X100 watt panel will operate @ 31v*5.55A = 172 watts and the others @ 320 each (less the eff of the controller of course).
Don't forget the cost of a new 24v inverter and/or dc-dc 24v-12v transformer!
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Post by rabird on Sept 10, 2016 3:19:35 GMT -8
2 chargers on one battery ok
so one charger has 2 x 320w x 24v the other will have 2x100 + 2 x 320 or whatever combination you decide in parallel.
the problems is that 2 x 100 is more than '24v'. Compare Voc, Vmp of the 12v x2 versus the 24v The lower Vmp of the 24v will drag down the 2x100 somewhat.
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Post by rabird on Sept 4, 2016 11:03:26 GMT -8
100 watt panel in bright light is ~5A charger (4 hrs a day). 2 x 100 ah battery is 200 ah @ 50% discharge that's 100 ah missing (yours' are more than 50% discharged). it will take a 5A charger 20 hrs+ of bright sunlight to replace 100 ah missing.
5/200 x 100 = 2.5% charger!!!!
amp meter?
leave ac charger connected overnight!
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Post by rabird on Sept 3, 2016 6:01:49 GMT -8
its the whole package not just one item, wire size/connectors, fuse(s), disconnects, controller (PWM/MPPT), application, panel(s) 12v/24v, mounting, sizing, ...
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