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 > Your search for posts made by 'liborko' found 31 matches.

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RE: Serial vs Parallel Solar Panel Shading

A glance at any I/V curve of a solar panel will immediately reveal that there is very little difference between Isc and Imp. That is what current sources do-they deliver current into any voltage(within reason). I agree..PWM and MPP don't make any sense in same sentence
liborko 01/03/18 07:33pm Tech Issues
RE: Serial vs Parallel Solar Panel Shading

Yes. There are limitations to solar power, heat is one of them. That is why I consider solar power a bonus and don't complain when there is nothing coming from solar panels. We in northwest have limited solar help most of the year. If I had to rely on solar only I would approach the problem differently.
liborko 01/03/18 07:09pm Tech Issues
RE: Serial vs Parallel Solar Panel Shading

The PWM controller does not operate at Isc. Isc is a short circuit current with zero volts on panel's terminals. What PWM controller does is switching the current on and off at BATTERY voltage once it starts controlling. Since solar panels are rated at their Maximum Power Point, only MPPT controller extracts panel's rated power because it operates at Maximum Power Point and not battery voltage which is lower. With panels in parallel only panels in shade are affected. With panels in series you have to rely on bypass diodes to get any output which is not what I am prepared to do. How MPPT controller works depends entirely on the manufacturer of the controller and we all know that there is abundance of bogus claims.
liborko 01/03/18 06:47pm Tech Issues
RE: Serial vs Parallel Solar Panel Shading

Comparing series wiring with mppt controller with parallel wiring with PWM controller is comparing apples with oranges. What is wrong with parallel wiring with mppt controller? PWM controller does not extract full power from any panel anyway. If I had 3 30V/8A panels I would wire them in parallel without any hesitation whatsoever. With mppt controller. While series wiring makes lot of sense in off-grid installations with long wire runs and mostly no shade installations it does not make any sense in RV installations which have short runs and are subject to shade conditions all the time. While solar panels being CURRENT source behave differently from what we are used to they are not that difficult to figure out.
liborko 01/03/18 05:47pm Tech Issues
RE: Serial vs Parallel Solar Panel Shading

CA Traveler: Please explain how the 30V/8A panel with one section shaded(becomes 20V/8A) and delivers 160W when in series but 0W when in parallel. How is partly shaded 30V/8A panel, now 20V/8A different from 4x9=36 cell 12V nominal panel that has full output at 20V/8A with Vmp around 18.5V? As long as the output voltage from the panel is higher than about 16V the panel will charge 12V batteries standing alone, wired in parallel or series.
liborko 01/03/18 12:31pm Tech Issues
RE: Serial vs Parallel Solar Panel Shading

There is a ton of errors in this post. ...panel shading is not always understood on this board...... -You are the one not understanding ...the same shading scenario for parallel panels means that reduced panel voltage does not contribute ... -wrong, it does the same as for panels in series-it produces reduced output ...at high noon if I had 7 section shaded the panel output would be 20V at 8A or 160W/14.8V=10A bulk charging... -wrong, it would be (20V-7*0.6V)*8A=15.8V*8A=126.4W/14.8V=8.54A of bulk charging at 14.8V ...assuming 8A the output would be 8A*70V=560W for the serial panels. For parallel connected panels the output would be 8A*30V=240W. -wrong again. Shading one third of panel reduces output by 1/3 to 8*2/3A*(30V-0.6V)=156.8W, not zero. With panels in parallel the output would be 156.8W+240W+156.8W=553.6W. The output with panels in series would be 8A*(70V-1.2V)=550.4W ...with shadows on 7 of 9 subpanels there would be 8A*20V=160W available for charging with serial panels... -wrong again, it would be more like (20V-7*0.6V)*8A=126.4W ...due to lower 20V from two panels they will not contribute any amps... -???????? Both panels will happily contribute 2/3 of 8A or 2*(8A*2/3)*(30-0.6)V=313.6W. The third panel will contribute full 240W with a total of 553.6W. With panels in series ALL CURRENT flows thru the bypass diodes of subpanels that are in shade. They better be in good condition and properly tightened for good contact or else you may lose charging current completely. With parallel panels only panel in shade lose output PARTIALLY. The rest of panels are unaffected. This applies to situation as described above on drawings.
liborko 01/01/18 11:37pm Tech Issues
RE: King Dome Satellite Dish

Perhaps this will help somebody KD service bulletin
liborko 12/14/17 11:19pm Class A Motorhomes
RE: Xanrex Inverter/Charger Over Charging

That is not what your invoice lists. Also Prowatt remote on your invoice does not seem to be compatible with Freedom HFS which should use #808-9017 remote.
liborko 12/03/17 06:39pm Tech Issues
RE: Xanrex Inverter/Charger Over Charging

I think the first thing to do is to establish what do you have. Freedom Xi is an INVERTER with built-in transfer switch, Freedom HFS is INVERTER/CHARGER. They look very similar: Freedom HFS-inverter/charger Freedom Xi-inverter with built-in transfer switch
liborko 12/02/17 07:03pm Tech Issues
RE: Car Stereo Replacement in RV Problems

My guess is the original radio was low power two channel type and had built in fader control. Since your outside radio has only two speakers it does not need fader control. So in order to hear sound from both speakers in any position of fader control they connected output for front and rear speakers together on both left and right channels. This is commonly done and is OK. Most radios today are high power BTL type with four separate amplifier outputs and built in fader control. None of the speaker output wire connections are grounded and MUST NOT be grounded. Each speaker has to have separate twin line. There are just too many different scenarios and all depends on a particular model off the radio you have. The instructions that come with a radio tells you what you have and how to wire it. Your speakers might be shorted but also may not be-depends on the meter you used. Good luck
liborko 11/27/17 08:59pm Class A Motorhomes
RE: 22.5 Wheel size ?????

As said before, there are two kinds of mounting: hub piloted that use big hole for centering and use nuts with flat washers and stud piloted that use conical nuts for centering. Chances are the wheel you are trying to match is made by Accuride and will have part number stamped on the inside of the wheel together with max load and max pressure data.
liborko 11/20/17 04:34pm Tech Issues
RE: It's So Easy To Make Primitive LED Diagnostics

The pictured item could be LED type but it could also be the old style neon indicator. I was recently testing some leds and got a surprise. The meter I use most of the time indicated bad led while I knew it was good. My Fluke 85 had no trouble determining the led was good. It turns out the meter that had trouble only puts out 2.5V in semiconductor test position while Fluke puts out 3.77V in the same position. 2.5V was not enough to turn white led on.
liborko 11/20/17 04:17pm Tech Issues
RE: RV Inverter Repair

I recently repaired my Xantrex PROwatt 600 SW. After about three years of flawless operation it just quit. No AC output. Customary eyeball inspection failed to detect anything unusual. No smoke, nothing burned. Further testing with instruments found both IRF 1404 mosfets shorted and 5.1 ohm resistors feeding gates open. Total cost: 2x $1.70 + 2x $0.13 $3.66. The unit is well built-good quality.
liborko 11/20/17 03:44pm Tech Issues
RE: SCR's Please Educate Me :)

SCR is a semiconductor device used to turn the current on and off. The SCR conduct in one direction when triggered, Triac in both directions. To turn it off the current has to be reversed or turned off by other means. They come in small sizes up to hockey puck size for controlling high power equipment. They were popular in equipment built in seventies and eighties.
liborko 11/20/17 01:41pm Tech Issues
RE: 8.1 Workhorse exhaust bolt broken

I removed several broken studs by drilling(carefully) 1/8" hole and spraying WD 40 thru the hole. Let sit overnight and use easy-out to remove broken stud.
liborko 11/14/17 09:06pm Class A Motorhomes
RE: Canadian Snowbird needs TV Satelite Help!

Make sure everything works before you leave. Don't ever call your provider from outside the country If you have to call for any reason, do it from your home address. Use it regularly or otherwise your receiver may get "out of sync" requiring phone call to your provider. Good luck
liborko 10/22/17 10:39pm Tech Issues
RE: Solar panel shading

Good catch time2roll. I realized that as soon as I posted it.
liborko 10/19/17 06:15pm Tech Issues
RE: Solar panel shading

CA Traveler: The math in your example is incorrect: Theoretical output of panels in series hook-up with no shade 8A*(30V+30V+30V)=720W Theoretical output of panels in parallel hook-up with no shade: (8A+8A+8A)*30V=720W Output from panels in series with one panel in shade: 8A*30V+8A*30V-8A*1.8V=465.6W Output from panels in parallel with one panel in shade: 8A*30V+8A*30V+0A*0V=480W Your analysis would work if there were 9 resistors in series. Instead there are 9 CURRENT sources in series. Not the same thing. Assuming partial shade of one panel,the output would be: Panels in series-anyone's guess Panels in parallel-at least 480 watts
liborko 10/19/17 04:38pm Tech Issues
RE: Solar panel shading

That is exactly what I was doing when I did initial testing of my panels. How do you explain total loss of output when only one cell shaded on the panel that had 3 by-pass diodes. Seems that things are not that simple when it comes to solar panels.
liborko 10/19/17 12:27pm Tech Issues
RE: Solar panel shading

Solar panel is a CURRENT source. How much power(watts) does it produce when short circuit amps are say 8A and voltage is 0V?
liborko 10/19/17 12:04pm Tech Issues
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