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For anybody that has upgraded their solar controller from a PWM type to an MPPT type, did you doing any testing comparing the two? I just got a Lensun MPPT controller, and compared it to my old PWM controller, and was sort of surprised by the results. The PWM controller consistently pulled 5.15 amps from the panel, and output 5.15 amps to the battery. The MPPT controller pulled 4.85 amps from the panel, and output 5.80 amps to the battery. The numbers from the MPPT controller also jumped around by about .2 amps, so those numbers are the most typical values. I was not expecting the MPPT controller to pull in fewer amps than the PWM. I'm wondering if my controller is pulling and outputting fewer amps than other brands.
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It's not really about amperage going in to the controller, it's better to compare wattage (power) and what is being sent to the battery.? Wattage = voltage*amperage .
Sometimes the amperage may be higher but if the voltage is lower overall wattage is decreased.
Hope this helps
On Thu, Mar 21, 2024 at 3:28 PM, Steve T <srtimm@...> wrote: For anybody that has upgraded their solar controller from a PWM type to an MPPT type, did you doing any testing comparing the two? I just got a Lensun MPPT controller, and compared it to my old PWM controller, and was sort of surprised by the results. The PWM controller consistently pulled 5.15 amps from the panel, and output 5.15 amps to the battery. The MPPT controller pulled 4.85 amps from the panel, and output 5.80 amps to the battery. The numbers from the MPPT controller also jumped around by about .2 amps, so those numbers are the most typical values. I was not expecting the MPPT controller to pull in fewer amps than the PWM. I'm wondering if my controller is pulling and outputting fewer amps than other brands.
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Surprisingly both controllers showed the same voltage as measured at the battery.? Both solar controllers gradually increase the voltage to 14.4 as the battery nears full charge.? With the state of charge of my battery it was around 13.8v, increasing by 1/100 volt slowly as I watched.
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On Thu, Mar 21, 2024 at 10:28 PM, Steve T wrote:
For anybody that has upgraded their solar controller from a PWM type to an MPPT type, did you doing any testing comparing the two? I just got a Lensun MPPT controller, and compared it to my old PWM controller, and was sort of surprised by the results. The PWM controller consistently pulled 5.15 amps from the panel, and output 5.15 amps to the battery. The MPPT controller pulled 4.85 amps from the panel, and output 5.80 amps to the battery. The numbers from the MPPT controller also jumped around by about .2 amps, so those numbers are the most typical values. I was not expecting the MPPT controller to pull in fewer amps than the PWM. I'm wondering if my controller is pulling and outputting fewer amps than other brands.
That's exactly the way an MPPT controller is supposed to work. Scott Ellington
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My question, though, is why does the mppt controller restrict the amps from solar panel to controller to 4.85 amps, instead of letting the full 5.15 amps through.? Do other solar controllers restrict panel to controller amps?
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On Thu, Mar 21, 2024 at 04:38 PM, Scott Ellington wrote:
On Thu, Mar 21, 2024 at 10:28 PM, Steve T wrote:
For anybody that has upgraded their solar controller from a PWM type to an MPPT type, did you doing any testing comparing the two? I just got a Lensun MPPT controller, and compared it to my old PWM controller, and was sort of surprised by the results. The PWM controller consistently pulled 5.15 amps from the panel, and output 5.15 amps to the battery. The MPPT controller pulled 4.85 amps from the panel, and output 5.80 amps to the battery. The numbers from the MPPT controller also jumped around by about .2 amps, so those numbers are the most typical values. I was not expecting the MPPT controller to pull in fewer amps than the PWM. I'm wondering if my controller is pulling and outputting fewer amps than other brands.
That's exactly the way an MPPT controller is supposed to work.
Scott Ellington
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On Fri, Mar 22, 2024 at 01:13 AM, Steve T wrote:
My question, though, is why does the mppt controller restrict the amps from solar panel to controller to 4.85 amps, instead of letting the full 5.15 amps through.? Do other solar controllers restrict panel to controller amps?
It's not "restricting" the current: It has found the maximum power point at a higher voltage and lower current. That's what it's designed to do. Scott Ellington
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What size panel do you have?? If it is a single 100 watt panel the mppt does not have enough room to adjust the voltage and current to get much more out of it than what you experienced. If you have a larger array, such as two 100 watt panels, connecting them in series or parallel gives much more room for the mppt to adjust either the voltage or the current to maximize the most amount of current to send to the battery.? My system is much larger but with it I can demonstrate what I mean above.? I have 400 watts of solar hooked up so that my voltage is approximately 43 volts & the current is 10 amps. Because I'm pushing to a 12 volt battery it can adjust the voltage down and the current up to put more energy into the battery. In this diagram from my system this morning, you'll see that the? current coming from the solar is 5.69 and the current going to the battery is 13.3  The voltages at the same time look like this second screenshot. When the current drops off in the top graph, that is when the battery is considered at 100% charged and it goes into the absorption cycle. At that phase of charging in a lead acid it is holding it there for a period of time at 14.4 volts to allow any sulfation that is happening in the battery plates to help drive it back into the electrolyte solution.? 
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"It's not "restricting" the current: It has found the maximum power point at a higher voltage and lower current. That's what it's designed to do."
So you're saying that as the controller pulls more current from the solar panel, the voltage from the panel drops, and depending on how fast the voltage drops, that will determine what current produces max power?
I wasn't able to measure voltage coming from the panel because there are no exposed connection points.? I'll have to make something to measure that.
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I have one 100 watt solar panel.? Other guys online are saying that for that panel, an mppt controller should give you about 1 more amp than a pwm controller.? When the 19 or so volts produced by the panel are reduced to around 14 going to the battery, those extra 5 volts get converted to another amp of current.? (Voltage numbers approximate).? ?I'm not seeing that much with my mppt controller.
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On Fri, Mar 22, 2024 at 02:25 PM, Eugene Breindel wrote:
What size panel do you have?? If it is a single 100 watt panel the mppt does not have enough room to adjust the voltage and current to get much more out of it than what you experienced. If you have a larger array, such as two 100 watt panels, connecting them in series or parallel gives much more room for the mppt to adjust either the voltage or the current to maximize the most amount of current to send to the battery.? My system is much larger but with it I can demonstrate what I mean above.? I have 400 watts of solar hooked up so that my voltage is approximately 43 volts & the current is 10 amps. Because I'm pushing to a 12 volt battery it can adjust the voltage down and the current up to put more energy into the battery. In this diagram from my system this morning, you'll see that the? current coming from the solar is 5.69 and the current going to the battery is 13.3
The voltages at the same time look like this second screenshot. When the current drops off in the top graph, that is when the battery is considered at 100% charged and it goes into the absorption cycle. At that phase of charging in a lead acid it is holding it there for a period of time at 14.4 volts to allow any sulfation that is happening in the battery plates to help drive it back into the electrolyte solution.?
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On Fri, Mar 22, 2024 at 06:58 PM, Steve T wrote:
I have one 100 watt solar panel.? Other guys online are saying that for that panel, an mppt controller should give you about 1 more amp than a pwm controller.? When the 19 or so volts produced by the panel are reduced to around 14 going to the battery, those extra 5 volts get converted to another amp of current.? (Voltage numbers approximate).? ?I'm not seeing that much with my mppt controller.
If you look at this screenshot there is a total of 89 watts coming in. if you look at the solar part of it you will see 33.57 volts * 2.6 amps which equals 87.28 watts. On the battery side of the mppt, you will see 13.47 Volts * 6.4 Amps Which equals 86.208 Watts.? The mpp is using a couple watts of power To do that conversion from the Solar voltage and current to get down to the battery voltage and current. They are both within the realm of 89 watts of power, Minus losses from conversion. With a smaller panel, the incoming voltage and current cannot be manipulated very much to get the higher currents out that you need to charge the battery with more than five amps. Doubling the panel can either give you more voltage for the MPPT to work with in series or more current to work with if you put them in parallel. on a single 100 Watt panel, you don't really need an MPPT. MPPT controller is just a pwm controller that rechecks the circuit every so often and see if it can tweak the incoming power to get a little more out of it to put into the battery. 
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Need is a subjective term.? The plastic housing on my old controller broke, this mppt controller was $50 more than a pwm controller, and it gets me 13% more power.? Given that solar controllers last 10+ years, the cost is $5 a year, so worth it to me.? I need that, because I consume pretty close to what my panel produces each day.
From what I'm reading, a better mppt controller can get 20% more power than a pwm with a 100 watt panel. Unfortunately none of the better controllers are waterproof, which is also something I need.
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On Fri, Mar 22, 2024 at 04:17 PM, Eugene Breindel wrote:
On Fri, Mar 22, 2024 at 06:58 PM, Steve T wrote:
I have one 100 watt solar panel.? Other guys online are saying that for that panel, an mppt controller should give you about 1 more amp than a pwm controller.? When the 19 or so volts produced by the panel are reduced to around 14 going to the battery, those extra 5 volts get converted to another amp of current.? (Voltage numbers approximate).? ?I'm not seeing that much with my mppt controller.
If you look at this screenshot there is a total of 89 watts coming in. if you look at the solar part of it you will see 33.57 volts * 2.6 amps which equals 87.28 watts.
On the battery side of the mppt, you will see 13.47 Volts * 6.4 Amps Which equals 86.208 Watts.? The mpp is using a couple watts of power To do that conversion from the Solar voltage and current to get down to the battery voltage and current. They are both within the realm of 89 watts of power, Minus losses from conversion. With a smaller panel, the incoming voltage and current cannot be manipulated very much to get the higher currents out that you need to charge the battery with more than five amps. Doubling the panel can either give you more voltage for the MPPT to work with in series or more current to work with if you put them in parallel. on a single 100 Watt panel, you don't really need an MPPT. MPPT controller is just a pwm controller that rechecks the circuit every so often and see if it can tweak the incoming power to get a little more out of it to put into the battery.
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On Fri, Mar 22, 2024 at 10:48 PM, Steve T wrote:
So you're saying that as the controller pulls more current from the solar panel, the voltage from the panel drops, and depending on how fast the voltage drops, that will determine what current produces max power?
That's basically correct. Think of the two extremes: zero voltage and maximum current, or maximum voltage and zero current. Both yield zero power. Somewhere in between is the MPP. If the panel looked like a battery in series with a resistor, that would be at half the open circuit voltage. However, that's not what the panel looks like, as you can see from the voltage vs current curves. The MPP depends on illumination, so the controller is constantly adjusting, but it is usually close to the open circuit voltage point. That's usually well above 12 Volts, so the battery current will usually be higher than the panel current.
I wasn't able to measure voltage coming from the panel because there are no exposed connection points.? I'll have to make something to measure that.
You can calculate the panel voltage by dividing the power by the current. Scott Ellington
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I'm going to measure the voltage at the panel.? It will be interesting how efficient the mppt controller is.? They say "peak conversion efficiency of 97.5%".? No mention, of course, of what min efficiency is.
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On Sun, Mar 24, 2024 at 11:11 AM, Scott Ellington wrote:
On Fri, Mar 22, 2024 at 10:48 PM, Steve T wrote:
So you're saying that as the controller pulls more current from the solar panel, the voltage from the panel drops, and depending on how fast the voltage drops, that will determine what current produces max power?
That's basically correct. Think of the two extremes: zero voltage and maximum current, or maximum voltage and zero current. Both yield zero power. Somewhere in between is the MPP. If the panel looked like a battery in series with a resistor, that would be at half the open circuit voltage. However, that's not what the panel looks like, as you can see from the voltage vs current curves.
The MPP depends on illumination, so the controller is constantly adjusting, but it is usually close to the open circuit voltage point. That's usually well above 12 Volts, so the battery current will usually be higher than the panel current.
I wasn't able to measure voltage coming from the panel because there are no exposed connection points.? I'll have to make something to measure that.
You can calculate the panel voltage by dividing the power by the current.
Scott Ellington
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On Mon, Mar 25, 2024 at 01:19 AM, Steve T wrote:
I'm going to measure the voltage at the panel.? It will be interesting how efficient the mppt controller is.? They say "peak conversion efficiency of 97.5%".? No mention, of course, of what min efficiency is.
At anything close to the nominal power level, it will probably be greater than 95%.
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I finally had a full sun day, so I could do some more testing.? Typical? results: PWM controller: ? Power measured at the solar panel:? 13.16v x 5.02A = 66.1 watts ? Power measured at the battery:? ? ? ? ?12.86v x 5.02A = 64.6 watts ? Efficiency of PWM controller:? ? ? ? ? ? ? 64.6 ¡Â 66.1 = 98% efficient Lensun MPPT controller: ? Power measured at the solar panel:? 16.32v x 4.72A = 77.0 watts ? Power measured at the battery:? ? ? ? ? 13.0v x 5.65A = 73.4 watts ? Efficiency of the mppt controller:? ? ? ? 73.4 ¡Â 77.0 = 95% efficient That was a bit of a surprise.? I expected to see a panel voltage that was quite a bit higher for the pwm controller, and then see the pwm controller throw that high voltage away.? But nope, the voltage was only a little higher than the voltage output to the battery.? I had discharged my battery down to 12.4v to do this test.? Earlier I had tried a test with the battery near full, and the voltage output to the battery was over 14v.? But then the charger quit charging and signaled battery full, so that test couldn't be completed.? So the majority of the extra power produced by the mppt controller was due to the power point tracking algorithm pulling a better optimized current that generated more watts. This testing was done at about 10:30 in the morning, and the sun was at about 45 degrees above the horizon.? The amps going into the battery weren't as high in this test as on other tests I've done.? I did a test on a day with a few light wispy clouds, and some jet contrails, and I saw the current put out by the mppt controller go ever 7 amps.? Maybe if I had tried the test later the total output would have been higher.? But I did the test in the morning because there were no clouds.? The test I tried with the light wispy clouds had the numbers jumping all over and the test was useless. If anyone upgrades from pwm to mppt, do some tests of both controllers and see what you get.? I only got around a 10% improvement going from pwm to mppt, and I think that may be low.? I'd be curious what others see. If anyone else is going to upgrade from pwm to mppt, and they want a waterproof mppt controller that can be easily installed outside on the side of the battery box, take a look at this one: It's the Epever TracerCPN (BLE) controller.? BLE stands for blue tooth enabled.? The other waterproof Epever controllers require you connect another display or Bluetooth model to them which is not waterproof, which is an install hassle. My install of the LensunSolar controller.? I put my hand in the pictures so you can see how small the controller is: 
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On Mon, Apr 1, 2024 at 09:46 PM, Steve T wrote:
So the majority of the extra power produced by the mppt controller was due to the power point tracking algorithm pulling a better optimized current that generated more watts.
That's precisely the point of MPPT. Scott Ellington
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What's surprising, though, is that when you read about mppt, everybody talks about how it converts the extra voltage to current.? Nobody talks about how it gets more power by reducing the current from the panel, which increases the voltage.
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On Mon, Apr 1, 2024 at 09:26 PM, Scott Ellington wrote:
On Mon, Apr 1, 2024 at 09:46 PM, Steve T wrote:
So the majority of the extra power produced by the mppt controller was due to the power point tracking algorithm pulling a better optimized current that generated more watts.
That's precisely the point of MPPT.
Scott Ellington
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It's not really about specific voltages or current, it's about power delivered to the battery.??
Voltage * current = power?
Power (Wattage) is the measure of work. Ie 746w = 1 horse power
You could have 10000 amps & .000001 volts and it's not really anything or vice versa 10000 volts and .0000001 amps and all you got is static electricity
Happy camping Dan S
On Tue, Apr 2, 2024 at 6:30 AM, Steve T <srtimm@...> wrote: What's surprising, though, is that when you read about mppt, everybody talks about how it converts the extra voltage to current.? Nobody talks about how it gets more power by reducing the current from the panel, which increases the voltage. On Mon, Apr 1, 2024 at 09:26 PM, Scott Ellington wrote:
On Mon, Apr 1, 2024 at 09:46 PM, Steve T wrote:
So the majority of the extra power produced by the mppt controller was due to the power point tracking algorithm pulling a better optimized current that generated more watts.
That's precisely the point of MPPT.
Scott Ellington
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One of the things I've noticed over the years is that even though a 100 watt panel delivers the same power as before, the rated amps have gone down and the rated voltage has gone up.? The solar panel I had 10 years ago had an optimal operating current rating of 5.8 amps, and it delivered that.? My current panel is rated at 5.29 amps for optimal current, and thats what it delivers in full sun.? But renogy has a new panel out now, and it has an optimal current of 4.86 amps.? So if you're using a pwm controller, you would have gotten another ~20% more power with an older panel than a newer panel.? The incentive to go to mppt is getting higher.
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Out of curiosity, have you ever measured the voltage of the panels unplugged from the solar?
It should equal the VOC number on the label of the panels.
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Eugene Breindel