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#31
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Solar panel controller
Dan Marotta wrote on 1/5/2021 8:19 AM:
On 1/4/21 6:35 PM, 2G wrote: On Monday, January 4, 2021 at 3:32:11 PM UTC-8, Dan Marotta wrote: On 1/4/21 2:22 PM, 2G wrote: On Monday, January 4, 2021 at 7:41:18 AM UTC-8, Rhubarb wrote: https://airbatt.de/navi.php?a=9114&lang=eng Unfortunately they don't ship to countries outside of Europe. Tom I have one of these: https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1 -- Dan 5J Besides been quite large and unavailable, it is not for use with LFP batteries. Tom Oops, I thought the thread was about charge controllers, not about the batteries they're charging. There ARE MPPT chargers suitable for LiFePO4, however.* They do cost quite a bit more but they deliver a higher percentage of the energy to the batteries. For glider use, they may not be worth the extra size, weight, and cost. It depends on the solar panels, and the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. If the panels could be rewired in series instead of in parallel, the MPPT controller may improve the charging rate. It's possible the constant changing of panel orientation in flight may render the MPPT controller ineffective; on the ground it's probably similar to an RV, where the range is often given at 10%-30% short term improvement, and perhaps as much as 15% average over a few months use. I've been researching this issue for my motorhome; currently (little pun there), I'm leaning to doubling the size of the system as simply and cheaply as possible by duplicating the system it already has, and paralleling the output from the two PWM controllers to the battery. If actual usage shows another 15% charging would be worthwhile, I'll replace the PWM controllers with MPPT units at about $200-$300 additional parts cost. I suspect additional batteries will be a better way to spend $200, however. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 |
#32
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Solar panel controller
On 1/5/21 11:41 AM, Eric Greenwell wrote:
the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. I'd like to see a proof of that... -- Dan 5J |
#33
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Solar panel controller
Dan Marotta wrote on 1/5/2021 10:48 AM:
On 1/5/21 11:41 AM, Eric Greenwell wrote: the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. I'd like to see a proof of that... Which statement: glider panels chosen to optimize PWM, or MPPT controller won't help with that type panel (ie, low voltage output)? In general, though, the big difference is PWM is more efficient with low voltage panels (like 18 volts), and MPPT is more efficient with higher voltages (at least 24 volts, 30 is better). Do you have the specs for your Stemme panels? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 |
#34
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Solar panel controller
On Tuesday, January 5, 2021 at 4:58:48 PM UTC-8, Eric Greenwell wrote:
Dan Marotta wrote on 1/5/2021 10:48 AM: On 1/5/21 11:41 AM, Eric Greenwell wrote: the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. I'd like to see a proof of that... Which statement: glider panels chosen to optimize PWM, or MPPT controller won't help with that type panel (ie, low voltage output)? In general, though, the big difference is PWM is more efficient with low voltage panels (like 18 volts), and MPPT is more efficient with higher voltages (at least 24 volts, 30 is better). Do you have the specs for your Stemme panels? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 That doesn't make sense: an MPPT controller IS a PWM power converter, it just optimizes the operating point. https://www.researchgate.net/profile...controller.pdf The advantages of a higher voltage panel a 1. Lower percentage losses in the MOSFET switch (not much of a factor). 2. Wider operating point to deal with less sunlight. Tom |
#35
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Solar panel controller
2G wrote on 1/5/2021 6:52 PM:
On Tuesday, January 5, 2021 at 4:58:48 PM UTC-8, Eric Greenwell wrote: Dan Marotta wrote on 1/5/2021 10:48 AM: On 1/5/21 11:41 AM, Eric Greenwell wrote: the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. I'd like to see a proof of that... Which statement: glider panels chosen to optimize PWM, or MPPT controller won't help with that type panel (ie, low voltage output)? In general, though, the big difference is PWM is more efficient with low voltage panels (like 18 volts), and MPPT is more efficient with higher voltages (at least 24 volts, 30 is better). Do you have the specs for your Stemme panels? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 That doesn't make sense: an MPPT controller IS a PWM power converter, it just optimizes the operating point. https://www.researchgate.net/profile...controller.pdf The advantages of a higher voltage panel a 1. Lower percentage losses in the MOSFET switch (not much of a factor). 2. Wider operating point to deal with less sunlight. Tom An MPPT charge controller includes a DC-DC converter (called a "buck" converter in the paper you reference) to convert power at the MPP voltage to the battery voltage needed for charging. A PWM charge controller, in the context of solar power systems charging batteries does not have the DC-DC converter. It just switches the panel on and off to the battery - no power conversion. Here's an example: My motorhome has two 100W panels in parallel, producing about 11 amps charging in good conditions. If I were to put the panels in series while using the PWM controller, the system would produce about 5 amps. If instead, I used an MPPT controller on that same two panels in series, it could produce about 14 amps of charging. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 |
#36
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Solar panel controller
On Tuesday, January 5, 2021 at 8:57:17 PM UTC-8, Eric Greenwell wrote:
2G wrote on 1/5/2021 6:52 PM: On Tuesday, January 5, 2021 at 4:58:48 PM UTC-8, Eric Greenwell wrote: Dan Marotta wrote on 1/5/2021 10:48 AM: On 1/5/21 11:41 AM, Eric Greenwell wrote: the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. I'd like to see a proof of that... Which statement: glider panels chosen to optimize PWM, or MPPT controller won't help with that type panel (ie, low voltage output)? In general, though, the big difference is PWM is more efficient with low voltage panels (like 18 volts), and MPPT is more efficient with higher voltages (at least 24 volts, 30 is better). Do you have the specs for your Stemme panels? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 That doesn't make sense: an MPPT controller IS a PWM power converter, it just optimizes the operating point. https://www.researchgate.net/profile...controller.pdf The advantages of a higher voltage panel a 1. Lower percentage losses in the MOSFET switch (not much of a factor). 2. Wider operating point to deal with less sunlight. Tom An MPPT charge controller includes a DC-DC converter (called a "buck" converter in the paper you reference) to convert power at the MPP voltage to the battery voltage needed for charging. A PWM charge controller, in the context of solar power systems charging batteries does not have the DC-DC converter. It just switches the panel on and off to the battery - no power conversion. Here's an example: My motorhome has two 100W panels in parallel, producing about 11 amps charging in good conditions. If I were to put the panels in series while using the PWM controller, the system would produce about 5 amps. If instead, I used an MPPT controller on that same two panels in series, it could produce about 14 amps of charging. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 A dc-dc converter IS pulse-width modulated (PWM). A series switching MOSFET is turned on and off (pulse-width modulated) to regulate current in an inductor. Here is an excerpt of the article I referenced: " Then depending upon power level it gives PWM input to buck converter which decides whether the solar panel is to be connected to battery or not for charging." Tom |
#37
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Solar panel controller
2G wrote on 1/6/2021 3:24 PM:
On Tuesday, January 5, 2021 at 8:57:17 PM UTC-8, Eric Greenwell wrote: 2G wrote on 1/5/2021 6:52 PM: On Tuesday, January 5, 2021 at 4:58:48 PM UTC-8, Eric Greenwell wrote: Dan Marotta wrote on 1/5/2021 10:48 AM: On 1/5/21 11:41 AM, Eric Greenwell wrote: the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. I'd like to see a proof of that... Which statement: glider panels chosen to optimize PWM, or MPPT controller won't help with that type panel (ie, low voltage output)? In general, though, the big difference is PWM is more efficient with low voltage panels (like 18 volts), and MPPT is more efficient with higher voltages (at least 24 volts, 30 is better). Do you have the specs for your Stemme panels? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 That doesn't make sense: an MPPT controller IS a PWM power converter, it just optimizes the operating point. https://www.researchgate.net/profile...controller.pdf The advantages of a higher voltage panel a 1. Lower percentage losses in the MOSFET switch (not much of a factor). 2. Wider operating point to deal with less sunlight. Tom An MPPT charge controller includes a DC-DC converter (called a "buck" converter in the paper you reference) to convert power at the MPP voltage to the battery voltage needed for charging. A PWM charge controller, in the context of solar power systems charging batteries does not have the DC-DC converter. It just switches the panel on and off to the battery - no power conversion. Here's an example: My motorhome has two 100W panels in parallel, producing about 11 amps charging in good conditions. If I were to put the panels in series while using the PWM controller, the system would produce about 5 amps. If instead, I used an MPPT controller on that same two panels in series, it could produce about 14 amps of charging. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 A dc-dc converter IS pulse-width modulated (PWM). A series switching MOSFET is turned on and off (pulse-width modulated) to regulate current in an inductor. Here is an excerpt of the article I referenced: " Then depending upon power level it gives PWM input to buck converter which decides whether the solar panel is to be connected to battery or not for charging." Tom In the solar battery charging context we are discussing, the label "PWM" refers to controllers that directly connect the solar panel to the battery with a switch to charge it. When the switch closes, the panel voltage drops to the battery voltage, so the charging current is limited to what the panel can put out at the battery's voltage. The label "MPPT" refers to controllers that have a logic controlled DC to DC converter in them that allows the controller to adjust the the DC-DC converter to maintain the panel voltage where the panel is putting out maximum power while DC-DC converter output is at the battery voltage, and the current is higher than the panel is putting out. So, in this context, PWM and MPPT refer to significantly different types of controllers, and it's irrelevant if the DC-DC converter uses pulse width modulation to control the DC-DC converter. Using the labels as I've described is common industry practice, even in the paper you referenced. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 |
#38
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Solar panel controller
On Wednesday, January 6, 2021 at 3:51:57 PM UTC-8, Eric Greenwell wrote:
2G wrote on 1/6/2021 3:24 PM: On Tuesday, January 5, 2021 at 8:57:17 PM UTC-8, Eric Greenwell wrote: 2G wrote on 1/5/2021 6:52 PM: On Tuesday, January 5, 2021 at 4:58:48 PM UTC-8, Eric Greenwell wrote: Dan Marotta wrote on 1/5/2021 10:48 AM: On 1/5/21 11:41 AM, Eric Greenwell wrote: the ones for gliders are usually chosen to optimize charging of 12 volt batteries with PWM charge controllers, and using an MPPT controller on those panels will gain little extra charging. I'd like to see a proof of that... Which statement: glider panels chosen to optimize PWM, or MPPT controller won't help with that type panel (ie, low voltage output)? In general, though, the big difference is PWM is more efficient with low voltage panels (like 18 volts), and MPPT is more efficient with higher voltages (at least 24 volts, 30 is better). Do you have the specs for your Stemme panels? -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 That doesn't make sense: an MPPT controller IS a PWM power converter, it just optimizes the operating point. https://www.researchgate.net/profile...controller.pdf The advantages of a higher voltage panel a 1. Lower percentage losses in the MOSFET switch (not much of a factor). 2. Wider operating point to deal with less sunlight. Tom An MPPT charge controller includes a DC-DC converter (called a "buck" converter in the paper you reference) to convert power at the MPP voltage to the battery voltage needed for charging. A PWM charge controller, in the context of solar power systems charging batteries does not have the DC-DC converter. It just switches the panel on and off to the battery - no power conversion. Here's an example: My motorhome has two 100W panels in parallel, producing about 11 amps charging in good conditions. If I were to put the panels in series while using the PWM controller, the system would produce about 5 amps. If instead, I used an MPPT controller on that same two panels in series, it could produce about 14 amps of charging. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 A dc-dc converter IS pulse-width modulated (PWM). A series switching MOSFET is turned on and off (pulse-width modulated) to regulate current in an inductor. Here is an excerpt of the article I referenced: " Then depending upon power level it gives PWM input to buck converter which decides whether the solar panel is to be connected to battery or not for charging." Tom In the solar battery charging context we are discussing, the label "PWM" refers to controllers that directly connect the solar panel to the battery with a switch to charge it. When the switch closes, the panel voltage drops to the battery voltage, so the charging current is limited to what the panel can put out at the battery's voltage. The label "MPPT" refers to controllers that have a logic controlled DC to DC converter in them that allows the controller to adjust the the DC-DC converter to maintain the panel voltage where the panel is putting out maximum power while DC-DC converter output is at the battery voltage, and the current is higher than the panel is putting out. So, in this context, PWM and MPPT refer to significantly different types of controllers, and it's irrelevant if the DC-DC converter uses pulse width modulation to control the DC-DC converter. Using the labels as I've described is common industry practice, even in the paper you referenced. -- Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me) - "A Guide to Self-Launching Sailplane Operation" https://sites.google.com/site/motorg...ad-the-guide-1 Ok, but the terminology is a bit confusing as they are both PWM controllers.. This Genasun MPPT controller is widely available and has been recommended on RAS before as a STROBL replacement: https://www.amazon.com/Genasun-GV-5-.../dp/B01N9BP7VL Tom |
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