# Tag Info

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MPPTs vary the impedance of the load seen by the panel, but this is varied as needed to track the maximum power operating point. They do not 'match the impedance' of a solar panel, but rather adjust the load impedance (typically by varying the duty cycle of a DC/DC converter) so the output current multiplied by the output voltage of the panel is at a ...

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The MPPT will do whatever it has been told to do. If it has been told it's attached to a big battery, then it will attempt to supply a lot of power. If in fact it's got a small battery attached, then it could overcharge it, or charge it too fast. Make sure you understand how your MPPT is programmed, and tell it the truth about its environment.

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I guess I understand what you're thinking. Q2 would actually drain your battery pack if only it were kept switched on for a time much longer than the actual switching frequency period. But that's never the case. This converter in the datasheet is called a buck converter, that is, it steps down your input voltage using the famous linear ratio \\$V_{out} = Duty\...

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That's for the flyback currents. In simple converters, this would be a diode. However with a little more complexity inside the chip, they are able to use a FET instead, which reduces losses and improves efficiency. The name of the topology is "synchronous converter". There's lots of info about them on the internet. Here is an example of both ...

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Never done this, but I think it could work: you could control the DC/DC converter's input for MPPT during CC charging, and control its output during CV charging and float charging. You would only have MPPT in the CC stage, and you would still have to monitor the voltage and current to decide which stage to start. If you want MPPT in all charging stages, I ...

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You don't want to charge lead-acid from a constant voltage, and if you do, you need to change the voltage depending on the state of charge of the battery (switching from constant voltage "second stage" charging to trickle charge). Google "lead acid charging algorithm".

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A solar panel is a current source over most of its characteristic; the voltage it shows is "set" by what you connect to it. When you connect a battery to it, the voltage will be set by that battery; connect a charger to it, and the voltage will be set by the input impedance of that charger. This voltage may be nowhere near the voltage at the MPP; ...

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MPPT and battery charging are 2 separate control laws, and operate independently, although will have some interactions. Explained below. MPPT stands for maximum power point tracking. Its aim is to get maximum power out of the solar panel. There is a relationship between the current and voltage wherby, if the controller draws more current out of the solar ...

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I think that is 100 percent correct. Technically, the charge controller will adjust itself to extract maximum available power from the panel. If the input voltage needs to change, the controller will change it. But the nature of the solar panel is that MPPT voltage only changes a little bit with changing light conditions. So that is why the solar panel ...

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Your line of thinking is correct. Think of current changes in terms of a cloudy day. Using a 12V solar panel, you will get the output voltage between 12.6 (very cloudy) to about 13.5 (very sunny). The current between these voltage variations also varies. MPPT solar chargers are supposed to be more efficient than PWM as you might have read already. MPPT are ...

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Why doesn't a charging cycle begin, when the MPP voltage isn't reached? Best guess: A solar panel is a current source over most of its characteristic; the output voltage is set by the input impedance of whatever charger is connected to it. MPPT in this IC probably works by reducing the current it delivers on the output until the MPP is reached. If it can't ...

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