What is MPPT charger (Maximum power point tracker)?
I'm trying to understand the difference between MPPT vs. PWM charger. In what way does maximum power point tracker controller are advantegous?
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Briefly, the MPPT charge controller boosts the current and voltage of the charging state of the battery while using the most of the available power of the solar panel.
The PWM and other charge controllers are dependent on the voltage of the battery. When the battery voltage is low (empty battery) the charging is slower.
The articles say an MPPT charges the battery at 18.3 V and 11.48A. but this is not correct. THat is the output of the solar panel at max power out assuming best sun. A lead acid battery will bubble above an input of 15v and the current a 100ah lead battery can take is limited by internal resistance to about 15 amps at that point. A dead battery will be mostly high resistance water and wont allow much current thru it. A MPPT will attempt to take the 14 to 18 volts in and put out a steady 13 to 14 volts and have a higher current capacity. That 18v/11a can now be 14v at 14a capacity. This is safe for a lead battery but the battery will only allow about 5 to 15 amps because of its resistance depending on charge level. Lithium batteries are different in that the resistance is very low and the current will be very high. Above 13.8 volts or so they become dangerous so the charge controller needs to limit the current and the voltage. You can easily get 30 amps into a lithium battery at a 14 volt charge voltage but it will hurt them.
In short a lead battery will not take a charge quickly and cant be charged with a voltage above 15v. A lithium cant be charged above 14v and doesnt like currents above 10% of its capacity or 10 amps for a 100ah battery. A lead battery has a high charge resistance so is self limiting but a lithium has a very low charge resistance and charge currents HAVE TO BE EXTERNALLY LIMITED. Remember lead acid batteries boil. Lithium batteries burn and cant be put out. So treat them kindly.
Comments
Briefly, the MPPT charge controller boosts the current and voltage of the charging state of the battery while using the most of the available power of the solar panel.
The PWM and other charge controllers are dependent on the voltage of the battery. When the battery voltage is low (empty battery) the charging is slower.
For more information, please read the following article: "How do MPPT charge controllers work?" https://www.greentechrenewables.com/article/how-do-mppt-charge-controllers-work
The articles say an MPPT charges the battery at 18.3 V and 11.48A. but this is not correct. THat is the output of the solar panel at max power out assuming best sun. A lead acid battery will bubble above an input of 15v and the current a 100ah lead battery can take is limited by internal resistance to about 15 amps at that point. A dead battery will be mostly high resistance water and wont allow much current thru it. A MPPT will attempt to take the 14 to 18 volts in and put out a steady 13 to 14 volts and have a higher current capacity. That 18v/11a can now be 14v at 14a capacity. This is safe for a lead battery but the battery will only allow about 5 to 15 amps because of its resistance depending on charge level. Lithium batteries are different in that the resistance is very low and the current will be very high. Above 13.8 volts or so they become dangerous so the charge controller needs to limit the current and the voltage. You can easily get 30 amps into a lithium battery at a 14 volt charge voltage but it will hurt them.
In short a lead battery will not take a charge quickly and cant be charged with a voltage above 15v. A lithium cant be charged above 14v and doesnt like currents above 10% of its capacity or 10 amps for a 100ah battery. A lead battery has a high charge resistance so is self limiting but a lithium has a very low charge resistance and charge currents HAVE TO BE EXTERNALLY LIMITED. Remember lead acid batteries boil. Lithium batteries burn and cant be put out. So treat them kindly.
Hello. Thank you for your comment. Here is a link to the answer for this question about MPPT.