Oh No ! I bought a Mppt Solar Controller
I don't believe it ! I bought it and I don't really even want it ! I was sure this would go for more than 12 bucks. Fooled me, oh well. Whats w/ links not working ?
Forum Discussion
Sorry could have made it a be clearer
The BUCK conversion within an MPPT controller drops the array voltage to the battery voltage - the controller then charges the battery with a PWM charging alogrythm. YES MPPT controller use a PWM charging scheme. So if you measure the array voltage at the controller inputs and then measure the battery voltage at the controller and find they are different the MPPT BUCK converter is doing its job. However it does not mean the controller has a proper tracking alogrythm just that the buck conversion is working.
PWM controllers connect the array directly to the battery - so if you measure at the controller and see both array and battery exactly the same voltage (assuming the battery is taking a good charge) there is no buck conversion or it is not working as it should.
The buck conversion stage can be though of as a voltage to current changer - it drops the array voltage to the needed batery voltage if 100% efficient Power in = Power out - a lower output voltage translates to a higher current - nothing magic at alll with a buck converter. The magic is in the MPPT tracking alogrythm
To directly answer your question "YES" It is expected to have the array voltage different from the battery voltage - My array voltage is typically 40 Vdc (the Vmp chages from the low 30's to the high 30's depending on the light / heat conditions) while the battery voltage is 14.4 or there abouts - the buck conversion does that.
The BUCK conversion within an MPPT controller drops the array voltage to the battery voltage - the controller then charges the battery with a PWM charging alogrythm. YES MPPT controller use a PWM charging scheme. So if you measure the array voltage at the controller inputs and then measure the battery voltage at the controller and find they are different the MPPT BUCK converter is doing its job. However it does not mean the controller has a proper tracking alogrythm just that the buck conversion is working.
PWM controllers connect the array directly to the battery - so if you measure at the controller and see both array and battery exactly the same voltage (assuming the battery is taking a good charge) there is no buck conversion or it is not working as it should.
The buck conversion stage can be though of as a voltage to current changer - it drops the array voltage to the needed batery voltage if 100% efficient Power in = Power out - a lower output voltage translates to a higher current - nothing magic at alll with a buck converter. The magic is in the MPPT tracking alogrythm
To directly answer your question "YES" It is expected to have the array voltage different from the battery voltage - My array voltage is typically 40 Vdc (the Vmp chages from the low 30's to the high 30's depending on the light / heat conditions) while the battery voltage is 14.4 or there abouts - the buck conversion does that.
