mppt vs pwm
Hi, A nice little video comparing mppt vs pwm with the batteries in bulk mode. mppt vs pwm
Forum Discussion
While PWM sort of chugs along no matter what, MPPT does way better at low battery voltage. We have people who use solar to run loads, and that activity keeps the battery voltage low, so they like MPPT
For battery charging your voltage keeps rising so MPPT might start out with an advantage, and lose it part way up. Depends which to choose on how much of each you do while RVing? If all you do is shallow cycles on solar, your battery voltage stays high, so the MPPT has no chance to shine. if you run loads at night so battery voltage in the morning is low (deeper cycles) then your MPPT has some time in the morning to show off.
Ken showed how MPPT does better in low light when panel voltage is lower using 24v panels, so that there is still some voltage difference for the MPPT (buck converter actually) to work with while PWM has shut down.
But how can Mr Wiz do better with MPPT on cloudy days with MPPT when he has 12v panels? Is there still some voltage the MPPT can do something with that would be noticed?
I wonder if the low light cloudy day MPPT thing might be mixed in with the low battery voltage MPPT advantage. On a cloudy day, the batts would be taking longer to recharge if the amps coming in were lower than on a sunny day, which means they would be at a lower voltage longer in the day, giving MPPT advantage longer to work its magic.
So it might be tricky to separate the two factors in deciding which is doing how much of what you might be seeing. One is based on panel voltage variations while the other is based on battery voltage variation. You can get more voltage difference by moving either one away from the other. You can move both of them either way and get smaller or bigger differences.
If you do a generator recharge first and then go to solar, your solar will be introduced when battery voltage is already up some. So PWM might be just as good by then to finish up.
It is all about the circumstances. I can't see any way to set up a fair fight that would have a general application.
For battery charging your voltage keeps rising so MPPT might start out with an advantage, and lose it part way up. Depends which to choose on how much of each you do while RVing? If all you do is shallow cycles on solar, your battery voltage stays high, so the MPPT has no chance to shine. if you run loads at night so battery voltage in the morning is low (deeper cycles) then your MPPT has some time in the morning to show off.
Ken showed how MPPT does better in low light when panel voltage is lower using 24v panels, so that there is still some voltage difference for the MPPT (buck converter actually) to work with while PWM has shut down.
But how can Mr Wiz do better with MPPT on cloudy days with MPPT when he has 12v panels? Is there still some voltage the MPPT can do something with that would be noticed?
I wonder if the low light cloudy day MPPT thing might be mixed in with the low battery voltage MPPT advantage. On a cloudy day, the batts would be taking longer to recharge if the amps coming in were lower than on a sunny day, which means they would be at a lower voltage longer in the day, giving MPPT advantage longer to work its magic.
So it might be tricky to separate the two factors in deciding which is doing how much of what you might be seeing. One is based on panel voltage variations while the other is based on battery voltage variation. You can get more voltage difference by moving either one away from the other. You can move both of them either way and get smaller or bigger differences.
If you do a generator recharge first and then go to solar, your solar will be introduced when battery voltage is already up some. So PWM might be just as good by then to finish up.
It is all about the circumstances. I can't see any way to set up a fair fight that would have a general application.
