mppt vs pwm
Hi, A nice little video comparing mppt vs pwm with the batteries in bulk mode. mppt vs pwm
Forum Discussion
Yes, you did drop down to 8%.
Fig 14 pretty much sums up the differences. The RV crowd are for the most part fair weather campers. That means cell temperature is in the range 40 to 80C. In that range, for the most part, mppt gains are between 0 and 10% better than pwm. On average it could be about 5%. Nothing to crow about.
I see no real advantage when using a higher Vmp. Temperature still reduces power by the same amount. 90's thinking still apply.
Fig 14 pretty much sums up the differences. The RV crowd are for the most part fair weather campers. That means cell temperature is in the range 40 to 80C. In that range, for the most part, mppt gains are between 0 and 10% better than pwm. On average it could be about 5%. Nothing to crow about.
I see no real advantage when using a higher Vmp. Temperature still reduces power by the same amount. 90's thinking still apply.
lorelec wrote:Salvo wrote:
Right, Don needs to review that thread.
I think Rogue dropped his gains after the discussion from 20% down to 8%; but it's been a while.
No, it's entirely possible to get 20% gain with MPPT. Much more than that, actually, if you're using an array with a Vmp far above the battery voltage (which only MPPT controllers will allow you to do with any measure of efficiency). If you've been stuck in the boondocks for a long time, you might not realize that the popular thing to do these days is to use panels meant for grid-tie installations -- which do indeed have a higher Vmp than traditional panels meant for off-grid installs.
For CONSISTENT gain, with an array that has a Vmp closer to the battery voltage (17v Vmp, for example, with a 12v battery), around 10% is typical when you factor in the effects of temperature on Vmp. This is 1990's thinking, though. Time to move on.
