Solar Costs - MPPT vs PWM
The continued lower price of the larger panels has now dropped the MPPT costs just below PWM for a larger RV solar setup. SolarBlvd Cynergy 3x$200 250W panels 750W $600 SolarHome Morningstar MPPT ...
Forum Discussion
Thanks for the extra testing. I think the controller operates in constant voltage (CV) mode when in absorption. The controller's output voltage is fixed. The 3 controllers may all be set to 14.4V, but they are not exactly equal. One controller has the highest voltage and another the lowest. The highest controller should supply all the current.
There is an exception though. The cable resistance between controller and battery is a factor. There should be no sharing if the controllers are tied together and just one cable goes to the battery. It's best to have 3 cables.
If you have 3 cables and the cable voltage drop (I * Rcable) is greater than the difference in controller output voltage then there will be some sharing. It won't be equal though.
There is an exception though. The cable resistance between controller and battery is a factor. There should be no sharing if the controllers are tied together and just one cable goes to the battery. It's best to have 3 cables.
If you have 3 cables and the cable voltage drop (I * Rcable) is greater than the difference in controller output voltage then there will be some sharing. It won't be equal though.
JiminDenver wrote:
When in absorb/float the controllers split the charging, each dropping equally until as I said, it's gets well into float. I'll have it all up this weekend so Ill pay attention to it more.
