Advice on deep cycle setup?

full_mosey wrote:
I believe what red31 has confirmed with Morningstar is that The MPPT continues on past bulk and that after bulk it will continue to harvest excess volts on the example 100W/100V/1A panels by using pulse width on/off modulation for tapering the Amps.

The PWM controller would behave like a 2A charger throughout all charge stages.

A pair of 12V 36 cell panels might fit better and they can be a 72 cell array if 24V are needed.

HTH;
John

It seems during Absorb, instead of tracking Vmp continuously as during Bulk, the controller bats back and forth between MPP voltage and zero voltage, which is a form of PWM. Creating a sort of average voltage higher than Vmp. It is controlling battery voltage from going above the set Vabs. It knows the battery voltage by being on the end of the controller output battery wire (can also have a sense wire)

If using a PWM controller that can handle a panel with 100 vmp and 1 imp that would make its Voc higher than 100 and its Isc higher than 1 amp. It should charge at the Isc figure

Sorry about my math error. 10% is for a panel temp of 50C, 25C above rating spec temp. If it is 25C out ambient you will get that 50C panel temp. If it is cooler out, panel temp above ambient might not be so much, so loss could be less than 10%. You can measure panel temp by using your ray gun on the back side of a tilted up panel aimed at the sun. (which allows a breeze behind it) Must be very hot under a roof mounted panel-no breeze.

I got no better with my Tracer or Eco-W MPPT using 12v panels in series than with my PWM controller with the panels in parallel. Sometimes the PWM did a little better for amps to the battery in the same conditions when I was running tests for that.

You do get slightly higher amps with the MPPT in the earlier part of the morning when the battery voltage is still low and temperatures are not up to daytime highs yet. It is fairly trivial in the daily AH haul comparison. the big thing is the 24v panels cost half what the 12v panels cost, and the Tracer and some other MPPT controllers are not expensive like some MPPTs are (ahem!) so if you have the roof space for a 24v panel that is most economical usually. Just don't expect any higher amount of amps, despite the advertising.