Finally getting around to doing some more testing of MPPT vs. PWM on LFP batteries.
It was stated by some that MPPT does not work well on LFP? I had never found this to be true.
Day 1 testing (with this particular set up) showed a 12.89% increase for MPPT over PWM. Course I was getting it set up yesterday and did not even fire it up until about 1:40 PM..
This morning I just checked at 9:30AM and the MPPT controller is handily beating PWM again, but it is early.
So far I am testing a Genasun GV-10 MPPT and a Morningstar PS-15 PWM..
I am doing "print screens" every so often because I am having trouble with the exported data files. Bogart has been helpful but I am using a Beta version so no guarantees. Easiest to just capture a "print screen" shot... The 400Ah LFP bank was drawn to -304Ah's or about 75% DOD before the controllers were let loose....
All wires are same gauge and carefully measured for exact lengths to be as fair and equal as possible. There is some slight voltage drop in the wiring
but no different than I see on most marine
Ah's returned are being measured by a Bogart Engineering Pentametric System fed to a laptop
via a USB interface. Each panel gets its own shunt.
are identical, Kyocera
140W, and are placed right outside my garage, in an area where both panels are treated equally to avaible light. I monitored them for a few days at different times for shading. Panels have been kept flat, like they would be on a boat.
I also have a Rogue MPPT 3048 and a MidNite KID to test, if I can get to it before I stick my LFP bank back into the boat.
It is still early to fully analyze but it is lining up with what I have seen on our own boat with LFP, and that is about a 10-15% gain for MPPT with LFP.... While not huge it is a gain that can be worthwhile when you run out of real estate. The real reason I use MPPT on LFP is for the programability of the MPPT controllers over a typical PWM...
Test Bench: The Victron BMV is used to measure the capacity of the LFP bank and the Pentametric is tracking solar performance.
L to R: LFP Bank, Fluke DVM for measuring LFP terminal voltage directly, LFP capacity test station with Victron BMV-602 and inverter
load for taking capacity out of the bank, Pro Star 15 PWM controller (gray), Genasun GV-10 (black), Rogue MPT-3048 (off white), MidNite KID (on top of Rogue), Pentametric Monitoring System and shunts, laptop
: Two Kyocera
Hope to have more data in a week or so...