Forum Discussion
996Pilot
Oct 21, 2017Explorer
time2roll wrote:
MPPT actually spends most of the day in PWM due to the long absorption phase of lead-acid.
That 'up to 30 percent boost' lasts for a very short period unless you have over discharged your battery.
Bogart with monitor will be very good about getting the length of absorption time time correct no matter what the level of charge at the beginning of the day. Most controllers including MPPT have a fixed timer and some not even adjustable.
Real advantage of MPPT is using large high voltage panels that may not even fit well on a TC.
I still count Bogart as an excellent controller when combined with the monitor like the OP has done.
Both MPPT and PWM controllers spend 100% of their time controlling a Pulsed Width Modulator (PWM) for charging. The difference is how the MPPT controller tells the PWM circuit what to do.
The charging of the battery at Maximum Power Point (MPP) is achieved by carrying out the process of Pulse Width Modulation (PWM)at
the switch mode of the DC-DC converter.
The MPPT controller pulse width modulation uses time proportioning. This divides the signals into high and low states. The proportion of time spent in the high state is known as the duty cycle. The MPP algorithm uses different duty cycles to match the impedances of the PV array and the battery to reach the MPP.
I mean - we can debate this all day but I don't believe any straight PWM charge controller will be as efficient at panel power extraction than a good MPPT charge controller. An MPPT controller is not JUST looking at the state of the battery charge but also what the panel is offering at that same time. When you're trying to extract the MAXIMUM you can from the panels you have during all phases of solar input (peak, partial, off angle, etc.) why go with PWM which is just a fancy ON-OFF switch connected to the panel. Why not use a little intelligent calculating to best match the instantaneous panel output of the panel with the current battery need?
Two ways to solve the OP's problem;
Elegant way - install MPPT Charge controller
Brute Force Way - Add more panels.
Lastly, for the discussion of equalizing AGM (I thought the OP said he had AGM). Many AGM batteries can be equalized (and should). Check with the manufacturers recommendation for your battery.
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