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 ...
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It doesn't know a slower, gentler rate. It only knows one rate and that's full speed when in boost mode.
What you're seeing in boost when running the coffee pot is that the pot wattage is greater than the solar wattage. Battery voltage goes down. MPPT charging current is a function of the maximum power point AND battery voltage.
Icharge = Psolar / Vbat
If Psolar = 200W and Vbat is 12V then Icharge = 16.7A.
When Vbat = 14V then Icharge = 14.3A
What you're seeing in boost when running the coffee pot is that the pot wattage is greater than the solar wattage. Battery voltage goes down. MPPT charging current is a function of the maximum power point AND battery voltage.
Icharge = Psolar / Vbat
If Psolar = 200W and Vbat is 12V then Icharge = 16.7A.
When Vbat = 14V then Icharge = 14.3A
JiminDenver wrote:
AND just because you look at the output of a MPPT controller and see x amps, don't think that that is the max for the system. The controller also tries to determine what is the best way to charge the battery. Left alone the Eco-w's will take a slower, gentler rate but if I hit the system with running the coffee pot early on, I'll see a 2-3 amp increase and it will stay that way until the you hit around 14v or so. Then they go into boost until you reach the set voltage before dropping to float.
