pianotuna wrote:
$219 for controller
$330 for two extra 150 watt panels
$415 for kit with mounting hardware
$964.00
Call it $1000 by the time you pay for mounts and extra wire.
If saving money is primary objective, this is the best route.
I doubt 4*150W+PWM will collect a lot more amp-hours than 3*235W+MPPT. 18% less total wattage is hard to compensate with better controller performance. Besides, there will be higher losses in wires with PWM. Another drawback is more work to mount 4*12V panels, beefy cable #6 or #4, and unsightly rooftop box.
Tristar 45A MPPT is rated 600W but at sea level you can go as high as 3*235W array. This would work nice in shoulder periods of morning/evening or overcast, with none or very little clipping at peak sun. It's been discussed many times - with MPPT you can max it up and even go a little over the limit. Or get TS 60 MPPT and install 3*250W. 24V panels from 220W to 260W are practically same size.
This is - if simplicity and maximum harvest is the objective.
