24 volt solar panel recommendations?

tpi wrote:
1. Several mentioned the controller clipping when fed above rated wattage. I'm familiar with audio amplifier clipping-and I assume controller is some kind of switching power supply. What is going on when the controller is clipping? The pulses can only be to a certain level?

2. When the batteries are fully charged what is the mechanism for the controller to back off the charging? I would assume it not shunt the excess power into heat.

1) No. With MPPT controller you can input as much amps as you want, and it will block the excess. You only need to watch out for input volts - max input voltage of the controller should not be exceeded.

2) No, MPPT controller won't shunt the excess into heat when battery is full.

When battery state is nearing Full, its resistance rises and current drops. Controller simply can't push into battery more current than it would accept. The only thing that controller "controls" at this stage, is the volts. At ~80% charge the controller enters Absorption stage where it's keeping the voltage constant and slightly elevated, 14-15V. Cheaper/simpler controllers have non-adjustable timed Absorption, usually 60 minutes. Better/more expensive controllers have adjustable timed Absorption (you can adjust the time), and also current-based absorption - the Abs stage ends when current drops to certain level (this level you can also adjust). Some other controllers change the duration of Abs stage depending on the voltage at the beginning of charging. Bluesky is not the most advanced line of MPPT, they are a "OK" line.

When Abs stage ends, controller enters the Float stage - at this stage it's keeping the battery at constant low voltage ~13.6V until the charging current drops to zero or sun goes down. Then controller shuts down.

As noted by others, we are talking here about MPPT controllers because with 24V panel you can only use MPPT. PWM controllers have the same Abs and Float stages, but they work differently when it comes to "clipping".