I purchased the HF system and I have been very pleased with it. I did have a prolem with the charge controller (only putting out 2.3 volts) but after I returned it and got another unit, it worked great! The buzzing was a bit intrusive, but my buzzer broke. ;-) Now, the charge light goes out and no buzzer.
I have noticed that when this happens, the controller does indeed disconnect the solar panels at 14.5 volts. Once the voltage drops back to 13.5 volts, the charge light comes back on and the solar panels start charging again. (you can see this by monitoring the panel voltage. It will be the same as the battery voltage until the controller disconnects them and then the voltage goes to around 25 volts - same as open voltage)
For the price, this system works great! (I got the 20% off the website price of 199.99) By the way, the price in most HF stores is 299.99. If you print out the website page, they will honor the website price at your local HF store. If you sign up for email notifications, they will send you coupons for % off. That is how I got 20% off the website price of 199.99. Mine cost 160.00 plus tax. That is 140.00 off the in store price!
I was tempted to see if I could replace the pezo busser with a small relay to use for a dump load. Then I believe I could hook up my newly made windmill directly to my batteries. The charge controller for the pv's would monitor the voltage and would turn on the dump load when the voltage reached 14.5 volts. (when the buzzer would normally start buzzing.
Does anyone think this would cause a problem? I believe it would utilize the monitoring circuit already in the pv charge controller. I might have to use two relays. One circuit board (low power draw relay) to drive a larger relay with the dump load on it. I believe the small relay would raw the same current as the pezo buzzer so it should not hinder the performance of the existing circuit.
Thanks for the great info and I hope I can help someone as well.
Paul