Jan 12, 2010 02:19 am
Re: Charge controller needed for mini hydro
PV is an exotic form of generation. The controller is trying to coax more power out of the panels for better efficiency. It then turns around and simultaneously looks at protecting the battery. That is why you have solar charge controllers.
With your hydro set up, the generator is going to produce a certain power level based on the current flow and the excitation logarithm. That power will come charging out like the bulls of Pamplona. It is active generation, not the passive generation of PV.
Until you are in a hydro unit large enough to justify the expense of flow control and excitation control to back the production down, you just have to take the full amount and do something with the excess.
You seem to be thinking that because solar works better with complex control, the same complex control is needed on hydro.
With diversion control, all it needs to worry about is protecting the battery. When the battery voltage hits the preset level, it starts diverting enough wattage to maintain the appropriate voltage. When the battery is full, all the wattage will be diverted.
Something you said gives me the feeling that you think dumping power is bad. Question for you. What is the difference between dumping excess power off of a hydro, and not producing the same amount of power with a PV panel because the controller choked it off?
To me, they are both equally wasteful. The difference is that if you choose the right diversion load (e.g. preheating hot water or pumping water to storage) you can have more efficient use of your generation. (Higher capacity factor) You may also be saving some other form of energy.