Hi all. i have been running my off grid cabin on hydro for over a year now. i have been useing a tristar mppt controller and fixing the correct voltage in order to load the turbine correctly. this voltage is around 50v under load. That is the ideal speed to load the turbine to in order to catch the most energy from the water. that 50v equates to the turbine moving at half the speed of the water leaving the nozzle, this is the optimum relationship between nozzle volicity and rpm.
Now i have had lots of problems with morningstar and decided to try a victron blue solar controler. I planned on useing the mppt controler to find the best voltage instead of me needing to fix the voltage to 50v. I have plugged it in and at first i found that is would be all over the place and not find a voltage and stick to it. It would sometimes get close to the right voltage but then do another sweep and loose it again. I put this down to the fact that it is acting differently from solar and could do with some large capacitors to smooth it out. I have done this now and tested it and it isnt all over the place anymore but it thinks the maximum power point is at 30v and it simply isnt. The maths says it is at 50v. i have been using it for a year at 50v and that has giving me the most power. (I have done endless testing) But for some reason the blue solar controler seems to think the maximum power point is at 30v My question is why? and has anyone got an ideas? It will sometimes do a sweep and the voltage goes up and as it does the wattage produced goes up to. but then it just goes back to the 30v again. at 30v i am loosing alot of my efficiency because that relationship between nozzle velocity and rpm is off.
Thanks for any help.