Back ground info.
The project is a control system for a 24v 700w wind turbine.
When wind speed is less than 15mph (approx) the voltage of the turbine is less than 24v and thus useless for charging the batteries.
The turbine came with a 12v PWM controller (it should have been 24v (slanderous comment)).
I set it up and the green light came on on the controller at about 8mph, yippy I thought until I checked the current to find it to be 0... The controller has a built in brake (not exactly sure how it works but it must run current through the field to cause magnetic braking, ish, if anyone would like to elaborate feel free).
The brake came on at about 17v which is when I realised it was a 12v controller.
I fitted a 3 phase bridge rectifier and on open circuit it developed between 45 and 65v when the forecast said it was 18 mph wind speed.
It works well on 24v if wind speed is above 15mph.
Well the project comes in two halves, so I will complete the first half than consider the second half.
Firstly if we call the two series connected 12v batteries battery A and battery B.
When wind speed is low I can charge battery A or battery B and still use 24v load.
If I connect the batteries using 4 relays I can switch A on (charge) when B is off and B on (charge) when A is off but not both at the same time...
Thus I can charge the 24v battery at 8mph+ wind speed.
So I want to set up an 555 timer to switch on an off at maybe 0.5Hz
Set up a counter to count from 00000 to 11111 then repeat, the time between 00000 and 00001 is 0.5Hz (approx) from the 555.
Using transistors to switch the relays of A and B it should switch every just over 2 mins.
So to go through the sequence.
A switches on (2 relays) at 00000 and switches off at 11111 then B switches on at 00000 and off at 11111 etc
There is a 2 sec (approx ) gap between 11111(off) and 00000 (on) so that there is not a short circuit.
It is a while since I read digital electronics and need to ask here or spend months reading to figure out the best chips to use for the counter and logic gates to get it to switch at the appropriate moment.
Do I need to use a shift register?
Also what transistors should I use?
I have forgotten so much, I understand the gist but have forgotten, it will come back.
The second phase is to automate the above.
When it is on 12v and current goes above say 10A I want it to switch not only to 24v but to 3 phase 24v so it charges via the new 24v controller with a brake, when 24v current drops below say 2A I want it to switch back to 12v.
I don't want to start the second phase until I have got the first phase up and running.
So that's about the size of it.
If any one can advise on what chips to use I should be able to get the data sheets and solder them to a board.
Will upload photos when done.
Any comments/advice welcome.
Reading Fundamentals of digital electronics by Robert K Dueck now but was hoping someone would solve the problems saving me months of reading.
(Third time I have read this ...yawwwwnnnnn... The last time was about 5 years ago, I forget so quickly, maybe I should see a doctor!
On page 20 out of over 1000 pages ...yawwwnnnnnn...)