where do i go from here?

jpk7180o

I recently was put in charge of my parents off grid set up, however i am no solar genius. They have a 12v system with a c60 charge controller and 8-75watt panels that are about 10 years old. My brother has just bought them 13-150watt 12 volt panels. And they have a 1600watt windmill with a seperate charge controller and dump load. Currently they have 6-12v 225ah batteries.

My question is...
1 what do i do to control the input of all the new amperage?
2 how many more batteries do i need?
3 is there any way to make all this work on there 12v setup without breaking the bank?


Thank you for any help

zoneblue

Welcome to the NAWs forum.

Hmm. 12v will become  an issue as that system grows. 12V was popular back in the day for various reasons, but no longer works well for anything other than a few panels. But, ok so if you leave everything else alone and add one more charge controller for the new array, thats the path of least resistance, right?.  (and doesnt rely on possibly overburdening the unknown dump controller loading.)

However its not one charge controller is it... the new panels alone is:
= 13*150W/12V*0.77 = 125A.
So your looking at two fm60s. (One classic would handle most of it if you werent fussy).

Then the batterys. For now if we just put the turbine aside, (because its productions is eratic), your peak charge rate is: 125A + 8*75/12*0.77 =165A
Thus your battery wants to be in the order (0.1C charge rate) of 1650Ah. Thats a nasty lot of parallel batterys, but you might find something in a forklift battery maybe.

As much as your not going to like this, you should look at the possibility of upgrading the system voltage to 48V. You are after all dealing with in up to 4kW of production capacity. Yes, that will mean a new inverter, new charge controllers throughout. Which is a lot of money, but then the system is bigger and merits design and investment. And a good watertight look over refresh of ciruit protection, disconnects etc.

If you dont need that amount of storage (btw whats the load requirement?) then you could perhaps consider alternative chemistrys that can handle higher C rates, but presumably theres a reason the system is growing... And Lithium is not for beginners.

mike95490

When nobody is around, lock down the windmill so it cannot spin.  Apply it's brake or install a manual brake.   An un-attended windmill is a disaster waiting to happen.  Generally, to save bearing life, you leave it locked till you need more power.   If you go on vacation lock it down,  Mechanical things and load banks tend to "break" or burn.

jpk7180o

They are getting power poles run to their house in about a month. Is an on grid inverter going to devert all excess charge to the grid and save me from needing a much larger dump load. Right now the dump is only there for windmill. Panels are set to shutdown when bank is full right now. If i add 2 more c60 controllers and up batteries to 16 will that work and should they be 3 banks of 6. How big of an inverter do i need, or would i be better off just putting 6 of the new panels up to the system they already have to max out their current controller and go with like 8 or 10 batteries. All they have for load is a fridge, some twisty lights, a tv, lap top, well, up flush toilet, washer.

Raj174

jpk7180o,

In my opinion, getting grid power will obsolete the current 12 volt solar power system. It is not compatible with grid tie and cannot feed the grid. If I were in your position I would sell what I could of the old system when the house gets connected to the grid. The only reason not to, is that you are interested in learning about solar power and have the money to do upgrades and replace components as necessary. 
 

zoneblue

If you have grid then the problem is solved. Sell the sytem for parts and move on.  Next question?

westbranch

Alternatively you could buy a GRID TIED system, totally different stuff, if that makes them feel good, saving the planet and all, so be it, but it will be costly... as you will need an all new setup, with different panels too.
BTW where are they situated?  That will have a big bearing on the economics and pay back period.

South Africa

I am with Zoneblue on this one. Thinking of my parents, having retirees relying on others for assistance, can cause a lot of worries and frustration for any power generation needs onsite action but more importantly, a substantial interest in the system.