Wind and Solar together

Re: Wind and Solar together

chicodesouza wrote: »

I have on my sailboat a wind generator (25A max-DC) and a solar generator (12A max).

Welcome to the forum. Sounds like you are enjoying life!

Use separate controllers is better in case of failure. But I think that I may not use separate controllers since one can interfere with the functioning of the other because the charge that each sends causing misreading of the situation of the battery.
First question: I am thinking correctly?

Probably need more details... Solar charge controllers are typically "series" based controllers... Basically they simply turn on and off the current from the solar panels to control the battery charging. You can put multiple series controllers in parallel to one battery bank and all will work fine--The charge controller with the highest voltage set point will "win" (that will be the charging voltage set point at any instance in time).

Wind turbines tend to use "shunt/dump/diversion" type charge controllers. The Wind turbine is connected directly to the battery bank and is always charging the batteries (when the wind is blowing). A shunt controller is connected to a "load bank" (typically electric heater) which turns on when the battery is "full". So it "dumps" excess charging current to the heaters to prevent over charging. Shunt controllers do work, but do not charge the battery banks quite as nicely.

You can put parallel shunt and series controllers on the same battery bank, but you can end up with weird situations... For example if your solar array is set to charge at 14.8 volts and shunt is set to charge at 14.4 volts, you can have the solar panels (plus generator) charging and the shunt load dumping.

Nominally, I would suggest setting the solar controllers to ~14.5 volts and the dump controller to ~14.8 volts (as an example).

They will work the other way, but you will be generating excess heat in the dump load.

Not being able to use two, think about combining the inputs of the two generators (isolating properly).
Second question: can I do this?

You should be OK...

Fourth question: what is the difference between "charge control" and "load control"?

There are "shunt" charge controllers that will turn on a load (heater, water pump, etc.) when the battery is "full" to get rid of excess charging current (typically from a wind/water turbine).

And there are LVD/Load controls (Low Voltage Disconnect). These are used to turn off loads when the battery falls below 11.5 volts (or other programmed settings). And some controllers can be used as lighting control (turn on lights for 4 hours after sun set, sun set to sun rise, etc.).

The simple Schneider/Xantrex Cxx controllers can be configured as either series or shunt charge controllers. Or as LVD controller too. (only one function at a time--You cannot mix/match functions in a single C40 type controller).

I will stop there for the moment... Questions?

-Bill

Re: Wind and Solar together

chicodesouza wrote: »

I studied a little more about the subject and the information helped me understand the texts because I am Brazilian and have some difficulty in English.

You are doing good. My wife and I spent a month in Brazil 2 decades ago... Very beautiful country. And seeing the afternoon thunderstorms in the north where amazing--Did not know that much water could fall in so short of time.

I am bad enough in English--Google Translate is my speed for anything else.

I'm in California for a few days and want to take to buy equipment and much here that s cheaper than in Brazil. But there are still some doubts.

That is difficult... Buy in the US, and no local service centers/technicians.

I believe, but I can't understand why the solar generator must have a discharge source, which the difference for solar panel?

I don't like the idea to have a source of heat (diversion charge) small sailboat.

Some charging soruces can be turned On and Off... Solar panels, just put a switch in-line with the panel. Switch on, current flows, switch off, current stops, panel does not "over-voltage".

For an alternator on a vehicle/engine... They are always 100% attached to the battery bank (battery actually regulates vehicle DC voltage). These alternators have internal rotating "field windings". The Alternator regulator sends ~2 amps of current to the windings to generate maximum current, and sends near zero amps to the field windings to generate little output current (of course, alternator RPM affects output power).

The typical Horizontal Wind Turbine (typically type you see anywhere) and many hydro electric turbines need to always have a load--If they are running in heavy winds/full power--If you opened a switch on the turbine/alternator, the electrical torque drops to zero, and the blades/turbines will spin faster and faster until the system "flies apart":

So, they need to be connected to the battery bank 100% of the time, and any excess power needs to be "dumped" or use "elsewhere" to prevent battery over charging.

The other question I have is, if I connect in single dump load mode, I also an engine with alternator 80A, this will not add to the load of the solar and wind, forcing me to have a controller 120A (> 117A)?

Generally, the Engine Alternator will be set to ~14.2-14.4 volts. And you should have your dump controller set to ~14.7-14.8 volts.

That will prevent the dump from "turning on" and loading down your engine (and wasting fuel).

If you got it backwards (dump load on, and alternator charging)--You really probably do not need the higher power dump. Basically, the alternator will shut down current when the bus voltage >14.5 volts (example) if it is working correctly. And the dump controller still only needs to "sink" the wind turbine's excess power. It is not something I would recommend, but I would not lose sleep over it.

Speaking as an engineer--Series controllers are, more or less, fail safe. They usually "shut down" if there is a failure.

Dump controllers, if they shut down when there is a failure will allow the wind turbine to "dangerously" over charge the battery bank. Boiling battery (will kill battery) or boiling dry (fire/explosion hazard). So, from a "code" point of view, shunt systems should have at least two "full" independent controllers so if one fails, the other one still functions (load banks can fail open too--And if they fail shorted, the protection breaker/fuse will open--And you still end up with an over charging situation).

The only "positive" wind turbine contribution--Very few wind turbines generate large amounts of charging current (and most of the time, generate near zero useful charging current)--So dump controller failures are not usually catastrophic failures.

The bigger problems with wind turbines, is how to shut them down (safely) in heavy/storm winds. As in the video above (and hundreds others), when the brakes/shutdown systems fail--All anyone can do is stand back and wait for the turbine to fall apart (energetic disassembly).

https://www.youtube.com/watch?v=uydJJdQzZv8

-Bill

Re: Wind and Solar together

Does he have significant loads or just the occasional sump pump cycling?

Solar panels tend to be more reliable, but on sail boats with lines, masts, swinging at anchor, etc... They don't always generate near the expected amounts of energy (any shade on a solar electric panel kills most of its output).

Wind tends to be less predictable.

-Bill

Re: Wind and Solar together

chicodesouza wrote: »

More questions:
1 ) Using the controller as a dump controller , a remote panel will not be useful because not be able to read how much power the generator send to batteryes that is correct?

All things being equal (which they rarely are), series charge controllers (typical solar panel type) are "easier" on the battery banks. Shunt/diversion controllers are "harder" on battery banks (sort of like hooking up a generator to a battery bank and flipping on and off a heater to "on average" control the battery's charging--Not great).

2 ) To connect two controllers as you say they must be connected in parallel right ?*The two equal 40A (30A wind , solar 12A without considering the alternator).

Should not be a problem. The solar charge controller will control only the panel current to the battery bank.

The shunt controller will only control current to the connected load (controller >= to heater bank current rating).

Both controller should be connected directly to the battery bank +/- buses. Both + leads should have breaker/fuses that are rated to protect the wiring in case their is a short circuit somewhere.

For example, a 12 Amp charging current (this is US NEC National Electric Code--Your local wiring/components may be rated differently):

12 amps * 1.25 fuse/wiring derating = 15 amp minimum rated branch wiring+breaker/fuse

You want the fuses/breakers/wiring to by 1.25x larger than your expected maximum continuous loads. If not, you may pop the fuse/breaker in some conditions.

3) I also find it a good idea to have 2 dump resistors in each (in case of one burn).

Redundant systems is always a bit of an issue.... 2x as many parts, 2x more likely to have something "go wrong". Adding complexity does not solve the problem of "cheap/unreliable" components.

But something that is left alone for months at a time--Yea, you don't want things to go wrong.

-Bill