Where to insert wind power in system

Re: Where to insert wind power in system

One handy site that keeps getting posted here is:

Smart Meter battery wiring FAQ

The point at which you connect your loads and chargers is the "balanced current flow" point for all of the batteries (all batteries share equally charging and discharging).

-Bill

Re: Where to insert wind power in system

I am not sure what your questions are...

Fuses should be sized to the gauge of the wire... A 15-20 amp fuse is good for 14 awg wire.

And the wire should be sized for 1.25 x the maximum current... Assuming your 60 watt turbine at 12 volts:

• 60 watts * 1/12 volts * 1.25 = 6.25 amp fuse/wire minimum

We also watch out for voltage drop (long wire run from turbine to battery bank)--Use a voltage drop calculator to ensure that your drop is around 3% maximum for your wire run.

What do you want to do with the battery switch? Turn off the inverter or turn off the turbine (not a good idea--normally a HAWT needs an electrical load 100% of the time to prevent over speed (the smaller ones do have a switch that allows you to either connect to the battery or short out the windings to stall the turbine).

-Bill

Re: Where to insert wind power in system

greenthumb76 wrote: »

I ran 10 awg cables the 15 feet from the solar panel to the controller. The rest of the cables are 4 gauge, to keep losses to a minimum, and to allow for additional panels, wind etc. later.

Keep the cables short and heavy from the charge controller to the battery bank... You want the controller to accurately measure the battery bank voltage and have very little voltage drop.

My question was--with 2 batteries, is one fuse between the batteries and inverter sufficient? (I currently have a 20 amp fuse there).

It is difficult for me to say... In your other thread, you have a 1,500 watt inverter which would require:

• 1,500 watts * 1/10.5v batt cutoff * 1/0.85 efficiency * 1.25 NEC safety factor = 210 amp circuit/fusing

So, for rated power, you are looking at a ~200 amp fuse and a 1 to 3/0 cable... If the inverter is only powering small loads:

• 20 amp * 10.5 volts * 0.85 inv eff * 1/1.25 NEC derating = 143 watts maximum

So--It all depends on your expectations. Obviously, a small panel+battery bank does not support a 1,500 watt inverter running at full power very long.

You mentioned a voltage drop calculator--do you happen to have a link to one?

voltage drop calculator (Excel spread sheet for designing system)
very simple drop calculator (the % voltage drop does not help for non-standard line voltages)

Notice that the wire length may be round trip (path through entire wire length) or one-way length (calculator doubles voltage drop for you). Just be sure you understand which "wire length" your calculator uses.

Here is a link to the wind turbine I plan to buy: http://www.usawindgen.com/30.html It is a 12 volt DC turbine.

The description says that the higher the wind speed is, the more power is produced. I am not sure what the max. current or volts would be, so I am unsure what cables and fuses it will require. I am thinking about placing it about 60 feet from the batteries.

Ummm... That is really not going to give you significant amount of power for your system (my guess)... You would be lucky if it averaged 6 watt power output in a pretty windy area.

They say it works great charging AA and D cell batteries--It is really not large enough to make much of a difference charging your storage batteries.

Another issue is the single turbine does not start generating until 15 MPH winds (remember that is still near 0 watts into your battery bank)--Most places do not have any where near that average wind.

Unless you have some special need for that turbine (teaching your kids, live on a coastal bluff, etc.)--I would humbly suggest to save your money. and invest it in more solar panels.

The reason I was considering a battery cutoff switch is to simplify things if I need to work on the system. It seems I'm always having to remove the battery (and other associated) cables.

Many times, people use a switch like that to isolate just the inverter so you can turn it on only when you need AC power (standby losses are a big issue with smaller systems).

You can place the switch at the battery bus + output and run your switched loads to a bus at the output of that switch. Usually, you would probably attach the solar charge controllers to the unswitched battery bank, and the loads to the switched battery bank (you normally always want the chargers permanently connected).

-Bill

Re: Where to insert wind power in system

greenthumb76 wrote: »

I don't mean to seem so argumentative, I'm just trying to clarify, because the things you are telling me seem to conflict with other things I have been told. I am on a VERY fixed income, and this system I am putting together provides ALL my power! I am very thrifty and use very little power, nevertheless, I wish to get the most power I can for my investment.

I know that averaged year-round solar will provide well--but that doesn't help a lot in the winter if most of the power is produced in the summer! Hence, my hope to complement solar with wind.

Asking questions and providing information is not a problem. I am not there and I can miss-understand questions/information provided.

I understand the issue of needing to generate electricity when the sun is not shining--Wind seems like a nice mix with solar PV. But, in practice, wind has lots of costs, issues, and limitations.

If you want to try it--Go ahead, it is not going to hurt anything if connected correctly.

I was told by a licensed contractor/electrician that a 20 amp fuse was sufficient. (1500 watts is the a/c output of the inverter (3,000 watts peak surge).) Was he wrong?

Would the one, 15 amp fuse be sufficient, with 2 batteries in parallel?

I was talking about fusing the DC input to the inverter--It sounds like your electrician is talking about the inverter output...

The DC input fuse is required for safety. The AC output fuse may not even be needed (many inverters have a fuse/breaker already on their output).

You're saying that the way it is set up now, I can only run 143 watts of lights or whatever, at most?

Again, if the 20 amp fuse is on the output--Then the limitation is:

• 20 amps * 120 VAC * 1/1.25 NEC fuse derating = 1,920 watts @ 120 VAC

Here is info regarding the wind turbine, that I was basing my expectations on:

"I have tested them in winds over 65mph and they just keep putting out more power. Depending upon what kind of load (higher loads require more wind to begin turning) you have hooked to it, it will start turning in as little as 4-5 mph winds. The Micro-2 can be wired in series to allow it to output 12+volts in about 9 mph winds."

The Micro-2 is what I was planning to get.

This, they say, is if it is only 5-6 mph winds.

Again, I was planning to get the Micro-2, wired in series, which they say will give "12+ output in about 9 mph winds."

9 mph wind is totally within reason, where I live, in the wintertime.

I do not have high expectations of this wind turbine. But I figured that, in the winter in Virginia, it would be equivalent to, or exceed, what my 50 watt solar panel could produce. It costs about 2/3 of what another solar panel would cost.

On my quick look through the site, I did not see any sort of output curve...

Please note that when a wind turbine outputs 12+ volts at 9mph--that is 12 volts at Zero current:

• Power = V*I = 12 volts * 0 amps = 0 watts

And to charge your battery bank--you need it to output at least 15 volts (14.5 volt battery charging + 0.2 to 1.0 volt diode/rectifier drop + wiring drop).

At what speed will the wind have to be for the system to output 60 watts at 15+ volts--For most HAWT wind turbines, they are designed to output maximum power at ~25-30 MPH. Pretty much a wind storm.

9 mph wind is a "gentle breeze" or A Beaufort scale 3 (Leaves and small twigs constantly moving, light flags extended.)

A 25-30 MPH wind is a scale 6 (Large branches in motion. Whistling heard in overhead wires. Umbrella use becomes difficult. Empty plastic garbage cans tip over.)

And 65 MPH is violent storm at 11 (Widespread damage to vegetation. Many roofing surfaces are damaged; asphalt tiles that have curled up and/or fractured due to age may break away completely.)

And, the problem is that low speed / turbulent wind (wind near ground below ~30') has very little power it in. The power in wind goes with the cube (^3) of the wind speed. And below ~10mph--it does not matter how efficient or large the wind turbine is (talking about real turbines, not marketing numbers).

• 9 mph ^ 3 = 729 units of power
• 25 mph ^ 3 = 15,625 units of power
• 15,625 / 9 = 1,736 times as much power in 25 mph wind vs 9 mph wind

So, without a chart/graph of output current/power at 15 volts--I can not even guess how much power it will output.

Given that info, you really think it would only produce about 6 watts?

Talking about long term average--And, yes, I think that 6 watts long term average for this dual turbine mounted on a less than 30' pole (really should be a 60' tower) is probably overestimating its output.

Now--remember that this is a long term average (over months/year)... And even 6 watts x 24 hours a day (average) is roughly equivalent to a solar panel in 2 hours of winter sun:

• 6 watts * 24 hours = 148 WH per day
• 148 WH per day * 1/2 hours of sun per day * 1/0.77 solar derating = 96 watt panel

So--If this turbine performs well in winter (well=6 watts average power), that would be the equivalent of a ~96 watt solar panel in average winter sun.

It is not unusual for a large wind farm to produce 2% of its name plate rating on an average day (60 watts * 2% = 3 watts).

Not sure if we're talking about the same thing . . . ?

link: http://www.amazon.com/Swan-Type-Battery-Cut-Off-Switch/dp/B001JE32H4/ref=pd_sbs_auto_4

"Want to save wear and tear and possible shorting of your battery cables when servicing your car? Then install one of these. Most mechanics now disconnect the battery to perform any maintenance on most cars these days to avoid shocks. the constant disconnecting and tugging / bending of the cables can lead to failure and shorts.

This device avoids all that. Long used by owners of collector cars and the like, the disconnect takes seconds to install and cutting battery power is as simple as turning the little wheel. Some switches have a small "lifeline" cable that allows only a trickle of power to keep your engine's computer alive while the main power is shut off. "

I was typing about this:
Blue Sea Battery Switch 1-2-OFF 350 Amp
Blue Sea 9001e 350 Amp Battery Switch Make-before-break contact design allows switching between battery banks without power interruption Ignition protected - Safe for ... mounting Meets American Boat and Yacht Council (ABYC) requirements for battery switches 3/8"-16 tin-plated copper studs for maximum ...

What you posted was a nice way of disconnecting a battery without using a wrench... Not a bad thing in itself--but there are some dangers with using this type of disconnect (or any disconnecting battery posts/cables too).

1. this is right next to the battery--you have to be very careful to not have a spark light off the hydrogen gas in the battery cells themselves. Battery explosions can be a very nasty thing. (a remote switch like above reduces the ignition hazard).
2. disconnecting the battery when everything is "Off" is one thing. With solar and wind connected, this can be the equivalent of disconnecting the battery with the engine running. In a car, if you disconnect the battery while the engine is running, the alternator output can easily go over 12 volts (even as high as 120+ volts). You run the risk of destroying your car's electronics/lights/etc. Disconnecting a wind turbine (or possibly even a solar charge controller) while charging and having other 12 volt items connected can over-volt. That is why I was trying to talk about turning off your loads (disconnecting from battery) vs simply disconnecting the entire battery from the chargers/loads.

Don't feel bad asking questions about what I (and others) type here... There is always the possibility of miss-understanding on my or your side. And since we are dealing with electricity and batteries--We need to be 100% clear in both our understandings before anything is done.

This will probably save you money on mistakes, and also keep you safe.

-Bill