Author Topic: battery sizing  (Read 4216 times)

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johnnym

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battery sizing
« on: December 22, 2016, 08:48:40 AM »
I have a question about batteries. This has been the most confusing thing so far with this wind turbine project.

The alternator is called "550 Watt SCS PMA 48 VOLT DC 2-WIRE Wind Turbine Permanent Magnet Alternator" (actually I think mine is rated at 875) so what 12 v battery would go well with this? My plan is to buy one 12 v golf cart battery and use it for 3 or 4 light bulbs for 24 hours a day. Once I get used to how this stuff works through hands on learning I want to add more batteries and solar panels for more power. I found some cheap 12 v batteries online rated 12v35amps. Would this type of battery work for what I am wanting to do here? It seems from what I have read online people tend to use batteries with a lot more amps. They are also a lot more expensive.

I am hoping that this turbine will be able to at least work good enough to power three 60 or 100 watt light bulbs. I have the tilt up tower up. It is 22 ft high. The wind here is erratic because of the terrain. It is either no wind or very high winds and sometimes of course mild winds so the power coming in is going to be very little or very high. I am sitting here typing this and hear the wind right now - the whoooosh noise. This is normal in my area.

The charge controller is supposed to handle up to 10,000 amps. What would also be a good inverter for this setup? If I added more solar panels and batteries would I have to buy a different inverter? I know that is a lot of questions and may be confusing. I am confusing myself trying to explain it, lol. I would appreciate it if someone could help me out here. This stuff is new to me. Thanks

I tried to attach a picture but it is 2 large to post.


Mary B

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Re: battery sizing
« Reply #1 on: December 22, 2016, 05:30:00 PM »
Modified car alternators are a scam and produce little power... unless you have gale force winds!

electrondady1

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Re: battery sizing
« Reply #2 on: December 22, 2016, 08:28:26 PM »
welcome to the forum johnny m
 you need a photos resizing program to fit a photo .
your windmill is up and spinning now ?
do you have a volt meter?
as Mary said converted alternators are less than ideal.
power output claims can be exaggerated.
i don't charge batteries but most here do.
you need to give information on the charge controller. if it's 48 volts your would need 4 batteries.




Adriaan Kragten

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Re: battery sizing
« Reply #3 on: December 23, 2016, 01:58:57 AM »
The minimum size of a battery is determined by two criteria. 1) The number of wind less days you want to bridge for a certain power consumption. 2) The current which a half full battery can absorb untill the maximum charging voltage is reached. I assume that your battery is equipped with a voltage controller and dump load which limits the maximum charging voltage op to 2.3 V per cel, so up to 13.8 V for a 12 V battery. Such device is needed to prevent that a full battery is over charged and that you will loose all water or that the battery becomes too hot. If your battery is small, this maximum voltage will be reached already at a low current and most of the power generated by the windmill will flow into the dump load, even if the battery isn't full. More information about this subject can be found in chapter 2 and 3 of my free report KD 378.
« Last Edit: December 23, 2016, 02:04:24 AM by Adriaan Kragten »

DamonHD

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Re: battery sizing
« Reply #4 on: December 23, 2016, 03:14:58 AM »
Note: even my reasonably-sized lead-acid battery bank is unable to absorb a 'normal' full charge at the moment because the battery bank is cold (in a shed).

That is another factor you may need to consider.

Rgds

Damon

johnnym

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Re: battery sizing
« Reply #5 on: December 23, 2016, 07:44:53 PM »
If it is rated at 48 volts but would I really need 4 12v batteries? If I have a dump load then it would work right? Is it possible to burn out a dump load? They seem to be very cheap. The cheap ones are around 10 - 30 bucks. I know the PMA is under-rated. It seems they tend to rate them at watts for extreme wind conditions. The wind here can be between 30-40 mph at times but of course that isn't consistent.

This is the instructions. The instructions for my model are pretty much the same.

http://www.hydrogenappliances.com/Hornetassembr.html#anchor1486296

I appreciate you all giving me advice because I don't know much about this stuff. It seems like it is gonna be a financial burdening trial and error lesson.

Adriaan Kragten

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Re: battery sizing
« Reply #6 on: December 24, 2016, 01:43:10 AM »
If your wind turbine is rated at 48 V, you may expect that the matching in between rotor and generator is good for the average charging voltage which is about 52 V. Good matching means that the Pmech-n curve of the generator for 52 V lies close to the optimum cubic line of the rotor (for matching see my free report KD 35 chapter 8 ). If you connect your wind turbine to a 24 V battery, the average charging voltage will be about 26 V. The Pmech-n curve of the generator for 26 V will lie very much left from the curve for 52 V (for measured characteristics of a PM-generator for different voltages see my free public report KD 78 chapter 4 and 5). The matching for 26 V will be very bad because the rotor will run at a much too low tip speed ratio. This results in a very low power output. So you must use four 12 V batteries to get a nominal battery voltage of 48 V.

If you use only small batteries, the maximum charging voltage will be reached already at a low current but if you have a voltage controller and a dump load which limits the maximum charging voltage up to 55.2 V, the windmill will run fine. However, a lot of power will be dissipated in the dump load. So for the windmill generator there is no difference if the current is flowing into the dump load or into a big battery which absorbes a much larger current at the maximum charging voltage than for a small battery.

The price of a voltage controller plus dump load depends maily on the maximum power which can be dissipated. Never use voltage controllers which are designed for solar panels in combination with a wind turbine because those voltage controllers have no dump load and can therefore be rather cheap. What they do is to disconnect the solar pannel from the battery if the charging voltage becomes too high. Then the solar panel goes to the open voltage which is about 40 V for a 24 V panel. But if you would do the same for a wind turbine, the open voltage can easily become 100 V at high wind speeds for a 24 V wind turbine and this high voltage will blow the electronics in your voltage controller. Another disadvantage of disconnection of the generator from the load is that the wind turbine will turn unloaded and so it will produce a lot of noise and the high rotational speed of the rotor may be dangerous.

If the batteries are full, only a little power will flow into the batteries at the maximum charging voltage. So the dump load must be chosen that large that it can dissipate the maximum power of the wind turbine. If the dump load can dissipate a large power, it must have large cooling plates or heat sinks to transfere the heat to the surrounding air. The area of the cooling plates can be reduced if the dump load has a fan but the noise of a fan may disturb you. So I would prefere a big dump load without a fan.
« Last Edit: December 24, 2016, 02:11:20 AM by Adriaan Kragten »

bigrockcandymountain

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Re: battery sizing
« Reply #7 on: December 24, 2016, 06:01:46 AM »
To put this in perspective, three 100w light bulbs will use 7.2 kwh per day if they are on 24hrs.  That is a huge amount of power. 

I have a roof full of panels and will have a twelve foot diameter turbine that weighs literally a ton and could just barely cover that much power. 

I would consider trying to run an 8w led light 24hrs.  That should get some education started.  (it has to be a dc light, otherwise you need an inverter) 

Yes, you need four 12v batteries and a dump load.  Batteries can be as large of as small as you want them to be.  The 12v you mentioned are likely 35ah rated so four of them will run your 8w led for 105 hours at a 50% discharge of the batteries.  It will run two 8w lights for 52.5 hours etc. 

They would run your 3 100w bulbs for 2.8 hours!

Adriaan Kragten

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Re: battery sizing
« Reply #8 on: December 24, 2016, 07:52:10 AM »
The give some information about battery charge controllers, I have just have made public the manual of my 27.6 V, 200 W battery charge controller om my website: www.kdwindturbines.nl at the bottom of the menu KD-reports (see also my post at controls).

johnnym

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Re: battery sizing
« Reply #9 on: December 25, 2016, 12:02:06 AM »
Ok, some of what you are all talking about is going way over my head. It is hard to believe that I have to buy 4 batteries because the pma is rated at 48 volts. Does it not sound reasonable that I should be able to charge one or two 12v batteries with what I have? My questions may be stupid/ignorant but I am stupid/ignorant with this stuff so I appreciate the help you guys have been giving me.

I am going to attempt to list all of what I have here. I am just copying/pasting each thing here:

     WIND TURBINE WIND GENERATOR 875 WATT 11 blade WIND 48 VOLT DC W/ 130A METER

     12-24V 10,000 Watt 440 Amp THER Digital Charge Controller for Wind Turbine G4

     10,000 watt 440 amp rated Continuous Duty Relay Switch 24 volt draws Solenoid

     40 Amp 600 Volt Stud Blocking Diode

I have yet to get:

     dump load resistor

     12v batteries

     and probably other things that I am not aware of.

I want to make this work for 2 light bulbs now. The led lower watt light bulbs make more sense now. This is for the chicken coop. I figured I should start here because I don't know much about this as I said, lol. I am a complete newb at this.











OperaHouse

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Re: battery sizing
« Reply #10 on: December 25, 2016, 01:33:56 AM »
I could get it to work, don't think many others could get it to work on 12V.  Seems to me there is a whole nuther back story here.  First, you say it is 550 W then now it is 875.  That doesn't matter much because it can likely not produce more than 200W which isn't that much.

Next there is a 24V dump controller.  How did that come about?  Dump controllers keep the speed of the mill from going too high.  That could be thrown on this.  If the mill starts slowing down at 24V or 12V.  It just wastes a lot of power and heats up, that may be OK with small loads.  So, how was all this stuff acquired?  It seems like it is from a defunct company, a deal for what is there for $10.  Still, not a fan of wham bam controllers.

Personally, I love higher voltage.  I would run this into a buck converter to make 12V. These are like a transmission trading high voltage for lower voltage and higher current. 48V is the donut hole for buck converters, but I could make it work.  I modify stuff and build my own designs.

I should say I know nothing about wind.  It looks like totally incompatible stuff if a conventional approach is taken.


electrondady1

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Re: battery sizing
« Reply #11 on: December 25, 2016, 07:25:29 AM »
at this stage i don't think you need to worry about your wind mill .
if you hook your mill up to  a 12 volt battery, the wind mill will be held down to producing  12 volts.
once the battery is fully charged, it will keep pushing the battery voltage up

  i can tell you from experience without a charge controller i once pumped a 12 volt battery up to 39 volts .
that battery is no longer with us .
it's the battery and the charge controller you have to think about .
is there a setting on your charge controller that you can choose 12 or 24 volts ?
if it says it's a 24 volt charge controller you need  two 12 volt batteries.
or 4 x 6 volt
if you had a volt meter you can find out what your charger controller is doing to the battery.
 borrow one from a friend?
don't let it get much over 14.5 volts.
 















« Last Edit: December 25, 2016, 07:29:37 AM by electrondady1 »

Warpspeed

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Re: battery sizing
« Reply #12 on: December 25, 2016, 02:15:49 PM »
Quote
I found some cheap 12 v batteries online rated 12v35amps. Would this type of battery work for what I am wanting to do here? It seems from what I have read online people tend to use batteries with a lot more amps. They are also a lot more expensive.

I am hoping that this turbine will be able to at least work good enough to power three 60 or 100 watt light bulbs.
O/k lets assume these are 12 volt 35 amp hour batteries. 
These will be rated at 35 amp hours, for the standard ten hour discharge period.
That is how battery capacities are rated.

So we can get 3.5 amps for ten hours at a nominal 12 volts out of each battery.   3.5A x 12v = 42 watts.
So ne battery will in theory keep a single 42 watt bulb lit for 10 hours.

Quote
My plan is to buy one 12 v golf cart battery and use it for 3 or 4 light bulbs for 24 hours a day.

Not exactly certain about all this, but I am assuming you need enough battery storage to run three 60 watt bulbs for 24 hours ?    That works out to 3 x 60watts x 24 hours or 4,320 watt hours.
If you do that at 12v you are going to need 360 amp hours of storage.

Probably about ten or eleven of those cheap 35 amp hour batteries will be required to do that.
And they will struggle even when brand new.
You might need twenty of those batteries if you expect the batteries last any length of time.

bigrockcandymountain

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Re: battery sizing
« Reply #13 on: December 27, 2016, 05:51:19 AM »
Electrondady is probably right.  The best way to proceed would be not to worry that the mill is 48v and just hook it up to a lower voltage battery and  take a bit of an efficiency loss.  Since your controller is 24v that would be a good start point.  You'll need to hook two 12v batteries in series (positive of one to negative of other).  I kind of think I know the charge controllers your talking about that auto sense 12 or 24v.  They actually work quite well.  They are all I use on several off grid water pump systems for cows.  The only thing to watch is if they run a 24v bank right down below 12v they will decide it is a 12v system and not charge. 

OperaHouse had an idea about putting a step down converter in the line before the charge controller.  If it works it would be perfect for what your doing as it would let your mill run at it's correct speed and that's a good thing.  Someone more electronically gifted than me can tell you how to set that one up. 

One thing you really need to know is this  Watts= Amps x Volts     aka Volts=Watts/Amps    aka  Amps=Watts/Volts

One last thing, there are lots of very cheap controllers that will turn off the lights in the daytime and on at night, usually combined with a solar charge controller.  Don't make the lights too bright though.  Your chickens might go crazy. 

Bruce S

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Re: battery sizing
« Reply #14 on: December 27, 2016, 10:38:53 AM »
johnnym;
This turbine sounds very familiar.
I will add just a few things, but firstly I have to agree with others.
Don't worry too much about the wind mill over-charging the battery(ies) for now. They wind mill sounds a lot like the Hornet units.
They will not reach their labeled max until you have sustained 20+mph winds.
You certainly CAN connect it to a 12V battery, BUT you will NOT reach the max output of the mill. BUT since this is currently a learning session , that's okay too.
I would however suggest you find some used deep cycle Marine batteries IF you can. These can sometimes be had for less than 1/2 a new cheap battery. I bought 4 that weigh in at 65lbs each for $20/ea.

IF you're using the lights to keep the chickens warm and laying, then you will certainly need standard light bulbs, IF however you are only using the lights to keep them laying then LED or even CFLs will be much easier on the batteries.

WE will need to know if the lights are for heat & light OR just light. This information really is important.

The 10,000 watt charge controller is rated for 24V at 12V it's only 5000 watt. BUT that is way higher then what you will probably acquire at this point.
 I will also add, meters. Meters that can show you the battery voltage. These can be the cheap digital ones that can usually be found at harbor freight for about $3- $4/ea. I prefer the swing needle (analog ) meters since they do not need a battery to work and stay connected to a battery.
Let us know about what the wind speed is, normally IF you have a smartphone, you can get it from places like Yahoo weather for your location.
Woshing sounds can be 10Mph for people used to constant 3mph or 20mph for people used to constant 10Mph.

ALSO: Let us know what OS you're using to post. There's dozens of ways to bring picture size down without spending a dime.

Cheers
Bruce S
A kind word often goes unsaid BUT never goes unheard

johnnym

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Re: battery sizing
« Reply #15 on: December 27, 2016, 11:18:37 AM »
"They wind mill sounds a lot like the Hornet units."

Yes, this is exactly what it is.

"I kind of think I know the charge controllers your talking about that auto sense 12 or 24v.  They actually work quite well."

According to the instructions they can be programmed for 12 or 24 volts.

I will answer all of your other questions later. Gotta go to work. Thanks for the help everyone.


johnnym

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Got a 12v
« Reply #16 on: January 03, 2017, 10:42:51 AM »
Ok I finally got a 12v battery. Can anyone tell me if this would work? If not I am going to take it back.

Duracell Marine and RV 24DC
MCA @ 32 degrees F - 685
CCA @ 0 degrees F - 550
Average mins @ 23 amp draw - 140

DamonHD

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Re: battery sizing
« Reply #17 on: January 03, 2017, 11:21:21 AM »
Would probably be useful to post here a part number if you have one.

Rgds

Damon

Bruce S

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Re: battery sizing
« Reply #18 on: January 03, 2017, 02:46:14 PM »
I'm guessing it's a Group 24.
Druacell is a good name
Bruce S
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johnnym

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Re: battery sizing
« Reply #19 on: January 14, 2017, 09:26:07 PM »
Ok, I emailed someone at the company who sold me the wind turbine this:

"I purchased this but it was rated at 875w 48v. So pretty much the same thing. I have one 12v battery that I am wanting to charge with the turbine. The charge controller I also purchased from you is 12-24V 10,000 Watt 440 Amp THER Digital Charge Controller for Wind Turbine G4. What type of relay and dump load would you suggest? I will be using this all for two 10 watt led light bulbs.

I purchased the "10,000 watt 440 amp rated Continuous Duty Relay Switch 24 volt draws Solenoid" from the seller called wind_turbine_generator but they said it was lost in shipping and gave me a refund. Would this work for what I am wanting to do? I see that you sell the same item.

Any help would be appreciated.

Thanks"

This was the response:

"Hi,  You can't charge a 12 volt battery with a 48 volt wind turbine, it will just bog down and not spin very well.

Wes"

Does this sound right? Basically he is saying that I have to have 4 12v batteries right? I guess I can test it out but I wanted to until I had all of the parts.

OperaHouse

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Re: battery sizing
« Reply #20 on: January 15, 2017, 04:02:09 AM »
"bog down and not spin very well."   That is running.   I never expected it would ever make more than 30W that way.  I could probably make it work with a modified buck converter, but I could never tell you how to do it. It would require a bit of experimenting.

johnnym

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Re: battery sizing
« Reply #21 on: January 23, 2017, 09:03:39 PM »
Ok, with all that has been said I am assuming having two 12v's (24v) would work better than one 12v? As in the PMA would run a little bit better with two 12v's instead of one. I can't afford three more 12v batteries, the battery regulator- relay, dump loads, inverter, cables, etc... The issue here is money. I can afford adding one more 12v battery and the rest of the items I just stated but nothing beyond that.