solar and wind turbine controller

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Sailingsaves

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Is this controller any good?

Whilst tinkering, I made a circuit that attaches to my bank of batteries.

When the voltage drops to about 13.1V, the controller 'opens' a relay and allows the current from solar panels and turbines to charge the batteries.

I have LEDs to let me know what is going on and over-ride switches.

When the voltage reaches 13.68 volts, the controller 'tells' the relay to dump the current to a suitable dump instead of to the batteries.

The voltages mentioned above can be changed, but I have chosen to keep my batteries at the specified float charge.

This was easy to make, but is it any good, does it do enough, what differences are there compared to purchased controllers?

Thanks in advance for any replies from those more knowledgeable than I am.
 
My first thought is that disconnecting at 13.68V seems very low. It appears that your batteries are always fully charged and you only every need a float charge. If that isn't the case your setup will probably never get them back to full charge. I see that you can adjust this voltage sounds potentially workable, though I'd need to give it a little more thought.

Could you supply a little more information about use, battery type and charging regime? It might help with feedback.
 
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Mistroma said:
My first thought is that disconnecting at 13.68V seems very low. It appears that your batteries are always fully charged and you only every need a float charge. If that isn't the case your setup will probably never get them back to full charge.

Could you supply a little more information about use and charging? It might help with feedback.
Click to expand...

13.68V is the specified float charge for the batteries. Any higher and I'd be entering equalisation mode or thereabouts.

When I disconnect the charging system, the batteries rest at 12.8 volts for days, so they are being charged aren't they?

I thought "float charge" was the charge required to keep batteries tip top (too high a voltage and gassing and too low and they won't be fully charged? Is that right? Cheers) EDIT - should have said, these are leisure batteries, not crankers such as those on a car where the alternator will charge at 14.5 V

The batteries are used for doing various things; powering soldering irons, inverter, lights...

The voltages I have chosen are such that (during a sunny day at least) I can take out 4 amps (not a lot I know, but just testing the system at moment) and 4 Amps will be simultaneously going in from the solar panels, (so batteries don't flatten).

At night, the voltage may drop below 12.7Volts as current is used, and if not windy, not a lot of current will be put back in - until daybreak.
 
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Manufacturer states 15.48V for an equalization charge for my batteries, yours will certainly be lower but a lot higher than 13.68V.

Think of your batteries as a bucket of water 3 feet high with a small tap right at the bottom. Water wants to gush out as soon as you open the tap. You are trying to fill it up with a small pump barely able to pump 3 feet up from the ground. To make matters worse, the filler pipe has a Y junction and a fair bit of water isn't even pumped to the bucket.

That's roughly what you are doing. Using even a few small devices overnight will drop the battery from 100% more quickly than you expect. Putting electricity back at 13.68V only achieves a slow charge for a flooded lead acid battery that's around 90% charged. Inefficiency at that state of charge also means a lot of power is actually wasted. I expect you will need to raise the voltage for the cut-off point by quite a lot (see other posts).

Raising the cut-off voltage will charge more quickly but control will be pretty crude when trying to get to 100%. Difficult to give much advice with so little information more would help.

e.g Battery size, solar bank size, wind gen. size & type, boat's location, type of sailing etc.

Your system will have no means of reducing or increasing charge, just reacting to voltage by turning on or off. It might work reasonably well in some situations but not be OK in others.

If you have a 1,000W solar and keep a small boat in the med. the control issues won't be the same as a 50 footer in Scotland with a Rutland 503 and 10W solar panel. Two extremes and I guess you will be somewhere in between. :D:D:D
 
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SS why not imitate the voltages and charge rates of established controllers ? I think you are re-inventing (meritoriously) the wheel.
 
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RichardS said:
You need to get any lead/acid battery up to around 14.4V before dropping to a float voltage of around 13.8V.

Anything lower and it won't ever be fully charged.

Richard
Click to expand...

The info I have is that the batteries must not be charged at above 13.68 V (except for equalisation).

If they are not being fully charged, why after months of use in the manner described, do they rest at 12.8 volts for days? (That (and not 12.7v) is the specified full charge voltage for this battery)

Banner Bull batteries I have used also and max volt charge was specified (by the manual) as 13.6 or 13.8 and after months of use they all rested for a week at 12.7 volts. So to my way of thinking that meas they are being fully charged?

Plevier, guru and knower of all things battery-wise, what is right and what is wrong?

Sarabande - I am talking about a controller that I can make by the dozen (for all my mates that are as penniless as me) for less than £2. I have a Ctek 5.0 for my car batteries. I don't know what other solar and wind controllers do (and certainly can't afford any) to compare to, as you sensibly suggested. The £5 ones on ebay from China have had some dreadful reviews, so no point trying to emulate them.

This site states 2.3V per cell (that's 13.8 v for a battery) :
Maximum service life; battery stays cool; charge temperature can exceed 30°C (86°F).

Slow charge time; capacity readings may be inconsistent and declining with each cycle. Sulfation may occur without equalizing charge.

If a battery I am using never drops below 12.7 volts, but always stays above 13 volts (even when under use), then surely I am looking after the battery really well? (As long as I equalise it now and again)

http://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

My aim is to provide float charge (actually, Banner manual calls 13.8V the maximum normal charging voltage - except for equalisation times - and does not call it the float charge) to a battery all the time (even when under load) to maximise longevity of battery. Equalise now and again for health. (the controller has twiddly knobs to allow me to make changes). Even very good deep cycle batteries do not like being discharged to 12.5V (according cpc farnell engineer) and hence my project.

I can also do constant current charge if I like for a few extra quid, but I don't know a lot about that yet and figure it is best to get as many amps into the battery at a maximum of 13.8 or 13.68 V (depending upon battery) to keep it fully charged.
 
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Sailingsaves said:
The info I have is that the batteries must not be charged at above 13.68 V (except for equalisation).
Click to expand...

I've no idea where that's coming from but it's incorrect I'm afraid.

A lead/acid battery will not start to charge until the voltage is 13.8 which is why this is the float voltage. However, at this voltage, or close to it, it will take a long time to charge which is why the normally accepted optimum charge voltage is 14.4V, after which the voltage should quickly be dropped to float level.

You can charge at any voltage between 13.8 and 14.4 but the closer you are to 13.8 the longer the charge will take.

You can charge above 14.4 but need to watch for excessive gassing, electrolyte loss and overheating which is why it is less common.

Richard
 
The info I have is that the batteries must not be charged at above 13.68 V (except for equalisation).
RichardS said:
I've no idea where that's coming from but it's incorrect I'm afraid.

That is the max charging voltage (not float charge ) for THE particular batteries that I own. Costs £500 new, but I bought it second hand for peanuts.

A lead/acid battery will not start to charge until the voltage is 13.8 I've no idea where that's coming from but it's incorrect I'm afraid for some batteries which is why this is the float voltage. I've no idea where that's coming from but it too is incorrect I'm afraid according to the manual with the Banner Bull batteries. They call 13.8 the MAX charging voltage However, at this voltage, or close to it, it will take a long time to charge Er, yes, that is what I have already quoted from Cadex (the man who made his millions from battery chargers and now lives in Canada) that: "This site states 2.3V per cell (that's 13.8 v for a battery) :
Maximum service life; battery stays cool; charge temperature can exceed 30°C (86°F)" I also stated my main aim was for battery longevity. which is why the normally accepted optimum charge voltage is 14.4V, after which the voltage should quickly be dropped to float level. That voltage will simply gas off my batteries = dangerous and wasteful of electrolyte

You can charge at any voltage between 13.8 and 14.4 but the closer you are to 13.8 the longer the charge will take.Yes, as I stated in post #8, so we are agreed.

You can charge above 14.4 but need to watch for excessive gassing, electrolyte loss and overheating which is why it is less common. And not good for the longevity of a battery - that being my main aim.

Richard
Click to expand...
 
Getting some information in bits & pieces. Now know it is some type of Banner battery and it costs £500 new, sounds like a large battery at that price (or several batteries if you meant them rather than it). Could be Gel, AGM or flooded or even something more exotic.

Might 13.8V be the maximum float voltage charge, rather than the maximum for normal re-charging? Just a thought. On most sailing boats it is undercharging which is usually more of a worry than overcharging.
 
Sailingsaves said:
The info I have is that the batteries must not be charged at above 13.68 V (except for equalisation).
Click to expand...

This is very odd.

What type of battery , lead acid, AGM or Gel etc, and which range of Banner Bull batteries are we talking about ?

Do you have a link to this info ? You refer in post #8 to a Banner manual.

I cannot find anything which suggests this limit on charging voltage, in fact Banner include the common range of Ctek chargers in their list of suggested chargers. These, of course, charge 14.4V (14.7 for AGM batteries) before reducing to a float charge at 13.6 V
 
(battery stats from manufacturer at end of post)

A lot of thread drift here an discussion of battery charging voltages rather than a controller that can be varied to allow current into a battery at an upper and lower level. Hopefully the pdf docs will satisfy.

The original post was: "Is this solar and wind controller any good?"

I was questioning my controller features and benefits. Sarabande made a good point, but I don't have any super dooper controllers that can be purchased for boats to compare to, hence the question to those of you that possibly do own such controllers.

But, tested on current battery (see details below) I can draw 1 amp continuously (24 hours) and 40 W of solar panel via my controller will give a max voltage into battery of 13.68 volts and then switch to dump mode, and if battery voltage drops to 13.1 V, the controller directs charge to battery again.

The battery has not dropped below 12.6V (it reaches that at about 2am in the morning when it is dark) and by noon 13.68 Volts and over 1 amp is usually going back into battery.

But for those interested in arguing / discussing battery specs.
http://www.enersys-emea.com/reserve/pdf/EN-V-IOM-005_1012.pdf

"To commision, charge at 2.27V per cell = 2.27 x 6 = 13.62 V"

On battery is printed float charge max = 13.68V

Full charge status of battery is 2.14Vpc x 6 = 12.84 V

http://www.enersys-emea.com/reserve/pdf/EN-VFT-PD-010_1012.pdf
http://www.enersys-emea.com/reserve/pdf/EN-VFT-RS-017_0615.pdf
https://www.osibatteries.com/p-2300...ed-lead-battery-12v-101ah-front-terminal.aspx

Plevier stated that this battery is not good for deep cycling and I use it in my garden for low cycle benefits and to act as a buffer mainly never dropping below 12.6V

I have 2 Banner Bulls:
Bottom of this pdf states:

"Charging voltage ²) max. 13,8 V"
"²) Recommendation with an external, voltage-regulated charge"

https://www.batteriesdirect.ie/magento/media/wysiwyg/PDF/95901.pdf DATA SHEET FOR THE BANNER BULL AS VICS sensibly suggested. Max voltage printed near bottom of document.

Equalisation Voltage is allowed to be above 14 volts, (I read that on another Banner website), but as you can see, the max charging voltage is recommended as 13.8 volts.

So many batteries and so many different regimes. Hence my controller that allows the truly intelligent (i.e. informed humans as opposed to electronics alone) to change the upper and lower limits to suit the spec of battery and allow dumping (for windturbine use).

It does what I want for now, but I still have no idea if it is any good for the use of boat owners (all my tests are landbased) because the discussion went off to whether I had stated my charging voltages correctly.
 
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Wind generator controllers often are short circuited (= a stop switch) when the battery is charged. Otherwise they freewheel at possibly VERY high speeds. Some will eventually throw blades off they go so fast.
 
Chalker said:
Wind generator controllers often are short circuited (= a stop switch) when the battery is charged. Otherwise they freewheel at possibly VERY high speeds. Some will eventually throw blades off they go so fast.
Click to expand...

My controller diverts the wind turbine to very high resistors automatically (what I have called the "dump").
 
RichardS said:
Charging and care guidelines for Banner "Energy Bull" deep discharge batteries:

https://www.roadpro.co.uk/userfiles/PDFs/product information/Batteries/Banner Batteries FAQs.pdf

Richard
Click to expand...

I thought you were out?

You previously stated: "You need to get any lead/acid battery up to around 14.4V

But you link states "The boiling / gassing point of a Banner Energy Bull battery is 14.5V"

So I guess you are posting to agree with me?

I already posted the data sheet in post #14 https://www.batteriesdirect.ie/magento/media/wysiwyg/PDF/95901.pdf for my battery (it is NOT a gel battery as my link shows clearly) with the maximum charge stated as 13.8V, so why post a link that does not seem to back up your previous assertions that I should be charging at 14.2 V etc? A little confused as to why you posted again, therefore.

But thanks if it was just to confirm that you agree I have my voltages correct for my particular batteries. Much appreciated.

More to the point, how does your controller work on your expensive and well equipped catamaran?
 
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