I looked up the specs on Fluke's web site. In the DCVolts mode, the input impedance is 10megΩ, meaning that the leakage in your battery bank which is "earthing" the bank is pretty high. Probably just moisture on the surface of the battery cases


Setting up a charge controller is a science unto itself, and the best authority is the company ("Siyuan"?) that supplied your batteries. If you don't already have it, visit their web site and download the product manual specific to your batteries.

If you suspect you have a bad battery, use your fluke to measure each 12V battery in your series string. If you see one of the 12V batteries that has a terminal voltage of ≈11V instead of ≈13V, then you might have a bad cell in that particular battery. At any given state of charge, all of your 12V batteries should have nearly the same terminal voltage; a difference from battery to battery is a sign of trouble. While doing this, look for a broken case. I suspect this could be where your battery bank is finding its mysterious ground.

Just to be clear (ala Omaba), when the battery voltage is ≤ 240V, pin 3 of the 555 goes HIGH, and the relay pulls in. It stays pulled in until the battery voltage ≥ 260V, at which point pin 3 of the 555 goes LOW and the relay drops out. Look at the updated simulation I have attached.

I updated the diagram to reflect some of the issues we have been discussing. Note the size of C3. With 13Vrms on the transformer secondary, if this capacitor is smaller than 470uF, the unregulated voltage sags below the dropout voltage of the LM317, and there is much ripple on the 12V line!
This depends on the resistance of the 12V relay. If your relay's coil resistance is higher than 120Ω, then C3 could be smaller.

Attached Thumbnails

 

 

Hello Mike,

On your first point concerning the batteries and their "earthing" problem, you could be right about the damp causing the power to leak. I'm restoring an old stone built farm, and the electrical equipment is located in one of the outbuildings (a pigsty). The batteries are in a large insulated case, but even so the damp seems to penetrate in spite of the ventilation. At first glance the fluid levels seemed OK but I haven't checked everything thoroughly. One thing that did catch my attention was that all the terminals seem to have turned white with some sort of mold over the cold winter months. I'll try cleaning it off and also checking out the voltages in case there's any faulty cells.

Thanks for the revised schematic. The circuit I've built is exactly the same except that the relay I have is only 6v and so I have pin 3 connected to the base of a transistor that triggers the relay at a lower voltage. Yes, it all works. The capacitor for the LM317 is 1000uF so it should be OK; the voltage is up at 12v and the relay toggles alright when the power is turned on.

I have since wired in a cable to bring 230VAC into the wind turbine controller to power the transformer. I've also installed another cable going from the controller across to the power input panel for the house where I've mounted the two relays; one to switch the house over from the national grid to the inverter output and the other to act as the toggle. I should be able to get the installation finished tomorrow and see how it works in practice. I'll keep you posted.

 

Hello Again,

Well the 555 circuit is finally in place in the wind turbine controller. It seems to be wired up correctly because there were no sparks or explosions today. The voltage division resistors are mildly warm, but apart from that nothing else is getting hot or smoking. It's mounted in a plastic case just to be safe; the trim pots are mounted on the side with knobs attached. At the moment the relay is pulled in keeping the load (the house) tied to the inverter/battery bank. There's a fair amount of wind here at the moment and so the batteries keep on charging. I can't say if yet the new circuit triggers when the batteries run low on energy.

After the 555 circuit was put in place I took a good look at the battery bank. I dismantled the cables and took all the batteries out from the case. I noticed quite a bit of damp where the batteries had been sitting. Could this have been the cause of the energy leak? I don't know if it was acid or condensation but I has now made a wooden lattice to keep the batteries off the case floor and to allow better ventilation. The terminals were white with some mild corrosion; they're clean now and all the batteries are back in the case and reconnected to the system. I checked the battery voltages; every one was somwhere between 12.3 and 12.7 volts. None of the twenty batteries were down in the 11 volt region so I assume all are OK for the time being.

I took a current reading from the battery bank cable and it showed that the batteries were being charged. Obviously the inverter and the house were taking less load than the incoming power from the generator. It seems unlikely that the inverter is drawing a high current and causing the problem. The system is up and running at the moment and all I can do is to wait and see if the batteries hold out any longer.

 

Hello Vielle,
I only saw this thread today for the first time and i am right into making my own wind generators. That 3kw downwind turbine of your from china is something a mate of mine is looking at to buy himself. I have sort of read through this whole thread but missed some important infomation.

Ok you say this is a 3kw turbine... What voltage does the generator is it 3 phase AC and does the chinese controller rectify the generator output.

You did say you had 20 12 volt batteries in series for 240 volts DC. what inverter do you have that takes a 240 volt DC input as I've never heard of such a beast and that kind of high DC voltage is lethal. A 12 volt battery is fully charged when it's 13.8 volts which is 276 volts on a 240 volt DC batterybank. Also if you want your batteries to last I'd suggest not taking them under 12 volts.

As far as using a servo for furling I'd throw the thing as far away as you can, the blades should self regulate the blade speed or a simple rpm sensor could short the AC windings with no harm done. Another solution if possible is installing a disk brake on the rear of the alternator and when a preset speed is attained the brake can engage. This feature can also stop the generator when a huge storm is approaching.

I have made my own charge controller using a LM358 Opamp and 2 169amp fets in parrallel to dump any excess load when my batteries are full and the genny is going flatout.

If you would like some help I'd be glad chime in mate

Cheers Bryan

__________________
" The only way to avoid human error is to avoid the use of humans"

 

Hello Bryan1,

The system I have does not rectify the output current. I have twenty 200Ah batteries (acid filled cells) that are connected in series to form the battery bank; these are charged by energy from the wind turbine and from some solar panels. These pass through a controller that has a couple of functions: First it signals when the batteries are above or below voltage (but does nothing to rectify the situation. Second it is connected to a dogvane and an anemometer that are used to control a servomoter that turns the generator into the wind.

The output from the controller is fed into an 50Hz sine wave inverter and the output is connected to the house. I've been gaining help from this forum to build a control circuit to switch from the wind turbine system to the national grid when the batteries are low and to reconnect when the batteries have sufficient charge.

The Chinese company make many different models of wind generator, solar panels, batteries and all the necessary equipment; the prices are very low and they have a lot to offer. It is a big company too, so don't feel nervous about purchasing from these people; I had no trouble with my order, all the equipment was delivered to my door in France. If you wish to contact this company for more information then here's the information you need: The contact engineer is called Cary, mention my name, Bryan (like you), the company name is Wuxi Kingship, and Cary's email is :
windpower02@gmail.com

It is not possible to add a disc brake behind the hub on this generator so I'll have to rely on the current design. I'd be interested to see your design for the excess load dump.
Thanks

 

Message to MikeMl,

Hi Mike, The batteries appear to be working a lot better after the clean up treatment yesterday. They were reading just a few volts down after last night (248v from 252v). Previously the batteries would dive to below 230v overnight and the system would crash. The system's running as it should be and the 555 controller seems to be functioning correctly.

Thank you once again for all your help in this project.

Best wishes, Vielle568

 

Hey mike if you would could you post or send me your schematic for your battery charger, so that i have something to work off of with my project?

 

If you look back on the first page of this discussion you will find a copy of MikeML's schematic.
Vielle568

 

ok, thanks. i am in contact with him on the subject.