Charge controllers can contain many things, including meters, fuses/breakers, and even MPPT devices but their main function is to control the way the turbine charges a battery so as to prevent overcharging it.
Solar charge controllers mostly ‘turn off’ or ‘turn down’ the power from the solar PV panels when the battery is full, but most wind turbines (and hydro turbines) need to be kept on load which means the energy needs to be diverted to a heater to prevent noisy over-speeding of the turbine and harmful over-voltage in the wiring.
I have published plans for building ‘dump load’ controllers using relays:
You can also buy controllers that work using relays from a variety of sources. The Morningstar ‘Relay Driver‘ is a software driven version with numerous options including both thresholds and delays.
This relay-based type of controller has some advantages – you can switch AC heaters on and off at grid voltage (via an inverter) or you can switch the turbine over from the battery, directly onto heaters and stall it out into a slow operating speed. The relay is relatively quiet in switching operation (a brief click).
On the downside it requires multiple small heating loads to control the battery smoothly or the voltage will oscillate up and down rather wildly. So you effectively need multiple control boards and multiple loads and multiple wires around the place for smooth charge control.
A much simpler, smoother voltage control can be obtained with a single heating load connected to a PWM (pulse width modulated) solid state controller that you can buy cheaply. These ‘third party’ controllers from Xantrex and Morningstar also have more sophistication. They can adjust their own voltage setting based on temperature and the length of time on charge. These controllers use transistors to switch the heater on and off very rapidly so as to control the amount of power being dumped.
The Xantrex C40 product was originally by Trace Engineering (a great company that got bought out, long ago) and was revolutionary, but is now obsolete. The Morningstar Tristar has much better response in operation, and easier to configure.
Both the Xantrex and the Tristar controller will make a buzzing noise in operation and so will their heating loads. This noise can become an issue with some users. For me it’s the sweet music of renewable energy, but my dump heater is deep in the hot water tank, which damps the sound.
Installing a Tristar controller
Buy a Tristar controller or a Relay Driver
Relay Drivers for load management
i need a note on relay dt is use in charge controller,all d procedure.
Hi I am not sure exactly what you are asking. You can use automotive relays for a 12-V charge controller. You can find more details of the charge controller shown above on my old web page at http://scoraigwind.com/circuits/chargecontrol.htm and in an old FAQ that I did http://www.scoraigwind.com/faq.html#battery_and_charge_control
I hope this helps. Hugh
Hi Hugh – we have a small 500W turbine and also a solar PV array. My problem is that I cannot find a single controller that will manage both sources efficiently. Currently we use a Steca controller for the PV and a little PWM kit controller that looks after the wind. Trouble is it causes misreporting of battery state, and on a day that is sunny and windy, can create issues as the voltage hits it’d top level.
Any suggestions? I did take a look at the Tristar a while ago, but couldn’t decide whether it did one or the other, but not both. I’m also beefing up our PV from 200w to 2kW soon, so the smaller units won’t cope.
all the best
Steve
I am not sure what voltage you are using so it’s hard to know what size controller you need. But charge controllers can work well independently if they have the same or similar settings. One exception is where they try to measure amphours in and out, but that is a rare feature. Otherwise a committee of controllers seems to be a good solution. Or one big one is fine too, diverting everything, if you can find one big enough and suitable loads for it.
Hugh
Hugh, in a similar question:
5 x 236watt polycrystalline solar panels using a PWM charge controller **and** a Sunforce 600watt/30 amp A/C wind turbine using a dedicated MPPT charge controller.
using a single 12v battery bank consisting of 6vdc series connected golf cart batteries for @ 1,000amp hours. a 5,000 watt modified sine wave inverter to provide incidental power take off from the battery array.
My concern is using separate charge controllers, that when the turbine is spinning, it may artifically cause the solar charge controller to read a higher voltage and shutoff the solar panels, or vice versa due to battery interconnect at same terminals. I get the impression that that when both charge controllers are channeling energy to the battery, that one of them is wasted due to the inflated voltage that would appear.
Any thoughts? I was hoping for a smart wind/solar integrated controller that would combine both sources internally before outputting to the battery array. Your comments about the xantrex being outdated technology is appreciated, as i was considering multiple C60 units.
PS: Thanks for writing your book on wind turbines – that is what got me interested in renewable energy.
hi roger,
Yes you may well find that the wind turbine may push the voltage up and turn off the solar PV. However this is not a fault in control. When the batteries are getting enough then you can’t use more. It would be better if the sun shone when the wind does not blow. But when they both come at once you need a big battery or you need to use more power (do the washing).
If you want to maximise the benefits of the wind and solar sources then you need to use the dumped power, or schedule your power use to dump less. Buying a bigger battery is probably the least attractive option as batteries are expensive and short-lived. Using a tristar for water heating is a good way to maximise the benefits.
The Xantrex units work OK but they are primitive compared with the Tristar and they have sluggish response for wind systems.
have fun
Hugh
Hi hugh,
I’m working on a oversized solar/wind project to reduce battery size and winter geektime privation
Let me explain.
First its not mppt, neither pwm. only shunt at the moment wich is not cool
Secondly I’d like to handle as many PV as I want by adding with the needed relay boards. wich is cool
I live in a off-grid place, so I listen to solar pro and bought 800w of solar pannel, a 600w windturbine, a 30A 24v mppt controler and a 275Ah 24v battery.
Most of the time its perfect. but sometime in winter, it can be cloudy and without wind
for weeks.
On mppt controler, its specified X watts max and you can configure the
charge rate so if you dont have a big battery no problem.
But they are expensive, no modular and most of them didnt even monitor and log.
worst you must absolutly have exactly the same panel spec and the same orientation in order to calcul the mpp. so you can forget second hand,or a new brand lower in price to complete your system later.
For exemple with my system, now in winter, with a bright day I only charge 15A. I could add twice the number of panel but in a month, they will produce more than 30A and the controler will likely cut all the input or even die.
So I was thinking to throw my controler away and use a diversion load when batteries are full, just like a windmill.
But, you cant charge a battery at more than 10% of its capacity. So this idea doesnt work as I cant add more panel either.
Well I thought we can use relais to plug/unplug dynamicaly the number
of panel and the windturbine needed to stay the closest to max charge rate as possible (pv and turbine are cheap now, under 1$ /watt so I can by a lot more, than battery and
expensive controler, they live 30 years, controleur 10 and battery even less)
SO in winter, let say I have 3kwc pluged and in cloudy/windless days I charge.
In half season some pannel are pluged the morning but unpluged the afternoon. I charge.
In summer nearly all panel are unpluged but I still charge. full battery @ 8am
As the relay board have 3 holes (common no nf), we can use it to charge the battery or to dump to a load (heating water or being connected to a inverter to get the full 3kw power if we need it)
The relay board would be controled either by a arduino or a raspberry
(I prefer raspi as I can do mesurement, relay control, distant acces, remote webcam etc all in one)
I was thinking to use a tinkerforge voltagecurrent bricklet and a temp sensor as well. this is cheap modulable opensource hardware/software.
Relay board from denkovi (4 8 ou 16 relay, more relay more precise would be the control as we could put les amps on each) so there will be not much electric arc and we avoid the high cost mosfet relay.
Everybody tells me, dont bother,buy a bigger controler, but the point is not here.
The point is to do a as more opensource as possible hardware/software, modular cheap controler either for solar windturbine or hydrogenerator.
What would be cool is also to find a way to use the same inverter, from the battery and from the diversion load, so at day time, we dont use the battery at all. but the problem is that the open voltage will make the inverter suffer for a millisec each time we start using it, and condensator can really help with the battery but not with a open circuit solar array.
Like that a person who want to be off grid can just have a small battery who hold only 1 day of power. Its reducing the initial and maintenance cost tu up to 80% over 30 years of lifetime.
Its greener as battery are not green thing
With a device like this we can give acces to solar to everybody, not only well payd people, and we put less polluant in rivers
We would not be mpp as we will always have enough power and we want non symilar PV and windturbine but a pwm would be good to keep batterys un sulfated.
At the moment it would cost 35€ for the raspi, 22+16+7€ for the tinkerforce masterbrick voltage/current bricklet and temp sensor, 48€ for a 8x relay usb board.
You can already handle a 2800wc solar field/ windturbine separated in 15amps 24v relay. and a 20Amps rcharge rate.
You need to add a 16€ bricklet for each 20amps rate charge slice you need and a 48€ board for each 2800wc you want to handle.
What do you think about that?
Hlw,i am a student studying Electrical and Electronics Engineering II year at Katmandu University Nepal,me and my group are doing project on “charge controller for wind energy system ” we are not allowed to do project underprinciple of PWM or MPPT due to our level of understanding during googling i found this site http://scoraigwind.com/circuits/chargecontrol.htm which i find helpful but i require more and detailed information about the circuit.hope for kind support.
hi Sailesh, Yes I am happy to support your project and answer questions. I am not an expert at electronics but I have designed and built a lot of circuits that work fine for may years.
Have fun, Hugh
hi hugh, i did the course in ireland run by eddie at imecofarm and will soon be making one of your turbines, got the magnets and wire so nearly ready to go.
i also recently bought a liten 1kw turbine aswell, 48v system and 4 12v batteries at the moment. its been running great for a month but i think the controller has blown a resistor and is not switching to its built in dump load in the last day or 2 and i think it went over voltage and damaged the 2500w inverter i had connected. haven’t got it connected in to house permanently yet, have just been testing it out. was not that happy with the controller anyway so am thinking to get one of the controllers you sell, the morningstar or tristar.
maybe you could recommend whats the best way to use the power. prefer the idea of batteries with inverter rather than just heating water.
and give me prices of the controllers
thanks in advance
fergal
hi Fergal,
The most likely reason the controller and inverter would be damaged is that the battery was not connected securely. If there is a momentary loss of connection then the voltage will shoot up and destroy the electronics. The wind turbine can produce several times higher than the battery voltage when disconnected.
Since you already have the batteries it’s a good idea to keep them and get another inverter and controller to convert and manage the power. You can use the dumped power for some useful heating maybe. For the power that you do not use directly by inverter.
Here are up to date prices for Morningstar stuff including VAT:
Morningstar Tristar 3 function 12/24/48V, 45A charge or load € 176.54
Morningstar Tristar 3 function 12/24/48V, 60A charge or load € 234.29
Battery temp sensor & 10m cable € 29.69
Relay Driver € 151.79
shipping € 35.00
In addition you would maybe need resistors.
cheers
Hugh