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Forum Index : Electronics : relay problem on charge controller
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| irishron40 Senior Member  Joined: 22/09/2014 Location: IrelandPosts: 251 |
hi. i have build this charge controller and was working fine untill i bought a 180 watt solar panel. once solar panel supplies about 20 volt the relay starts switching extremely fast on and off. it seems the 12volt relay cant handle this higher voltage. would a 24 volt relay work.not sure if it would operate also at 13 volt the low trimpot is set at 13volt and the high trimpot at 15 volt here is the link of controller I build. http://www.thebackshed.com/windmill/articles/TL084-Controller.asp thx |
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yahoo2 Guru  Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
relay chatter is usually caused by not enough energy being supplied to the coil to hold it against the spring tension. usual causes are low voltage, poor connections, overheating or damaged coil or a heavy load robbing power from the relay. The only other things I can think of is the diode that is across the relay coil in the circuit might be faulty and causing a voltage spike. or a poor connection somewhere in the circuit is stopping the battery from charging or the electronics from seeing the correct battery voltage. that could make it rapidly cycle, especially if your high/low setpoints are quite close. I'm confused, no wait... maybe I'm not... |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
What battery are you using? How good is its condition? If the battery is weak, 180 watts could cause the controller to switch quickly from charge/dump mode. To confirm, try setting the controller to 12 and 16 volts, and see if that slows down the relay clicking. The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
its a brand new battery. it only happens when the solar panel supplies 20 volt and over.i did hear that a 12 volt relay coil would over heat and start burning out by voltages over 18 volt. i have 2 batteries connected paralel |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
The relay and rest of the circuit is powered by the battery, so should never go much above 15 volts. So no way should the relay ever see 20 volts. Just wondering how you have the controller set up. If it was me, I would have connected the solar panel where the windmill bridge rectifier is show in the circuit, and dispensed with the dump resistor as its not needed for solar. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
thx, pin 85 and 86 are connected to the 2 wires form veroboard which indicate relay coil. pin 30 is connected to + of solar panel pin 87a is connected to + from battery and + from veroboard pin 87 is dumpload which i dont use thx |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
180 watts at 12v is 15 amps, and that can result in some serious voltage drop across the wires from the battery to the relay 87a contact. As you are also connecting the controller to the 87a contact, its going to be affected by this voltage drop. Chances are the controller is measuring something like 20 volts, while at the battery its only around 14 volts, so the controller is switching the relay off. Ideally, the controller needs to be connected directly to the battery terminals, so its measuring true battery voltage. I would connect the controllers positive and negative input directly to the battery terminals, and see if that fixes it. The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
ok thank you Gizmo. I will try that |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
just thinking Gizmo. the battery doesnt show 20 volt. it happens when the supply from the solar panel reaches about 20-21 volt. I still think that the problem is whith the high voltage going into the relay(pole 30)as its a 12 volt relay. and normaly could take upto 130% of its rating.which would be about 16 volt. any higher the coil would get hot and burn out. correct me if i am wrong please. thx |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Hi, A 12V battery -can't- show 20 V, the most you see if its really really fully charged is around 14.5V. Think of a 12v battery like a sponge, it can hold only so much water (charge) no matter how wet you try to make it. Your solar panels -should- put 20V to the -input- side of the controller. You -must- power your relay from the output (battery) side of the controller. Klaus |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
yes according to these 2 diagrams it shows input to veroboard is from battery. it shows input from turbine is or solar is connected thru the relay. now Im confused. its working fine untill solar panel gets full blast sun and supplies 20 volt and over. 
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Pretty confident if you connect the controllers Batt+ and Batt- directly to the battery, it will work. In your post you said "pin 87a is connected to + from battery and + from veroboard", meaning you have two wires going to the 87a contact. Ideally, this should be at the battery, otherwise the controller input voltage, which it uses to monitor battery voltage, will be affected by a voltage drop in the wire from the battery +ve to the relays 87a contact. At 15 amps in full sun, this voltage drop could play havoc. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
ok I will give that a try Glenn. no harm in trying. but I am also still concerned about the relay getting fed 20+ volts. its only a 12 volt rated relay. thx ron |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
ok changed it so that + from veroboard is going strait to battery. I also connected my volt meter dirrectly to battery. I did notice that voltage reading was a little lower now. so far no rattles. I keep it like this for an other day to see did it really fix the prob. I now also understand that this way the coil get less voltage. Fair play to you Glenn. I think you have proven right. AGAIN lol |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
well glenn. that did seem to have sorted the problem.. I only didnt get a chance to run a separate neutral. I also lowered the low trimpot to 13 volt. now it may only click once every 5 min. thx very much for your help. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
When you said you had connected both the battery and the controllers + input to the relay contact, I knew that would be the problem. The wire between the contact and the battery will show a voltage drop along its length when the panel was switched on, and this could be a couple of volts for a 180 watt panel, depending on wire thickness and length. Therefore the controller would see a voltage much higher than the actual battery voltage when the panel is switched on, so it switched the panel off, and so forth. The solution was to put the controller as close as possible to the battery terminals, or use very thick wire. I'll add a note to the page about the controller when I get some time. Glad its working OK now. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
thx glenn is there also a need to run a separate neutral? i didnt do that yet |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Ideally yes, but if its working OK now, no need to bother. If you upgrade the panels at a later date, do it then. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
ok thx glenn.much appreciated |
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| irishron40 Senior Member Joined: 22/09/2014 Location: IrelandPosts: 251 |
I might pick your brain once more. I am new to electronics and still learning. I bought on of these http://www.ebay.com/itm/DC10-30V-120W-Max-PWM-Motor-Speed-Controller-w-Reversing-Switch-CCM2U6-/321455273916 and have connected it to my old power supply . I have a bridge rectifier after the transformer. I wanna use it as my variable power supply. when i set output to 12 volt and connect a small motor rated 2 amp, the voltage drops to about 9.5. how can I overcome this. or is this normal when the rated output from power supply is 3 amp , and motor 2 amp. I have a range from 3 to 23 volt dc now. transformer I used was from a 3-5 amp rated power supply. thank you. |
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