I am trying to run small 24v 200w water pump on solar panel.
To prevent pump from damage I would like to cut off power when voltage is insufficient.
I did try multiple solutions with PWM Solar charge controller and set of two 12v batteries conected in series to get 24V .
Solar charge controllers suppose to do exactly that - cut off power when voltage drops - say below 22 V or so .
But all solar charge controllers detect 12/24 v automatically this days.
When I connect fresh battery they do detect properly 24v but then when voltage drops they detect 12V and keep running!
I did damage already few deep cycle batteries because controllers keep discharging 24V bank to 10 volts then cut off.
I wonder if anybody come with solution how to cut off power below 22V ? using relay ? zenner diode or something that will over ride those stupid solar charge controllers? Or advice solar charge controller that works.
I did try many bought on eBay and all comes with same fault - keep discharging battery till complete damage.
I think problem is universal and many camper users also may use 24V system , not 12V.
I will be grateful for advice
So Marco are you using one of these Chinese controllers with the pump on the load (light) output? https://m.ebay.com.au/itm/30A-12V-24V-PWM-Solar-Panel-Battery-Regulator-Charger-Controller-AU-STOCK-LD296-/232164658946?_trksid=p2385738.m4383.l4275.c10&_mwBanner=1
Youcan program the hysteresis (cut out and start up) voltage. You're saying that it drops further and then decides it's a 12volt converter and switches in the luad again? Ii f so I'd firstly be concerned with draining your bank that much. But anyhoo I would personally avoid 24v like the plague. You will save money by going 12v appliances and using a battery balancer to compensate for the uneven draw from the bank.
24v is horrible and expensive shxt. If not I have used said controllers (just not in 24v load) and they work well
There is a lot of different ways to do it and I am far from the expert but I thought a relay that trips at say 13V or 20V or whatever?
Use a solid state relay and a trim pot to modify the signal voltage so it turns on and off at right time????
You need an electronics guru, its a really simple question for them. Or google...... arstechnica.com/civis/viewtopic.php?f=11&t=1205415 and an electronics person
I'm only guessing.....
Mathew where are u
Select to expand quoteMark _australia said..
There is a lot of different ways to do it and I am far from the expert but I thought a relay that trips at say 13V or 20V or whatever?
Use a solid state relay and a trim pot to modify the signal voltage so it turns on and off at right time????
You need an electronics guru, its a really simple question for them. Or google...... arstechnica.com/civis/viewtopic.php?f=11&t=1205415 and an electronics person
I'm only guessing.....
Mathew where are u
Yes, that what i thought and did try. Solid State relay but later realized that are mainly designed for AC current. They will wll start conducting fine but later do not release when stearing current is disconected. so they do switch on DC but later do not switch off.
I ordered now DC-DC solid state relay ( but it takes a month to arrive ( from China of course) .
I am sure that for any electronic person this must be very easy to answer how to make a simplest circuit / device to cut off voltage.
I am sure that many of you also want to protect their camper-van batteries.If that solar Chinese controller had a manual switch - 12 / 24 v problem will be solved easy. Their automatic detection is useless.
Select to expand quotemyusernam said..
www.redarc.com.au/voltage-sensor-24v
Yes, that could be it. but the price is a bit high for such switch. Solid state relay 30A cost $6 and Zener diode - $0.75
so such device cost less then $10 to make
I am also a bit concerned because in description they again mention that sensor works for 12 v and 24v !!!! application,Can not be right , because I want only for 24V
You want a Low Voltage Disconnect, Search for a LVD, the 24 volt ones are going to be more expensive than the the more common 12v ones. Your $10 home made one won't work, you can make your own but need a few more components than that.
If you know your way around a soldering iron:
www.jaycar.com.au/universal-voltage-switch/p/KC5377 - (I think I have one of these controlling my vacuum pump by using a MAP sensor)
If you know your way around Arduino you could also setup something to sense the voltage using a voltage divider and switch whatever you need.
The Arduino stuff is much more fun as the electronics are pretty simple and the code then allows you to modify things around a bit.
Macro, are you handy with a soldering iron? I'm happy to draw up something simple for you with an adjustable level if you want.
*edit*...Just saw Formula Nova's post. Why wouldn't you just buy that? Adjustable hysteresis sounds perfect to prevent continual start/stop on days of marginal sun.
You're right about those products sold by the solar companies. I've had a look inside some of them...charging $100+ for something that should be $20.
Select to expand quoteFormulaNova said..
If you know your way around a soldering iron:
www.jaycar.com.au/universal-voltage-switch/p/KC5377 - (I think I have one of these controlling my vacuum pump by using a MAP sensor)
If you know your way around Arduino you could also setup something to sense the voltage using a voltage divider and switch whatever you need.
The Arduino stuff is much more fun as the electronics are pretty simple and the code then allows you to modify things around a bit.
A bit sad that I could not buy such already soldiered, of the shelf . On another hand I spent already much more time that 1 hour needed to soldier this kit.
BTW now is 10.30 AM did disconnect all controllers , batteries and plug solar panel directly to pump.
Work perfectly, pumping plenty of water but need a human now to turn the switch when the sun goes out.very temporary solution, but cattle are happy for now.
Yes, I need to learn this Arudino robotics stuff. Hobby farm is fantastic place for ideas. I have already satellite internet and wifi cameras with 24/24 access from anywhere , smartphone or computer.
Next project will be : remotely opened gates. I am sick of coming out ATV to open and close paddock gates. Sliding remotely operate will be perfect. But first is water for animals.BTW way nobody guess what I am not converting to electric . A tractor. Small Chinese tractor failed V belt transmission in first hour. So I found that electric motor will be ideal. Hopefully lithium batteries comes down in price due to EV growing popularity.
Make sure your solar panel is mounted high enough so that the cows can't get to it. They are very inquisitive and like to scrape their heads on the corners of things,... like solar panels, controller boxes, meter boxes, etc.
Also, make sure no electric cables are in a position where cows can chew on them. They love to chew on chewy things, like electric cables.
Oh,..and get rid of that Angus and buy in some Hereford or Hereford cross. Angus are lazy sods and can't be othered foraging. They just wait around for food to be delivered. Herefords are better at foraging for themselves.
I'm glad I don't own a farm. There would be wifi enabled Arduino boards everywhere. You could monitor the water and turn it on and off, all without really needing something so complex.
What about bluetooth tracking for the cows? I'm sure someone has already done that. You could then individually feed them using the bluetooth tag to tell you if they have already eaten.
Select to expand quoteFormulaNova said..
I'm glad I don't own a farm. There would be wifi enabled Arduino boards everywhere. You could monitor the water and turn it on and off, all without really needing something so complex.
What about bluetooth tracking for the cows? I'm sure someone has already done that. You could then individually feed them using the bluetooth tag to tell you if they have already eaten.
GPS Tracking is great idea , that I research already . The problem is that all GPS locators require Mobile SIM to work. Till now I could not find GPS locator that works on WiFi alone ( Bluetooth is not an option) because too short distance for location.I am not going to pay for SIM card and mobile account for every animal tracked.
But I am looking also for RFID - or similar device to identify and register.
For example I could install RFID readers at gates between paddock, water, food etc On every pass I could run automatic program applying : spray against fly, some medicines pour on, even install scale and register weight automatically on every pass.If data goes directly into database / spreadsheet I could see complete picture of every animal ( like growth in weight etc) .If you know about RFID tag or Bluetooth that I could clip to cattle ears and some software to read let me know.
Macro
You sure you have wired up the controller correctly for it to detect 12v/24v ?
At 12v battery connected the controller will turn off the discharge from the battery at about 10.5v and turn off the charge from the panel at about 14.5v
At 24v it will do the same job around 21v and 28v.
So if your 24v battery drops to say 20v the controller wouldn't recognise it as being a 12v battery. It would only recognise it as a 12v battery if it dropped to around 14v, which your 24v battery would never do as the controller stops discharge below 21v.
Provided you plug your battery in at 24v in the correct sequence so the controller first recognises it then it shouldn't be an issue.
I've got a couple of controllers very similar to the one in the link and they works fine for me in plug and play mode on 24v or 12v.
Could you post a picture (or diagram) of how you have it connected to the battery and pumps ? and in what sequence you turned everything on ?
Select to expand quoteMacroscien said..FormulaNova said..
I'm glad I don't own a farm. There would be wifi enabled Arduino boards everywhere. You could monitor the water and turn it on and off, all without really needing something so complex.
What about bluetooth tracking for the cows? I'm sure someone has already done that. You could then individually feed them using the bluetooth tag to tell you if they have already eaten.
GPS Tracking is great idea , that I research already . The problem is that all GPS locators require Mobile SIM to work. Till now I could not find GPS locator that works on WiFi alone ( Bluetooth is not an option) because too short distance for location.I am not going to pay for SIM card and mobile account for every animal tracked.
But I am looking also for RFID - or similar device to identify and register.
For example I could install RFID readers at gates between paddock, water, food etc On every pass I could run automatic program applying : spray against fly, some medicines pour on, even install scale and register weight automatically on every pass.If data goes directly into database / spreadsheet I could see complete picture of every animal ( like growth in weight etc) .If you know about RFID tag or Bluetooth that I could clip to cattle ears and some software to read let me know.
WIFI user tracking is already established in the WIFI industry. They use this to work out when customers are near shops and try to target them with ads specific to that shop. They also try to enable bluetooth to improve the locating accuracy.
With enough access points dotted around the place you should be able to triangulate them easily enough or have them at the boundaries only.
This feature may only be on business grade WIFI access points though.
WIFI devices are becoming so cheap that I wouldn't be surprised if you could buy a device powered by a battery that would be useful.
Bluetooth LE is becoming very common and you can buy the tags from ebay sellers for almost nothing. The clever bit is in the receiver. It seems that vendors lock their software down to only work with their tags (using the MAC addresses?), so finding cheap tags and receivers/software might be challenging.
I wouldn't be surprised if Carantoc's suggestion uses these. (edit: I just checked and its using RFID)
I don't think RFID has the range you are after, but I could be wrong.
Give them all WIFI so that the sheep or cows can chat and skype amongst themselves... Internet of Cows.
Select to expand quoteCarantoc said..
Macro
You sure you have wired up the controller correctly for it to detect 12v/24v ?
At 12v battery connected the controller will turn off the discharge from the battery at about 10.5v and turn off the charge from the panel at about 14.5v
At 24v it will do the same job around 21v and 28v.
So if your 24v battery drops to say 20v the controller wouldn't recognise it as being a 12v battery. It would only recognise it as a 12v battery if it dropped to around 14v, which your 24v battery would never do as the controller stops discharge below 21v.
Provided you plug your battery in at 24v in the correct sequence so the controller first recognises it then it shouldn't be an issue.
I've got a couple of controllers very similar to the one in the link and they works fine for me in plug and play mode on 24v or 12v.
Could you post a picture (or diagram) of how you have it connected to the battery and pumps ? and in what sequence you turned everything on ?
That how it suppose to work. When I wired everything over weekend and observed for two - three day everything works fine. But when left for whole week unattended arriving next weekend I found all batteries died and water tanks empty. Three consecutive weekends the same. Recharge battery, run again , next weekend all discharged completely.
I they could just produce 24V version of that solar controller , there will no room for error. Will cut off load at 21 volts every time. Even smallest manual micro switch could do . Why they keep doing auto smart detectors if they simply didn't work every time - only from time to time. Deep cycle battery bank could be quite expensive to replace, but this $30 cheap Chinese crap that make mistake recognizing voltage could ruin everything.Temporary I run different solution: 12V timer swith the run the pump 8 am to 5 pm, no battery at all Straight from solar panel. It somehow works so far. so I have still battery 12 V only to run timer switch, solar panel than run pump directly.
I have been thinking to el eliminate battery completely and maybe use supecapacitors instead.But supercapacitors are 2.7V max so need at least 12 pieces in serial for safety.
Altought I am not sure if supercapacitor arranged in serial may require balancing BMS like lithium batteries,
The cheapest option could be use cheap lithium 16850 x 7 batteries but again this BMS is required.
two such banks of 6 should be enough to replace 24V lead acid battery to run pump on solar charge controller 24v
If you are plugged directly into the panel why would you use a timer ? Just makes things more complex for no apparent reason.
And the problem doesn't seem to be the battery so why try to solve that ?
Problem (apparently) is the controller. I have two of these :
Had them about 3 years. Both work fine straight out of the box. They have loads of settings but I just used as plug and play, never fiddled with anything on them.
Right now one is on a 12v panel / normal supercheap auto car battery (not a deep cycle one) / water pump for horses / shed sink.
Other is on 12v panel / electric fence energiser (DakenAg or Speedrite can't recall) / old 12v battery from my tractor which I replaced (but problem turned out not to be the battery and it still works fine on the fence). I have this set-up in an old esky and also use it as a jump start battery for everything that doesn't start, so have extra output terminals connected directly to battery as well as the fence charger coming through the controller. That way I can flatten the battery trying to jump start something if I so choose.
One used to be on 24v battery in another tractor that I also ran lights off in my shed. Hardly every used the tractor so just had panel to controller, controller to tractor battery and controller to shed lights all on Anderson plug so I could disconnect whatever and drive off if I wanted.
I've never had an issue. I never changed any settings when I went from 24v to 12v. And they cost $10 not $30.
You sure you have it wired like above, with the pump where the bulb is and you don't have anything other than the controller connected to the battery ? So just one +ve wire and one -ve wire from battery to controller ?
(and you also connected the battery to controller BEFORE you connected panel to controller or pump to controller ?)
(and a 24v solar panel for a 24v battery ?)
**edit : can't believe your solution to "cheap Chinese crap" is to replace a simple and robust system using an Australian bought battery with more "cheap Chinese crap". I'll give those capacitors 3 months exposed to farm conditions. Terminals will corrode with cow piss or something.
that on purchased specially to run 24V pump. You are right $33 for 3pcs
pump
I should buy the pump version for 12 v to avoid this problem in first place, but my solar panels are 270W provide higher voltage 37 v max ? , may not be efficient to load 12v battery without another DC-dc inverter.
Ideally if pump could have such over and under voltage protection inbuild. So no other controller is required. But apparently my pump trying to work when the sun is dying and also works like crazzy at full day on my 37v Max panel. So i decided to add battery bank to extend life of the pump.
