Neebie tearing his hair out and dont have much !

[yorkat]

Hi

Just joined. First post ,please be gentle !

Hi.

Am in uk

I bought a 50w solar panel and a controller and an inverter a few months ago.
I also got a 12v 74AH Bosch battery second hand .

I wanted to run my small pond water pump (25w) by solar rather than mains.

Having watched some videos I put it all together and turned it on. Although not a very sunny time of year it worked straight away and last about 40 mins. I tried it again a couple of days later with similar results.

I then left it a while until we got longer periods of sun. Excited to see how long it may work for now , I recently tried it out again.

Now as soon as I plug the pond pump into the inverter and turn it on I get the error noise and have to turn it off again. I have done a fair bit of fiddling with the controller settings so they possibly are no longer the same as when it worked. However I have also tried just attaching the inverter to the battery and I get the same error noise.

I can connect a usb to either the panel, controller or inverter and each time it charges the device attached.

Although research suggested my equipment could cope with a pond pump ( and it was working) I wondered if somehow it was the pump so I tried attaching a coffee machine to the inverter and again I get the error noise and it turns the coffee machine back off.

I have a usb hub which has a 3 pin plug and when I plug that into the inverter it works and stays on.

At one point I wondered if it was the battery so I bought a cheap 12v one. It's made no difference .

I will try to list as many things below as possible but as a newbie may be missing some details.

25w pond pump
50 w solar panel
Solar controller
Bosh 12v battery 74AH
Lucas 12v battery 7AH
Inverter input Dc12v output ac 200-240v 50hz

The inverter has an on/off switch and two three pin socket holes and 4 usb sockets. It has a display which is currently showing DC input 12.3 and AC output 220. (Green led on )

Settings on controller

First screen shows panel icon and arrow going to battery (currently 12.6v)
Second screen showing battery icon at full 14.4v
Third screen shows 13.0v going to load
Next screen shows 10.7 v (atomatic turn off ?)
Next screen is on 24 hrs. ( I have tried reducing down to 1 or 2)
The last screen is battery type and showing 61 which I think is correct and was at that when working.

Both the pond pump and coffee machine work fine when plugged into mains electricity.

Any advice much appreciated

Alan

 

[Mattb4]

Do you have a DMM to measure battery voltage? Both the pump and especially the coffee maker are sufficient loads that if the battery is less than fully charged the resulting voltage slump is likely creating an inverter low voltage error and shutdown.

A 50W panel is very marginal for keeping a 12v 74ah battery charged. 50W/12v=4.2A if it is working at 100% (and it is not) 74ah/4A=18.5 hours for fully discharged to be recharged. Your supplemental 7ah battery has so small of capacity that a big enough load could easily draw voltage down to inverter low voltage point.

The reason it worked initially was you started from a full battery and overtime the incoming PV did not keep up with loads causing the battery discharge.

Try charging your 74ah battery with a plug in AC to DC charger. Once full (if battery not damaged) I expect you will be able to run the pump for the 40 minutes again.

 

[dustyPanels]

I'd like to see the video you were using for inspiration. Also you get credit for having an idea and then taking action to make it happen.

Alas, you are going down the same unfortunate path that others have taken to learn about solar energy, batteries and equipment.

Starting with the battery, most folks don't know that solar systems use Deep Cycle storage batteries. They are designed differently than the starter batteries we use on our vehicles.

A starter battery won't be able to handle being a storage battery. It will lose capacity each time you discharge it and recharge it back.

A deep cycle battery will endure more charge and discharge cycles. But if you read about lead acid batteries, you will learn that they will endure more charge and discharge cycles if you only use half of the stored power before you recharge it.

So you need to select a deep cycle battery with twice enough storage to do what you want. That includes all the extra appliances you might be tempted to add when the system is working .

A LiFePo4 battery will be more efficient than a lead acid battery, but they are less forgiving if not configured properly. It's easy to destroy an expensive LiFePo4 battery with the wrong voltage settings.

You also need to account for the power that the charge controller and the inverter will use just to operate. I suspect they are using more power than your pond pump.

Once you determine how much power you are using in 24 hours, then you can think about how big a battery you need. If you want the system to function even when the weather is cloudy, then you have to multiply your 24 hour figure by how many days you want to cover.

Another power loss is how efficient your battery happens to be. Charging a lead acid battery isn't 100% efficient. It will require more power going in than it will give back. I don't know how efficient they are, I just keep charging until they are full. In some cases you could lose almost 30% of your power going into the battery. A little research will give a better answer.

After you figure all of that, you will be ready to figure out how many watts of solar panels you need. But remember that you will need to be able to recharge your battery and power your loads before the panels stop producing for the day. I'm certain you will need more than 200 watts to do what you want. Perhaps a lot more if your equipment consumes more power than your pump.

So is your pump really using 25 watts?

How many watts are your charge controller and inverter using?

As others have said, you could recharge your battery with an automotive charger and then test if your inverter and pump are still working.

 

[yorkat]

Do you have a DMM to measure battery voltage? Both the pump and especially the coffee maker are sufficient loads that if the battery is less than fully charged the resulting voltage slump is likely creating an inverter low voltage error and shutdown.

A 50W panel is very marginal for keeping a 12v 74ah battery charged. 50W/12v=4.2A if it is working at 100% (and it is not) 74ah/4A=18.5 hours for fully discharged to be recharged. Your supplemental 7ah battery has so small of capacity that a big enough load could easily draw voltage down to inverter low voltage point.

The reason it worked initially was you started from a full battery and overtime the incoming PV did not keep up with loads causing the battery discharge.

Try charging your 74ah battery with a plug in AC to DC charger. Once full (if battery not damaged) I expect you will be able to run the pump for the 40 minutes again.

Thanks for replying i Will try that on the 74 ah battery. I don't have a DMM but do have a charger. I did try charging the battery but maybe I didn't leave it on enough. Totally newbie but the second reading on the controller seems to indicate battery at 14.4 v and the full icon . I was faking that as battery is full ?

 

[yorkat]

I'd like to see the video you were using for inspiration. Also you get credit for having an idea and then taking action to make it happen.

Alas, you are going down the same unfortunate path that others have taken to learn about solar energy, batteries and equipment.

Starting with the battery, most folks don't know that solar systems use Deep Cycle storage batteries. They are designed differently than the starter batteries we use on our vehicles.

A starter battery won't be able to handle being a storage battery. It will lose capacity each time you discharge it and recharge it back.

A deep cycle battery will endure more charge and discharge cycles. But if you read about lead acid batteries, you will learn that they will endure more charge and discharge cycles if you only use half of the stored power before you recharge it.

So you need to select a deep cycle battery with twice enough storage to do what you want. That includes all the extra appliances you might be tempted to add when the system is working .

A LiFePo4 battery will be more efficient than a lead acid battery, but they are less forgiving if not configured properly. It's easy to destroy an expensive LiFePo4 battery with the wrong voltage settings.

You also need to account for the power that the charge controller and the inverter will use just to operate. I suspect they are using more power than your pond pump.

Once you determine how much power you are using in 24 hours, then you can think about how big a battery you need. If you want the system to function even when the weather is cloudy, then you have to multiply your 24 hour figure by how many days you want to cover.

Another power loss is how efficient your battery happens to be. Charging a lead acid battery isn't 100% efficient. It will require more power going in than it will give back. I don't know how efficient they are, I just keep charging until they are full. In some cases you could lose almost 30% of your power going into the battery. A little research will give a better answer.

After you figure all of that, you will be ready to figure out how many watts of solar panels you need. But remember that you will need to be able to recharge your battery and power your loads before the panels stop producing for the day. I'm certain you will need more than 200 watts to do what you want. Perhaps a lot more if your equipment consumes more power than your pump.

So is your pump really using 25 watts?

How many watts are your charge controller and inverter using?

As others have said, you could recharge your battery with an automotive charger and then test if your inverter and pump are still working.

Thanks for replying.
I'm going to try reconnecting the 74ah battery after recharging it . It's a basic charger so maybe I didn't leave it charging long enough last time.
Someone locally has also suggested that the inverter itself maybe pulling too much power ?
Will update in a couple of days.
Thanks again for your help

 

[Mattb4]

Thanks for replying i Will try that on the 74 ah battery. I don't have a DMM but do have a charger. I did try charging the battery but maybe I didn't leave it on enough. Totally newbie but the second reading on the controller seems to indicate battery at 14.4 v and the full icon . I was faking that as battery is full ?

If you are going to be setting up your own power supplies you really should have a digital multimeter (DMM) for checking polarities, voltages and connections. Using voltage readings from chargers and devices can be helpful but may not always be accurate. Especially since hooking them up wrong can damage them.

Now when it comes to lead acid batteries. Voltage readings can be a bit deceiving as to capacity. You can find that a battery is showing full charge voltage but it is only a surface charge and once you load it it drops like a rock. So you compensate your voltage test after charging with a load placed on battery to see how badly the voltage slumps. Good batteries will hold a working voltage.

 

[yorkat]

Bit of an update. Am doing this in stages hoping that it may mean more to someone than me.
As was suggested I charged the 74AH battery with the charger overnight.
I then set the system up again.
Battery first which showed up as 14.4 when connected.
I then connected inverter to battery. Turned it on and off all good
I then attached the panel and again all good. Panel icon showed up and with arrow going to battery icon. In sunny parts of day reaching 13.8 and falling back to just over 12 as sun was going down.

I tested usb again all fine.
Then tested a usb hub with a plug and again fine.

To change things slightly I then tested with a table lamp which was 12w. Again this works fine. Showing about 12.2 on the inverter display.

I disconnected the lamp but left the inverter on . About an hour later the inverter reading was down to 11.8 and have checked it a couple of times since and it is slowly going down.
Before trying to attach the water pump I thought it best to check a couple of things first.

Is the inverter display reducing when nothing is attached normal or does it mean something

It could be complete coincidence but I have checked the display on the inverter and controller several times during the day and the two figures each time are virtually identical. I understand the controller one reducing as the first display is the strength of the panel but was surprised the inverter was reducing and seemingly at the same rate as its attached to the battery which I charged.

Any thoughts much appreciated and I will delay attaching the pump until I hear back

 

[SunDave]

Sounds like the battery is weak. The inverter being turned on even with nothing attached could still use quite a bit of battery power.

For a rough example, let's say the inverter uses 40 watts just to run itself. That would mean you would have about 10 hours of nothing plugged in until the battery was dead. That is if the battery is in good shape, and there is no solar input.

In this example, the battery could not run the inverter all night, with nothing else plugged in, even if you charged the battery each day with the panel. Since the panel is 50 watt rated, and in reality is pulling less, it's possible that there is just not enough power left over to run anything.

Your initial run of 40 minutes was because your battery was fully charged. Once in use, your draw exceeds your charge, so it will only work until the battery is drained again.

 

[OhYou_]

It has a display which is currently showing DC input 12.3 and AC output 220. (Green led on )

what does it change to when you turn on the pond pump

 

[yorkat]

Sounds like the battery is weak. The inverter being turned on even with nothing attached could still use quite a bit of battery power.

For a rough example, let's say the inverter uses 40 watts just to run itself. That would mean you would have about 10 hours of nothing plugged in until the battery was dead. That is if the battery is in good shape, and there is no solar input.

In this example, the battery could not run the inverter all night, with nothing else plugged in, even if you charged the battery each day with the panel. Since the panel is 50 watt rated, and in reality is pulling less, it's possible that there is just not enough power left over to run anything.

Your initial run of 40 minutes was because your battery was fully charged. Once in use, your draw exceeds your charge, so it will only work until the battery is drained again.

Thanks . By accident I left the inverter on without any devices plugged in and it started the alarm going off at 10pm. Cannot remember exactly when it will have been left on but am guessing it was early afternoon

 

[Mattb4]

Thanks . By accident I left the inverter on without any devices plugged in and it started the alarm going off at 10pm. Cannot remember exactly when it will have been left on but am guessing it was early afternoon

Looks like you proved your battery is of diminished capacity and on its way out. It might be recovered some by doing a full equalization charge. While true that you lack enough supply (batteries are not supply they are storage) to keep loads and battery working it is also true that lead acid batteries can be damaged by being too long at a low state of charge.

More PV and a new battery is recommended.

 

[MikeInKingman]

If your Charge Controller has USB ports on it, it is a Pulse Width Modulation(PWM) Charge Controller...almost certainly(regardless of any claims to be MPPT that it might make).
This means to get any real charging of your setup, your Solar Panel needs to be putting out at least 5v more than your battery voltage.
I don't think you are going to get where you need to be with a 50w panel.
Even if it IS putting out 17v under load, that would be at just under 2 amps.
Which would mean even with the 74ah battery, you'd only be able to shove about 20ah of charge back into it in a day....and that's assuming a perfect 10 hours of charging, at 2 amps per hour...which you won't see.

 

[45North]

If the pond pump is DC and only runs in daytime, why not run it directly from the panel? You save on the conversion efficiency and if it's off overnight and cloudy days, does it really matter?

 

[yorkat]

Plugged 5he pond pump into the inverter today and no instant alarm !
It was pretty cloudy at the time and the solar panel to battery figure and figure on inverter again we're very similar and dropped at same rate. Only left it on for about 5 mins and it had gone from 12.1 to 11.7 (as had the panel)
I've ordered a battery meter as the figure on the controller just stays at 14.4v. I thought that was the battery level but possibly isn't?

 

[SunDave]

The controller may say a higher charge because that is what it is attempting to charge at. It has to get the solar panel voltage above the battery voltage for charging to occur. Even if slowly.

The simple issue for your setup is that your inverter and pump draw more power than your solar panel can make.

 

[yorkat]

Battery monitor arrived.
Checked it twice and it's showing 100% and 12.3v
Tomorrow I'm going to run the pump and see if it works and if so how long it lasts. Have a free day so can keep a close eye on readings etc

 

[yorkat]

Turned it on and it lasted about 5 mins before the alarm went off and it stopped. Have no idea what's happening.Left it a few hours and same again

If the pond pump is DC and only runs in daytime, why not run it directly from the panel? You save on the conversion efficiency and if it's off overnight and cloudy days, does it really matter?

I like the sound of that but the pond pump has three wires , live,neutral and earth ?