Thank you. I will get weeding tomorrow. It was completely dry and dead but the rain we have had is unusual and everything has grown like crazy.
Urgent help please
- Thread starter Emm
- Start date
MisterSandals
Participation Medalist
Lets mess with numbers...
7 panels x 31Vmp = 217V
This is easily well into your 120V to 450V MPPT range.
You could wire 7 in series strings twice and then connect the 2 strings in parallel with a simple pair of MC4 Y connectors.
While it sounds like you have plenty of solar with your existing setup, you could spread out your charging by facing one 7 panel string east-ish and the other west-ish. One would start charging earlier and the other charges later in the evening. Maybe useful if this helps your daytime energy use pattern.
Its odd and disturbing that an installer would not put all 14 panels to work.
Honestly. The installer was just some bloke off Facebook. I know I know! I am a woman, my husband has had to leave to work in England. I live on a Spanish island and I am alone up here in the mountains with my two boys. Okay so I am not an idiot. I was kinda desperate to get power but now it's all gone bad I will learn everything I need to to sort it out myself.
I have learnt so much over the last two weeks! And learning more every day.
So, I rewire the panels in two strings of 7, clear the weeds, I have changed all of the charging parameters and wait and see. If in a couple of days everything is still bad, try to charge individually, try equalisation, if all else fails replace the batteries, but not the inverter.
MisterSandals
Participation Medalist
Yurtdweller
Solar Enthusiast
There is a lot to learn. I started with a single 100 watt panel, and have been learning and upgrading for 8 years. It's gotta be tough to jump right into a 3kw system. If you choose to replace your batteries, and don't want to go with LiFePo4, I'd recommend AGM batteries. I never ran more than two 12v agms in parallel, so you're already beyond my expertise with 8 batteries in series. I've since switched to LiFePo4 that I assembled myself into four seperate 12v sets, built from 16 individual cells, but that is also a steep learning curve. Not for a beginner. You might also try buying a single 48v LiFePo4 pre-built, off-the-shelf battery which can easily be scaled up. While lead batteries should be all purchased together, LiFePo4s are more tolerant to being purchased over time. Although the interval should be kept to a minimum. This would give you the option to try it out before going all-in. Good luck
Thank you. I have already been looking at possible upgrades. My budget doesn't allow for any at the moment. I had to get a loan to manage this set up. Obviously if the batteries are already done for them I need to figure something out. But I will give it a few days and see what happens. I have turned the inverter off for the night to hopefully give the batteries a chance tomorrow with the new settings. We will see I suppose.There is a lot to learn. I started with a single 100 watt panel, and have been learning and upgrading for 8 years. It's gotta be tough to jump right into a 3kw system. If you choose to replace your batteries, and don't want to go with LiFePo4, I'd recommend AGM batteries. I never ran more than two 12v agms in parallel, so you're already beyond my expertise with 8 batteries in series. I've since switched to LiFePo4 that I assembled myself into four seperate 12v sets, built from 16 individual cells, but that is also a steep learning curve. Not for a beginner. You might also try buying a single 48v LiFePo4 pre-built, off-the-shelf battery which can easily be scaled up. While lead batteries should be all purchased together, LiFePo4s are more tolerant to being purchased over time. Although the interval should be kept to a minimum. This would give you the option to try it out before going all-in. Good luck
Quattrohead
Solar Wizard
Also that fuse holder is absolute junk, please replace it with a properly rated circuit breaker of 100/125 amps and make sure it is rated for DC.
MisterSandals
Participation Medalist
Okay will do. Also, the solar array to inverter does not have any circuit breaker and I am pretty sure it should have. Mixed readings from Google that I am struggling to comprehend.
MisterSandals
Participation Medalist
I am not familiar with that fuse holder. But, if its not warm or hot, it should not be a cause or related to this battery capacity issue(s).
Last edited:
On that now
stienman
Mostly Harmless
- Joined
- Jan 6, 2021
- Messages
- 476
Thank you for all the detail, and reporting back about what you're trying! This is going to be long because that's just how I am, and I apologize in advance for the wall of text.
Let me summarize your system so we can think about it and what's going on.
Solar power:
12 250w panels is maximum 3kW energy when in direct sun.
5kW MPPT charge controller in the all-in-one inverter
8A maximum current on the string and wiring going to the inverter
No fuse or disconnect - so the only safe way to work on this is at night. (consider adding a disconnect and 10A fuse in the future)
Don't know what size wire is being used, or distance to the array. If it's thin wire (14awg, 16awg, etc) and/or long distance you'll lose some power, but since it's a high voltage array the loss won't be significant.
On a long sunny day you can expect them to generate 10kWH to 24kWH of energy, depending on a variety of factors. Foliage, overcast, rain, dust/debris will all reduce power output.
Inverter/MPPT charge controller:
5kVA inverting capacity
This is pretty much the same as growatt and several other "value" inverters. They have their quircks, but mostly work pretty well. The one thing that I've discovered is that the MPPT controller is very sensitive, and prone to failure. If your installer wired up all 14 panels to test on a sunny day, the MPPT controller is fried. The symptom of a fried Growatt/etc all in one MPPT inverter is that the solar panel voltage will equal the battery voltage. So during the day check the solar panel voltage using the inverter's interface and verify that the panels are about 370V.
Battery:
8 UP-GV600-6RE.pdf cells
424AH at C10 (ie, 42A) draw
Trickle/float charge voltage: 6.9VDC/cell, 55.2VDC pack
Bulk charge: 7.4VDC/cell, 59.2VDC pack
Nominal voltage: 50.4VDC pack
The pack will hold less than 21kWH
Gel batteries have good deep discharge characteristics, however they will last longer if only discharged to 50% depth of discharge. This is about 48.72VDC, and means you'll only be using about 10kWH of the pack's capacity - assuming it's in good condition. If it's already damaged then you might be able to count on 5kWH to 8kWH of usable capacity to avoid further deep discharge degradation.
Damage will occur under 48.72VDC, but it won't be really hurt unless it drops under 46.5vdc
Your battery cutoff voltage was 43V, and since you don't have grid power the "back to grid" voltage does nothing for you. So you have been drawing the batteries down into the danger zone, and they have been damaged. Gel batteries, however, are very resilient, so unless you've been doing this cycle for months you probably still have a significant amount of capacity left.
Load:
Daytime ??? over 8 hours
Night 200W over 16 hours
I understand you're calculating the time it's actually dark, but the panels won't generate much power until the sun is within 45 degrees off perpendicular from the panel, and you're not going to get much more than 8 hours of that. This is all very ballpark, though, every installation is different and without solar survey data I can only guess.
Note also that while you may only be consuming 200W overnight, the inverter could be consuming as much as 65W as well. Lastly, the inverter is not 100% efficient, nor are the batteries, and the wiring also has some losses. All together you're only going to be able to use about 80%-90% of the actual solar energy that the panels generated during the day.
Two things you can quantify here to help diagnose the issue is to find out how much power you're actually generating, and how much you're actually storing. Getting two power meters with AH measurements will help you with this. The solar array is high voltage, so you'll need a 500VDC meter, such as this one https://www.amazon.com/Wireless-Charging-Capacity-Detector-Coulometer/dp/B0948NTML1 , for the solar power side, and you can get a cheaper one, such as one of these https://www.amazon.com/Charge-Discharge-DROK-Voltmeter-Watt-Hour-Multimeter/dp/B07YWVCBRN for the battery side. I chose these because while they require you to disconnect cabling to put the cable through the sensor, and you still have to wire + and -, you don't have to come up with another cable and connection to connect a shunt. This type isn't as accurate as a shunt type, but you're not doing laboratory measurements, you just need a general idea of how much power you're generating and storing. While I've linked to the amazon listings, these are the cheap generic models you'll find from many places, so you should be able to get something very similar at a low cost.
These meters provide voltage, current, and more importantly they measure how many watt hours of power moves through them. So you can look at both at the end of the day and know that your solar generated 10kWH, the batteries stored 3kWH, so you probably used 7kWH during the day - about 720w for 8 hours after losses and inverter consumption - and now only have about 3kwh/16h = 187W to use each hour overnight, and with the inverter using 30w - 60w you might only have 130w you can use overnight. With a 10% loss for conversion and wiring losses, you're looking at 110w if you want to drain your batteries down to 50% overnight - and this is all assuming the batteries are not damaged and can still hold 20kWH of power fully charged.
You should be able to get some of this from the inverter - kwh produced (from solar panels) and discharged (from batteries), by day, and total over its lifetime. You can also use the inverter's current and voltage measurements - write them down several times a day collecting the battery voltage and current, and solar voltage and current - and this will give you some insight into your power in and out. If you solar panels are hitting 250V and 6A on what you would consider a sunny day then they are only generating 1/2 their possible power. You can then investigate shading concerns, tilt/angle, system/wiring losses, inverter settings, etc. If your MPPT charge controller inside the inverter is bad it'll have a 54V and 8A output, and your panels will be generating just over 400W - 1/7 what they're meant to output, and you'll get 4kWH - 7kWH on a sunny day. It's not a small amount, but it won't charge your batteries much, and they'll run low quickly when the sun goes down.
Note, however, that the inverter's internal measurements are inaccurate. It's probably within 10% of the actual reading, but don't take its reported values as absolute truth. They are ballpark numbers. Some won't measure their internal consumption, either, so users don't complain when they disconnect all the loads and don't see 0W output.
I use separate meters (as above, except my array voltage is lower than yours so I use two of the cheap ones) and that gives me enough information to narrow down most problems (such as the MPPT controller failures I've experienced) or panel shading issues, or high load consumption issues.
Once you figure out how much energy is going into the system and how much is going out, you'll have a good idea of how much you can use overnight.
Lastly, as others have pointed out, your battery settings aren't optimized. Set the battery cut off to 48.7 (and back to grid to 48.7 for good measure), the float to 55.2, and the bulk charge to 59.2. The 1v difference may seem small, but this does make a difference in how much power you can push into the battery. These numbers are from the battery specification. The charge current isn't much of a concern. Worst case scenario, your solar array producing 3kW and you battery almost depleted at 49v then the current is 61A. Even if the battery is damaged and can only hold half its original capacity, that's still a C/4 charging rate, which is fine for these types of batteries.
That you originally had the bulk and float charging voltages at 54v and 56v - 3 volts under the battery's rating - could account for a rather substantial decrease in stored energy.
So, to sum up, your system is reasonably well matched, and adding a little more measurement and monitoring will enable you to determine whether the batteries are truly bad, or if there's something else going on with the system.
Let me summarize your system so we can think about it and what's going on.
Solar power:
12 250w panels is maximum 3kW energy when in direct sun.
5kW MPPT charge controller in the all-in-one inverter
8A maximum current on the string and wiring going to the inverter
No fuse or disconnect - so the only safe way to work on this is at night. (consider adding a disconnect and 10A fuse in the future)
Don't know what size wire is being used, or distance to the array. If it's thin wire (14awg, 16awg, etc) and/or long distance you'll lose some power, but since it's a high voltage array the loss won't be significant.
On a long sunny day you can expect them to generate 10kWH to 24kWH of energy, depending on a variety of factors. Foliage, overcast, rain, dust/debris will all reduce power output.
Inverter/MPPT charge controller:
5kVA inverting capacity
This is pretty much the same as growatt and several other "value" inverters. They have their quircks, but mostly work pretty well. The one thing that I've discovered is that the MPPT controller is very sensitive, and prone to failure. If your installer wired up all 14 panels to test on a sunny day, the MPPT controller is fried. The symptom of a fried Growatt/etc all in one MPPT inverter is that the solar panel voltage will equal the battery voltage. So during the day check the solar panel voltage using the inverter's interface and verify that the panels are about 370V.
Battery:
8 UP-GV600-6RE.pdf cells
424AH at C10 (ie, 42A) draw
Trickle/float charge voltage: 6.9VDC/cell, 55.2VDC pack
Bulk charge: 7.4VDC/cell, 59.2VDC pack
Nominal voltage: 50.4VDC pack
The pack will hold less than 21kWH
Gel batteries have good deep discharge characteristics, however they will last longer if only discharged to 50% depth of discharge. This is about 48.72VDC, and means you'll only be using about 10kWH of the pack's capacity - assuming it's in good condition. If it's already damaged then you might be able to count on 5kWH to 8kWH of usable capacity to avoid further deep discharge degradation.
Damage will occur under 48.72VDC, but it won't be really hurt unless it drops under 46.5vdc
Your battery cutoff voltage was 43V, and since you don't have grid power the "back to grid" voltage does nothing for you. So you have been drawing the batteries down into the danger zone, and they have been damaged. Gel batteries, however, are very resilient, so unless you've been doing this cycle for months you probably still have a significant amount of capacity left.
Load:
Daytime ??? over 8 hours
Night 200W over 16 hours
I understand you're calculating the time it's actually dark, but the panels won't generate much power until the sun is within 45 degrees off perpendicular from the panel, and you're not going to get much more than 8 hours of that. This is all very ballpark, though, every installation is different and without solar survey data I can only guess.
Note also that while you may only be consuming 200W overnight, the inverter could be consuming as much as 65W as well. Lastly, the inverter is not 100% efficient, nor are the batteries, and the wiring also has some losses. All together you're only going to be able to use about 80%-90% of the actual solar energy that the panels generated during the day.
Two things you can quantify here to help diagnose the issue is to find out how much power you're actually generating, and how much you're actually storing. Getting two power meters with AH measurements will help you with this. The solar array is high voltage, so you'll need a 500VDC meter, such as this one https://www.amazon.com/Wireless-Charging-Capacity-Detector-Coulometer/dp/B0948NTML1 , for the solar power side, and you can get a cheaper one, such as one of these https://www.amazon.com/Charge-Discharge-DROK-Voltmeter-Watt-Hour-Multimeter/dp/B07YWVCBRN for the battery side. I chose these because while they require you to disconnect cabling to put the cable through the sensor, and you still have to wire + and -, you don't have to come up with another cable and connection to connect a shunt. This type isn't as accurate as a shunt type, but you're not doing laboratory measurements, you just need a general idea of how much power you're generating and storing. While I've linked to the amazon listings, these are the cheap generic models you'll find from many places, so you should be able to get something very similar at a low cost.
These meters provide voltage, current, and more importantly they measure how many watt hours of power moves through them. So you can look at both at the end of the day and know that your solar generated 10kWH, the batteries stored 3kWH, so you probably used 7kWH during the day - about 720w for 8 hours after losses and inverter consumption - and now only have about 3kwh/16h = 187W to use each hour overnight, and with the inverter using 30w - 60w you might only have 130w you can use overnight. With a 10% loss for conversion and wiring losses, you're looking at 110w if you want to drain your batteries down to 50% overnight - and this is all assuming the batteries are not damaged and can still hold 20kWH of power fully charged.
You should be able to get some of this from the inverter - kwh produced (from solar panels) and discharged (from batteries), by day, and total over its lifetime. You can also use the inverter's current and voltage measurements - write them down several times a day collecting the battery voltage and current, and solar voltage and current - and this will give you some insight into your power in and out. If you solar panels are hitting 250V and 6A on what you would consider a sunny day then they are only generating 1/2 their possible power. You can then investigate shading concerns, tilt/angle, system/wiring losses, inverter settings, etc. If your MPPT charge controller inside the inverter is bad it'll have a 54V and 8A output, and your panels will be generating just over 400W - 1/7 what they're meant to output, and you'll get 4kWH - 7kWH on a sunny day. It's not a small amount, but it won't charge your batteries much, and they'll run low quickly when the sun goes down.
Note, however, that the inverter's internal measurements are inaccurate. It's probably within 10% of the actual reading, but don't take its reported values as absolute truth. They are ballpark numbers. Some won't measure their internal consumption, either, so users don't complain when they disconnect all the loads and don't see 0W output.
I use separate meters (as above, except my array voltage is lower than yours so I use two of the cheap ones) and that gives me enough information to narrow down most problems (such as the MPPT controller failures I've experienced) or panel shading issues, or high load consumption issues.
Once you figure out how much energy is going into the system and how much is going out, you'll have a good idea of how much you can use overnight.
Lastly, as others have pointed out, your battery settings aren't optimized. Set the battery cut off to 48.7 (and back to grid to 48.7 for good measure), the float to 55.2, and the bulk charge to 59.2. The 1v difference may seem small, but this does make a difference in how much power you can push into the battery. These numbers are from the battery specification. The charge current isn't much of a concern. Worst case scenario, your solar array producing 3kW and you battery almost depleted at 49v then the current is 61A. Even if the battery is damaged and can only hold half its original capacity, that's still a C/4 charging rate, which is fine for these types of batteries.
That you originally had the bulk and float charging voltages at 54v and 56v - 3 volts under the battery's rating - could account for a rather substantial decrease in stored energy.
So, to sum up, your system is reasonably well matched, and adding a little more measurement and monitoring will enable you to determine whether the batteries are truly bad, or if there's something else going on with the system.
Will definitely add the fuse and disconnect. The inverter readings were recording around 26kw on a good day. But it is dropping now to only around 3kw. Because the batteries are showing fully charged and my load is very small. Also had a couple of cloudy days so difficult to give an accurate reading.
The inverter is showing high voltages of around 400 from the array.
The batteries are fried I am pretty sure. The cut of voltage has now been set at 48v ( can't seem to set it to 48.72) and now shut off as soon as the sun starts to go down at around 6pm. Disconnected they are reading 6.5v on six of them and 5.2, 4.2 on the remaining two. Under charge and load all of the voltages are slightly different from 5.2- 7.2.
I have ordered the meters but as I said above, I am pretty sure the problem is the batteries.
I did change the settings exactly as you mentioned with the exception of the cut off ( which can only be set at 48) I think the damage has already been done though, so my best option is to try and nurse the 6 good batteries (as far as I can tell) to use elsewhere and replace the whole string with probably a lithium? My budget is pretty non existent, I am going to have to get a loan but I am thinking the pylontech 5000c would be my best option. And then add to that, change out my inverter and upgrade the panels at a later date. I can't get any confirmation from suppliers that it would be compatible with my current inverter though so that something I need to clarify before going any further.
I am not sure on the equalisation settings I should use, maybe I could try that but I don't think it is recommended for the sealed batteries?
Also the separate charging whilst in situ, I don't even know how I would do that. I would have to buy a charger. I do have one but it is a fast charger for multiple voltages so I think I would need a specific one.
Also the separate charging whilst in situ, I don't even know how I would do that. I would have to buy a charger. I do have one but it is a fast charger for multiple voltages so I think I would need a specific one.
Quattrohead
Solar Wizard
I have already replaced one. Thing is I am reluctant to replace two more and end up having to replace the lot anyway. They are €450 each! think I am better just to start again with a smaller lithium , I can get the polytechnic 4.8kw for €1500 and save the hopefully good batteries for another project?
stienman
Mostly Harmless
- Joined
- Jan 6, 2021
- Messages
- 476
The nice thing about smart lithium batteries is that they'll shut themselves off if the inverter/charger tries to overcharge or overdischarge them. So at minimum they'll last longer than the lead acid batteries you have.
But yes, the two batteries reading below 6 volts are physically damaged.
But yes, the two batteries reading below 6 volts are physically damaged.
The retailer is telling me that my inverter is not compatible with lithium batteries... But another is trying to sell me three pylontech us3000. I am not sure which way to go. Would there be any benefit to 3 x US3000 over 2 x US5000 ?
MisterSandals
Participation Medalist
I looked back thru this thread and see that in post #34 you inverter has a "user defined" battery profile. More often than not, from what i have seen, this is more useful than a specific lithium battery profile. Many lithium profiles are very aggressive in charging to the theoretical cell limits and many batteries do not have cells that stay balanced at these extreme voltages. So in these cases, as well as when folks want a conservative charge profile, a user profile is needed.
I have 5 SCCs that i use regularly and only one has a lithium profile (Victron 100/30) and i choose the user defined battery profile.
Last edited:
Similar threads
