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Solar Charger Not Charging Battery, need advice

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KnowerOfLittle

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Jun 5, 2022
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I have 5 - 440w panels in parallel going to 2 MPP Solar LV 6548 inverters with a 10kWh 51.2V 200Ah Lithium battery. I tried to copy Will's set up from this video.

I have the panels installed on a carport free from any shade and at the end connections from the array, I am getting 44Vdc. I have the inverters programmed correctly and am able to get AC voltage to the breaker panel but the inverters are not charging after plugging in the solar array. I am plugging in the solar array at my 2P1 inverter into the PV input connections.

To sum all of this up into a question to someone with more experience with these inverters, is my PV voltage too low to charge the battery or is there some programming I am missing to charge the battery. I am not grid-tied if that makes any difference.

Thank you for your time.
 
My guess is you have all five panels in parallel. If you set them up 2S2P you will see 88 volts and will start charging. You may be able to set up 5S, but would need to know the specs of the inverter. As a rule, you need to have five volts above charging voltage for an MPPT to start working.

That is just a guess. My other guess is a wrong setting on the inverter.

To see if this guess is correct:

What are the panel specs?
What is the panel setup?
What are the charging specs for All in one or SCC? (If panels are put in series, what is the max charging voltage?

Edit: I just read you had a 2P1s solar panel setup, so I doubt you’re making charging voltage for a 51.2 (I assume 48 volt) battery pack.
 
Did you read the manual for the LV 6548? The PV input MPPT range is 90 to 230 Vdc. You're only giving it 44V. 5 panels won't work. You need 4 panels in a series string, and you've got 1 extra panel you can't use with this inverter. Your string voltage should be around 200V, and the 440W x 4 = 1760 Wdc. To make this inverter work at full power from solar, you need 7 more panels, so you have 3 strings of 4.

DO NOT connect all 5 panels in series, it will go over 250V and will exceed the input rating, which could blow up your inverter. For 440W panels, 4 is your maximum, assuming Voc < 50Vdc. Panels are temperature sensitive. If the temperature drops 25C, the Voc will go up 3 or 4 volts above the rated Voc. You need to add that to the string voltage. So 5 in series would be > 250V at low temperature, and that's what kills your inverter.

Screen Shot 2022-06-05 at 12.35.48 PM.png
 
Chrisski got it right. The incoming solar voltage is too low. Here are the specs for the 6548. Since it states the voltage range is 90VDC minimum, even two panels in series might not be adequate. Five panels in series might bring your Voc to >250VDC on a frosty morning, so I think your best option would be to get one more panel and wire them 3S2P instead. For now, just wire up a single string of 3S or 4S and see what happens.

1654447110733.png
 
ncsolarelectric said:
Did you read the manual for the LV 6548? The PV input MPPT range is 90 to 230 Vdc. You're only giving it 44V. 5 panels won't work. You need 4 panels in a series string, and you've got 1 extra panel you can't use with this inverter. Your string voltage should be around 200V, and the 440W x 4 = 1760 Wdc. To make this inverter work at full power from solar, you need 7 more panels, so you have 3 strings of 4.

DO NOT connect all 5 panels in series, it will go over 250V and will exceed the input rating, which could blow up your inverter. For 440W panels, 4 is your maximum, assuming Voc < 50Vdc. Panels are temperature sensitive. If the temperature drops 25C, the Voc will go up 3 or 4 volts above the rated Voc. You need to add that to the string voltage. So 5 in series would be > 250V at low temperature, and that's what kills your inverter.

View attachment 97336
Click to expand...
Thank you for the information and I apologize for my naivete.

I took the fifth panel out of the array and wired the remaining 4 panels in series. I checked voltage and was getting 138Vdc. It was around 7pm so I wasn't worried about the array's output.

Even after this though, the inverters are not showing that they are charging. Would there be a program setting that I am missing? I really appreciate your patience with my questions.
 
KnowerOfLittle said:
I checked voltage and was getting 138Vdc. It was around 7pm so I wasn't worried about the array's output.

Even after this though, the inverters are not showing that they are charging. Would there be a program setting that I am missing? I really appreciate your patience with my questions.
Click to expand...
At 7pm, most likely you are not making any power at all, with the sun close to setting. How were the panels oriented to the setting sun? Facing South, I'd guess they are almost shaded? Even shaded panels will produce close to rated voltage, but next to no amperage, needed for charging.

The real test should be today, when the sun is up and you are getting full insolation. What's happpening at about 10AM at your location? BTW, if the batteries are full, they don't necessarily get any charging amperage. The best test would be apply a load close to your panel output and see what happens to the inverter after turning the load on.

Since you have four 440W panels, a big load, such as a 1500W toaster oven, would be a good one to apply. If you turn on the toaster oven while the sun is shinning, and you don't see a jump in amperage, then something else is wrong.

The first thing to try is to disconnect the AC, then disconnect the solar, and finally disconnect the battery bank. That means physically removing a wire, or flipping a breaker so no power can flow. Try pressing the "ON" button once everything is disconnected to bleed off any stray electrons still in the capacitors.

Once the unit is stone-cold, reboot the unit on battery ONLY. Once the unit has booted up properly, then reconnect the solar input. At this point, do the toaster oven test again. I would expect things to be OK at this point. If not, further troubleshooting will be required.
 
MichaelK said:
At 7pm, most likely you are not making any power at all, with the sun close to setting. How were the panels oriented to the setting sun? Facing South, I'd guess they are almost shaded? Even shaded panels will produce close to rated voltage, but next to no amperage, needed for charging.

The real test should be today, when the sun is up and you are getting full insolation. What's happpening at about 10AM at your location? BTW, if the batteries are full, they don't necessarily get any charging amperage. The best test would be apply a load close to your panel output and see what happens to the inverter after turning the load on.

Since you have four 440W panels, a big load, such as a 1500W toaster oven, would be a good one to apply. If you turn on the toaster oven while the sun is shinning, and you don't see a jump in amperage, then something else is wrong.

The first thing to try is to disconnect the AC, then disconnect the solar, and finally disconnect the battery bank. That means physically removing a wire, or flipping a breaker so no power can flow. Try pressing the "ON" button once everything is disconnected to bleed off any stray electrons still in the capacitors.

Once the unit is stone-cold, reboot the unit on battery ONLY. Once the unit has booted up properly, then reconnect the solar input. At this point, do the toaster oven test again. I would expect things to be OK at this point. If not, further troubleshooting will be required.
Click to expand...
Thanks for answering. The panels are facing south free from any shade. I used a meter to check the voltage today and was getting 180vdc but after plugging them into my 2p1 inverter there is still no charging symbol or indication there is pv plugged in. The battery is showing that it is at 50% charge.

I tried running a load on the system. A small 6000 btu air conditioning window unit. The unit came on and ran. No change though from the inverters charging wise. They are still just running off battery.
 
KnowerOfLittle said:
there is still no charging symbol or indication there is pv plugged in. The battery is showing that it is at 50% charge.

I tried running a load on the system. A small 6000 btu air conditioning window unit. The unit came on and ran. No change though from the inverters charging wise. They are still just running off battery.
Click to expand...
Have you done the full shut-down procedure yet? What might have happened previously, because you were feeding too low a charging voltage, the controller board might have gotten "confused".

That's what the purpose of the full-shutdown is supposed to deal with. By cutting ALL power to the unit, all the unit's settings get set back to their defaults, and starting up from a cold reboot allows for the chips software to start out with a completely fresh copy of instructions.

What is your time of day right now? If still early enough in the day, I'd do the reboot asap. If you still see no charge current after rebooting, then I'd say your controller board is bad, and you need to contact the company about a warranty repair.
 
MichaelK said:
Have you done the full shut-down procedure yet? What might have happened previously, because you were feeding too low a charging voltage, the controller board might have gotten "confused".

That's what the purpose of the full-shutdown is supposed to deal with. By cutting ALL power to the unit, all the unit's settings get set back to their defaults, and starting up from a cold reboot allows for the chips software to start out with a completely fresh copy of instructions.

What is your time of day right now? If still early enough in the day, I'd do the reboot asap. If you still see no charge current after rebooting, then I'd say your controller board is bad, and you need to contact the company about a warranty repair.
Click to expand...
I did the full power shutdown and discharged capacitors and tried again and I am still getting no pv info to show up on the display. It is 2:30 PM where I'm at currently. I am going to try reverting to factory settings and try the full power shutdown. I will check pv connections from the inverters next if that doesn't work.
 
TomC4306 said:
What is that?
Click to expand...
I have two mppt lv6548 inverters set up in split phase 240v. So the 2p1 is my first inverter that puts out 120v and my other inverter is designated as 2p2 and puts out the other 120v. I'm calling them that because in the programming, that's how they are designated.
 
I'm having a similar issue. My generator is supposed to charge batteries. No panels, due to a fire last week.

The inverter won't charge the batteries. This MPP is a POS.
 
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