Hi--Hope someone can give me some info please?

I have a SPL5000ES growatt inverter (450v) and 4x455 Canadian panels connected in series --Total voltage average 160vdc--- Now I have connected a extra 4x460 Canadian panels also in series and the total voltage went up to 328vdc----On the growatt I see that the wattage fell away to about 120w and amp to about 0.3amp ???????--With the higher voltage isn't the wattage to be double with the volts that is double (mppt suppose to work like that)

I am at wits end here.

 

Any info please.

 

Cheers

MArk

 

1 hour ago, zs1ssm said:

Hi--Hope someone can give me some info please?

I have a SPL5000ES growatt inverter (450v) and 4x455 Canadian panels connected in series --Total voltage average 160vdc--- Now I have connected a extra 4x460 Canadian panels also in series and the total voltage went up to 328vdc----On the growatt I see that the wattage fell away to about 120w and amp to about 0.3amp ???????--With the higher voltage isn't the wattage to be double with the volts that is double (mppt suppose to work like that)

I am at wits end here.

 

Any info please.

 

Cheers

MArk

 

Yes you are correct that the power should be much higher. It is assumed you had more than 120W load switched on when you looked at the output.

The 8 series is still within the operating range of the inverter.

Batteries (2x5kw lithium)were supplying power to the inverter --After I disconnected the 460`s then the voltage came down to 150v and the wattage went up to over 600w--Will run the system only on the 460`s for a test and see what is the results--I just hope that the 460 aren't pulling the amperage down

 

2 hours ago, zs1ssm said:

Batteries (2x5kw lithium)were supplying power to the inverter --After I disconnected the 460`s then the voltage came down to 150v and the wattage went up to over 600w--Will run the system only on the 460`s for a test and see what is the results--I just hope that the 460 aren't pulling the amperage down

 

What is the Imp for each of these panels?

As @Scorp007said, make sure you have enough load to check the panel output. If your batteries are full it will not run the panels at full power. When you turn on the PV after removing panels it may jump up in watts for a short time when the charging starts but will drop quickly if the batteries are full.

6 hours ago, Scorp007 said:

What is the Imp for each of these panels?

Here are the specs:

Nominal Power (PMAX)  455w  and 460w

Operating Voltage (VMP) 42.6v and 42.8v

Operating Current (IMP) 10.69A and 10.75A

Open Circuit Voltage (VOC) 51.8v and 52v

Open Circuit Current (ISC) 11.3a and 11.39a

 

I have 2xLBSA 5.1kwh batteries in parallel and the batteries were asking for a full charge +- 40A (batteries were at 65% charge) and house was pulling about 1.5kw  .

 

It was like the MPPT did not convert the extra voltage to current but actually limited it

As I said --will test the 4x460`s on Monday to see if they perform better without the 455`s in serie --just waiting for more cable.

Can I do the following 4x455 inseries and 4x460`s in series and connect the 2 streams in parallel ?

I have asked 2 electricians here and both gave different answers .

 

Cheers

Mark

 

Those panel specs are almost identical, I can't see them interfering with each other much. The 460W panels will just run at 10.69A instead of 10.75A in series, not much difference at all.

If you want to connect them in parallel, you need to make sure your inverter mppt can handle up to 25A as you will double the current.

1 hour ago, zs1ssm said:

As others have said, the panel specs are virtually identical and the difference should hardly degrade your performance. You should see roughly double the Voltage and double the power output maximum. But just judging from the power graph above, I wouldn't change anything back just yet, rather keep the 455W and 460W panels connected in series for a full day or at the middle of the day to see what it does over a longer period. The point is, you connected the 460W panels at around 16:00, with rapidly falling light. There was a blip of sorts to 200W around 17:00, but then from after 18:00 the generation curve looks very normal for that time of the day.

I'm just afraid you think that something is wrong, when maybe there isn't. Consider that the performance at 17:00, 5 hours after noon, roughly mirrors the performance at 07:00, five hours before noon.

Also note that the slope ramping down is clearly higher than the slop ramping up at 06:00 in the morning, so there is something indicating that the panels are operating as expected.

 

1 hour ago, zs1ssm said:

 

I notice that your power curve was already on the way down before you added the panels, are you sure your batteries weren't already full? It was also quite late in the day, so there wouldn't have been as much sun power after 4pm. Are your panels all facing the same direction and same angle? That will make a big difference to panels in series.

20 minutes ago, jumper said:

I notice that your power curve was already on the way down before you added the panels, are you sure your batteries weren't already full? It was also quite late in the day, so there wouldn't have been as much sun power after 4pm. Are your panels all facing the same direction and same angle? That will make a big difference to panels in series.

The 455 are facing north and the 460`s North,North/East

 

1 hour ago, jumper said:

Those panel specs are almost identical, I can't see them interfering with each other much. The 460W panels will just run at 10.69A instead of 10.75A in series, not much difference at all.

If you want to connect them in parallel, you need to make sure your inverter mppt can handle up to 25A as you will double the current.

 

3 minutes ago, zs1ssm said:

The 455 are facing north and the 460`s North,North/East

 

Spec sheet says 100A max solar charge current

 

18 minutes ago, zs1ssm said:

The 455 are facing north and the 460`s North,North/East

if North/East means the same as it means to me, by 4PM those would not get much sunlight, so there may be your answer why...

3 minutes ago, Kalahari Meerkat said:

if North/East means the same as it means to me, by 4PM those would not get much sunlight, so there may be your answer why...

Understand But then the 455 "should still deliver" or is the 460`s that has no sunlight causing this situation?

From 9am everything is fine.

Just now, zs1ssm said:

is the 460`s that has no sunlight causing this situation?

any panel in a series string that is in shade or not good sun is going to severely impact the power of the complete string...

Just now, Kalahari Meerkat said:

any panel in a series string that is in shade or not good sun is going to severely impact the power of the complete string...

Thanks

 

14 minutes ago, zs1ssm said:

Thanks

 

If I connect the 460`s in parallel with the 455`s will that sort it out---example 4x455 in series --4x460 in series and the the two streams in parallel ?

 

The solar calculator can not help me here--Will the impact be the same as with the above statement?

Sorry for asking so many questions. 

 

6 minutes ago, zs1ssm said:

If I connect the 460`s in parallel with the 455`s will that sort it out---example 4x455 in series --4x460 in series and the the two streams in parallel ?

No, that will not really help.

Firstly you double up on the amps into the inverter if you put them in parallel, and you will exceed the maximum amp input of the inverter, so it will have to throttle current and scale down production. And that's if all the panels are in the same direction.

Secondly, you would also still be faced with panels pointing in different directions, so the voltage is likely to be different on each string, and the more shaded string will likely  pull down the voltage of the one in more sunlight. Or something like that.

1 hour ago, zs1ssm said:

The solar calculator can not help me here--Will the impact be the same as with the above statement?

Sorry for asking so many questions. 

 

In my opinion it could make a difference if they are in parallel, but I have no way to test or prove it. Theoretically the voltage of the panels will remain fairly constant with changing sunlight conditions, but the current will vary a lot. The voltage of the panels is mainly affected by temperature. In series, the NE facing panels will be dragging down the current in the whole array, but in parallel only the voltage will be dragged down and if that voltage drag is less than the current drag in series then theoretically you should get more power.

Here's an article on current and voltage relationships and shading, but it doesn't go into series vs. parallel setup: https://www.victronenergy.com/blog/2020/02/20/pv-panel-output-voltage-shadow-effect/

9 hours ago, jumper said:

In my opinion it could make a difference if they are in parallel, but I have no way to test or prove it. Theoretically the voltage of the panels will remain fairly constant with changing sunlight conditions, but the current will vary a lot.

@jumperI am with you on the voltage being very steady. Unlike normal voltages from a source with panels it is not the voltage driving power but the current that increases many fold. Refer to this graph how the voltage is the same at 06h00 than before 10h00 yet the current and power is 10 fold higher at the same time before 10h00.

As far as the problem @zs1ssmis concerned the direction alone cannot be the cause for the much lower power as soon as the 2nd lot of 4 panels are connected. As was suggested it would be a good call to try these 4 panels alone. If they provide a lot less power than the 4x455W then I would zoom in into those 4x460W for a defective panel. There might be some diodes faulty or even some cells. I once had it where adding a 4th panel to a series string I got less power than with 3 when connected in series. This 4th panel would only provide full amps for a few minutes and then throttle the string big time.Panel was replaced but if I did not have graphs to prove it it would have been difficult to convince the seller.

Still funny that the 460W panels provide the volts but no amps due to a throttle effect.

The inverter will only throttle at 22A and not easy to get any of these panels in 2 string to provide over 22A. Worth a try but I doubt one will get any improvement.

Edited November 26, 20223 yr by Scorp007

11 hours ago, zs1ssm said:

Understand But then the 455 "should still deliver" or is the 460`s that has no sunlight causing this situation?

From 9am everything is fine.

I somehow missed this reply. Yes if the 460W has no sunshine they block the 455W. This is the reason you can report after 09h00 all is fine.