Eg4 3000 EHV and solar charging question.

[RubeSolar]

Hello! Total newbie question here I'm sure but I've done research and can't figure out if I'm doing something wrong or not.

So here is my smol boi setup.
Eg4 3000ehv 48v
Eg4 LL pro 100ah 48v battery
4 santan 250w panels
Panels specs are:

• Open circuit voltage (VOC): 37.6 V
• Max power voltage (VMP): 30.3 V
• Short circuit current (ISC): 8.85 A
• Max power current: 8.27 A

Each panel is pretty close to spec. Lowest panel is 37.2 v and 8.5a SCC

In series not connected to the invterer I get 135 ish v and 8.1 amps. (I covered them all with sheets to disconnect them)

As soon as hook them up to the inverter everything drops. Inverter shows an input of 121v and a max of 4a. The time from my measurements to connecting to the inverter is like 20 seconds at noon so the sun didn't change.

Am I missing something? I've got the settings of the inverter mostly at default save for Max ac input which is at 15a.

So yeah is this normal or am I missing something dumb?

Thank you!

 

[mountkay]

Inverter shows an input of 121v

Your Max power voltage is 30.3v. multiply that by the 4x panels and you get 121v. seems correct to me.

The reason you were getting a higher voltage before connecting to the inverter is because you were getting an Open circuit voltage. This is the voltage when there is no Load applied. The inverters MPPT charge controller acts as a Load when it is pulling power from the panels.

I realize the 121v * 4a, is only about 500w, not close to the 1000w the panels are rated at.
Did you leave the panels plugged into the inverter for some time to see if the output changed at all?

There will always be some inefficiencies.
The panels dont work as well when they are hot. Im guessing they were hot since you said it was Noon and it sounds like it was a pretty sunny day.
There is also the angle of the sun, loss in the wires, etc.
But 50% of their rated power seems like there could be an issue if you really think they were getting full sun.

Are they brand new or used panels?

 

[RubeSolar]

,

 

[RubeSolar]

Your Max power voltage is 30.3v. multiply that by the 4x panels and you get 121v. seems correct to me.

The reason you were getting a higher voltage before connecting to the inverter is because you were getting an Open circuit voltage. This is the voltage when there is no Load applied. The inverters MPPT charge controller acts as a Load when it is pulling power from the panels.

I realize the 121v * 4a, is only about 500w, not close to the 1000w the panels are rated at.
Did you leave the panels plugged into the inverter for some time to see if the output changed at all?

There will always be some inefficiencies.
The panels dont work as well when they are hot. Im guessing they were hot since you said it was Noon and it sounds like it was a pretty sunny day.
There is also the angle of the sun, loss in the wires, etc.
But 50% of their rated power seems like there could be an issue if you really think they were getting full sun.

Are they brand new or used panels?

Hello! Thank you for your reply.

To clarify, I do understand VOC is different than when it is under load. That wasn't the surprising thing, it was the amps that dropped down to less than half. I connected the positive and negative of each panel to themselves and measured with a clamp meter the dc amperage. In the sun at the time I was measuring each panel was at about 8.5 amps.

I then put them all in series and plugged the ending positive and negative to each other which made the ISC come out as 8.3 amps.

I get that the ISC is greater than when under load but would it really be less than half that when I put it into the Eg4 3000 30 seconds after the ISC measurement?

I did leave the panels plugged in and charging the battery for hours and the amps never got higher.

And the panels are used from SanTan solar. Yes at noon they were very hot, but again, less than half the amperage 30 seconds after ISC is measured?

That was my big noob question, I understand VOC drops when underload but does ISC operate the same way? Or is there a setting in the Eg4 that i need to change? As I understand amps don't exist until they are 'needed' as it were. If the EG4 is only pulling 4 amps then the panels will only produce 4 amps. SOC on the battery was less than 50% and the setting on the EG4 3000 are mostly default. I am not sure what I am missing, hence the rube question.

Thank you again for your response and I hope my rambling is at least somewhat coherent.

 

[Johno1066]

I am using 25 Santan solar 240 watt panels giving me 5 strings of 5 panels in series and they are producing nearly 80% of their rated power at mid day if my batteries are not filled by then. I checked every panel separately when I got them for open circuit voltage and short circuit current before putting them up to make sure that I did not have a faulty panel among them. I am also using 2 EG4 300 watt inverters in parrallel with 2 strings feeding one and three strings the other. Still have more than 60 days to the summer solstice so expect the rated power to increase a little more. Any shading of the panels also reduces power substantially.

 

[mountkay]

Yes at noon they were very hot,

I have a 6.8kw array at 40deg angle. right now its noon here and full sun and hot (74F). only pulling 5.1kw. about 75%.

panels are used from SanTan solar

my panels are not "used" persay, more like "un-used", extras from a big solar farm install. but depending on how old your panels are, they could only be outputting 80% (80% after 20 years is a good rule of thumb, about 1% decrease in efficiency per year).


Regarding your settings:

Is your setting 5 set to EG4 with battery communication or USE?

EG4 mode will automatically limit the amperage coming in (setting 2) if the battery is nearly full.

if in USE mode, check setting 2 to see if amperage is limited. (probably not since you are saying only 4 amps, but you can check this setting easily).

amperage will also be limited in USE mode if you are near your Bulk voltage setting (setting 26) or near your Float voltage setting (setting 27).

those are the only settings I can think of that would change the power you are pulling from your panels.



EDIT: "" would it really be less than half that when I put it into the Eg4 3000 30 seconds after the ISC measurement?""

unfortunately I dont know the answer to this.

 

[Johno1066]

what do you have set to 15 amps is it #11 which is: Maximum utility charging current and what do you have #05 Battery type set to. If your battery and your PV are connected to the inverter it should still charge you battery if so does it remain at around 4 amps.

 

[RubeSolar]

I have a 6.8kw array at 40deg angle. right now its noon here and full sun and hot (74F). only pulling 5.1kw. about 75%.


my panels are not "used" persay, more like "un-used", extras from a big solar farm install. but depending on how old your panels are, they could only be outputting 80% (80% after 20 years is a good rule of thumb, about 1% decrease in efficiency per year).


Regarding your settings:

Is your setting 5 set to EG4 with battery communication or USE?

EG4 mode will automatically limit the amperage coming in (setting 2) if the battery is nearly full.

if in USE mode, check setting 2 to see if amperage is limited. (probably not since you are saying only 4 amps, but you can check this setting easily).

amperage will also be limited in USE mode if you are near your Bulk voltage setting (setting 26) or near your Float voltage setting (setting 27).

those are the only settings I can think of that would change the power you are pulling from your panels.



EDIT: "" would it really be less than half that when I put it into the Eg4 3000 30 seconds after the ISC measurement?""

unfortunately I dont know the answer to this.

I am very sorry that I didn't respond sooner I had my response saved as a draft and not actually posted! Ack!

I ended up figuring it out being a combination of dumbness on my end and your comment about the battery limiting the incoming power. What I did wrong was....wait for it.....hold the panels are the optimum angle while doing the isc test and then.....laying them back at a different angle to string them all together. Feels bad man heh. Anyway thank you for the insight!

 

[ovenmitzz]

I have just finally set up my emergency backup solar system, which is enough to run some small appliances.
EG4 48v 100ah battery, EG4 3000 charge controller and nine 325-watt panels. I also felt there was something wrong with my system because my wattage has been very low. Until yesterday, the most output I have seen was 300w. I checked each panel individually, and everything checked out.

It was not until I added a heavy load to the AC output that the charge controller began showing the wattage input from my array.

Does anyone know if there are settings within the charge controller to see the total solar input without drawing a heavy load?

 

[FilterGuy]

I have just finally set up my emergency backup solar system, which is enough to run some small appliances.
EG4 48v 100ah battery, EG4 3000 charge controller and nine 325-watt panels. I also felt there was something wrong with my system because my wattage has been very low. Until yesterday, the most output I have seen was 300w. I checked each panel individually, and everything checked out.

It was not until I added a heavy load to the AC output that the charge controller began showing the wattage input from my array.

Does anyone know if there are settings within the charge controller to see the total solar input without drawing a heavy load?

When the batteries are full and there is no large load, the MPPT will throttle the current from the PV. As the MPPT throttles the current, the actual power production from the PV goes down. At the limit, the MPPT can take the PV current all the way down to zero. Consequently, you could have a bright sunny day with zero production from the PV.