Need help - Low Amps from solar array, but expected amps with a single panel. Watts OK.

[lucl]

Hi guys,

I ran into a strange issue and I'm new to solar so I would appreciate some suggestions/ideas.

My setup:

* Outback Flexmax 80 charge controller
* 4x 100AH LIFEPO4 batteries setup as a 48V system
* 4x 200W Panels hooked up in series* - Per panel stats: Pmax: 17.0V, current at Pmax: 11.76A

The current I'm getting from the solar array (hooked up in parallel) is only about 11 AMPs combined (measured by both Flexmax and manually via a multimeter). The wattage appears to be almost as advertised for the array at around 720W in full sun (60.2V "IN" reading in Flexmax), but the advertised amperage for the panels is not being achieved and I can't figure out why.

When I plug a single panel into the charger (or measure its current manually via multimeter) it's at around 7.2A in full sun per panel. But when I plug the entire array in (parallel) the current never exceeds more than 11A while the wattage is added up as expected at around 720W.

All wiring is done via standard high quality solar cables over a distance of about 10 feet (testing) from panels to charger.

Any ideas?
Thank you!
Luc

 

[Supervstech]

Yes. That is how series arrays operate. Amps do not increase. Watts and volts do.

Your panels need perfect angle and sun to achieve max wattage.
11.76A is a dead short. It isn’t what the panels will produce.

 

[lucl]

Yes. That is how series arrays operate. Amps do not increase. Watts and volts do.

Your panels need perfect angle and sun to achieve max wattage.
11.76A is a dead short. It isn’t what the panels will produce.

Got it. Sounds great and thank you for the speedy response.

Another follow up question. From a battery charging standpoint, in the scenario I described above, does it make a difference in terms of battery charge speed if I configure the panels to be in parallel or series (when hooked up to the charge controller)?

I'm trying to figure out if there is a better configuration for charging the 4 batteries I have so that they can charge within a reasonable time (ex: 1-2 days in Arizona sun). My charge controller supports charging in 12v, 24v and 48v configuration. I currently have the batteries setup in a 48v configuration and the panels in series as described above.

Thank you!
Luc

 

[Bud Martin]

I am a little confused here, the system is 48V system, but you are feeding the SCC with <20V
Per OP:
* Outback Flexmax 80 charge controller
* 4x 100AH LIFEPO4 batteries setup as a 48V system
* 4x 200W Panels hooked up in parallel - Per panel stats: Pmax: 17.0V, current at Pmax: 11.76A

Is this SCC a boost converter type?

 

[lucl]

I am a little confused here, the system is 48V system, but you are feeding the SCC with <20V
Per OP:
* Outback Flexmax 80 charge controller
* 4x 100AH LIFEPO4 batteries setup as a 48V system
* 4x 200W Panels hooked up in parallel - Per panel stats: Pmax: 17.0V, current at Pmax: 11.76A

Is this SCC a boost converter type?

The charge controller reads ~62V IN from solar array when the panels are in full sun.

 

[Bud Martin]

But you have panels connected in PARALLEL, so how can you have > Pmax of the panel rating?

 

[lucl]

Apologies, I'll correct the original post. The panels are currently hooked up in a series.

 

[Bud Martin]

OK, that makes more sense.

 

[Supervstech]

Apologies, I'll correct the original post. The panels are currently hooked up in a series.

Your post still says hooked up in parallel in the second paragraph.

 

[Supervstech]

Got it. Sounds great and thank you for the speedy response.

Another follow up question. From a battery charging standpoint, in the scenario I described above, does it make a difference in terms of battery charge speed if I configure the panels to be in parallel or series (when hooked up to the charge controller)?

I'm trying to figure out if there is a better configuration for charging the 4 batteries I have so that they can charge within a reasonable time (ex: 1-2 days in Arizona sun). My charge controller supports charging in 12v, 24v and 48v configuration. I currently have the batteries setup in a 48v configuration and the panels in series as described above.

Thank you!
Luc

As queried in the previous responses, those panels cannot charge the 48V battery except in series.

Additional or different panels with a higher pmax voltage might work parallel, or series a pair then parallel that.

The issue with series is shading anywhere lowers the pmax voltage cutting production. Parallel won’t lower all the voltage when partial shading only affects a single panel.

Good luck!