Too much wattage from panels to Flexmax60 charge controller?

Skipmca

I'm installing 6-370 watt panels in parallel to my Flexmax60 charge controller.  Is that too much wattage for that controller?

Photowhit

Should be;

No problem for a 48 volt system...

Close for a 24 volt system...

Too much for a 12 volt system...

When in doubt consult your manual;

Microsoft Word - 900-0009-01-00 Rev D.docx (outbackpower.com)

Dave Angelini

You are fine ! Typical to over panel by 20% so 2,400 watts nameplate solar would be the max in a hot climate.

Skipmca

Thanks Photowhit and Dave.  I have that chart.  That is why I asked.  Seemed like quite a bit more than reasonable.  I now have two sets of panels. 6-320 watt and 6-370 watt. Switching from the 320s to the 370s temporarily until I can install an additional cc (a flexmax80). Also going to reconfigure batteries for 36v.  I would change to 48v, but I have 12-6volt batteries. 

Photowhit

Skipmca said:

Also going to reconfigure batteries for 36v.  

Not a lot of 36 volt inverters or applications...

Skipmca

I had a feeling there was a reason not to do 36! Thanks.

Vic

Skipmca said:

I'm installing 6-370 watt panels in parallel to my Flexmax60 charge controller.  Is that too much wattage for that controller?

Hi Skip..,

Well,  like so many things,   it really all depends on the EXACT specs of the PVs.    Assume that you have a 24 V system,  still.

BUT,  the OB FM60 and FM80 have a Maximum total PV  Isc spec  --  80% of the output current rating.   For the FM60,  this is 48 A total for the sum of the Isc  rating of each string,   or of each PV,  it the PVs are singles,  all in parallel.

What is the manufacturer and model number of the 370 Watt PVs that you would be using?

Thanks,   VIc

Skipmca

Hello Vic: Thanks for replying.  Yes, 24 volt system.  Here are the panel specs:

Dave Angelini

You should really just consider 48v and recycle/repurpose the other batteries.

Skipmca

"You should really just consider 48v and recycle/repurpose the other batteries."

Hello Dave: Do you mean do one string of 8 batteries for 48v?  I would still have adequate power with that setup.  They are Rolls L16s at 428ah.  

Dave Angelini

Definitely yes ! A fine battery for a 48V inverter/charger. For many people living in a home, a 400+ AH bank at 48v is all they need. Use of an Outback inverter will allow you to network the system.

Vic

Skipmca said:

Hello Vic: Thanks for replying.  Yes, 24 volt system.  Here are the panel specs:

Hi Skip,

Re  your original question,  the total maximum Isc for six of those PV all in parallel,   is 59 Amps.   The Limit for the OB FM60 is  48 Amps,  so,  the proposed configuration results in excessive total PV Isc.

Strings of two of the PVs  should be OK,  as that halves the total Isc (29.5 A).

OR,  an FM80 (64 A total max Isc rating)  should be OK with all six PVs in parallel.

The way I see it,  Vic

Skipmca

Thanks Vic.  I'm proposing to hook up 5 of the panels, so the total amps would be 49.  Also, the wattage would be 15% over recommendation.  Does that sound ok?

Vic

Skip,

Well, five of the 370 W PVs on an FM60 is certainly less-risky than are six.

It would probably be OK,  in most situations,  but,  still a bit over-spec on the max PV power.   Would worry less about being about 2% over the total max Isc.

Your decision.   Good Luck,  picking nits,  over for now.    Vic

Skipmca

Thanks Vic.