New solar setup, advice needed

[bbbuddy]

We are about to buy 6 new 100 watt solar panels, at only $1.20 per watt.  They are 99.29 open voltage, not sure yet what closed circuit voltage is...the amps are 1.5 per panel.

I know we need a OutBack FLEXmax 60 amp Charge Controller or similar, to handle the voltage.  Our battery bank is 4 Trojan L16's, but they are old and pretty much toast, also we have an ancient Trace 2012 inverter/charger, probably 20+ years old.

Most of our power useage is during the day, just switched from a propane fridge which died to a 110 fridge, and a small chest freezer.  Along with internet use, that is our main power draw.  Some tv at night.

Until now we have charged up with a generator to the inverter/charger, the 40 watts of solar we have is nothing.

Before we buy the panels, is there a problem with using such high voltage panels with a 12 volt battery bank?

Is there anything we need to know, I don't want to spend the $ and find out the panels are useless for us, lol.

Thanks much!
Maddy

[Tritium]

As long as the panels are in parallel they should work fine with the Outback MPPT controller. If series connected then the max voltage of the controller would be exceeded greatly. At 12V my MX 60 is good for about 800 watts of panels.

Thurmond

[dnix71]

Without decent batteries you won't accomplish much. I have 7 marine hybrid deep cycle batteries and only 310 watts of panels that rarely produce more than 1/2 the name plate rating with a BZ mppt. I hit float by 1 pm and have power to spare. I can do two loads of wash on a cool sunny day and still have a full charge at the end of the day.

If you want to run a fridge properly you need lots more batteries or a proper 12v fridge like Waeco or Engel make. Those use 1/2 the power of a regular fridge and don't require an inverter.

[Airstream]

Is this your panel?

http://sunelec.com/Specs/DuPont/DuPont%20DA100-A1.pdf

Choosing the Outback charger is smart - gives you plenty of room to update your battery string to 24 or 48V in the future.

You never want to see above 145VDC  at the OutBack FLEXmax as it will record it as a warranty event to the logic and 150VDC shuts it down for good. Voltage spikes from loose wiring or connecting up under load are to be avoided.

You may live in some sunny southern climate but as far as I read the major killer of FLEXmax chargers is running too high voltages during cold weather, with thin-film the extra 'bonus' outputs of new panels should be considered too as initial voltage - power may be significantly higher than the ratings. With thin film the panel outputs 'flatten out' after some months to their rated output. 

The above PDF lists the panels temperature coefficient is 0.30% /°C - so the most you could see at the rated -40°C temperatures has the cold raising output voltage to 120VDC leaving you a 15% margin of safety.

[bbbuddy]

Thanks for your replies!

Tritium, yes they would be in parallel...
dnix71, we already are runnning the 10 cubic foot 110 volt fridge, off the inverter, plus the batteries.  we recharge the batteries with a gennie.  The solar will just allow for less running of the gennie.

Airstream, YES, that is the panel, from sunelec.  We are in the high country in AZ, so getting them from Phoenix is not a problem.  The sales lady there told me about the panels before they arrived.
Thanks for your detailed response, you've helped out a great deal by giving me peace of mind that this great deal won't turn out to be a "pig in a poke"!

[ruddycrazy]

Yea I run 14 kaneka thin film panels on my house array and when my AERL900B MPPT went south I got a Flexmax60 under my insurance. The thin film panels were hooked up in 7 series/parallel strings and when I hooked them up to the FM60 it went straight into safe mode as the input voltage was close to 150 volts. So I re-wired every panel in parallel and it's worked a treat ever since.

Cheers Bryan

[bbbuddy]

Well, we picked up the panels today, but at that price, I upgraded myself to 8, not 6, so we have 800 watts plus an outback fm60, for $1478!

The panels are beautiful, and have nice long connectors built right in on the back.

[hydrosun]

I looked at these panels but rejected them for larger systems because of all the extra parallel connections needed. And extra mounting because of lower efficiency.  The other potential problem is matching the voltage  if you want to add panels to the system in the future.  The added price for 200 watt 18 volt mpp at $1.74/watt  was worth avoiding those problems for me. Last I looked sunelec had 150 watt panels for $1.50 watt in Miami.
Chris

[bbbuddy]

Hydro, good for you!

We live off grid, the 800 watts should be more than enough.  We've lived for 7 years with 40 watts, lol, plus the gennie.

We have 40 acres, we aren't hurting for room.

I'm cheap, the next cheapest panels out here were $1.82, or $496 more... so buying these paid for the Outback controller!

[ghurd]

We've lived for 7 years with 40 watts, lol, plus the gennie.

Yikes!
You should have got a lot more panels a lot sooner!

[bbbuddy]

Yikes!
You should have got a lot more panels a lot sooner!

Yes, I know, the little screamer gennies have taken a beating!

I always told my husband, when solar gets down to $1 per watt, we're in!

We go through about 1 per year of the el cheapo $299 3000 watt ones.  We have one bigger one we try not to use too much, mostly for doing some laundry and filling the 3000 gallon water tank once a week or so.

800 watts will be a real luxury.

I'm hoping to get a magnum 4424AE or 4448AE and new batteries to be able to run the 1 hp well pump once a week, get off the gennies if possible.

We are on four 7 year old L16's, I know they are tired now.