Finally hooked up the system, WOW

Re: Finally hooked up the system, WOW

Is "DH" "dear husband"?

By the way, remember that the batteries do need their charging current--so during the day, you should be pumping as much energy into them as possible for you to draw out later at night.

If you are barely charging during the day, you will not have the reserve power for night-time loads.

-Bill

Re: Finally hooked up the system, WOW

bbbuddy wrote: »

But I need to see what happens amps-wise when I do so, because the FM60 can put out 60 amps, and our batteries should only bulk charge at 40 amps or so, I don't want to charge them at too high a rate. So I may need to leave the computer and a light or two on to keep the amps around 40 into the battery.

Typically, for your system, the peak average solar charging current will be around:

• 8x100 watts * 0.77 derating * 1/14.5 volts = 42 amps or so

You have thin film panels which will provide extra power (20% or so) during their first few months before falling back to their rated values.

I would not recommend "wasting" power to keep the battery charging current low(er). Hot summer days, you will get less current. Cold winter days you will get higher current but less hours of sun.

Goal #1 is to not let the battery become "deficit charging"--I.e., using a bit more energy per day than you are returning back to the battery.

The Battery and Charge Controller will work out their differences. Once the batteries are nearly full--then you can use "free energy" while the sun shines (typically water pumping, washing cloths, etc. during the afternoons).

-Bill

Re: Finally hooked up the system, WOW

Will you get more out of your system with new panels on a cool day--Your peak could easily be > 60 amps:

• 800 watts * 0.95 charger eff * 1/13.0 volts charging battery = 58.4 amps or more

As the thin film panels age (around 6 months), as you hit higher summer temperatures, as dust collects on the panels, etc... The peak current will slowly fall.

The big thing to remember is your hardware will work pretty well no matter how you beat it up (within reason)... The batteries, however, will not. If you do not treat them well, you could kill them in weeks or months (or even days) instead of getting the 5-10 years or so you would like from them.

It will take you few days to see how your system performs and what your loads are like... And you will probably see your system in "float" in the afternoons and that is the time to start adding your optional loads.

Remember, the charger is outputting all the available current until the battery system hits ~14.5 volts (or whatever your absorb setting is). At that point, the battery is ~80-90% charged and it is starting to reduce its current draw.

And, at the same time, the charge controller may be throttling back on its current output to keep the set-point voltage.

At that point, you can start drawing your "free power" for other needs--as otherwise, that current will be lost (battery will accept less current as it approaches 90-100% state of charge).

If you are getting your batteries above ~90% state of charge at least a few times a week, and avoiding much time below ~75% state of charge (sulphation region), and avoid going below 50% state of charge very often--You should have a nice long battery life.

Also, if you have flooded cell batteries--watch the water usage... Too much water usage, you may want to crank back on the Absorb time/voltage. Too little water usage, check your loads and voltage set-points/timers.

What is the "optimum" amount of water usage--Just a guess but if you refill (not overfill) about every 2nd month on average--You should be doing OK.

And you may want to change the absorb time between winter and summer (winter >4 hours; summer ~2 hours)...

At least as a starting point. Others with Outback chargers can probably give you better pointers than I.

-Bill

Re: Finally hooked up the system, WOW

From where you were last August (2010):

bbbuddy wrote: »

Background:
We have been off grid for 6+ years in northern AZ, and have lived with an old Trace 2012, 4 L-16 batteries, and multiple generators which have supplied the power. Oh, we do have 40 WHOLE WATTS lol of solar that came with our 5th wheel.

The Trace charger function has now messed up badly twice and ruined the battery bank, it holds maybe 1/9th the amps it should.

So, while exploring options online, I ran across the sunelec.com $1.20 per watt Dupont solar panels, and jumped on it, along with a Flexmax 60 controller for those 76 volt panels.
We bought 8 panels, and a neighbor bought 2 but later had second thoughts, so we will get his as well, for a total of 1000 watts.

Naturally we have to get a new battery bank, and now NEED to upgrade to 24 volts to handle the panel output (76 volts @ 13.34 amps in parallel).

Our 8cf propane fridge let all the ammonia out earlier and rather than fix/replace for $1200+, we got a 10cf 110v fridge from Lowes for only $340 thus helping to pay for the solar panels.

So, being that we already had a 10cf freezer to store my DH's occasional elk, etc. we now have about 2200 watts total of cooling (freezer AND fridge) to deal with, my 8+ hour per day internet habit, 240 watts of lights at night, and tv at night.
I figure about 4200 to 5000 watts per day would keep us fat dumb and happy.

Laundry and once-a-week well pumping could stay on the gennie.

Naturally at this point I thought all I had to deal with was mounting the panels, and buying the new inverter and load center, although my DH is a commercial construction electrician-turned-superintendent, so I was thinking maybe we could make do without a commercial load center and wire the components up ourselves...

So my first question here remains what problem(s) with the Flexmax 60???

Oh, I will have a ton of future questions, too, lol.

It does have to be almost magic now that you will have most of the year with Zero genny noise.

What you do not want to do is put large amounts of current into your battery bank for long periods of time... Short time is not going to be an issue..

The 13% rate is the typical (always check the battery manual for your vendor's recommendations) maximum sustained charging rate recommended for a long battery life--Higher rates could overheat the battery bank--Monitor your battery temperature and makes sure that it does not get too hot.

13% becomes the, roughly, a cost effective maximum array size... People put 25-30% sized battery chargers on banks all the time--mostly these are grid and generator powered devices (high peak power is typically much cheaper than paying for all that solar glass out there).

Watch the Specific Gravity and understand the Trimetric and what it is telling you.

No water for flooded cell batteries could indicate undercharging.

-Bill