3kW PV, 48V battery bank, Schnider SW4840 ... haven't updated for a bit

I have not updated for a bit now.

We added another row of ten 100W GrapeSolar panels, so were now at 3,000W PV. We also moved from a bank of eight 6V golf cart batteries configured as 4 parallel sets of 2 in series to now running all in series for a 48V bank. The Schneider SW4048 works well and puts out good clean power (when the sun is flying high). The only complaint I have with the Schneider is that the phases have to be balanced if you are going to allow external power to supplement solar and solar will only be used on the least of the banks. Kind of screwy and didn't know it before purchasing. It's still a good inverter, but the system will need to change to be what we are wanting in the future.

What we've learned after 2+ years and a current stable system:
- we were over discharging our batteries, now we have the system programed to stop at 49V.
- with a battery based system, you will only get maximum PV output when there is a need for it: what that means is that in the middle of the day if the battery's are full, the Controller will try to maximize the battery state - NOT power. EX: when the sun is bright and there is plenty of power, the PV will only be feeding the controller what it needs, even if there are another 1,500 Watts of PV available, it'll never see it. I didn't know the system worked that way. It makes since now, but that's not exactly the system we want.
- the Schneider SW4048 is a good inverter, but not for the case where you are going to supplement with external power unless it is being used for 240V applications due to the phase balancing requirement it has.

Where I'm thinking of going next:
- to a system that is grid attached so the PV array can be putting out maximum at all times AND all breakers on the main can be using solar power.
- it will be less efficient, but I'll use the solar generated AC to feed my existing Schneider to maintain my battery bank and feed emergency circuits if/when the grid is not available.

So, a hybrid system is where I think we're heading, just taking slow steps to get there.

I would still encourage all interested in solar to get started!

Added 5 more 100 W panels 2kW ttl

This evening as the sun was going down I added the 5 panels that we purchased a few months ago when they went on sale for < $1.00 / watt. Rather than run new cabling from the roof to the combiner box I've added the standard combiner cables and have joined the two runs of 5 panels together at the roof. So the system is 4 runs of 5 panels with two being joined on the roof and those being routed to a combiner box on the board. There is room on the roof for one more row of 10 of these panels if we go that route.

Our PV Array is now 2kW (20x100W panels).

The next improvement will be moving from our 12 volt inverter to a 48 volt inverter. I am currently thinking of the Schneider SW4840 as our next inverter.


Once the panels see the sun I'll add more information.

1.2 kW PV, 832 Ah Battery Bank, 2000 W SW Inverter

With summer under full swing now, we just added to all the components of our off grid system:
- 2 more 208 amp hour 6 v golf cart batteries == 832 Ah @ 12 V
- 4 more 100 W panels == 1.2 kW arranged in 3 groups of 4 panels
- replaced 1500 W modified sine wave inverter with 2000 W pure sine wave inverter
- replaced 62 amp breaker between controller positive output and battery bank with 100 A switch
- replaced 6 AWG positive lead from controller to battery with 4 AWG

PV: 800 to 1.2kW
The system is working well. The AC power is very nice, properly grounded and can run small electronics with out any problems, hissing or issues. The system was 2 runs of 4 panels, combined on the roof in a combiner box and then put into a 16 A breaker before entering the controller. The 4 new panels are a third series and run straight to the board and into a 8 amp breaker before joining a combining bus and entering the controller. The current controller can handle just a little more at peak sun, so due to the current sale on 100 W panels, looks like I may be adding 1 more panel to each series for a total of 1.5 kW and according to MidNite, needing 1.1 classics -- just under the 1.2 recommendation of adding a second controller.

Battery Bank: 624 to 832 Ah
Added two more 6 volt golf cart batteries giving me the equivalent of four 12 V batteries in parallel. This gives us good reserve capacity and the ability to use most of our capacity during the day w/o any problems.

Inverter: 1500 modified to 2000 W pure sine wave
The output from this inverter is very nice. We've had no components complain, or fail as we did with the modified output. We will stay at 12 for now and possible add a second inverter if we need more power - mainly due to the large cost increase of purchasing a 24 V sine wave inverter. Checking the output with a standard plug checker shows that everything is properly grounded and the neutral is correct.

Still to do:
Add a transfer switch in the house so it's easier to have access to this energy.

How are we using it:
Things currently running are deep freezer, fan in green house, 2nd refrigerator/freezer, air cleaner, large DE-humidifier, radio ... with additional items as needed: including the crook pot, small oven, electric grill...

I think the max power was just over 1100 W yesterday - but it's not been clear sky all day so we're seeing about 6.1 kW for the day.

Spring Sun.... 800 Watt's of PV - 4.5 kW for the day

Today is the second day of full Sun and it's Great to get the batteries fully charged and to be able to use the Sun's energy. Yesterday and today we used/captured 4.5 kW each day. Some stored into the 4  battery bank and some used by the garage freezer, greenhouse fan, blender, box fan, backup refrigerator and the washing machine.

Our current system has 4, 6v batteries giving us 2 x 12v in parallel. We're just about ready to add 2 more batteries and increase our overnight and reserve capacity. We have 8 panels: 2x4 in series and parallel. I'd like to add 2 more 100 W panels to bring my capacity up to 1 kW and raise my Spring capture over 5 kW on a sunny day.

It's very satisfying to use energy from the solar system.

132 AMPs 12V DC cooking pizza

It's a nice February day with lots of sun. On days like today, I like to 'USE' the solar energy that is available: today that means running the garage freezer, backup fridge/freezer and my son is cooking pizza outside in the electric oven. We have a 800 Watt PV input stored in a 12 V battery bank (4x 6V 205 Ah golf cart batteries) with a 2300 Watt inverter.

During the Winter we're getting about 3 KW's on a normal day. My panels are set for Summer sun, so that would increase if/when I move the panels. None the less - it's nice to cook out side on a beautiful day like today!


Photos:
- Lunch! Cooked outside with solar power to our small elec oven.
- 132.2 Amps being used by the inverter
- 612 Watts PV to 51 Amps to the battery / inverter, about 85 Amps coming from the battery to make up the difference.

If only I had more panels, batteries, ... it's a never ending adventure!

2/0 AWG vs 2 cables of 4 AWG

I've got the Hydraulic crimping tool and the 2/0 cable lugs - but no 2/0 cable yet. What I do have is more 4 AWG. So I have redone the negative cables (from the battery to the shunt; shunt to inverter): doubled up two sections of 4 AWG wire .. wow, it's a nice connection. [I had to cut one apart with a hacksaw to see what it was like and it was like a single solid cable, absolutly amazing!]

I have a 200 AMP switch in the Positive line that I need to move before I recable the positive side. Once I figure that out, I'll make new positive runs as well.

From the information I've read, the two leads will have just a tiny bit more cable area than the 2/0 that I've not purchased yet. I don't expect to go much over 150 Amps and that only for a short time.

4 PV panels in series, in parallel, with 4 PV panels in series

My eighth 100 watt panel came earlier this week, but once I started taking it apart, I realized that I didn't have all the connectors I (thought I) needed.

Today the additional cables came, and a trip to the auto store for some butt connectors and I was ready to get on the roof and add the new panel. It is the same brand and model as the others (Grape Solar 100 watt). The system was wired 7 panels in series. That was giving me 156 volts now that winter is coming and my Midnite 150 goes into Hyper Voltage mode at over 150 volts.

With the addition of this 8th panel, I have wired them differently: 4 panels in series paralleled with 4 panels in series. The panels are in a row on the roof - but are intertwined so every other panel is in the same series. The end result will be half the voltage and double the amperage. It's still under 15 amps from the PV array and about 85 V.

I had to cut one of the MC4 extension cables and attach them to the 10 AWG wire that comes from the wire panel. The good thing was I was able to use the hydraulic crimper ... very nice.

Unfortunately it was finished in the dark, so I've not seen it 'work' yet. And the forecast for tomorrow is rain, and the next day, and the next after that. So, it may be a few days before I can observe how it works.

None the less, it is nice to not be over voltage and to add another 100 Watts to the system.

Only thing on my mind to upgrade still is the 2/0 cable to replace the 4 AWG.