Homemade Solar PV Update

[sandovalch]

Well, It's been quite a while since my last diary entry. I have done some major changes with my homemade PV system.

Here I finished the room for my batteries, inverter and charge controller. Still have to save some money for more batteries, but that has not been a priority just yet.

My batteries and inverter, I have changed the cabling going from the inverter to the utility/solar switch. I put in a 10AWG cable. It was just a 8m run.

This is the most significant improvement in terms of energy production. I changed my Trace C-35 and installed a C-60 charge controller. Noticeable are also the cables coming from my solar panels. Since my configuration is a 12V and I am 14m away from the solar panels, I had to more than double the cable size. Now I have 2 x 2AWG cable + 1 x 4 AWG cable. It should be the correct size for my setup when I finish installing all the solar panels.

This is a view from all of my solar panels so far. 18 in total, but hoping to install about 6 or 7 more.

Another angle. Noticeable is also the angle of the panels, since I had to compensate for the angle of the sun.

This is the reading of my charge controllers panel. This photo was taken today at about 10:30 in the morning, so no full charge capacity, and the weather was a bit misty. The batteries were also at 13V at that time.

I'm still not at my 40-50 amp capacity and still have to work on a solution on why the 18 panels do not produce more power.

One mayor improvement in the whole configuration was the introduction of shottky diodes, It seemed like some panels (which had whole cells) were cancelling out others which had chipped and broken cells.

But 400Watts for cheaply made panels I think is a good deal, at least enough to energize half of my home for the whole day.

What do you guys (and girls) think?

[BT Humble]

I'm still not at my 40-50 amp capacity and still have to work on a solution on why the 18 panels do not produce more power.

...

But 400Watts for cheaply made panels I think is a good deal, at least enough to energize half of my home for the whole day.

If you've constructed 400W worth of panels then I think you're running about right.  

To compare it to my setup:

• 4 x 140W Shell Solar panels;
  
• 2.5m cable run, 2 pairs of 10mm2 cable;
  
• 24V system
  
  

The best output I have seen (~11AM on a cold, clear midwinter day, batteries at ~26V) was 21 Amps.  That would equate to 42 Amps in a 12V system, or 42 / 560 = 0.075 Amps per watt.  

0.075 * 400 = 30 Amps, so I think you're right on the money!  Well done! ;-)

BTH

(And I'll bet your panels didn't cost you $4800 either!)

[Tom in NH]

Nice looking system! Your charge controller is going to limit the current depending on the state of charge of your batteries. Maybe that's why you're not seeing the current you expect. The current in my setup varies from 5A to 35A depending on the S.O.C.

The days when I get a beautiful sunshine and all I put into my batteries is 10 amps because they're pretty well charged by 11 a.m. makes me think I should add more batteries or a dump load.

--Tom

[BT Humble]

The days when I get a beautiful sunshine and all I put into my batteries is 10 amps because they're pretty well charged by 11 a.m. makes me think I should add more batteries or a dump load.

Those are the days when I do my clothes washing.

(Not that I'm implying anything by that!) ;-)

BTH

[ghurd]

It looks great!

Powering half the house is no small achievement!

Sandovalch and Tom,

Sounds like you both could use more batteries, IMHO.

Most of the days solar power is between about 10:30 and 2:00.

If the batteries are high enough for the controller to start regulating before 12:00, then much of the days available power is not going into the batteries.

If the batteries are undersized, the controller is reading surface charge more than SOC, so the batteries are not actually full.

A couple more batteries would help, but I can not say how many is best.

Does that make sense?

G-

[sandovalch]

Thanks for the comments and input. I definately need more batteries and in a short time I will be aquiring more.

[Tom in NH]

Yeah, it makes sense to me, Ghurd. One thing that impresses me about a PV system is the delicate balance of all the components. You go changing one thing like adding a battery and everything else shifts. I would like to triple or quadruple my battery capacity (currently at 500 AH)one day soon. Of course, then I'll need more panels, a larger load, bigger fuses, larger battery cable....   --Tom

[ghurd]

With all that effort, add a couple extra panels more than you need.

But that will mean more batteries!  

G-