Sun hours

mountainman

Recently I was only getting 4 hours of direct sunlight on my array. Trees blocking wrong side of mountain and in a valley.  
So the first of July.   got a new chain for the saw and selected 4 trees to cut.
This gave me an area where I'd get sun for 6 hours. 3 before solar noon and 3 after. 10:30 to 430
Just my luck it was in the middle of the biggest boulders on the property.
With the help of my neighbor and his Kubota, we managed to clear off the top layer. 4 days of digging and lifting  out boulders.
Now after a rainy day. The next day with good sun I can get to 1or 2% before the sun leaves. Surprising what a week of work and  2 more hours of sun will do!!!
With only a 2.5 kw bank and a 1kw per day usages. I doubled my bank and array. 780 watts of pv  on a 5kw bank. 
Roughly a 2 and half day reserve. Picked up the 2 new batteries checking the sg 1.220 must have been on the shelf a while. 
Even after eq 1.265??  My old batteries show 1.275. So rather than connecting the batteries together. 
I put 4 100  watt panels on pwm on 2batteries
  And 2 190 panels in series on mppt on the other 2.
The pwm system runs all the dc rv loads. And the mppt runs all my inverted loads. 
So far its now working great. Come fall guess I'll be sharpening my chain.

BB.

A major downside of Lead Acid batteries... They need "time on charge"--And the deeper you discharge (towards 50% state of charge or less), the longer the absorb time needs to be (2-6+ hours of absorb, depending on depth of discharge).

When deeply cycled (towards 50% or less), it frequently takes ~2 days to get a battery bank fully recharged because of this.

Trees/partial shading and solar panels just do not mix well. Chainsaw--A necessary evil.

-Bill

mountainman

That was my strategy on increasing storage. I was using 40℅ daily now im using 20℅. Less time to charge on a sunny daily basis. 
After 2 days of no sun im at at 60℅ soc. 
I run the gen on the next day to bulk hopeful the sun will come out for absorb.

icarus

2 quick comments...first mixing new and old(er) FLA batteries is generally not a good idea.  The new ones quickly “take on the age” of the older ones.  

Secondly, and perhaps more importantly, a classic error many make when they over draw batteries is to increase battery size.  FLA batteries NEED proper charge current to remain healthy, generally ~10-15% of AH capacity.  

If your signature is correct, you 208 ah battery would then want ~20-30 amps of charge.  (If you have doubled that, 416 ah would like 40 60 amps.). 

780 watts into 12 volt battery bank, on an ideal day might push 48 amps at best. 6 hours, at 30 amps average might put out 180 ah.

1 kwh of use from a 12 volt bank would be ~80 ah, or about 20% of ah capacity.  

Tony

mountainman

@icarus 48 amps max is what I'm seeing. My question is how do you do the math on  average ah production?

icarus

Get a good monitoring meter, like a bogart, or Victron, which will count, and record AH in vs out, on a daily basis.  That will give you a real time look at your consumption and production.  Tony