Something tells me if nasa can send that satellite to touch the corona of the sun and still get data back then they can go pretty high in temps , at least some. (although they do use a heat shield it still get bloomin hot). Worth knowing though, that some degrade, can you automatically turn on a sprinkler system when the heat gets over a threshold….

LeeCavanagh wrote: ↑Mon Jun 26, 2023 9:14 pm Can you automatically turn on a sprinkler system when the heat gets over a threshold….

YES

That automatic system would be me with the hosepipe

BTW: I have ordered one one of those Infrared Laser Temperature Meters
So I can get some readings from the surface

I have just been up on the roof now @ 4:40 to open the doors wider to get some draft through
as a matter of interest I put my hand on a panel, I can cope with the heat for about 8 seconds

Albert H wrote: ↑Sun Jun 18, 2023 9:52 pm How are you going to use the power? The batteries you'll need will be incredibly expensive.....

OK mate...... I will reveal the secret
BTW: You are correct incredibly expensive

I have one of these at the moment but I'm planning for more

Pylontech 48V lithium battery US3000C 3.5kWh]

The Solar input panel Meters arrived today
I'm getting there

Testing the 3.5kWh Pylontech Battery

Specs say Nominal Capacity (Wh) = 3552
With a Usable Capacity of 95% (Wh) = 3374
Therefore with a usable power 3374W / 1000W = 3.37hrs -or- 3:22

On test with a Full Charge from Solar and with a 1000W resistive load...
and...
1)- A setting of Battery voltage point back to utility @ 48V it did 2.35hrs -or- 2:21 = 2350W = 66.2% of Capacity
2)- A setting of Battery voltage point back to utility @ 47V it did 3.12hrs -or- 3:07 = 3120W = 87.8% of Capacity

I'm happy with 87.8% it means it will last just that bit longer

Nice.

It's tempting to keep running them to a lower cutoff voltage but an exponentially decreasing amount of energy is available as you do so, because the voltage drop is not linear over time with a constant load.

Here's some curves of a battery I tested (admittedly it's lead-acid but it's still the same story regarding the droop) at a constant 2 A, with a cutoff limit of 10.6 V. The battery voltage is shown in blue (left axis) and the integral (in Watt hours) is shown in orange and uses the right axis. X axis is in seconds.
It's subtle on this scale but the orange curve is trending towards the horizontal, which makes sense as it's V x I x t and there's exponentially less of the unit V available as t increases linearly and I is constant.

Here's an image with a linear trajectory put on the top of the orange line to make it a bit more obvious:
The point is that in squeezing more out, you approach the damage limit very quickly for very little extra energy extracted.

I think about 85-90% of the nameplate capacity is a realistic and good figure to achieve. I this example the test lasted for about 47.2 hours until the cutoff circuit kicked in, at a constant 2 A, giving a real capacity of 94.4 Ah, with the nameplate stating 120 Ah, so just under 80%. I was happy with it at the time and still am.

I could have just found a curve on Google and pasted in but I thought it'd be nice to show some real-world results.

thewisepranker wrote: ↑Fri Jun 30, 2023 6:41 pm I think about 85-90% of the nameplate capacity is a realistic and good figure to achieve.

For a Lithium battery true

Like it says in the DataSheet
Depth of discharge (%) 95
+
Cycle Life >6,000 25℃

thewisepranker wrote: ↑Fri Jun 30, 2023 6:41 pm I could have just found a curve on Google and pasted in but I thought it'd be nice to show some real-world results.

Excellent stuff - I love graphs charts

Free tip: Use a couple of these babies in series!

https://www.nkon.nl/rechargeable/lifepo ... grade.html

ronald001 wrote: ↑Wed Jul 05, 2023 12:20 pm Free tip: Use a couple of these babies in series!

https://www.nkon.nl/rechargeable/lifepo ... grade.html

Free tip for who ?

I already have a Pylontech 3.5kW and I am planning more

Then there was two

I've had to change the Solar Panel layout because of the shadow the water tower casts in the Winter.

I hope the all day results will be as good as expected.