How many Ah would you expect to get from a 400W solar bank?

The manufacturer of the cells and the manufacturer of the panel isn't always the same. So you could buy panels made in Germany, but constructed using Chinese cells. Technically, i suppose you could also buy Chinese panels made up of German cells, but i can't see that happening. Those Solara cells linked to by Kelly are extremely good, i have a pair of 30w Solara panels on the coachroof that were fitted 30 years ago.

I've always said that Solar is a long term investment, so you might as well buy decent panels. It also makes sens to buy the best you can get for other reasons. If you fit cheap and nasty low yield panels you are wasting space on the boat. You then have to fit more panels to get the yield that you want, so they don't actually work out as cheap as they might seem to be.

Oh, my newest panels don't come from Germany, or China, they are made in the US (or at least the cells are). I've got a pair of "back contact cells" panels. As all of the contacts are on the back they are more efficient for the size of panel. Not the cheapest, but they do work very well.
 
KellysEye said:
>My "German" panels were made in China!

In that case you didn't check who made them before buying them. An example of German made panels is here: https://www.solara.eu/home/
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As is usual for you, that is not a logical conclusion. Graham may well have checked but, lacking the crippling effects of your xenophobia, decided that there is nothing inherently wrong with Chinese panels.
 
These answers make it sound as though solar power is very complicated to operate. I've found it very simple - the batteries charge up when it's day light via a simple or complicated regulator. I've used Lensun semi flex panels which I believe are made in China with no problems cheap eBay pmw regulator to prevent overcharging. The system looks after itself with no attention from me. Batteries always charged.
 
ghostlymoron said:
These answers make it sound as though solar power is very complicated to operate. I've found it very simple - the batteries charge up when it's day light via a simple or complicated regulator. I've used Lensun semi flex panels which I believe are made in China with no problems cheap eBay pmw regulator to prevent overcharging. The system looks after itself with no attention from me. Batteries always charged.
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The only complication arises when one has the possibility of a shadow falling across some of the panels. I have 4 panels so could have 4 in series, 4 in parallel, 2 x 2 in series/ parallel, 2 x 2 in parallel/series and many more 3 x 1 permutations and each variation will yield different results according to the exact conditions. :ambivalence:

If you think that's "very simple", you are Albert Einstein's mini-me and I claim my £5. ;)

Richard
 
PaulRainbow said:
But it is also a very valid point that solar yield will vary with state of battery and level of load. I was looking at mine yesterday, for instance, the batteries were charged and the controller was in float mode, putting 0.8a into the batteries, but also matching the load. So if i turned things on and off the controller would increase or decrease the output to maintain the load, whilst still putting the same 0.8a into the batteries.
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I have 450w on an arch pretty much unshaded. Yesterday in good sun I recorded 11.8A going in at 1015 when the batteries were recharging and under no load. Later (1300) I recorded 21A when the electric toilet was being flushed. As the batteries came up to fully charged, the Amps ‘dropped’ to 0.3A still in good sunlight. These are real time figures and yes I was bored!!!
 
dslittle said:
I have 450w on an arch pretty much unshaded. Yesterday in good sun I recorded 11.8A going in at 1015 when the batteries were recharging and under no load. Later (1300) I recorded 21A when the electric toilet was being flushed. As the batteries came up to fully charged, the Amps ‘dropped’ to 0.3A still in good sunlight. These are real time figures and yes I was bored!!!
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:) I've sat looking at my battery monitor and solar controller monitor a few times. Sounds a bit boring but it does give a good insight as to what's happening, how the system operates in real time and how to make the most of the solar yield.
 
Admittedly, I've only had one panel at a time, small output, no live aboard, no fridge, fixed panel, but no particular shading problems although on swinging mooring. Limited experience I know. I would say in your situation, 2 banks of two in parallel would give best output with least shading problems.
RichardS said:
The only complication arises when one has the possibility of a shadow falling across some of the panels. I have 4 panels so could have 4 in series, 4 in parallel, 2 x 2 in series/ parallel, 2 x 2 in parallel/series and many more 3 x 1 permutations and each variation will yield different results according to the exact conditions. :ambivalence:

If you think that's "very simple", you are Albert Einstein's mini-me and I claim my £5. ;)

Richard
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As an update to this I took some of the advice and yesterday re wired two in series in parallel with another two in series. This gave me about 40 V and a couple of Amps, the sun kept changing, but not much improvement.
I then noticed that the short circuit current from each panel was behaving strangely and it would drop off to zero after 10 seconds and one panel gave half the voltage and no current.
On investigation the wires supplied with the panel had corroded terribly after less than 6 months so I opened the connection boxes on the back of the panels and soldered new wire and am waiting to reconnect and test again.
I didn't realise that I could access my charger setting through a dongle, I will have a look for one.
 
RichardS said:
....The maximum I have achieved since changing around my parallel/serial configuration for my 4 x 100W semi-flexible panels is 1300 Wh although that was in the Med in late September and the sun was getting lower.
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The very simple answer is just divide by 4, which equals 100Ah. But this depends on you longitude. Divide by 3 in the Med.

Your 1300Wh is about 100 Ah.
 
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