phil.g00

Yes, this borehole was a game-changer, deep water is bug-free and this is as clear as lemonade.  
Until then my then girlfriend and I where pumping out of the river into a farm dam and using flocculant.
A couple of days in between while the tank settles.
My parents would now drink tea when visiting, they told me later that the tea had been too high protein for their tastes before the borehole.

I know how it is with family.
Just today I spent two hours at the wife's grave.
She thinks I am digging a pond, poor thing.

I know how it is with family.
Just today I spent two hours at the wife's grave.
She thinks I am digging a pond, poor thing.

Hi
Today I installed an alternative to the mechanical pressure switch which is used on most pumps with a pressure tank. These switches need to be able to set for a low-pressure pump switch on and a high-pressure pump switch off. I have replaced the mechanical pressure switch twice.
The switch I found to replace this is a digital switch with a digital led readout. It is larger however was easy to fit and programming was relatively easy. 
The best feature for me was that it has a pump dry cutout that can be set.
The switch is a Coelbo Switchmatic 2 which I purchased on special from DIY Direct SA.
The pressure switch does not come with the full instructions only a quick setup. I have posted the full instructions here.
switchmatic12_en.pdf SWITCHMATIC.pdf

No.
The combined positive and negative cabling length of parallel batteries should be the same so that voltage drops over cabling is the same.
Which in turn means that parallel batteries are equally charged/discharged at the same rate.
The same logic would apply to other parallel devices that are likely to draw high current during operation.

Balancing and equalization are not strictly the same thing and not really done for the same reasons.
The short answer: All batteries types can be balanced, but not all equalized. Don't equalize gel batteries.
For the long answer: Spend a while reading up on things.

If you feel intimidated, go ahead and comply.
I am just saying my stance would be, unless it's a law, they can huff'n puff and then go swivel.

If you feel intimidated, go ahead and comply.
I am just saying my stance would be, unless it's a law, they can huff'n puff and then go swivel.

@gooseberry I understand your logic.
Batteries won't save you money the costs are not on your side.
So that leaves a grid-tie inverter.
Legalities aside, some practical economic considerations:
If your array is uniform all your power will be delivered in about one 4-5 hour mountain sometime during the day.
If your tenant is at work no-one will use it and your inverter will throttle. (No sales)
If your tenant is home and doesn't need it at the time you produce it your inverter will throttle. (Minimal sales)
When a user uses his/her own solar he/she has an incentive to schedule his/her loads to match production to save money.
What incentive does a tenant have for scheduling their usage to make you money? 
 

I've seen recommendations of 6 inches minimum (Type L copper) vertical loop height within the first horizontally 6 inches of the cold water inlet and hot water outlet.

I think after analyzing his water needs, storage plus a smaller surface pump for night time and a smaller solar driven borehole pump during the day is by far the most logical solution.
But if your hands are tied by a dictatorial client present him with the pro and cons (and associated costs) of his options.
The cost of 9 inverters,  ( and the size of battery to run this at night steady state) and knowing that one failure puts him out of business should be enough to tip the scales.
Otherwise give him what he wants, if he's paying and accepts the costs and risks.
 

You cannot exceed the voltage rating of the MPPT, this is a hard limit. In your case I believe 4 panels in series will be the maximum length of string. 
Exceeding this voltage will damage the MPPT.
The number of strings is  a different story, this is the current output limit superimposed on you by the MPPT.
It is not a strictly a power limit but depends on your battery voltage. It might be known as a 48V system, but the charging voltage may be 10V higher. It is a current limit, in your case it is 100A.
If you added another North-facing string that peaked simultaneously with you existing panels you would experience "clipping". In other words you'd hit your ceiling output and the peak would be a flat line. Exceeding this limit shouldn't damage anything.
Indeed it may be worthwhile having a number of strings so that most of the year you don't clip, and only clip on great days.
I am a proponent of not having North-facing panels, and rather having E/W panels. This way I can get a lot more panels for the same noon peak. More panels are better when it is overcast.

No, you will exceed the voltage rating of the MPPT if it gets cold.
Normal slope I am referring to your roof pitch slope, vertical is self-explanatory. Not many people go vertical.
Probably in this ballpark, but I think you are being slightly optimistic with these numbers.
 

Read the specs of your panel, there is a temperature coefficient for voltage, meaning the Voc will rise as it gets colder.
If it gets cold enough the Voc will exceed 50V, meaning that 5 panels in a string will exceed 250V.
You may get away with it on the coast, but generally in the low minuses it exceeds 50V.

Just to have all the relevant info in one thread:
From this study:
https://www.solaracks.com/solar-mounting-structure-to-create-air-gap-required-below-solar-pv-modules/
"Conclusion
The installation of Solar PV modules on sheet roof is most ideal to have an air gap of 100mm to 110mm. Lower air gap will lead to increased module temperature, which will result in lower generation output. Higher than this dimension will have negligible cooling impact, but will have adverse effect of increased moment loads of fixing."

You cannot exceed the voltage rating of the MPPT, this is a hard limit. In your case I believe 4 panels in series will be the maximum length of string. 
Exceeding this voltage will damage the MPPT.
The number of strings is  a different story, this is the current output limit superimposed on you by the MPPT.
It is not a strictly a power limit but depends on your battery voltage. It might be known as a 48V system, but the charging voltage may be 10V higher. It is a current limit, in your case it is 100A.
If you added another North-facing string that peaked simultaneously with you existing panels you would experience "clipping". In other words you'd hit your ceiling output and the peak would be a flat line. Exceeding this limit shouldn't damage anything.
Indeed it may be worthwhile having a number of strings so that most of the year you don't clip, and only clip on great days.
I am a proponent of not having North-facing panels, and rather having E/W panels. This way I can get a lot more panels for the same noon peak. More panels are better when it is overcast.

Some reviews here: https://ie.trustpilot.com/review/tesup.co.uk
Hugh Piggott of Scoraigwind literally wrote the book on small wind. I would not discount his views out of hand.
He thinks VAWT are toys. 
However, even with a great turbine you need wind, if you don't live in a really windy place you don't have it.
If you add vertical E-W panels, you can produce watts earlier and later in the day using the same charge controller. They wont produce energy at night, but it is still at a time when your present set up isn't generating.
Maybe not a lot more watts, but I'd wager many times more than that VAWT in a year.

I was looking at the very same wind charger to supplement my solar system. I was doing a lot of research because I didn’t want to waste money on something that would essentially not work. I found this article (among others) and decided to rather just add more panels, as they are cheaper. Also panels have no moving parts. 
 
https://scoraigwind.co.uk/category/vertical-axis-wind-turbines-vawts/
 
However you can take a chance and see if it works for you. If it does, then I will buy one too... 😂😂

Maintaining water temperatures of between 20-50 deg C is a breeding ground for  Legionnaires’ disease.
Keep cold water below 20C, and hot water should be delivered in the tap at above 50C.
Geyser temperatures should be set at a minimum of 60C, and maintain that for 30 min before use or every 3 days minimum if in tank.
So watch yourselves with the down-rated elements and the incomplete heating cycles.

The ESS control loop adjusts PV-inverters every 5 seconds, but MPPTs generally react in the 100ms bracket? 🙂
 

I have two systems, with two different goals, one is there for load-shedding and one is to save money on the bill.
I don't really remember how many panels there are, but lots, around 25kWp maybe slightly more, but completely unoptimized.
The highest peak I have seen from my these is about 14kW on the larger save-money system.
That is over and above what the off-grid system is drawing.
(The 2 systems are on the same battery bank and only the save-money system has online monitoring).
When it is raining all those panels (now at a much lower % yield), prop up the smaller off-grid system.
The second bigger save-money system gets ditched (sort of like non-essential loads).
From a paper I've read, a flat panel yields about 50% more than an optimized north-facing panel when it's overcast.
Mine aren't flat, but at many combinations of mainly E-W at flatter that the optimum slope. ( Whatever slope that piece of roof happens to be).
The night-time demand on this off-grid system is very low, but the daytime demand fluctuates between 0.5kW and 3kW'ish.
The battery bank although theoretically large, is absolutely shot, and I mean absolutely shot.
5 year old Lead acid car batteries.
All I know is if the available solar doesn't meet my off-grid demand during the day the system will go down and it doesn't.
Because the system still trundles on those batteries remain, they are really more of a system buffer/dampener than a battery at this stage.
So all I have is a educated guess out of that +/- 25kWp in the rain, I am getting maybe 5 to 12%'ish.
But as I say the offgrid system doesn't the fancy VRM Victron monitoring that the save-money system has, so I can't give you definitive values.

Agreed.
I have a different approach though.
I have a big enough battery to see me through the night. It costs money and wont last 25 years. I begrudge the expense.
Instead of adding more storage, I add more panels. I don't add them at optimized slopes or directions, I slap them up as cheap as possible.
And what this does for me is this:
I don't care how overcast it is, I can charge those batteries and still have enough to get through the day.
I squeeze my MPPT's so that they have no margin's. I use AC coupling as well. I actively avoid noon day peaks in favour of a long solar day.
This combination of a great deal more sub-optimum panels on an overcast day still gets the job done. 
Every single day, .....40 days of Noah's flood if needs be.
How big would the battery be that could do that?
You'll get a shedload of panels for the price of these fancy batteries.
 
 

I'll see your 5-8Kw, and raise you... Currently I throw away 17-20Kw per day. But yesterday, in Joburg, I only just filled my batteries enough for the night.

Lesson: Have more than more than enough!

I'm going to connect up another 2Kw per hour array (array #5) right now.

(Damn... this drug...)

It depends on the situation and what you want to achieve.
For example: A grid-tie inverter in the right situation could save money for every watt it ever made without a battery at all.
But your lights would go out during load-shedding. Now what's it worth to you to keep your lights on?

So when charging the highest charged battery switches off both batteries when that battery is charged and the other battery doesn't reach full charge.
When discharging the lower charged battery switches off both batteries, while the other battery still has some in the tank.
Seems to me that if you top balance the two batteries, that the issues should be minimized.
Connect them both in parallel and charge them at the correct charge voltage for a day or two, and your issues should not be as bad.
Alternatively, get a HA01 battery balancer.