Regie

After more than a year I finally reassembled the old Microcare unit. Older forum members may remember I repaired it some time ago. It had blown the DC/DC converter stage used to drive the main power MOSFET on the high side. My solution was to rip out the discrete implementation and replace it with a small 12V-15V isolated converter.
Of course I did test it back in the day: It worked fine up to 140W and then it would reboot itself. I'm still hoping that problem has to do with the noisy power supply I was using to test it. I cannot find anything wrong on the board, so I'm going to assume it is fixed until I find that it isn't. If it isn't fixed, then the PIC-based control board will get chucked in favour of something based on the ATMega 328P. Time will tell.
Anyway, this post is to report on some current numbers. Now that it is fully assembled again, I measured the quiescent current (on a 12V battery setup), and I can report that it needs somewhere between 40mA and 50mA. My meter sadly doesn't do better than the nearest 10mA. Because I know that the very first item in circuit on the board is an SMPS, you could probably expect this number to drop to less than 20mA at 48V.
I noticed another interesting behavourial aspect. When I did a similar test with the Victron BlueSolar MPPT and a current limited supply to simulate the PV side, the behaviour was to run into the current limit and then back off cyclically, but the cycle was slow, maybe 1hz. My PSU has an LED that lights up when the current limiter is active. On the BlueSolar, it goes dim and bright cyclically at around 1Hz. On the MC this behaviour is different. It simply runs it into the current limit and then holds it there. So the algorithm is definitely a little different :-)

I did PM Chris D last night with my Axpert Guide.
I am happy with the setting as proposed by Mark and yourself. 
My own system the battery bank is undersized at 260Ah. Chris D's system is very similar in other respects to my system but his battery bank is even smaller than mine. A major drawback is that Chris D is limited to only 10A charging whereas on a good sunny day he has the potential to be producing about 45A. Chris D needs to probably micro manage his loads to gain the full potential of his investment. I have to manage my loads but it is easier with a larger battery bank. A battery bank of 400Ah + is probably what we should be aiming at.

According to the datasheet of the CEIL POWERSAFE NXT batteries:
Bulk charge should be at a voltage of 14.5V - 14.7V per battery => 58V - 58.8V for the bank Float charge at a voltage of 13.7V per battery => 54.8V for the bank Axpert (voltage) settings
05 - Battery type - USE 26 - Bulk charging voltage - 58.4V (the maximum on the Axpert) 27 - Float charging voltage - 54.8V The current settings etc. etc. depends on your preferred way of charging, your set-up and your application e.g. 2000Wp worth of panels, off-grid, only charge via solar etc. etc. You'll have to elaborate on the rest of the system and your application in order for us to make more suggestions.

What interconnects are you using?
Are all the bolts /  nuts secured properly? 
Can you take an ohm reading of each interconnect and compare them?
And, perhaps, take a multimeter and compere the Voltages with your BMV, especially when the readings are high - just to rule out a bad BMV / bad cables / bad fuses / etc. 

Have a look at  each of the thin wires supplied with your BMV. Use your multimeter to check the resistance Ω. They should be the same. Each wire is fused (the lump in the middle). Have the fuse and its setting checked. If the cables are fine you are noticing the early stages of batteries going out of balance, which happens first in late absorb and then the time period gets longer and longer. I have also noticed it is worse when charging current is higher.
They are Chinese manufactured battery balancers.
http://www.ebay.com/itm/Battery-Equalizer-HA02-4-X-12V-Used-for-Lead-acid-Batteris-Balancer-Charger-/122138833727?hash=item1c700ab33f:g:ZIwAAOSwLF1X3ksV
If you are based in South Africa you can get them from @Chris Rossouw. They only start operating above 2.4V so with 56.4V as your bulk charge the won't work with individual cells. You could pair the cells up. I was mistaken so you will not be able to use a HA01 which is specifically designed for 12V.  You will get away with 4 HA 02 balancers. 

Lightning will probably jump almost any fuse, so I doubt that any fuse will prevent a lightning strike from causing harm down the line.
Your best bet is to divert the lightning with the shortest possible path with the least resistance directly to ground, but even if you do that it is not guaranteed not to char few things down the line.

Price per kwh stored is all I care about. If the cycle life is similar, go with the 12V one seeing as it is cheaper :-)

Hacked the Carlo Gavazzi into a lights circuit to check what these MR16 down-lights really use. As expected, the real power is on the low side (mixture of 5W and 7W lamps totalling 32W, plus some losses on the transformers). But look at the apparent power!
Theory: by retrofitting the MR16 to the existing wire-wound iron-core transformers, I now have a 5W lamp on a 50W transformer. Unladen transformers have notoriously bad power factor, typically less than 0.4.
With all the lights on at night, we're running maybe 200 watts, but over 600VA. I don't like that.
So some solutions. First one, rip out the MR16s and go GU10. Another solution is to place more of them in parallel on the same transformer. This would mean I can never go back to halogens, not that I would want to... but a future home-owner or tenant (if the unthinkable happens and we have to sell or lease it in future) might. Third option, replace them all with the electronic variety, some which will actually work fine in this low-wattage application, eg:
http://www.gelighting.com/LightingWeb/na/images/led-mr16-transformer-compatibility-table_tcm201-23431.pdf
http://za.rs-online.com/web/p/lighting-transformers/8117140/
Right now I'm thinking, just parallel them up and add a 5A fuse for safety, in case someone tries to use a halogen.
What say you guys?

That's like the blonde joke of "only the bottom part of the tyre is flat". No, not how it works. With flooded batteries there is SOMETIMES an issue with stratification, in that the electrolyte might not be consistent across the whole plate (with higher liquid densities sitting at the bottom), but a good charge cycle will sort that out. With AGMs... no such thing. Gravity does not determine where the chemical reaction takes place :-)
I heard similar arguments though, but it has a different basis. Basically, if you look at the cycle life of most batteries, there is little difference between permanently leaving them on float of doing a shallow cycle. So the 25% cycle comes mostly from there (as far as I know?), because such a shallow discharge does not significantly shorten the life any more than "not using" them at all.
Trojans (flooded batteries) need a good boil every now because of the stratification issue. With AGM I wouldn't bother.

i've found general rule of thumb calcs are about 4 to 5 times the constant load gives you PV Watts, then Battery watt hour is constant load x 30 for roughly 20-30% DOD.
in this case then what the guys are saying works out. 300W constant is 1200W worth of PV and 9000 watt hour storage, on 12V that is 750Ah. 
 these calcs work out nicely if your talking about a constant load.
just because you arrange them differently to 12v and then have more amp hour capacity doesn't give you more storage.its the same amount no matter how you arrange it. you will need double the batteries and have 1200W of PV to attempt off grid.
ps, Deltecs not bad batteries at all. not truly deep cycle and more Leisure caravan that sort of thing but good none the less.

We all know that in SA there are two types of electricity supply. Single phase and Three phase. What most people don't know is that when it comes to how the "earth" is supplied there are also different ways. (All legal and above board). One of which is tapping a wire off the neutral and supplying it as a earth wire to the consumer.
When you have a 3 phase power supply you will have 4 (or 5 wires) coming from the municipality. 3 of them are the live phases, one of them is Neutral. The three phases (live wires) will have 230 Vac relative to the Neutral wire. Remember Voltage is always measured between two points. In this case a Live phase wire and Neutral. In the distribution network the Neutral is always considered as the reference voltage (0V). But by convention the Earth (the planet) can also be used as a reference voltage 0V. It would be a very bad thing if the Neutral wire would be at a much higher voltage than the earth... So what Eskom does is they earth the neutral wire that come out of the generator. They also earth the neutral at various points in the distribution network. This is to ensure that the voltage difference between neutral and the real earth is very close to 0V. So in theory there is nothing wrong with splitting the Neutral wire into two, one they give you is labeled earth and the other is labeled neutral. (This is fine because the neutral is suppose to be earthed further up stream in the distribution network.) In an ideal world this would be the end of the story.... but..
Here's a little test you can do. Take a volt meter and switch it to measure mV. Now take the two leads about a meter apart and see what it measures. It will most likely never be 0V. The further apart the two points you measure the higher the voltage can be..  Depending from how far you are from the point where they earthed the neutral and how well its earthed you may find that there is a voltage difference between the Neutral and the real earth at your property. Typically this should be a small voltage difference.
The thing that really mess things up is when they steal cables.. If they break the neutral cable before they break the live cables you can potentially get hundreds of volts on the neutral wire and serous voltage differences between a given live and neutral wire!  This is because breaking the neutral cable they've effectively disconnected it from the ground.
In many cases (such as yours) the earth wire that you get from the municipality is nothing other than the Neutral wire. In addition to them bonding it to the earth, it is also connected to all the metal fittings in your house and all the other houses, all these fittings are connected to the earth really, so they all pull down the voltage of the neutral/earth back down to 0V relative to the earth. The problem comes in when its not done this way and the neutral is not bonded to earth properly in the distribution network...
If your sparky picked up that there is a high voltage between the earth/neutral supplied by the municipality/eskom and the real earth it could point to a wiring fault on the local distribution network. If I were you I'll contact the municipality and ask them to check it out.
Normally your appliances (inverter, fridges etc) would not be affected. They only really use the live and neutral to operate, they only care about the voltage difference between those two wires. The problem comes in with the earth wire you get from the municipality, if its connected to the metal casing of the fridge for example and you touch it you might not like it very much.
In theory the earth you get from the eskom/munisipality should be at very close to 0V relative to the earth and it should be perfectly acceptable to use it in your DB and for grounding your PV panels etc. It should be okay to connect it to your own earth spike as well. In your case I would not do that until the municipality had a look at why the earth/neutral is at high voltage.
 

I think in an off-grid situation the Axpert comes into its own. It is not a true hybrid and is therefore either 100% solar or 100% grid/gennie backup. You not paying for functionality that you would rarely use. It is nearly pointless to run a gennie and then only use portion of the available power. You are paying for the fuel so only using a portion of the energy generated is false economy.
I would like the ability to combine gennie power with inverter power to power oven and hostess at the same time when we entertain. Two Axperts would do but I fear I could not parallel them and have them on different phases of my 3 phase generator so back to square one.
Addition: If I was crossing the Pacific I would want the best kit money could buy since my life would depend on it. But back here in the Karoo I have two generators as backup and essentially the most critical items would be perishable food and vaccines that need to be kept cool. Worst case scenario in a urban environment is SWAMBO sh!ts on your head and your Eskom bill is higher that month compounding your financing of your inverter repairs.

HaHa TTT. You not going to win this one. I quickly looked on PV Output and 76% of systems reporting to PV Output from South Africa are Axperts. If they were cheap and nasty I don't think the figure would be so high. Victron is very good kit well built and with good (not not excellent) documentation, but is that enough to warrant the premium one is paying?
I am not going to scratch out new prices but using prices when I installed my Axpert a year ago. For a 5000/24 Multiplus Victron you can get 1 Axpert 4kW, 4 x  260Ah batteries and 6 nearly 7 250W panels. I have not included a SCC. That would also be worth a couple of panels. I will be the first to admit that I have not had a failure which would be enough to temper my enthusiasm. Mike's reporting of failures on Axperts is troublesome. Still 40k is a lot of money and extends you ROI by a third on an average system.
In short would I like a Victron over an Axpert - yes. Would I pay R 30 k more for that privilege - no. Maybe when my ship comes home I will indulge myself.
 
Now that I have the PDF open I see it is a total Outback system. Price?

Aaai man... a little bit of common sense really. If they are the same voltage and you put them in parallel, then they can be different wattage. P=VI, but V is the same (because they in parallel), so they will simply contribute current according to their capacities. This is more or less true, except for one little caveat, the power curve might not be matched.
So back to basics, a PV panel is a constant current device over the linear voltage range (if you look at the power curve, you'll see the middle of the chart is more or less a straight line, hence "linear"). See the stolen attached with different curves for light levels and temperatures. This breaks down at the edges, at low light and as you approach Voc. Now imagine you have two panels with slightly different Vmax levels. You will then have two panels in parallel that behave similar to what you see in the attached chart at different light levels: One of the panels (or strings) will be pushed out of that linear region (off the cliff on the right) if you push the voltage towards the Vmax of the other panel (or string).
Now consider what the MPPT does. Most of them do perturb and observe: You perturb the voltage a little and see if the power increases. If it does, you continue perturbing it in the same direction until you see the power come down, then you perturb it in the other direction, until the same happens, until you oscillate around Vmp. What happens when this is done with two strings where one has a lower Vmax? I cannot conclusively say or prove this... BUT... what I would expect is that the drastic power drop that happens in the string with the lower Vmax will be noticed by the MPPT and it will therefore approach the lower of the two Vmax values. This means your panel with the higher Vmax will run at a less than optimal voltage and you will lose some power there. How much? Well, subtract the two voltages from each other and multiply it by the current rating of the suboptimal panel, that's how much you will lose.
So say you have a 300W panel (37V at 8 ampere) and you parallel with a 200W panel (36V at 5.5ampere, for illustrative purposes), then you will lose 8 amps at one volt, or 8 watts per module.
That's not optimal, but it is FAR from losing a third of the power, which is what happens if you series them.

If the strings end up having the same voltage it will technically work and not blow up but its generally avoided. One reason i can think of why this is not recommended is that if you run the exact same panels with all the same characteristics facing the same way and angle, the MPPT will track easily and accurately, this is not so if you mix panels. Different panels will have different "power curves" even if the OCV or rated voltage is the same, basically its not optimal and it will likely just perform poorly. 

Real problem with going too small on a turbine is that it will only deliver that power at a very specific wind speed, any period of time the wind speed is lower or higher than that derates the turbine. So to get an average of your base load you have to install much bigger. I think the general rule with wind turbines are that on average they generate 1/3 of their rated capacity on an annual basis.

here is my battery state overnight. must say we have had good wind the last few days. 11pm we peaked at 1928w
 
file:///Users/michael/Downloads/solWeb.html
 
solWeb.html

Mockup

Well done, Weasel, you've spotted most of it.
This is a monitor and control system for my Solar installation, it will feature:
Monitoring each battery's voltage individually (string of 4). Monitor each battery's temperature (up to 16). Measure current into and out of the batteries. Measure current and voltage from PV's. Read grid voltage/Wh from the inverter. Integrate all this to determine Wh obtained form the sun, into batteries, used by the house, etc. Control the (Axpert) inverter to make optimum use of the batteries (not just based on voltage, but on SOC). Try and optimise usage of the PV panels. Display any 10 parameters (on the 7-seg LEDs) in real time - for viewing at a glance / from a distance. UI on the LCD for configuration, graphs (maybe), etc. Log to an SD card. Report via WiFi for remote access. Alarm indication with buzzer. Relay outputs to allow, for example, an aircon or geyser to use excess PV energy instead of wasting it once the batteries are full. Estimate remaining battery run time and display in real time. Integrate with the battery balancer (coming soon) Count battery cycles, monitor battery health over time to guess life expectancy. Etc. All this without having to keep your computer on.

Photo was taken at about 8 am so shade never covers panels during day, even in winter, I made sure of that.  4 strings, 3 in series.  Did the installation myself.

The compressor motor of an inverter aircon runs on DC and the speed it runs at is adjusted according to the difference in temperature between what it is set at and what it currently is at.  I'll try and explain it by means of an example.  If the aircon is running in cooling mode and the temperature is set to 22°C and currently the room temperature is at 24°C the compressor motor will not run at full speed but say at 25% because the delta T is not much and if the aircon was specced correctly and no other unforeseen external factors are present (e.g. a fireplace heating up the room at that moment) the aircon should be able to reach the set temperature quite soon. If however the aircon is set to 22°C, but currently the room temperature is at 30°C, the compressor motor will probably run at full speed or close to that since the delta T is quite big. Obviously the faster the compressor motor runs, the more power is used. Therefor the aircon might use as little as 300 to 400W if the room has almost reached temperature and just have to maintain that temperature, but on the other hand it will use a lot of power (run at max) if you've set the temperature to 16°C and it is 40°C outside and all the doors and windows are open. 
Conventional aircons work like typical refrigerators where the compressor always runs at maximum speed until the set temperature is reached and then it switches off completely until the temperature has changed by a degree or two and then the compressor is turned on fully again until the set temperature is reached again - this is called cycling. Obviously if you've set the temperature to 16°C and it is 40°C outside and all the doors and windows are open the compressor will also run continuously and theoretically draw the same amount of power as an inverter aircon under the same circumstances.
Where an inverter aircon also use less power is where an aircon is specced incorrectly or used incorrectly. Unfortunately aircons are frequently underspecced, because things like insulation on the ceiling, sun shining directly onto a window, large windows, a room on the second story / highest part of the house to name a few all influences the size of the aircon required and in most instances only room size is used to determine the size of the required aircon. The the biggest problem is user training - a comfortable temperature to set the aircon at is between 22 and 26°C for cooling and around 18 - 20°C for heating and most people does not know that and often sets aircons at 16 or 18°C (lowest possible setting) for cooling and 30°C for heating and most of the time the aircon will never be able to reach those extreme temperatures unless they were initially overspecced for the specific room / area. In such an instance a non-inverter aircon's compressor will constantly run and never reach the set temperature and obviously constantly use maximum power, but under the same circumstances an inverter aircon's compressor motor might initially run at full power but will gradually start to run slower and use less power as the delta T becomes smaller and therefor an inverter aircon might use less power than a non-inverter aircon.

It's not always that bad. The kinds of things that blow are electrolytic caps, switch mode power supplies, and things like that. Those caps can make an almighty bang, in fact in a second I will tell you a story about those. The CPU and control circuitry will often run from 5V or even 3.3V, so there will be a step-down converter in there. These tend to get expensive for high input voltages, so it will be rated just high enough for the intended voltage. If you are lucky, you blow up that SMPS and nothing downstream from it. So your CPU and control circuitry might be okay. Then there will be a boost stage for driving MOSFETs, might have blown something there too. And then there is your MOSFETs driving output stages, might have blown some there too. Do not underestimate the cost of a high-power MOSFET, they are anything from R5 to R100 a piece depending on part number.
So this story I wanted to tell you. I was in a Technical/Academic high school, which means we had a technical subjects alongside our usual academic maths/languages/physics. So in the last two years I sat in the electronics class, where we had this long work bench with electrical sockets. So what we would do, is take an electrolytic cap, then use a pencil to open the shutters on the socket, put in the cap, pull out the pencil. Everyone get out of the way... flip the switch:  *BANG* that thing takes off like a rocket.

Of course, it wasn't long after that when the teacher turned off the breaker to those plugs.

Hi TTT
Have a look here
 

Charging is limited to 15A so @ 12 V maximum is 200W and @ 24V 400W. Extra batteries and you will get better production out of your panels.
 

The big trick for using grey water is that you DON'T want it to stand. It becomes smelly very quickly.
My shower, washing machine and bathroom basins flow into a 100l tank. You could even get away with a 50l tank (No need to dig a big hole) Then I have this:
http://www.dabpumps.co.za/web_network/southafrica/en/page_471.php?serie=352&linea=68&language=en&minisito=13
It is linked to an ordinary garden hose with a "Skilpad spuitjie" at the end. It switches on and off by itself based on the water level in the tank.  In summer we move it once a day, rotating it through a section of the garden over 3 days.  I have disconnected the automatic sprinklers from this section of the garden.
PS - Make sure you are aware when somebody is in the shower or the wife is doing laundry.....

I know it's overpriced! But it does look nice and helps when you have limited space ;-)