Louisvdw

1. You can run a full house on a 5kva. It all depends on how many things you want to switch on and use at the same time. For 99% of the time I run my house of a 3kVA Multiplus II. I have scheduled the big items to try and minimize concurrent use of those, so my geyser (heat pump) switch on at times when the stove and oven would mostly not be used. If it is used it will fall back and add extra power from the grid. 
2. Most of the time 5000VA is not 5000W. There is a power factor at play and if there was no losses in conversions then it would be possible. But not in real life. For instance my Multiplus 3kVA give 2400W, but only 1700W if it is very warm (65 deg). The better the components used, the better the power factor, so don't expect to much from that cheap inverter you buy at that sale.

@LouisvdwI just realized that you are the one and same that has done some great work on BMS comms/drivers etc.  That is just great work and you have distinguished yourself.
 
So I have question you might be able to entertain :  busy hacking the Qucc AFE ( anolgue front end ) and it's a sinowealth SH367309 . Also managed to download the data sheet albeit in Chinese , but Google translate was very good.  Actually impressed with what is packed in it. Question is , do you know the AFE of the later smart Daly models? Would crack myself if they one and same.😊  Was tempted to open up my own Daly ,BUT , the heatsink thermal sandwiches , don't want to scratch where it doesn't itch , plus it's brand new . 
 
Which begs a brand new question, do you think it's good  to repaste the heatsinks every 3 years or so, like we do with the high end PC graphic cards? I've done it twice , and tell you some paste has turned into crumbed rock to due heat , useless.
 
 

This on is my favorite. Might be closer to your Healey.
Also: Freedomwon batteries started as a convertion for a Jeep Cherokee. You might want to talk to them as they are in SA.
 
 

I've create the first release for the serial battery driver for VenusOS, with a few steps to install this.
https://github.com/Louisvdw/dbus-serialbattery
Currently this driver only works on the LLT Smart BMS range. 
Basicly any of their BMS that use the bluetooth app that looks like this:

 

No this will not work well for you. With 2 panels your 102.98V gives you 51.5V per panel and with 3 panels this will be 154.5V (will be even higher in winter). That is a bit too much over your limit. Your MPPT will shut down too much and you will loose production. I suggest you stay with 2 panels.

You loose very little. We are talking <5% so it is not worth buying an extra MPPT.
I have a MPPT where the one string face East and the other string West and this works great. All panels on the same string have to face the same direction though.
 
A assume this is 2S4P (4 strings of 2 panels in each string). You should be able to do 3 panels in each string (check your panel's spec for the Vmax). On paper your Vmax (the open circuit one) might be more than 50V which would limit your strings to 2 panels only, but in practice here in SA it is never so cold that you will get to that value. 
If you have been running your current install for more that 1 year you would have done a typical winter. So go check the stats on your MPPT in the Remote Console. Under Overall History you will see what the very max Voltage is your MPPT ever reached. If for 2 panels per string this is < 100V with some margin I will say it is safe to add a third panel to each string to get closer to the 150V
Here is my 100/20's history with 2x 425W panels per string.
The best thing is that even if you did go over the max for a little bit, your Victron SmartSolar has over voltage protection and will not break anything, but just shut down safely until the overvoltage has cleared. This is not true for all other manufacturer's MPPT though.

The latest build V0.3 of the driver has been released.
With the new version the driver will
automatically set your battery max voltage according to the amount of cells in your battery, so it will work out of the box for 4 cells (12V), 8 cells 24V or 15 or 16 cells for 48V setups (or anything in between if your BMS can handle it. it also has an auto installer that works with a USB flash drive/SD card which means you don’t need root access anymore. https://github.com/Louisvdw/dbus-serialbattery

I totally agree. I felt like a smithy in the middle ages hammering away on those big cables to make them fit nicely. 🔨
Might also be the reason that plastic DB cases don't work so well... 

I would suggest reading this forum. Everything is here. 
Not sure about which books if you want to read offline though

@Craigm I am no expert, but the Geyserwise PV system is specified so that it normally heat your geyser in around half the day. So if all conditions are good your tank should be heated by midday(ich).
However it is never just so easy. It depends on the sun your house receives, the weather, your water usage, geyser size and your house efficiencies (long distance from the geyser to where you use the hot water). 
Do the following test: switch your geyser on around 11am for 3 hours and then switch it off. That should be enough to heat the water to temperature. 
Now use your hot water as described above and see if it last. 
This is what any solar geyser will give you. You get the water heated during the day while the sun is shining. In winter there is less sun and in summer there is more. 
When you use hot water in the evening it is replaced with cold water. During the night this cold and hot water does exchange heat between the layers in your geyser giving you not so hot water in the morning (no matter how much you insulate your geyser as the cold water is already inside).
So in practice you will see that if everyone showers in the evening, or everyone showers in the morning a solar system will work fine. 
If some people shower in the evening you will need to use electricity to heat the water for the morning shower person to feel happy.


PS. This is true for any solar geyser system. 

Update now that it has rained. It got really hot before the rain came with 35 degree days, and these seedlings would have all expired if it wasn't for the mulching. The bare ground in other places was too hot to walk on, so the plants would have shrivelled.
We are getting a few weeds coming up now, so I just go around with a weedeater every now and then, and put some more straw close to plants. Or just stomp on the weeds and put straw down. Easy!
Tomatoes being staked up with first fruit:

Squash, pattipans, beans etc:

Pumpkins, hubbards etc:

 
 

If you do go the DIY option, I would suggest you look at a BMS that do have some sort of communication options (the normal Daly does not, but they do have a Smart Daly version. Or the ANT, or Smart LTT/DJB BMS). 
If you do have comms then there is always the option to link it to your inverter in some way like the driver I did for the Victron system. 
https://github.com/Louisvdw/dbus-serialbattery

You can add another bank in parallel. Charge both to full charge separately and then add them in parallel. That way they should have the SOC.
It wont be perfect, but it will very close.

No, the study is about the impact of a mix on a single MPPT. 
 

No, the study is about the impact of a mix on a single MPPT. 
 

I started to use my shower water (stand inside 2 plastic buckets while showering) to flush the toilet. The row of buckets next to the toilet became boring, I then decided to build a stand above the cistern to gravity feed water into it. On the stand I put a 68L Rough Tote box with a drain pipe and installed a extra float valve in the cistern. A normal float valve didn't work in this application due to the height difference was only 1m. On the internet I found Brooks Valves makes a high flow low pressure valves for cattle troughs, installed that valve and now the cistern fills within 40sec. I now throw my bucketed shower water and washing machine water into a 210L drum outside and pump it from there into the Rough Tote once a day, to fill the toilet. I used the extra float valve to control the level inside the tote but later had to install a Y type strainer in the supply pipe, because the hair sometimes started to stop the cistern valve from sealing 100%. After a while the water started to smell a bit funky, but now I  just pop a mini chlorine pill (small pill for jacuzzi etc) in the tote and that sorts that for about a month plus. Btw shower water doesn't start to smell fast, but the washing machine water goes funky within 24hrs in the tank. I use the remaing washing machine water or shower water to water the garden. I think this Brooks valve, will work for your rain water to flush toilets in the same setup as mine. In the past 6 months I've never used fresh water to flush a toilet. Once or twice I had to pump water from my rain tank to the toilet supply tank because there was more toilet flushes than showers. As a backup if the tote runs dry, you can just put your hand through the bathroom window and open the ball valve which opens the original municipal water supply to the cistern. Sofar it works 100% for me. My next venture will be to dig a hole for a underground 60L tank so that I don't have to carry buckets through my hose and the put limits on the pump sustem. It is a very rewarding project for me. Enjoy

The is an ANT-BMS. It works well. We are working on adding this to my driver. But it does not have that interface yet, although the BMS is capable of serial communications (RS485 with the screen and bluetooth to your phone). This is a good option for a BMS.
Let me try and explain it another way:
All Victron equipment can work independently, but then you then need to set each one up independently as well. They can even work with other manufacturer's equipment. However if you do not know what you are doing this could potentially give you some headaches. In the Victron world if you want to interconnect the pieces and let them talk to each other, then you need some kind of GX device. There are many options with the easiest those that are built into the inverters. See the comparison list here. If you do connect everything, you get more that the sum of the part. This is where their ESS(Energy Storage System) comes from.  You can also create your own GX device using a Raspberry Pi if you feel more adventurous, but as the Pi does not have all the same inputs as the other GX devices you need to use more expensive cables to make this work. So in the end if you don't already own a Pi (with power supply and case) then you will only save R1500 of the R5000 that a VenusGX or CerboGX cost and mostl likely even less than the built in GX cost. So my suggestion to make this much less complicated  is to use a build in GX (least complicated) instead of a Raspberry Pi(most complicated).

No. Everything connects to the GX device (the Pi in my case). So the MPPT, the BMS and the inverter connects to the GX device.
The GX is the brain of the system. If you do not have a GX device, then nothing talks to each other.
On top of managing everything, it then also offer remote monitoring.
My suggestion will be to take the Multiplus with the built in GX. It will make your install so much easier. Less (and cheaper) cables you need to buy and set up.
That is the Daly BMS that they sell. It is a solid BMS, but with no communications. So it cannot talk to the inverter and the inverter has to guess the battery SOC (State Of Charge). It works, but you do get that what the system think the SOC is and what the actual SOC is get out of sync. When this happens there is less of the battery that can be used. So not an issue, but better if they can talk. Then you can use the full potential of the battery. 

Try the Inverter section and mention Multiplus II ESS in your heading. It will stand out to all the Axpert posts trying to get their inverters to work. hehe 😂

24V will be fine if you stay under <3000W. The big thing is the cable sizes that need to handle the current. For the same power (W) you will double the current when you half the voltage. The cost of the cables and difficulty working with such think wires is why you would want to move to 48V with a system >2000W. 
We are talking about the cables between your MPPT and battery, and battery to inverter. You PV cables is not influenced.

@Racer if you do want to go the Victron option here are 2 options that you can look at. Both are good.
If you want to do a Victron blue trolly, look at this thread. This is a 12V, but you can do it as a 24V just the same. 
 
The other option is to go full install, using 48V. Something like what I did here 
 
 

Try the Inverter section and mention Multiplus II ESS in your heading. It will stand out to all the Axpert posts trying to get their inverters to work. hehe 😂

Both positive and negative DC can run in the same trunk.
You just cannot mix AC cables and DC cables in the same trunk. 

For me, Victron has nothing to do with pride. You are building a system with presumably R60k+ worth of batteries and R30k+ of panels. Maybe another R10k for DBs and a bit of wiring. Now decide what inverter you want. I can go on and on about why I think Victron is an amazing product, with brilliant support, flexibility and reliability. However, I could also say:
You probably want to go solar because you are sick and tired of Eskom’s unreliability. In that case, you probably want to replace Eskom with something reliable.

Not sure what the 3Kv is?
But lets look at the other questions.
If your need is for a 300W usage then you need a 300W-500W inverter to cover some margin. There is nothing wrong with 24V or even 12V. If you go over 2000W then the amps start to get a bit high and you need very think cables, so then it is more economical to go for a 48V system. So for 500W I would say 12V or 24V will be perfect.
Here is how that works: P = V * I where P is the Power in Watts, V is Voltage and I is the current in Amps. So for 300W at 12V the current is 25A. That same 300W at 24V have a current of 12.5A  so you need half the cable size. (Cable size is rated to handle the current)
Lithium batteries are expensive but can handle more cycles (charge and discharge). If you are going to use it as energy storage that you use each day this is the way to go. 
For a UPS that just works when the power fails Gel Lead Acid will be fine and might save you some money. If you choose your system wisely you can swop to Lithium batteries later without having to change components. (You need something where you can change the charge voltages)
As to size you need to handle 300W x 8hours which is 2400Wh. If this is a 12V system then this is a 200Ah battery, or 100Ah battery for 24V. For Lead Acid (Gel) you should not use more than 50% so double that battery size (400Ah or 200Ah), while for Lithium you can use up to 80% (240Ah or 120Ah), but again add some margin for losses.
You might want to look at this tread. You might need a bit more battery power to get to 8 hours, but the rest will fit perfectly: