PhilFM

I think you are at a good level currently, given that your panels are able to recharge completely during the day and you do not need grid power to do so

Picture of the mounting system used, worked really nicely on the IBR sheets

Picture of the mounting system used, worked really nicely on the IBR sheets

I am not a plumber or an expert but have installed 4 gas geysers of various siizes where water pressure is an issue, built a "donkey" with a 44 gallon drum for an al fresco shower stall.
As far as I am aware all the geysers I installed needed a minimum of 0.2 bar pressure to function.
1bar = 10metre head (? I think).
Therefor your shower head looks like it is probably less than 2 metres below the tank and is thus marginal. If the tank is full you may have enough pressure but as it empties you lose too much causing the geyser to shutdown.
Solutions? Raise the tank or install a "on demand" pressure pump, either 220v or 12v with solar.
B.t.w. If your geyser is of "modern" design you don't balance the temperature with the cold tap, you set the desired temperature by balancing the rate of flow thru' the geyser and the flame/fire.

Hagu13, I think you are set up nicely and as you said when there is loadshedding, you can plan for that with the needed SOC
Unfortunately for us here in rural Limpopo, infrastructure maintenance is a huge problem so it's almost always a gamble with how deep you discharge your batteries as one storm, one gust of wind, one fart in the wrong direction can mean anything from 1 to 24 hours without grid, and this happens a lot.
So I run my batteries from 2am (can probably start at midnight rather), then wait for PV to start up after 6am, charge batteries during the day, which is usually done around mid day on a good day, then we add load as needed to maximize PV and switch back to grid around 5pm.
I can extend my night hours on the batteries, but then we have no backup should something go wrong and there is a rainy day or two. Here in the Lowveld it gets seriously overcast some days, we had two weeks now with very little sunshine and lots of rain, but we do not complain as we are coming from a severe drought. Unfortunately it is under these conditions (wet/damp) that we experience most of the grid cable faults, potentially leaving you without grid for a long time.
All this said, it basically just comes down to different circumstances, there is no one correct answer for everyone and it seems you understand your needs and risks well and plan/run your system accordingly

I think you are at a good level currently, given that your panels are able to recharge completely during the day and you do not need grid power to do so

Finally got around to installing more panels in my offgrid setup in Noordhoek.
 
Originally I had 6 panels -> FM80 ->  Dead Acid ->Victron 24v 3000va
At some point earlier in the year, I finally got around to installing the 10KW LFP I had lying around since 2019.
...and Now, I finally got around to installing another 6 panels to make it 12 panels on the roof as of yesterday.





Setup is fully offgrid.   I've been offgrid here since I built the place on the plot, never ever had Eskom or CoCT
6 panels worked fine for me on my own, even in winter, but now the GF is living in the house, electricity use has gone up, and we needed more generation, mostly for the crappy winter days, as 6 panels was pretty marginal.   I was fine with turning off stuff and waiting for a day or two to do clothes washing.  The woman wasn't.
Doubling generation capacity enables me to not worry about that.

We're already quite low on power usage - we hover around 4KW / day usage, with NAS+POE Camera's + Electric Fence + Fridge + Lighting ++ 
Current setup here is a 48v 3000va Victron Multiplus + 12 x 300w panels + FM80 + 10KW LFP
The FM80 doesn't talk to the Victron so no stats on solar (will be replacing it next week).

Was enough originally to last about 4 days of crap weather, now we shouldn't be too perturbed about things.
You can see where we installed the panels in the middle of the day yesterday, then the sharp increase in generation.


 
Overall quite happy with the slapdash way I've handled the install.   Panels have been reused as I need them from my other installs.
The backend side will be installed properly in a week or two  once I have the Victron MPPT that my accountant is selling me.  
No photos till then of that, as its a... mess.
 
Its been a mess for 5+ years though, so...
 
 
Panels are installed in 3S 2P x 2
36v x 3 = 108v @ 8a per string of 3 panels in series.  Which is then paralled for 108v @ 16a for the 3strings in parallel x 2.
And I have 2 sets of that running back the MPPT in the house.  

Used a Y adaptor to conjoin the strings on the roof, as I didn't feel like running more cabling.
Once I get the Victron MPPT will be wiring in a DC disconnect on the backend.    It's been wired directly for a few years, as I like to live dangerously (aka it worked, and I left it to do other stuff).

 
 
 
 

Same here. How long have you had your system. I thought it was because mine is only two months old. 🤣

Or even 57.6 V (14.4 V per 12 V module); that covers most temperature ranges,
I assume that these are flooded types, and you are regularly watering then with the appropriate type of water.

Hi Cuzz
No you need to connect 1 to 0, see attached

Ill do that thanks
 

Hi PhilFM,
 
Thanks for this. I see where I went wrong. The available power to him is not 500W. This is what he wants to draw consistently. 
Happiness, it makes sense to me.

Totally agree, it's very dependent on your appliance setup and guests.
In my case there is no municipal water so a pump is required that pulls about 1.2kw which is the main concern. With added guests come showers, hand basin and toilet use, washing machine use, extra dishes etc so the pump is running a lot. They also bring laptops and on occasion an x-box.
So my situation is a lot different to yours where you only need a bit of extra power for lighting. In your case lithium is the obvious choice.
In my case I normally only use about 20% of my capacity daily so I have 80% spare capacity for use on these occasions. Using lithium in that same way would be very expensive and would not make much sense.

Pylontech Batteries! 🙂

It depends on the inverter you are using. 
If you have a 48V system then you would need to have 4 batteries in series which essentially equates to a 48V 200ah battery.  If you then want to increase your capacity you would have to add another bank of 4x batteries.  You can't mix and match.

@Jos
First you need to do an energy audit. 
Two main things to look at is how much power you need at any one time and secondly how much power you need per day. 
Peak demand or maximum power would be the kW of all appliances that will be on at the same time. This will be used to size your inverter. A geyser alone would pull 3kw depending on the element. Best would be to get an energy meter measuring peak demand on the main supply. 
Total power would be the kWh used in a day. If you have a 3kw element in your geyser and it runs for 3 hours it will use 9kwh. I don't look at kVa but at kW and kWh as it's easier to work with. 
A sunsynk 5kw or 8kw inverter should be sufficient. I have the 8kw sunsynk inverter with 28 x 305w panels producing on average 40kwh per day. 
Batteries can be stacked to have a bigger capacity. Normally only the same size and make batteries can be stacked. I have 3 x 3.5kw pylontech batteries. 
Battery bank can be sized according to how much electricity you need at night. 

You don't say where you are, but no matter: We should all know where our meters are and read them. Even if you don't read the same day as the municipality you can check your bill, see the read date and then when you compare to your own records you should be in the ball park.

City of Johannesburg customers can mail in photos of their own meters (these must include the meter's serial number) and they will use those as provisional readings until they get around to reading (you can do this with water as well). 

I think we can do a bit to control our billing. Don't run your geyser until the water is unusably hot is one example. Don't burn lights in rooms you aren't using etc.
But people aren't always rational. I don't expect anybody to be happy about load shedding, but I know folks whose response is to turn on EVERYTHING in their house the moment the power is restored just to show Eskom who is who. Their general attitude is that they will burn electricity just because they can, so you can imagine what their bill is like. 
Anyway, to start answering your question: One should get one's consumption under control first, and you should know what your consumption is because the more you use the bigger the solar system you will require. 

Finally, how does one justify it?

When I got my system my back of an envelope calculations suggested that after 7 years I would break even and it would be all joy from there on (my consumption was and still is under 500 kw/h per month). I am not so sure now, but that depends on increases in years to come. This is looking just at what I do pay, what my system cost and what I would have paid without solar. But there are softer issues too and people will weigh these differently.
most of my property still has power through a Joburg 4 hour load shed, in fact it can go longer than that. All we lose is the swimming pool and the appliances in the out buildings. because of that our fridge and deep freeze are always on so we don't lose the contents and have to claim from insurance (driving our NCB up) or go and repurchase security systems always stay up yes, we could have got a generator. But I have no interest in disturbing my neighbours in the wee hours, and the so-called silent generators need a lot of servicing. And you know, even just being able to watch TV and have a cold beer or a hot cup of tea makes a difference during load shedding. That's worth something, though exactly how much it's worth will vary between families.

This is terrible and creates such a bad name for solar suppliers and installers alike! Firstly please name and shame the installer and the supplier so everyone can be made aware not to use their services or buy product from them.
Do you have a PV Combiner box and can you switch off the Solar Panels?
Do you have a fuse switch between the battery and the inverter? Because that error says the the fuse between the battery and the inverter is blown or there is loose connection between the battery and the inverter.

Thanks for all the info PhilFM. 

Hi All. I have an AXpert 5KW inverter also connected to utility power ( eskom ), with 9 x 360w Canadian solar panels and 4 x Probe 12TE220 ( http://www.probegroup.co.za/LinkClick.aspx?fileticket=gHjZzUNluW0%3d&portalid=0 ) batteries. With this I have the ICC software with the victron BVM700. This system is hosting a critical server room drawing +- 950w 24/7. System is setup in UPS mode. In general ( for now ) I would like to save the batteries as most as possible and have them charged at 100% ready for when there no utility power at night. 
I have some questions would would love some help on this:
I've used the "Use time for control" from 0900-1600. System switches over from utility to Battery(solar) mode at 0900, but does not switch back to utility at 1600. It only switches back when the PV voltage reaches 0v. My guess is that this has something to do with the "charge source priority" and the "output source priority" which is currently set to "utility first" ? any help :-) Under the "Use time for control" I have 3 option, utility, SBU, SUB. What is the difference between SBU and SUB? how does this work? Under "inverter setting" currently battery type is set to flooded. I guess this is wrong? But what should the charging current, Back to grid voltage, Bulk charging voltage, and Float charging voltages be with these batteries I have: ( http://www.probegroup.co.za/LinkClick.aspx?fileticket=gHjZzUNluW0%3d&portalid=0 ) Some system screenshots below. 
Thanks for all the help in advance, and let me know if you have any questions.
Thanks
Regards

Hi CDK Jnr
I see your time setting is set up with the day hours as SUB, only the Axpert King supports SUB, I do not think your Axpert will support that, only Utility or SBU. Had the same issue on my side, then Centurion Solar helped me out here, showing the mistake, switched over to SBU, now it switches on time morning and afternoon.
But as per your post, you do not want the batteries to be draining during the day if you do not have sufficient PV. This will be a challenge on your Axpert as you will either have to run only Utility or accept that the inverter will use PV and supplement with battery if there is not enough watts coming in.
If you bought your ICC through Centurion Solar, you can give them a call for help on other settings as they are very helpful, they might be able to advise better on a solution that could help with your batteries, maybe by playing around with the back to grid voltage. If you keep this quite high, you can still run SBU during the day, but limit the drain on the batteries and keep the SOC high.
Hope this helps

Welcome Swartkat
Luckily I got the wife involved in the project from the start. She now likes playing around with settings even more than I do 🤣. She even helped me install the panels on the roof, despite her fear of heights.
Bottom line, if SWAMBO is on board, it is all good going forward, even the upgrades later 😉

Good day everyone,
My first post and intro here on this forum.
I am not a complete newbie and understand a fair amount more than your average Joe, but I have recently invested in a small Victron solar system for my house and have a lot to learn in that regard. So far the system (basic and humble as it is) impresses the socks off of me.
It consists of:
- 48V 3Kva Multiplus II
- Venus GX
- BMV 712
- 150 | 35 MPPT
- 4 x 12V 200Ah AGM batteries
- 5 x 22V 135W panels in serie
So looking forward to sharing my experiences with it and to learn a lot from the big boys here!
Will now go and search for a thread where hopefully what I need to know was already discussed. 
 
Cheers everyone!

LOL. I was about to make a chirp about doing what you want WHEN THE SUN IS SHINING!. But I see others beat me to it.