IdlePhaedrus

I took a chance and bought a 200Ah one.
The Wh number on the comx site is wrong  when you do the math and you can see that someone edited a 180Ah manual to indicate 200Ah - which makes it seem very dodgy - BUT the included manual that I received have numbers that make sense. (it seems that there are 180Ah and 200Ah units. 180Ah was out of stock with mustek/mecer when I enquired)
Overall outer condition seems fine (the battery shell is plastic, but no obvious dents/cracks/scratches - shell actually looks 100% - no idea what the inside looks like and will not take to opening it up...yet).
battery terminals had no sign of use/tool marks etc.
Specs indicate it weighs "approx. 23Kg" - mine weighs 23.4Kg (google suggest the specific energy of LiFePO4 to be 90-120Wh/Kg. So while not knowing the exact weight of the cells, the numbers should get you at least past 2000Wh (160Ah for 12.8V nominal)  at the lower spectrum ...I guess it could contain only 4 cells and some lead bars...)
My cheap multimeter showed a voltage of 13.19V  before hooking it up for the first time (probably fairly meaningless for a lithium, but at least it did not arrive @ 10V) 
I charged it with a Multiplus inverter/charger @ 35A (the manual indicates standard charge as 15A and maximum as 100A) - I was keen to have it charged as I knew we were in for load shedding later the day. It took close to exactly 3 hours before indicating "absorption". Multiplus held absorption for another 1 hour (current tappering off). By my math (which is worse than my spelling) using info from my VRM log, by the time absorption was reached the battery "accepted" about 105Ah and absorption probably added another 15Ah. As far as I know lithium batteries are shipped at about 50% charge. So assuming the shipping charge state and the known charge cycle the math would suggest that it probably is in the 200Ah range.
While charging nothing felt warm (my hand being the closest to a scientific instrument for temp testing).
When load shedding takes a break I  might see if I can get a more definitive answer on the capacity with a sustained fixed load.
The battery has been used this past week and seemed to happily power the very modest average 200W load for 2 hours, then charge @ 15A and be ready at least an hour before the next load shedding session commenced, and repeated this cycle another 2 times per day for 4 days in a row. (I lowered the charge rate to 15A to "baby" the battery when possible, but if we hit stage 6 load shedding I will up the charge rate again). 
The battery has done momentary (couple of seconds) discharges @ >250A (NOT a typo) and so far nothing has melted/tripped/caught fire. The manual indicates maximum continuous discharge as 100A - no information on pulse current. How well the BMS does what it is supposed to do (or whether it is even there...?)  I do not know  and have no intention to short out the terminals, or charge it to 16V to find out. 
The "manual" is 1 piece of A4 paper, but at least it is double sided, glossy, in colour and not written in the worst dialect of Changelese. Probably the biggest issue is one part of the page indicates a charge voltage of 14.6V, and another 14.1V - I suspect the 14.6V is probably the high cut-off. (I set the voltage at 14.1V)
Whether the battery will give me 1500 cycles (this I assume is to another 80% capacity loss) I do not know.
Should you consider one, or more, of these keep in mind (according to the manual):
You  can NOT parallel connect to get 400Ah, but you can series connect to get 24/48  "Bulk"/absorption voltage is 14.1V (float @ 13.6V) for 12V system "Bulk"/absorption voltage is 28.2V (float @ 27.2) for 24V system "Bulk"/absorption voltage is 56.4V (float @ 54.4) for 48V system  

Yes, very much so.  You can have surge when the power returns, and also because everyone in your street's geysers and pool pumps come on the supply can be erratic for a few minutes after power returns (or at least that is how I understand it anyway).
For example there is an Ellies fridge intelligent surge protector which will only supply power to the device some minutes after the power has returned.
Interesting that the insurance wouldn't pay, one of my folks garage door motors went after loading a little while back, and the insurance did pay.  In fact they sent someone around and just replaced it.
Not sure who they are with, but I expect it very much depends on the fine print in the policy.  I just had my house insurance moved to a different broker, and the new policy was over 20 pages long, and there was a section that covered surge.  It's a pain, but you should always read your policy document carefully to avoid tears down the line.
I have an ancient AC Coromaster garage motor.  After load shedding a week or two back all its settings were reset.  The open and closed positions were defaulted about two centimetres away from each other in the closed position.  It was an absolute b@stard to set it correctly.

Communication was a bit sketchy, but I did receive my order.

Assuming this circuit is one of those that can chop even after the peak, then theoretically, there may only be a range where it is bad. Nearly full on and nearly full off, you will probably get away with. When its chopping around the peak of the sine wave,( half-power) I'd reckon it'll be at its worst. I haven't gone into these too much though, so I might be wrong.

That's my biggest worry really.  Have had previous harmonics issues due to other unrelated issues.  But it isn't a lot of money so if it causes it problems it will simply be removed.
I will report back when the deed is done (and possibly reversed)...

Common is the connection to neutral. I would not use a dimmer like that on a geyser, for the reason mentioned earlier in this thread: harmonics. An inverter is also not going to like chopped current at 15A.

My geyser is running at PV idle times, two slots a day and normally only comes on for the first slot. On Tuesdays this slot is also used for ironing/vacuuming etc. and in the beginning I had a 3kW element, which pushed it to importing some grid. Luckily my geyser burst and got a replacement with a 2kW element. This gave me enough room to handle most loads during a geyser slot, unless the wife really wants to also use the microwave and dishwasher at the same time 
 

Yup, my OCD-o-meter also goes a little crazy whenever someone says such a thing.
So how far is your office from your home? Oh, not far... only 50km/h!
🙂
The SI unit of energy is actually the Joule, but it is a bit unwieldy for electrical use, so the Watt-hour is used instead. There is 3600 Joules in a Watt-hour. A joule in turn is a watt-second, so literally one watt wizzing past every second.
Again, massive confusion with terms here. Technicially a Hybrid inverter is also a grid-tied inverter, as in all hybrids are grid-tied, but not all grid-tieds are hybrid 🙂
I really have a lot of sympathy for newbies... I do.

Where I think you can score, is not necessarily with a timer, but by timing.
There are times when the solar generation has been throttled because the loads aren't there, so a realizable amount of energy isn't realized for the sake of turning on a load.
If you could schedule your geyser to be on at a time of the day when the potential solar production exceeds the actual loads, then you would get something for nothing.

I want to run my electric geyser off my solar without incurring cost from the utility.  If I can control the energy given time of year I can adjust the gadget and the time the geyser runs in order to do that.  I suppose one could even make it 'smart' if you don't want to do it manually.
For less than R300 (excluding installation) this will enable me to do that (if it works, and given above there is no guarantee, so lets call it an expriment).
A replacement element will cost similar and a solar geyser would cost a considerable order of magnitude more.

Expect you're more likely to be run over by a taxi or catch it from the water bottle in your car when you spray your wind screen with the windows open.

The energy use is the same of course. Well, kinda. With an electric geyser you have a standing loss, energy it loses slowly all of the time amounting to around 2kWh per day. So anything below 100W and you might as well forget about it.
Also, it takes 1.16Wh to heat one liter of water by one degree centigrade, so there is the additional issue that at very low power levels (1kw for example) it would take a full 8 hours to heat 150 liters of water from 15°C to 55°C... and you don't have that much peak sun. So the actual usable range of this experiment isn't all that wide, it's really somewhere between 1.5kw and the standard 3kw.

The water in Africa is so full of shit that we actually have to heat it above 60 degrees for a minimum of 20 minutes to kill the bugs. It is called pasteurization.
The moment you open your tap and cold water flows in your pasteurization effect is nul and void. if you set your geyser to 65 and leave it on for the full 24 hours you might be able to kill all the bugs in it.
We have so many bad bugs in the air and in our water that even if we do all the 1 million things correct will end up dead. that is a guarantee.
If you worry you die if you dont worry you die so why worry. Live life to the fullest.
 
 
 
 

I doubt it. It looks like it's made out of a heat sink! Interesting controller! It looks like it's locally made and a nice job!
The name is confusing though: It will only be useful as a speed controller with a universal motor such as a power drill (not good for an induction motor since there you need to change the frequency) Dimmer or soft starter is a better name.
Safety is not an issue and the thyristor will be up to the task. Really rugged devices those..

Yes, just check if there needs to be an additional heat sink.
 
You wouldn't want one. That is a very lossy solution.
A variac is a variable transformer, which would work, but would be an expensive solution. 
 

I cant see that you will be doing this without creating extra losses. Its going to be cheaper to buy a standard 1.5 or 2 kw element and stick it in the geyser and you will ensure that all the energy is used to heat the water and not dissipated into the air through losses, and you will limit the current to the geyser. 

This is a thyristor controlled device, same thing as a light dimmer.
Yes, it's safe, if properly spec'd.
It's not lossless, but it's not lossy either. I've seen numbers like 1.5W/ amp.
There are a few things to know though.
1. It doesn't limit the current to the geyser,( like say a series resistor or a Variac would), it just doesn't allow the whole sine wave through. That portion that it does let through will still peak at the same magnitude as if it was a full sine wave. Everything still has to rated for full current, so it is more correct to say it limits the energy to the geyser.
2. Using one of these on a device that draws sufficient power will cause harmonics on your AC supply that things like inverters may not like.
 

We needed a UPS for a small office (about 8 PC's, server and network hardware) to be able to continue working through loadshedding (4-6 hours at a time).
We are renting our office and did not want a permanent setup.
 
Requirements:
- Ultimate long term reliability - high quality brand
- Expected lifetime: about 15 years for inverter and 7-10 years for batteries (expecting much more regular loadshedding while eskom repairs its infrastructure)
- Backup system that works for many years without maintenance
- Standalone system ( rack on wheels)
- Ready to be moved to a new office if we have to move, OR be re-purposed into a solar home ESS system (just add MPPT and panels)
 
If we bought an off the rack 3KVA UPS system with 6000 WH runtime, we could probably get it for about R20k.  But I have a long history with cheap UPS systems - they never make it to 2 years - then you have to replace the batteries - at huge cost, labour - weekend time etc.  At about 4 or 5 years the inverter's cheap capacitors start sweating and it becomes very unreliable - almost worse than not having a UPS. Not one lasts over 6 years - and in the process, the PC's that you are supposed to protect are subjected to many power spikes and failures due to the unreliable UPS.
 
So we went this route - about 4X more expensive but we know it will last, and protect the sensitive equipment properly for many years:
- Victron Multiplus 3000
- Victron Venus controller
- 2 X Pylontech US3000 batteries
- 19" computer rack on wheels
- Small DB with input breaker, earth leakage on output, and two circuits on output.
- DC Fuses, cables and building the rig (took about 5 hours).
 
 
@Jaco de Jongh built this rig for me:

From the webinar on Nov 29 2019 it was stated that hardware/software limiting can be used to throttle it within spec:
https://arepenergy.co.za/city-of-cape-town-webinar-nov-2019/

This topic quickly went from registering to a discussion about something completely off this topic.
I believe the following
1. If your system is less than 20KW and off grid you should not have to register
2. You should be able to produce a COC for the installation to proof that it is safe if asked by the authorities and your insurance
3. If your system is grid tied and you can feed back it should be registered in order for the workers to be safe.
4. I believe the building regulation should be changed that all new building should have at least 3kw of solar installed when a new house is build.
5. i believe generators must be banned from residential areas  

There's actually some industry standard ways to do it, but not all grid codes require the same level of "paranoia" if you will. NRS097 requires some basics (voltage within the right range, frequency in the right range), plus one active measure (you get to pick one). Active measures include (I am sure there are more...):
1. The inverter usually has a phase locked loop locked onto the grid frequency. You can introduce a slight error into this so that the frequency would increase up once the lock with the grid is lost. The frequency then drifts out of range the moment you lose the grid and you disconnect as you hit 53Hz (as you normally would).
2. You actively try to change the power factor by shifting the voltage and current a few degrees left and right.
Within the literature, which I admittedly understand only partly, there is something called an NDZ (non-detection zone), which happens when you somehow manage to have conditions just right so that the detection fails. @IdlePhaedrus's inverter could possibly be non-faulty and he observed the one-in-a-million NDZs... or... and this I actually think is more likely... he has an inverter with a large NDZ which was not picked up in testing.
As another analogy, this is now happening with crash testing in cars. There is a specific set of tests that are run. It is standardised and manufacturers know what they are, so they specifically optimise for them. A car can pass with flying colours, and then you may discover later that it has weak points where you didn't look. That's why crash tests added an "small offset frontal" test. Cars were getting good ratings... as long as large enough part of the frontal face is involved in said crash 🙂
 

My guess is that it is shades of this:
The grid represents an infinite bus. in other words something so vastly huge and immovable that the the little 'ole inverter couldn't cause the system to alter the presented frequency or voltage or phase shift. Then there will be a feedback algorithm that tries to do exactly this (with some portion of every cycle say), and if it can actually do it, it knows the anchor of grid isn't there so it switches off.
Least ways that's how I'd do it.

There is a term in the electrical testing world called "type-testing". This is where you take a representative sample and throw it as many curved balls as conceivable repeatedly for long enough until the tester is confident that this device will function to its specifications in every scenario reliably. It is a very rigorous process and things are often tested to destruction.
I don't doubt this was your experience but I do doubt that the testing house that certified the Solis inverter would've let a single abnormal operation due to a type of load get past them. 
It is more likely that your inverter was faulty, at the time at least.

Be careful not to confuse feeding into the grid with anti-islanding. It is possible to form an energized island even without feeding energy into the grid. I always use the example of the inattentive backhoe operator who manages to nick your cable "just so", so that you have a grid outage and your own connection to the grid becomes high impedance. If you energize your end of that cable, no energy will flow into the grid... but if anyone touches those cables in an attempt to fix it, and they will get the shock of their life.
Even where you do feed energy into the grid (legally), anti-islanding is still a requirement. You must stop energizing the line (whether you feed in or not) the moment the grid fails.
 
Agreed. Anti-islanding is a requirement in all the grid codes. It's not as if it is okay in the UK to feed energy into a dead connection... (I mean surely you have heard of health and safety and how popular that is... 😛 ). It's more likely that something was wrong with the inverter itself.

I actually do remember you saying this, which is why I carefully worded my statement to include that a grid-tie inverter was not "designed" to do this.
I think your inverter is/was faulty.
Solis is an approved inverter that has been recently certified by an independent testing facility to not do this.
The G59 settings weren't your problem. Different country standards will reflect that country's frequency and voltage windows and frequency/power response, but they are unanimous on the no-grid-no-power aspect. 
I run a Solis inverter with G59 UK settings on it, ( I bought it second-hand from the UK) and I have confirmed that if there is no grid it shuts down immediately. I am an electrical test engineer, so it is my nature never to take things for granted.
Before I get the complaints, I run this grid-tie inverter on the AC out of a Victron Phoenix, which in turn has no grid-tie so I am not bound by any country-code. The Phoenix inverter is the grid equivalent in this off-grid set up.
In fact, I have an ABB grid-tie inverter in parallel with the Solis, also with UK settings that equally shuts down immediately on loss of grid.
I do think your inverter behaved abnormally at the time and had you not of caught it before the grid returned, the returning grid would have destroyed it. An out of phase fault can be the most severe of all faults types because up to double the voltage is involved.