introverter

adding to the "how crazy is it to stick a home fridge on a UPS/backup power supply?" topic... my position in favour of doing it is also influenced by the following... (I decided to try harder to reduce my wordy posts ... so the kids can help if the adults struggle): 🔌 📉 💡 🚫 🕯️ ❄️ 🌡️ 📈 🍗 🛒 👨‍🍳 🍽️ 🤢 🚽 💩 🧻 🙊 🤮 🥶 🆘 ☠️? 🕓 ⛅☢️? 🧪 🚀

Btw, even though it won't help much for load shedding and fridges, something that I found made a very big difference to "mobile cold transport" (i.e. trip to Kgalagadi/Kruger etc.) is to put a space blanket inside the coolbox almost forming a big bag in which you place all food/ice packs etc... fold remaining bit of space blanket over the top of the contents before closing the lid. Unlike normal aluminium cooking foil the space blanket allows much more for forming around weird shapes and angles without tearing, and withstands repeated folding and unfolding also better than aluminium foil... and adds no weight.... you also KNOW when someone is digging around in the coolbox with all the "ge-ritsel" 😈...I did this with normal coolboxes but I think it should even help with camping fridge/freezers to reduce consumption from the battery system. Normal addis plastic coolbox also seemed much improved by drilling a couple of holes in the lid and filling the lid with expanding PU foam and later sealing the holes with some silicone (to help keep moisture out of the foam which may contribute to funky smells at some stage). The plastic fillable ice cube packets also are handy as double purpose (keep contents cold and have ice for drinks), they also allow for a degree of shaping around some of the contents but they do tend to leak when defrosting even slightly, so putting them inside a ziplock bag helps keep dry what is preferred dry. enough off-topic from me...🤐

Correction to myself... SOME of the trolleys are the same as what you will put on the wall. The generally available ellies and mecer trolleys will lend them less to being taken apart to be mounted on the wall...

Some of the Bosch fridge/freezers actually have (had?) specific space in the door for the supplied "freezer blocks" with the stated aim to help maintain the temperature in case of power failures. something I previously read is that a fridge and freezer should also maintain the temperature a bit better the fuller they are (air warming up quicker than the solids) - could help reduce overall electricity consumption and maintain temperature when eskom goes to bed. At one stage I even considered getting some polystyrene blocks to add as the week goes by and the fridge starts looking a bit bare. I also only recently noticed how much our existing kitchen layout probably makes life very difficult for the fridges... fridges are backed to a western wall that bakes nice and warm in the afternoon sun... the eye level oven is also positioned 90 degree to the side of the fridges and vents all the hot air towards the fridges 🙄

Oh come on Richard what does mybroadband, or renewable energy (RE?) for that matter have to do with anything that, up until now, was posted in this thread? Maybe you consider an opinion that the electricity grid is not in a good state and putting an appliance like a fridge on a UPS/backup as a sign of RE hysteria ?

Unfortunately I have come across very few sales people that will take effort to sell me what I need versus what they want to sell me. I would say before pricing replacement options, first as accurately as possible determine what you need peak and base power wise, add possibly a nice to have (microwave...not hairdryer 😉) - then you know minimum inverter and battery requirement. Decide how much autonomy you need/want - then you know how much extra battery you need or to have options for a generator to help out when solar is a problem. At a glance a 8000W inverter and 1000Ah battery for your described loads/use is like shooting an impala with a 416 Rigby. Discuss with, and get a quote from someone like @Jaco de Jongh and make sure you understand what you have (on paper the existing system should cope with a microwave...). With a Victron setup you could even potentially end up being able to monitor/control your system when not on the farm via the VRM portal 🙂 In short, the pylontechs should protect themself from over discharge, ideally for battery total life span it is probably better if it does not get that low though. You could however still end up with a problem that the inverter will not start up until there is a charged battery, and the battery switched itself off...I have no idea whether this would end up requiring manual intervention like having to physically switch something on/off again..

@Richard Mackay you seem to have a problem with my (assumed) mindset and posted comments so please be more specific than the thinly veiled reference to the extravagance of my vast solar array, numerous battery banks, gold plated toilets and the fact that I clearly only wear my socks once. What comment/s do you take issue with? I agree with the benefits of the high efficiency appliances but it does not necessarily solve all the OP's issues. For how long can the fridge be off before you have a problem? At what ambient temperature? What if the fridge is already A+++ and you still end up with food spoilage related to power outages? What if you need to open the fridge door while the power is off? think the flexo should run even a less efficient fridge (supposedly can tolerate a 1200W surge) but it requires manual intervention (need to plug it in and out to charge) so you lose the convenience factor of a plug-and-play-and-forget automatic UPS setup and the OP's family is in joburg where I think (scheduled) load shedding is 4 hours and not convinced it will power even an A+++ for that long? I see the flexo people have a bigger option now ... about 2.5 times capacity of the flexo but you guessed it...also about 2.5 times the price.

Is a late reply but what the heck... any cost related to load shedding is to some extent going to be "throw away". You will likely recoup very little from selling on later, so leave it out of your calculations/decision making - in my opinion. Your core needs on the face of it should easily be met by a 3000W or so inverter (depending on realistic peak load probably even smaller but 3000 is a safe number that will allow wide use). The things to be weary of are those 2 laser printers (they tend to have a very high power draw, easily 1000W+ when starting up) and maybe the bar fridge (if keeping some cokes cold, take it off the list.... if keeping meds for patients at a required temperature then obviously not an option). No idea what aquarium pumps draw but doubt it will be much (though running permanently)... the heater is bit of an unknown (you are not exactly running sea world but it could add up a bit for the battery requirement). So, even though budget is tight, before spending money on inverters I would seriously look at buying/borrowing a watt meter (like this) to confirm actual power draw of things like the TV, aquarium pump + heater, etc. I would personally not spend money on any clone/copy of the axpert type inverters - the money you save will probably be short lived. If going with an axpert type setup look for an actual voltronic produced version (I think the Mecers are voltronic) Hopefully someone else will chime in on the solar part but for what you want PWM should be fine - and may be irrelevant since solar might happen only when you upgrade in the future some time? Overall I think MPPT will give you greater efficiency compared to PWM but I am not exactly all that clued up on solar. Your battery calcs are technically incorrect 24v x 200ah = 4800Wh....or 4.8kWh (not 4800kWh). Making some wild assumptions (and not really making much provision for the laser printers) I suspect your day time practice, home/office and Finding Nemo power requirement to be around 800W-1000W. Which will equate to 2000Wh for a 2 hour load shed (which will be [2000W/24V]/0.8= 105Ah... *2 (for 50%DOD) = ~200Ah). 2 x 12V 200Ah batteries should leave less issues around balancing etc. than 4 x 12V 100Ah batteries. Btw, the inverters on the trolleys are exactly the same as what you will wire into the DB...someone just screwed them down onto a trolley....so if you get a good deal (better than buying a lose inverter) on a trolley for some reason (maybe 2nd hand one?), just remove it from the trolley and have the sparky mount it on the wall. If the only thing you can get/afford is a trolley you could also consider running an extension or two through conduit and route it in a creative way that keeps it mostly off the floor/out of the way so there is no need to push it all over the place... If you want to avoid spending double, and seriously plan to expand in the future (by adding more loads on the backup side and potentially adding decent solar capability), go 48V from the start ...and depending where you are an inverter on the NRS approved list if wanting to add solar.

I am definitely a supporter of reduce your loads and be frugal so the cheapest way to cope with load shedding is to do nothing but while at it one can then also ask "If I do not need it for 4 hours, do I need it for 8h, 12h, 24h..... at all?". Using no electricity even when eskom is available should save quite a few extra Rand. I choose to keep some electricity based convenience and for me, during load shedding, being able to open my fridge without my wife having to run a stopwatch is worth the (extra) cost (powering a hairdryer or TV is not worth the cost for me). While batteries will obviously need replacement at some point (even if not using the pesky inefficient middleman inverter), the grid state in general but especially following load shedding, may also contribute to whatever appliances are connected to mains needing replacement, so one might have to choose which is cheaper - replacing batteries or appliances.... and the one appliance that is likely running 24/7 on mains in many homes will be fridge/freezers. So to my mind the fridge/freezer on a UPS/backup supply is like the spare tyre in my car - I might not need it but I prefer to have it. In the bigger metropolitan areas the problem is likely also greater than just eskom - a lot of the electricity supply problems are not solely eskom's issue so even if eskom based load shedding ends this year, localised unplanned outages of fairly long duration and unstable/out of spec grid supply will be part of our existence for many years. I suspect the size of load (and total duration) is limited only by budget and not some inherent characteristic of UPS/inverter based backup power supplies?

the basics of your sums look correct to me (Ah x V = kWh) so you know how to get to Ah and Wh for the comparisons but you must keep some things in mind. The lead acid 25% DOD is about longetivity of the battery bank. To make the batteries last a number of years you should not discharge them below a certain level, at least not on a regular basis - BUT you still have spare capacity that you CAN use. If you have another (backup) energy source ( like a generator) or if clouds are something you only get to see in books then you may not need all that extra capacity but if this is your only energy source and it powers very essential loads, what happens if you have 3 cloudy days in a row? You would have to determine what your actual power need is for at least one day, and then decide how much autonomy (how many extra days) you need if running only on batteries. For that, 4 pylontechs could be enough but only you will know for sure. Also 4 pylontechs with BMS communication will more likely be ~11.3kWh (BMS will only let battery discharge down to 80%), and if installed without BMS comms should be ~12.7 kWh (only 90% discharge allowed by internal BMS) - your setup will not allow for BMS comms cable connection. The C-rate on the lead acids will tell you how the total capacity changes in relation to the size of the Amp draw on the battery (the higher the Amp draw, the lower the total capacity of the battery - you can read more about the Peukert effect if wanting to know why). In other words, the 100Ah battery is only a 100Ah battery if discharged at a very specific Amp draw (and at a very specific temperature) - if you discharge it at a higher Amp rate, it actually turns into a 90 Ah battery during that use period. On the lithium batteries the C-rate will tell you generally two things. What the maximum rate of charge/discharge is that the battery internal BMS will allow before disconnecting the battery, and what the preferred charge/discharge rate is to help you get to the 10 year warranty number. The total capacity of the lithium battery does not really change much based on the rate of discharge like it does with the lead acids (it stays a 100Ah battery regardless of the Amp draw). basically as long as you can set the correct charge voltage, maximum charge/discharge rate and low voltage cut-off, lithium should work with an inverter/charger. I think your inverter unfortunately does not really allow for this. From what I can see the low cut-off options are 38V, 40V and 42V. Highest Pylontech low cut-off recommended is 45V. The solar charge controller could possibly allow for correct voltage settings (I did NOT actually check this) but you must also have the option to disable equalisation charge etc. (lithium do not need that) - so you will have to check how many settings you can change on the Outback that will meet the lithium requirement. The Bluenova "drop-in" replacements (mentioned by @Louisvdw ) have voltage profiles that more closely fit with existing lead acid chargers etc. but price per Wh is very expensive on those (compared to something like a pylontech) and connecting them in series and/or parallel can also be bit of an issue. If you had more fexibility in setting charge voltages etc. the lithium batteries would be an easier fit. So if looking at a possible R120K battery bill it could be a good exercise to look at total cost of replacing the inverter and charger and adding lithium to the capacity actually needed? Last thing, some people do not realise that the 10 year warranty is to still have 70% capacity left (not 100%), you also have to send pylontech photos of how the batteries are installed to qualify for the full warranty period. You shold also confirm with your supplier that if the batteries are installed without any comms cable how that affects the warranty (I think it cuts it down to maximum 5 years). Only relevant if the warranty period is a major selling factor. Like cars, etc. you may find they still work without a warranty or service plan....

Two reasons I can think of 1) why do we put most things on a load shedding solution? For convenience. If it is running on backup power much less need for "should refrain from opening the door frequently" especially since eskom does not seem to mind switching off the lights while one is preparing dinner or feeling peckish. 2) when the power comes back for 1 minute after scheduled load shedding and then the substation trips and power is off for another 8 hours (follow the City Power twitter account during load shedding - especially if you live in joburg... the number of "trips" after load shedding should give you nightmares). (not even looking at the scenario of the substation going up in flames because it dislikes being treated like a giant light switch).... and unlike a sometime quoted line from a popular TV series... "summer is coming" so warm ambient temperatures and no electricity are not ideal for food safety. Possible third reason but may not apply to OP... many fridge freezers are now exactly that...a fridge and a freezer in one unit. Good move on the gas cooking. One less thing to have to spec inverter/battery for. For light we actually use these (ledlenser MT10). It is expensive for a torch but as all load shedding related expenses are grudge purchases for me at least you get more use from this (it doubles as our cycling lights, or just general torch use around the house). ... if you want light during load shedding you adjust the beam to the wide pattern, put it on the medium power mode, stand it upright on the base and the light reflecting off the ceiling and walls lights up a fair sized room sufficiently to easily see the peas rolling towards the mash in your dinner plate. (and if you eat slow it will probably last 4 or so hours on a single charge). If you want to read... whack it on full power (only going to get about 2 hours of reading quality light though). When you head off to bed, take the torch along (no candles etc. left burning and no need to have inverters wired into the DB to switch on lights). You can also buy some spare 18650 batteries should it be necessary. I posted this before: Especially fridge and/or freezers can be sneaky buggers - especially if of the more modern persuasion. One of my upright fridge/freezers when you measure will draw about 15W...open the door...drops to 5W...close the door and some 10 minutes or so later it draws 90W..... but if you wait long enough somewhere during the daily running stages it will draw about 200W for 10 minutes or so. Even with the 200W draw the one thing you do not see is the in-rush current when the compressor starts which for 1/2 a second or so reaches 1800W. I run two of these (Bosch) fridge/freezers (and some other small odds and ends) on a 12V Victron multiplus 1200kVA inverter/charger and a mecer 2nd life lithium battery. Based on all indications this setup should run both fridges for 16-20 hours (so when gambling that the local substation won't catch fire I can also run the TV etc. if I can manage to find anything worthwhile to actually watch). The inverter will mention overload alarms in the log when the compressors start - but these are informational they are not yet at the point where it is an actual overload which will cause the inverter to shut down. Barring any unforeseen breakdown this setup should get me at least 3-4 years of service if actually used everyday. So it should get me to the point where either eskom is doing better or I know to get a big hamster and a wheel connected to a dynamo for the future. (I suspect lead acid batteries will be replaced more than once in 3-4 years). With all of that said, if I had to redo this today I will likely opt for a 48V Multiplus II 3000kVA inverter/charger and associated (pylontech etc.) battery - total outlay will be more than for a 12V setup but it represents much better value in my book and leaves room for future expansion - especially if wiring into the DB to avoid trip-and-fall hazard extension leads lying all over. If wanting/needing to keep budget a bit lower, the ellies/axpert trolley with the 3000kVA inverter could be worthwhile... just ideally with a lithium battery (lots of threads about the lead acid batteries - deep cycle and what not - just not lasting long). If your parents are unlikely to use solar much, or even at all, you could even hunt around for the Axpert type inverters with PWM solar charge controller (they are a fair bit cheaper that the MPPT versions last time I looked) and have someone stick it on a trolley (again according to me not lying flat like the ones already made up by all the solar shops), and add a lithium battery.

maybe try these guys (bought a replacement laptop battery from them some moons ago... finishing on the plastic was a bit iffy but battery worked as advertised). If those are 18650's you might want to have someone with the right equipment spot weld the tabs etc for the leads... (link provided do custom packs etc). not want to buy online? .... vape shops... but check info regarding leads/soldering etc

Maybe the admins must put a pin/sticky somewhere...? The MO is generally the same. Batteries with 10 year warranties, at 50% discount as "end of year" (or "end of yeah" when they get sloppy with copy/paste), black friday, christmas, load shedding special, stock clearance sale. .... often with a nice big count down timer reminding you how close you are to losing out on the amazing special (or there are only 2 units left...). The scam likely has 2 components. Some people eventually get (clearly used/abused, identifying info removed, no manual etc.) batteries (? stolen cell tower leochs etc.?). The second component is probably letting people pay via EFT/cash deposit and just not supplying any goods. (gumtree/olx/facebook etc will have a number of these ads). They seem to do some homework and likely also take note of this particular forum since the newer site/s specifiy the "online only shop" part (too many people started asking about addresses and google street view?) so maybe the 50% discount will change to 45%....and the warehouse move to Askham... They also appear to have people posting positive reviews on hellopeter to counter negative comments. Many of the web addresses seem chosen to look like existing companies but with a strategic hyphen or variance of spelling that one will easily gloss over. Also they do not seem to bother to setup a mail account on the domain so fancy web domain only operates via gmail... From info in the public domain here is a sample with some unifying themes and some info that is useful to cross reference with google when the next add/site pops up.. solarenergyrsa.co.za/?product=12kwh-lithium-ion-batteries-with-10yrs-warranty-last-chance-yeah-end-stock-clearance-sale-50-off +27 84-302-7691 +27-65-952-7634 +27 62-456-0626 Offices: East LondonDistribution warehouse: Johannesburg(Please Note that We are fully a Online Store) thewattsstore.co.za/product/12kwh-lithium-ion-package-discount-on-special-price-sale/ +27 62 456 0626 Beaconsfield Rd, Braelyn, East London, 5201Warehouses in Port Elizabeth, Cape Town, Durban & Johannesburg thesolarwarehouse.co.za/index.php/product/6-0kwh-tesvolt-lithium-ion-batteries-with-10yrs-warranty-with-8000-cycles-days-life-now-month-end-50-off-clearance-sale/ +27 67 791 9959 +27 67 809 0979 Shipments from JHB/CPT Warehouse li-iontech.co.za/index.php/product/12kwh-lithium-ion-batteries-with-10yrs-warranty-last-year-stock-clearance-sale-50-off/ +27 64 489 1208 Head office: Moffett Retail Park, Port Elizabeth, RSA Distribution Warehouses: JHB & PE solarcityrsa.co.za/index.php/product/6kwh-lithium-ion-batteries-with-10yrs-warranty-last-chance-holiday-stock-clearance-sale-50-off/ +27 65 346 6447 +27 64 489 1208 JHB Wearhouse address: Items are Drop-shipped from suppliers in JHB, CPT & Germiston RSA thesolar-shop.co.za/index.php/product-category/lithium-ion-battery/ +27-65 952 7634 +27 68 011 2309 +27 61 363 4125 +27 79 763 3694 gooffthegrid.co.za +27 65 346 6447 +27 68 233 2924 +27 83 998 1589 Shipments from JHB/CPT sethsolar.co.za +27 83 854 5027 Wearhouse Address: Port Elizerberth thesolar-experts.co.za +27 64 489 1208 Head Office: Moffett Retail Park. Warehouse in JHB & PE solarstorage-experts.co.za/index.php/product/today-only-get-a-24kwh-lithium-ion-batteries-with-10yrs-warrant +27 64 489 1208 solarguru-rsa.co.za +27 83 854 5027 solarmarket.co.za

Both dyness and pylontech are LiFePO4, which still get generally lumped into the broad category of being "lithium batteries". (almost nissan x-trail and renault koleos without any CEO hiding in a suitcase...)🙂

manners first, all well thanks. you and yours? 🙂 Fact: all the major South African banks seem to offer some sort of "alternative energy" finance option. There are also numerous smaller/independedent finance options specifically aimed at solar (I am not posting links to these or the banks ...they can generate their own traffic). You should be able to access your bond to finance shiny things on the roof (suspect solar is the new Gucci for some people..if you understand Afrikaans there is an Anton Goosen song that deals with things on a roof...and Gucci) - especially if you are a bit ahead on the bond (been paying extra every month...) or have reduced the outstanding amount a bit. Opinion: Unless you MUST, don't do it for the reasons as already posted by the much more qualified members. How to test?....see how eager the bank is to finance/refinance etc. what you want.... the more eager they are the more likely you know you are to get screwed from a financial benefit perspective. It is different if you are a business/commercial enterprise that NEEDS electricity to produce income... or work from home with potential VAT and tax benefits ... but then you would likely have asked the question to the people doing all those nice income statements and depreciation calculations etc. for the friendly people at SARS ( not the one that used to operate trains). If you need to power grandma's iron lung, maybe also worth it..... Advice: If you need to keep up with isidingo...or want to avoid the barefoot dance of joy, with all known and newly coined expletives as backing tune, after stepping on a lego in the dark (that also gets you called into school because the source of the stray legos repeated your gansta rap to absolutely no amusement of his grade 2 teacher)... rather buy a torch and a chess board.

Load shedding is alot like the droughts... makes (some people) think a bit how you take for granted where the stuff comes from when you open the tap/throw the switch. So better load management should be first port of call. The Flexo definitely ticks the "charge it, put it in the cupboard till load shedding comes around again and you should have a working battery" box. If only used for load shedding should also technically get you 2+ years of use (claims >500 cycles), so probably doing better than (most) lead acids. Western Cape type load shedding with mutiple sessions in a day depending on stage can be a pain - LiPO battery charge rate means 6 hours recharge. Used one last night (was last used and recharged post stage 6 load shedding... mid march?.... switched it on had 4 of 5 "state of charge" lights on. powered TV, router, AV Amp for 2 hours... 2nd last state of charge light was flashing). Did not time it but think was about 5 hour recharge this morning. So bit bigger capacity of the Flexo would be very nice (the 4x4/camping guys also realised that). In the R15K ball park for <200W type loads (TV, light... i.e. keep the kids entertained) the 12V LifFePO4 + 800/1200kVA Multi combo beats the 24V lead acid options for me (just pass word to Victron to come up with a value 12V multiplus option that has a MP-II GX type screen to set user defined voltages without needing extra cables etc.... easy right 😉).

Try and be a bit more specific about what exactly is the concern, the inverter going back/forth/back/forth between eskom/battery? Not staying on Eskom when you put the mains back on? What the best voltage settings are? From what I gather it seems your safest bet during the weekend of loadshedding, and with your intended goal of using it as a utility based UPS is to set program 01 as "Utl" for now. Also post your different voltage settings etc. so others can (hopefully) have an opinion on that. The car revving type sound could be the fans that come one while it is inverting/charging (I have no idea what axperts sound like 😳)

Ag no man, that is cheating like saying the best fuel economy solution to your 5L V8 is to buy a Prius...😉 (unfortunately also my conclusion for our load shedding trolley scenarios).... but the people who just can't afford to push the budget to lithium are left a bit buggered (sure the guys selling batteries don't mind...). Example of someone who through maybe a bit of bad luck/expensive school fees managed to get only 1 year (and almost no actual use) out of a set of omnipowers. He just needs a victron temp sense then I think he has added every blue accessory available to his (green) axpert to try and get a fair service life from his batteries but doesn't look promising. The out of pocket cost on lithium is quite high and below 48V also seem very bad value for money (other than some "second life" or build your own options).

This should probably become a new topic in the battery section but I suspect lead acids are just not meant for what we have in 99% (arbitrary number) of our local load shedding solutions and scenarios. I want to look into it a bit more, unless someone knows the answer ( @plonkster, @Coulomb, @Chris Hobson .. who else?). If leaving out deep discharge/abuse and crap quality I wonder if "deep cycle" (AGM etc.) batteries actually offer any advantage over less exotic (less pricey?) types for "trolley load shedding" use? In essence you need a battery that is a UPS battery (happy to float for long without intervention) but when a fantactic 4 days of load shedding come around once every 2 months you need a deep cycle battery that is happy to charge/dischagre more frequently and at a fairly high rate. It looks like the AGM/GEL/general "deep cycle" batteries do no better when floating in terms of service life than less "exotic" types? .... I came across a reference (not exactly a peer reviewed journal I know) that if lead acids are routinely discharged no deeper than 5% they develop Lead Dioxide buildup which also cuts their life short... which is why I wonder about AGM's and floating. So simplest answer is maybe, other than the usual appropriate voltages/C-rate/DOD etc, maybe cycle your trolley with AGM's once a week?

As pointed out by @plonkster the are (should be?) the same inverter to some extent (not sure if they differ in terms of MPPT rating etc. - too many variants to try and keep up with). I would likely go with the Mecer branded just in terms of potential repair/backup (NOT from personal experience I assume mustek may have more options to repair/replace than geewiz might).

Usual disclaimer (caveat lector): I am not fully conversant in Axpertinese 😜 Other than the premature float issue, using solar vs Eskom should not make a difference to the batteries - but with solar you are at least not paying extra for charging them. This is not your main priority at the moment so shelve it for now. Did you previously switch off the mains and all worked fine and then last night something different happened that was different from all previous tests? Or was the system sitting there after being installed and you for the first time switched off the mains last night? Without knowing I will speculate a bit.... I suspect the inverter is set to "Sbu" (programme/menu 01) where it will use solar first to power loads, if solar is not enough it will use battery, and the utility will only get used to power the loads when the battery voltage reaches a certain set point. So you flipped the switch, the inverter used the battery to power the loads and the battery voltage started dropping. You flipped the main back on and the inverter used Eskom to power the loads and charge the battery. The battery reached a voltage set point (programme/menu 12& 13?) where it then stopped using Eskom to power the loads and started using the battery again....the battery voltage started going down and after 20 minutes the inverter started using Eskom to power the loads and charge the batteries... rinse...repeat...rinse...repeat... The fact that we have active load shedding likely also means that the grid voltage and frequency is somewhat all over the place which could also influence the inverter jumping between on grid... off grid....on grid.. I suggest you post: your exact inverter model (especially MKS vs King etc) - photo of the label on the side of the inverter could maybe be simplest settings for the various programmes (numbers could be different/options different) - especially 01 (source priority), 10 (operation logic), 12 (voltage back to utility), 13 (voltage back to battery), 16 (solar priority). Maybe @Coulomb will then weigh in if no one else on the forum has an answer

I think the mecers are actually voltronic produced so are technically "original" (i.e. not clone)... it could of course be a counterfeit Mecer Unfortunately I suspect you already have the answer to the home issue. Rewire and ideally have a second DB with all the backed up loads (and a transfer/bypass switch for if the inverter gives trouble). Only other option is to manually manage your loads better (wait before boiling the kettle) I am often wrong but I am not aware of a Mecer/Axpert that can "feed back" to the non backed up circuit (even though it is called a "hybrid" it does not have the ability to push power back through the incoming AC side like the Goodwe).

Btw, you could (maybe) find with a higher float voltage that the batteries last longer in terms of powering the load (i.e. they power the computer for 2 hours and not just 10 minutes) but the overall life time of the batteries will be shorter (instead of giving you 2 years service they just happen to pack up 1 month outside of the 6 month warranty). MAYBE there could be justification for higher voltages to compensate for low temperature but I doubt this is the intention (and also not sure it will explain batteries failing in 3 months with what seems to be battery manufacturer spec settings on the inverter in general South African climate). Last thing to rule out is measurement error by the inverter - the BMV should make this easier already but comparing voltage readings with a multimeter compared to what the inverter reports should also help rule out that the inverter says it is charging to 29V while it is actually charging to 24V or 32V. (could also help confirm that the settings via software are actually applied by the inverter).

I am not generator or axpert "certified", so double check with others but yes, the generator takes over the role of the utility. BUT it will at times not do the job with the same quality (voltage and frequency will vary more). So most likely all was working fine and perhaps due changing loads etc. the generator input went outside what the inverter considers "correct", so it disconnects the "replacement utility". Setting the inverter to "appliance" vs "UPS" may help with voltage fluctuation from the generator but if frequency is a problem I do not know if you can set that on the axpert. NOT comparing makes etc. but the multiplus inverter/chargers have an option where you can tell the inverter to sort of ignore the quality of the incoming AC power which is at times used if a generator+inverter combo seem to struggle to get along

Other than singing them a lullaby every night I think you have done all you can to look after the batteries (I see the skyking battery manual advocates a 72hour float charge when connecting batteries in series before doing anything else..) The omnipowers on the "AGM" setting might have suffered from chronic undercharge if only charging to 14.1V per battery (as per @Coulomb's explanation of the AGM setting). I see a 14.4V charge voltage advocated for the omnipowers (OPR AGM / GEL). So that is maybe a bit of bad luck when initially setting what seemed to be the most obviously correct options that ended up being incorrect 🙄. (i.e. the omnipowers set as "user" with corresponding voltages etc. probably would have lasted (much?) longer). I will not hold my breath for the new and older skyking combo to be trouble free but floating at 29V does not sound like such a wonderful idea. The other side is that based on your recent experience if you get 3 months out of the batteries it will be par for the course, so maybe try a higher float (not convinced of the 29V+ though) for a week or two and see what happens (do your own discharge tests to get a sense of capacity, check individual voltages, etc. a couple of times) so before the original 2 month warranty is over, and while everything is hopefully still fresh in the supplier's mind, you should have a sense of whether the batteries are coping better - if they don't then the supplier must be happy to keep on replacing the batteries every 3 months or explain what the problem is and how to remedy it... or refund you the original amount.