Richard Mackay

The OP (now I know what that means..) who caused all the trouble.. I've been had before believing that there is a serious soul asking a serious question but I have my doubts. JosephineFlexton appears to have joined this forum on Thursday morning, posted her(?) question and then disappeared leaving the die-hard regular contributors to tear each other apart..

I'm not being vindictive. My point is that it's difficult to be objective. If you want to really experience 'confirmation bias' then read some threads on a RE subject like this on MyBroadband. I reckon this forum is less hysterical but one must tune in to where people who post questions are coming from.

I totally agree! This thread is: Simple UPS for mostly fridge. This is a question about surviving power outages, not about embarking on a RE installation with the ultimate aim of going off grid. This matters because one is influenced about what to do largely due to your mindset. I presume Introverter's comments are motivated by his particular mindset (and the PV array and inverter + battery banks that he has installed at a substantial cost)

JosaphineFlexton srtikes me as trying to help her family with tried and tested solutions during power outages. I think if one can avoid installing an inverter UPS for load shedding one should do so. The batteries cost plenty and before you know it they need to be replaced. You will not be able to power all electrical loads on the UPS due to limited capacity of the UPS anyway..

Why do you believe the freezer needs backup power? The ice in the freezer needs to melt first before the temperature gets above 0 deg C (first having to give up its latent heat). I find during load shedding my freezer hardly changes in temperature. Of course you should refrain from opening the door frequently..

If it is a grid tie system it simply draws power from the grid.

In a series config these BMS circuits (on small devices) don't equalise the battery voltages of each cell. So if one battery is kaput it will discharge first and the BMS will switch off the whole bank. You have to manually charge that cell back to the voltages of the other cells..

This is why most of the battery packs are connected in parallel. This simplifies the BMS circuit to only one circuit that protects against over voltage when charging and under voltage when discharging.

Has the torch worked hard? If not just check their capacity first: Looks like they are connected in parallel. Charge them to 4.2V and discharge using the lamp as a load (disconnect one battery so you check one at a time). Measure the current so you can do a rough calculation on each battery's capacity.

If you can persuade the landlord to get an electrician to have a look at your setup do so. If it's an electrician with some ability you can then ask a few pertinent questions..

What is the function of the transformer? Victron are well supported so I would phone their main support centre and speak to their repairs dept. They might have a scrap PCB with a good transformer.

If the price of these solutions is getting too high then there is always the DC backup option to be considered. (Search Mini UPS) A fair number of the devices listed can be powered from one of these at a fraction of the price..

There are smarter ways to do this. CBI make ECM (and LCR) products for this purpose: http://cbi-lowvoltage.co.za/content/cbi-electric-assists-customers-auto-load-shedding I have a few load control relays LCR 6A which you are welcome to if they will do the trick

Solar water heating would only be beneficial for evening hot water so this isn't a total solution. So you need some way to heat water in the morning. The heat pump is way more efficient than an electric element. (3x maybe more??) You need to run the calcs and see your ROI..

Does the underfloor heating switch on/off when it's on? (like a hot plate of an electric stove does on low/med settings)