CliveSA

A combined invert/battery setup. https://www.sunsynkmobile.com/the-powerlynk The 5kw version will be landing shortly. It look as though it will only be IP20 rated. Not quite the same but quite nice.

If you are looking at installing a new system I would definitely go with 48V. It is the market standard at the moment. I would say that Victron is the slightly better product - and can handle large surges better than Sunsynk can. In car terms I would equate Victron to the Mercedes Wagon and Sunsynk to a Lexus. That said, there are definitely a lot more installers that are familiar with Sunsynk. The Sunsynk app is a big selling point and Victron hasn't replicated that functionality "out-of-the-box". But it is easier to connect Victron to the likes of Home Assistant. That said, the gap is closing with the work done by a couple people on this, including https://github.com/kellerza/sunsynk and https://smarthomeintegrations.co.za/product/smartdeyedonglev4/ The Victron system is a modular system and needs a few more parts. The MPPT and Venus device have to be bought separately. This will push up the price - to be higher than Sunsynk. For just battery backup, I still think you need the Venus. The Victron is more quiet than the Sunsynk and doesn't require the same clearances. This is because the design. The Victron is only IP20 rated with open fans. The IP65 rating of the Sunsynk means there is no internal airflow. I currently have a 5kw Victron inverter and can run all my lights, PC's, two fridges as well as the kettle and microwave. I try not run the kettle and microwave at the same time but the inverter handles it for extended periods. My normal base load is a bit lower though at about 350W - until a fridge kicks in. Other than my stove and geyser - everything is powered by the inverter. You may need to be careful with the aircon - older models can kick a bit and will be heavy on the battery. I love my Victron, it has served me well. But I would have to give Sunsynk a serious consideration if I repeated the exercise. The new 5.3kw Powerlynk XL combined battery/inverter unit is about to land. The pricing looks like it will be really good and make for a nice install. https://www.sunsynkmobile.com/the-powerlynk The 3.6KW version is priced at R34k. Your power consumption looks a little high - maybe check your bulbs that you are running. Nothing like a few 50W downlights to up your consumption. To run 800w average for 4 hours you 3.2kwh which equates to 4kww of lithium battery - assuming 80% DOD. To replace your current your current batteries you would need to get about 4 batteries at R6k a pop. Your spending R24k. That's a little less than the cost of a Sunsynk battery. To size you system I would look at some type of a watt meter, Fluke clamp or current meter. It will give you a real idea of what some devices can use - and plan your system appropriately. I would really consider solar panels. With the current Eskom prices - and how lithium batteries can be cycled - you can really start saving money. Sunsynk and Victron can supply non-essential loads. Your solar can help power your geyser & everything.

As the inverter is attached to the buildings it should be covered under buildings insurance - and the rates will be a lot lower. All risks is effectively meant for items you can carry around - and get stolen (lost) easily. A rule of thumb, if you turn your house upside down does the risk stay behind. For an inverter the answer is yes so it is covered under buildings insurance. The insurance industry is "struggling" with inverters and their risks - it is only very recently that lots of people have installed inverters. Policy wordings (and procedures) ae not always up to speed. Most insurers are now insisting on a CoC. I would make sure that you keep the communication with your insurer - in case their are any issues at claim stage. I would keep a record of: The invoice The exact items installed; The CoC that was provided. With load shedding and the rise in claims many insurers have removed cover for power surge - or limit cover. It poses a risk to you as an inverter system could easily be worth R100k+. Whilst the risk of a power surge is really limited, it could be a financial mess if your system is wiped out by a power surge and your cover is limited to R10k. Be very careful here. Some insurers have also required surge protection (arrestors) - and this protection to be checked regularly - for their to be cover. Surge protectors are usually installed with an inverter - don't think many people think of maintaining them.

Hi @Scorp007, Very valid calculation - and don't disagree. A bit of an overly blunt (generalized) statement from my side. My argument was based on: There is currently PV installed - likely producing excess electricity There is a geyser installed - changes which heat pump to buy. A heat pump will probably cost R17k today - there is no Eskom rebate and there are also installation costs. The excess electricity from the PV, assuming there is some excess, costs R0. The batteries will have a useable capacity of about 9kwh. The average solar production maybe sits somewhere around 18kwh. Some of that will be solar production will support the daytime usage but I suspect - on a normal day - there is a lot of excess solar that is going to waste. If I look at a family of 4, mainly showering, you should average 240kwh for the geyser in a month - 8kwh per day. At current electricity prices (JHB, prepaid, worst block) of R2.54/kwh, it will cost R7.3k over a year. But if majority of the electricity comes from PV then the savings reduce significantly - could be 30% (or less) of the figure. With a solar system I would expect most houses should fall into a lower tariff block. The heat pump should theoretically cost nothing to run as the excess solar should cover the heat pump electricity usage - but the timing of the heat pump could create some Biggest differences between my (and your calculations): I worked on my average hot water usage which is lower - about 50%. How much electricity is sourced from PV vs Eskom - impacting the unit cost. What is the return you need, what are your usage patterns, are you going to stay in the house for 12 years, what will Eskom prices do, ... so many assumptions. I guess we all have to be comfortable with the decisions we make, knowing the you will be wrong - just how wrong.

Don't know the Deye inverter very well but I believe you have a non-essential load. The Sunsynk has this functionality. Your stove & geyser should be on the non-essential load - so when you use the devices they make use of the excess solar. As a first step I would place the geyser on a timer switch. Run the geyser at about 1/2pm. This should mean you get an immediate saving - but some of the power may be drawn from the grid. Using a 2kw element will double the time your geyser runs for - but then most of the power will be pulled from solar. With 4.5kwp, a 4kw geyser will exceed what can be provided by PV - along with the load for the rest of the house. If you don't use a huge of hot water you won't see the impact of a 2kw element. The reality is that the geyser only runs for brief periods of time. For example: You use 100l of (pure) hot water in a day, The incoming water temperature is 15C You heat your water to 65C. You need approximately 6kwh to heat the water, heat losses (for modern) geysers is minimal. A 2kw element means your geyser needs to run for 3h whilst a 4kw geyser would only need 1.5h. You can increase savings by heating your water up - to say 70C. It will avoid running the geyser at night. Maybe have a look at the GeyserWise smart system - that works with Wifi to optimise your geyser. A heat pump will save more electricity but the ROI doesn't make sense to replace your geyser. I am doubtful on claims on more efficient geyser elements - any waste will be converted to heat which will be released into the geyser anyway.

Hi, Have done similar research and it gets a bit tricky. The issue comes with: Geysers - which will run for 45min Stoves which could use 8KW for long periods of time. Heaters which could run for a long period of time. Smart switches - with Wifi - could drop the geyser and stove quite easily. Heaters (and similar) are more difficult. I would not run a geyser on battery backup. There are huge economies of scale that you can get from a central system. If we exclude geysers, ovens and large electric heaters I doubt that many of the units will use more than 500W average - even in the evening. But when a kettle gets turned on that will raise to 2.5KW. Adding a microwave at the same time and you could easily get to 3.5KW - 4KW. However, this happens rarely. Although people do eat at similar times - the times will never completely overlap. A single unit will likely escape with less than 2kw - about 90% of the time. In this way a combined system can benefit from the "diversification". Batteries are the expensive part of any system. From my personal experience, I need a 5KWh battery to run a run 5KW load - which happens less than 1% of the time. But, my average load is less than 500W - implying not more than a 2kwh battery to survive 4h of load shedding. I have used 3kwh less than 1% of the time. If you can reduce the maximum demand (per unit) with a combined system - you will have huge savings. The cost of batteries is roughly R7k/kwh. Using my example - that is a R21k saving per unit. The issue is that a few users could impact everyone negatively - and then it becomes a free for all. But if you can get people to "play ball" the cost is significantly less. Charging people more for power when there is load shedding - particularly at night - might help solve some of the issues but trying to explain that. A couple offsetting factors: In older buildings, provisioning a Wifi network might be more difficult. The individual installations costs are reduced - with all the addition DB wiring, space, batteries, etc. The additional costs of the additional smart switches, Wifi, etc. As a starting point it might be worthwhile to monitor the overall power demand and see how that compares to 5KW per unit.

I have used the Shelly switches. They are really small, the "Plus" version can monitor power consumption and you can remotely control the devices. They have an app but also can be integrated to HA. Removes the guesswork in determining what ate you battery. Haven't yet build the automation to kills certain devices when their is load shedding - or the battery is struggling.

Simple rule is if it heats or pumps. The biggest appliances would be your geyser, pool pump, heaters. As others have mentioned there are smart switches which can help control these loads. Just be careful as most of them can't handle a large load running for hours. Rough rule, reduce the stated rating by 30% to be on the safe side. CBI makes a device that works well with a geyser. I quite like Shelly switches. A couple topics on this forum what people have done with Home Assistant to automate loads. Really cool stuff!

I discussed the topic on the forum a while ago: I can confirm that a solar charge controller doesn't work. There are some technical reasons on why it doesn't work. (

Agree with @cbrunsdon. I have installed lots of 12V strip lights for friends and family. My approach has been: 12V Remote dimmer switch: https://4x4direct.co.za/dimmers/6015-remote-controlled-dimmer-for-led-strip-12-24-volt.html A COB warm white strip light: https://www.ledz.co.za/product/led-cob-strip-light A 45 degree profile for mounting: https://www.ledz.co.za/product/flat-bed-45-degree-surface-mounted-profile 6.4A Alarm Power Supply: https://www.securityking.co.za/products/sherlo-battery-backup-power-supply-6-4amp?variant=35044907253913&currency=ZAR&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&utm_campaign=gs-2020-06-08&utm_source=google&utm_medium=smart_campaign 20Ah Lithium Battery: https://www.makro.co.za/home-garden/lighting/home-automation/smart-electrical/securi-prod-lithium-iron-phosphate-battery-12-8v-20ah/p/c77cb036-8458-4192-92ec-97ff26553ac3?gclid=CjwKCAjwov6hBhBsEiwAvrvN6HhtJvmx3v6fDaHRwpYA_7uqP24bwgMBFo0UcVOw3kPV2hvcuz9JuRoC43QQAvD_BwE 2mm Speaker Wire You need to bridge the outputs as each output can only handle 1A. I use 1mm wire of the same length with a cable joiner to do this. You also need to cut the speaker on the alarm power supply - so that you don't have an alarm sounding for 4h of load shedding. For added protection, I have added a DC fuse in case their is a short in the system. I use the 2mm speaker wire to help reduce voltage drop. I have been able to run 20m of cable with minimal voltage drop. Effectively you can run about 70W of LED lighting. That translates to about 7m of lighting. I like to run 2m lengths - so that gives you (bright) lighting for 3 rooms. The remotes can be mounted on the wall next to the light - and they are barely visible. These remotes aren't the cheapest but have a unique code to prevent interference from other remotes in the house. They also have a dimming function. I like the 20Ah lithium battery as they can run for a long time. Running 6m of lighting continuously you can get about 3 hours of light without overly discharging the battery. Even this comes under pressure with Stage 6/7 load shedding. An alternative is to run the lighting directly from the battery. You can then link a charger to the battery. The charger will charge the battery when the voltage drops. A simpler approach but doesn't give much in terms of low voltage, shorting, etc protection. The advantage of the power supply is that it automatically switches between grid and battery - and doesn't just use the battery.

Almost certainly overkill but Revov has designed a ‘cube’ that could work, it comes with a lot of the necessary wiring and circuit protection built in. https://revov.co.za/wp-content/uploads/2022/12/9-REVOV-CUBE_SpecV2-Refresh.pdf

Depends a lot on budget. If you are serious about getting solar at a later stage I would look at a Sunsynk - they are getting really good reviews and are well supported. Sunsynk is not as good as a Victron but the pricing is a lot better. If solar is not an option then a Mecer (Axpert) inverter will do the job.

I would save up and get an Efergy (or other brand) monitor. They use a (CT) clamp that goes around the input wire on your DB board - so no cutting. It's a lot easier than installing a smart DB switch. Data gets uploaded to the cloud so you can monitor your peak usage and when you use electricity. It does monitor total demand but you get an idea of which devices (circuits) are using electricity quickly - and can focus on finding inefficient devices. Check your draw, switch on a device, wait 30s and then check the app again. From experience, it's a very good way to save electricity quickly. You can comfortably say goodbye to tumble dryers, halogen lamps, large pool pumps,3 geysers, etc. It will also be really helpful to help size your solar system as you have a far better idea of your power usage. Batteries are expensive and to get the most ROI you will want to maximize your power usage during the day. IF you need to you can take it a step further. A kill-a-watt meter can also help to look at specific devices that operate off a plug. You can also make a power monitoring device using a Sonoff/Shelly/Tuya smart switch. Many of them have power consumption meters and will give more detailed data than a kill-a-wat - just a bit of DIY. I would use a Sonoff IP66 box and you can make a mini extension lead to see the demand profile over a period. Make sure you keep your load (well) below the rated maximum.

Not 100% ideal from a safety perspective if something goes wrong with the lithium battery. I know that some electricians have refused to sign-off a CoC if the battery is installed indoors. However, this is the arrangement I and my parents have - two independent parties were OK with a battery indoors in a room. Mine has been running for a couple years with no issues. From a safety perspective I would argue that a fully compliant inverter, with a lithium battery, is probably the safest option - a lot better than extension cords, batteries, SLA batteries, et al. I have this setup and load shedding is (basically) a non-event. I don't connect my stove, geyser & dishwasher. Everything else runs off the battery. Other household members have shown that it works well with hairdryers & and irons. We have had no power for about 12 hours and comfortably remained working from home, having tea, lunch & dinner. The batteries dropped to 20% on that occasion. I can cook with the microwave oven function. Only once had a warning light when using the microwave oven & an induction plate at the same time - for a while. You don't need to worry about the geyser as water will remain hot for 4 hours. Connecting the stove will be problematic as you could easily forget and overload the inverter - and battery. The advantage of going complete overkill is that it will be very difficult for something to trip or go wrong - and the resulting panic that it could cause. A hairdryer and kettle being used at the same time. An inverter with a passthrough function will also help - as it reduces the likelihood of tripping further. You really want something that is simple and can be left alone. I wouldn't bother too much with remote monitoring - you won't be able to do much. Trying to troubleshoot over the phone will be difficult. You will need to check this. Some inverters need a lot of clearance which can be difficult in a smaller room. My Victron clearance limits meant this was fine - a story for another day on why that inverter, it was a long time ago. But is does occupy a fair section of the wall - as it had to be positioned away from the wall. I close the bedroom door if there is load shedding. That switch from inverter to grid can be heard. You also hear the inverter when the batteries are charged - but that lasts a couple minutes. You also hear it if there is a large load for a while - but nothing irritating. Some inverters will be a lot noisier - unfortunately price will play a part here. Cheaper Solution If you have the budget, that would be an amazing solution. 👍 I would say go for it @MdF Unfortunately, not everyone has those resources. I have found that sometimes a simpler solution can do the trick. A repeat of @Bobster.'s views, largely. It's a little bit of DIY & no where near the inverter option but could be something to consider. Most people are happy with a few basic essentials - lights & entertainment. A trolley inverter can be setup in a corner - not to be moved. It can be used to run all those devices. A simple 12v transformer can then be used to supply LED strip lighting throughout the house. If you get a slightly larger (1.5KW) inverter, you get those portable 650W 1 cup kettles - and a cup of tea can be made. Alternatively you can use an alarm power supply to give lighting to different rooms. A 2m strip (18w of COB LED strip) will comfortably light a room. An RF transmitter switch works really well. A couple emergency backup bulbs, I like Aurora, and it ensures you can see where you are going at night.

On a couple other forums (4x4 forums) people have done this. It is recommended that you use a battery balancer. The forum store used to stock Hubble batteries. You can also look at Revov, FreedomWon, BlueNova, etc