June 19, 20233 yr Hello everyone, I have a Deye 5kVA inverter with 2x Hubble AM2 batteries and 10x 455-watt solar panels. Currently, my 150L geyser and stove bypass the inverter and directly run on Eskom power. I was wondering if a simple solution to save more power would be to change the element in my geyser from a 4kW to a 2kW element. Then, I could wire it through my inverter and set up a timer to turn the geyser on at 10:30 am and off at 5:00 pm. This way, the majority of my water (if not all) would be heated using solar energy, and my batteries would still remain charged for the evening. Would this be recommended, or do you advise against it? Should I stick to the current setup until I can afford to replace the geyser with a solar or gas unit? Thank you.
June 19, 20233 yr To complicate your solution, you could also consider adding a heat pump to heat your water... Maybe try getting one of these, they are apparently 20% more efficient and last longer: https://www.livestainable.co.za/product/geyserwise-ptc-stainless-steel-230v-electrical-element-1-5kw/?gclid=EAIaIQobChMI5dW-ieXO_wIVGvntCh14UgNeEAQYAiABEgL5kvD_BwE
June 19, 20233 yr 1 hour ago, Nick555 said: Hello everyone, I have a Deye 5kVA inverter with 2x Hubble AM2 batteries and 10x 455-watt solar panels. Currently, my 150L geyser and stove bypass the inverter and directly run on Eskom power. I was wondering if a simple solution to save more power would be to change the element in my geyser from a 4kW to a 2kW element. Then, I could wire it through my inverter and set up a timer to turn the geyser on at 10:30 am and off at 5:00 pm. This way, the majority of my water (if not all) would be heated using solar energy, and my batteries would still remain charged for the evening. Would this be recommended, or do you advise against it? Should I stick to the current setup until I can afford to replace the geyser with a solar or gas unit? Thank you. You need to be guided by data. There must be a tool that will show you the various flows of electricity in your system, the total load, what is going to or from the battery, what is being drawn from grid, battery SOC... Be guided by that. If you batteries are just charging by mid afternoon then maybe you don't want to put the geyser on the essential side. If you have plenty left over, then do what I did. I moved my water heating to the essential loads and watched it carefully for a couple of weeks. It's not hard for an electrican to move the geyser from one side of the DB to the other, so if I wasn't happy with the outcome it was no big deal to reverse the change I'd had made. Don't cater for an ideal situation (sunny day, no appliances being run) but an average day (dishwasher etc get run). Note that the geyser will now contribute to the 5kW limit on the backed up circuits. So this is something else to look out for: If you are getting peaks above 3kW already, then you don't want to move the geyser over. It only takes a few seconds over the limit to trip the inverter. Or maybe those peaks are fairly predictable and you can use a timer to make sure that the geyser can't be on when the peaks occur. Trial and error. Your general idea is the right one. The way to maximise a PV system is to do as much electrical work as possible whilst the sun is up.
June 19, 20233 yr 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. Edited June 19, 20233 yr by CliveSA
June 19, 20233 yr 2 hours ago, Nick555 said: Hello everyone, I have a Deye 5kVA inverter with 2x Hubble AM2 batteries and 10x 455-watt solar panels. Currently, my 150L geyser and stove bypass the inverter and directly run on Eskom power. I was wondering if a simple solution to save more power would be to change the element in my geyser from a 4kW to a 2kW element. Then, I could wire it through my inverter and set up a timer to turn the geyser on at 10:30 am and off at 5:00 pm. This way, the majority of my water (if not all) would be heated using solar energy, and my batteries would still remain charged for the evening. Would this be recommended, or do you advise against it? Should I stick to the current setup until I can afford to replace the geyser with a solar or gas unit? Thank you. I changed mine to 2kw. The difference is that my geyser is on the aux port(i use a heat pump to primarily heat my water). I only use the geyser when there is "Excess" solar power to heat up the water to 70 degrees since heat pump only goes to 60.
June 19, 20233 yr 34 minutes ago, phidz said: I changed mine to 2kw. The difference is that my geyser is on the aux port(i use a heat pump to primarily heat my water). I only use the geyser when there is "Excess" solar power to heat up the water to 70 degrees since heat pump only goes to 60. Very clever, I like that, perfect use of the Aux port.
June 19, 20233 yr 4 hours ago, CliveSA said: A heat pump will save more electricity but the ROI doesn't make sense to replace your geyser. You don't have to changed your geyser when using a normal heat pump. You only T in on the cold and hot water pipes. Refer to my 12 year saving with mine using a normal geyser. Subject is "Heat pump yes or no" Edited June 19, 20233 yr by Scorp007
June 19, 20233 yr 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. Edited June 19, 20233 yr by CliveSA
June 19, 20233 yr If you use a PTC geyser element instead of a conventional one, it would be more efficient
June 19, 20233 yr Take a look at PV direct water heating. i Have 3x 325w panels that directly heat a 150L geyser with 4000w element (70C) on a digital thermostat timer switch for the past 5 years without any problems. Tankless gas water heater for backup.
June 19, 20233 yr 11 hours ago, Nick555 said: Hello everyone, I have a Deye 5kVA inverter with 2x Hubble AM2 batteries and 10x 455-watt solar panels. Currently, my 150L geyser and stove bypass the inverter and directly run on Eskom power. I was wondering if a simple solution to save more power would be to change the element in my geyser from a 4kW to a 2kW element. Then, I could wire it through my inverter and set up a timer to turn the geyser on at 10:30 am and off at 5:00 pm. This way, the majority of my water (if not all) would be heated using solar energy, and my batteries would still remain charged for the evening. Would this be recommended, or do you advise against it? Should I stick to the current setup until I can afford to replace the geyser with a solar or gas unit? Thank you. yes, it will help to go downgrade the element to 2kW , sacrificing the existing time to heat up to about double , but this comes with the territory , we living in the age of energy management. At 2kW you will give your pv energy profile a sporting chance to deliver more energy because its over a longer sunny period. But youalso have this grid tied Deye, the good thing about that is you can export excess pv directly onto your own grid loads , without moving the geyser to essential. Are you currently configured for export onto your non-essentials?
June 20, 20233 yr 22 hours ago, Nick555 said: Hello everyone, I have a Deye 5kVA inverter with 2x Hubble AM2 batteries and 10x 455-watt solar panels. Currently, my 150L geyser and stove bypass the inverter and directly run on Eskom power. I was wondering if a simple solution to save more power would be to change the element in my geyser from a 4kW to a 2kW element. Then, I could wire it through my inverter and set up a timer to turn the geyser on at 10:30 am and off at 5:00 pm. This way, the majority of my water (if not all) would be heated using solar energy, and my batteries would still remain charged for the evening. Would this be recommended, or do you advise against it? Should I stick to the current setup until I can afford to replace the geyser with a solar or gas unit? Thank you. Lots of great advice and I have installed lower-watt elements for decades on my geysers, even when electricity was cheap. Running your geyser on essential load gives you minimal headroom for when we have load shedding and panels are not producing (low light overcast day). If your CT coil is correctly installed, then excess solar (and to a degree your battery if set) should be powering your geyser. I just had an electrician do a final COC check on my installation yesterday and corrected the CT coil installation at the inverter side. We immediately saw my geyser draw display on the unit. I have an 8KVA Deye but will still keep my geyser on non-essentials.
June 20, 20233 yr Author 42 minutes ago, cbrunsdon said: Lots of great advice and I have installed lower-watt elements for decades on my geysers, even when electricity was cheap. Running your geyser on essential load gives you minimal headroom for when we have load shedding and panels are not producing (low light overcast day). If your CT coil is correctly installed, then excess solar (and to a degree your battery if set) should be powering your geyser. I just had an electrician do a final COC check on my installation yesterday and corrected the CT coil installation at the inverter side. We immediately saw my geyser draw display on the unit. I have an 8KVA Deye but will still keep my geyser on non-essentials. Thank you. I do notice that my geyser draws power from the (PV) system when it is on during the day. However, I assumed it was a mistake because it remains off during load shedding. So, are you suggesting that even though it draws power from Eskom, the Deye inverter is actually supplementing its power during the day? Edited June 20, 20233 yr by Nick555
June 20, 20233 yr Author 12 hours ago, BritishRacingGreen said: yes, it will help to go downgrade the element to 2kW , sacrificing the existing time to heat up to about double , but this comes with the territory , we living in the age of energy management. At 2kW you will give your pv energy profile a sporting chance to deliver more energy because its over a longer sunny period. But youalso have this grid tied Deye, the good thing about that is you can export excess pv directly onto your own grid loads , without moving the geyser to essential. Are you currently configured for export onto your non-essentials? where would i check on my inverter if its configured for export onto non-essentials?
June 20, 20233 yr Author 20 minutes ago, chrisc said: A 2.2kW PTC element is equivalent to a 3kW conventional element thanks i think this might be the first route i take to change it to PTC and monitor the usage before i move anything over to the inverter https://xtendelements.co.za/products/
June 20, 20233 yr 21 hours ago, CliveSA said: 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. I'm not sure I understand this feature of the Deye/Sunsynk inverters. My Goodwe is able to push excess solar to non-backed up circuits, and it does this as long as there is a grid connection, which looks like the same thing on the face of it. Am I right in saying that the Deye/Sunsynk has a rule based way of doing this whilst the grid is down?
June 20, 20233 yr 27 minutes ago, Nick555 said: Thank you. I do notice that my geyser draws power from the (PV) system when it is on during the day. However, I assumed it was a mistake because it remains off during load shedding. So, are you suggesting that even though it draws power from Eskom, the Deye inverter is actually supplementing its power during the day? Correct. The CT coil installed at the DB board helps the inverter determine how much excess power to push back. You can also see how the inverter goes into the red from the house load. This is just bad user interface design from Deye, Sunsynk users have it better. Right now the battery is being charged before the excess is pushed to the home load.
June 20, 20233 yr 48 minutes ago, Nick555 said: where would i check on my inverter if its configured for export onto non-essentials? Well to start off with you need a CT coil at your incoming mains. Do you have one? As per the actual settings one of the SS gurus will need to help us.
June 20, 20233 yr 44 minutes ago, Nick555 said: thanks i think this might be the first route i take to change it to PTC and monitor the usage before i move anything over to the inverter https://xtendelements.co.za/products/ Joh!! Watch out for the temperature of this device! 😅
June 20, 20233 yr I run my 3kw element on the Inverter 8kw, I upgraded it from a 2kw element found it worked quicker and better. 2kw took way to long. IF solar is available i manually control it to run during the day. Sun = free energy so why not take advantage of it. That is if the inverter and solar you have installed can handle the load. On average my geyser takes about 30-45 minutes to heat up to 60. So why not. Every cent you can save on eksdom side why not. Even if she uses 2000watts of the batteries for 30-40 minutes im not faced as there is normally enough time and sun to charge it up again after the geyser gets to temps. Also add a blanket around your geyser. I went cheap and got some underfelt(the stuff you put under carpets grey looking stuff) and wrapped the geyser in that 3or 4 layers cant remember. Works better than these stupid geyser blankets hold heat much better now. Just remember to switch it off on very overcast days as it will drain the batteries very quickly. I am 95% offgrid so my eksdom is off most of the time. But sometimes i have to tuck my tail between my legs and ask for some power from the big man 🤣 then i will switch my incoming eksdom on.
June 20, 20233 yr 4 hours ago, Bobster. said: I'm not sure I understand this feature of the Deye/Sunsynk inverters. My Goodwe is able to push excess solar to non-backed up circuits, and it does this as long as there is a grid connection, which looks like the same thing on the face of it. Am I right in saying that the Deye/Sunsynk has a rule based way of doing this whilst the grid is down? No the law states no power can go to the non essential without going to the grid when power is down. This applies to all grid tied inverters. The essential side would work. AFAIK you can use battery if you wish to non essential if the grid is on then the CT can prevent export to the grid from battery. This is how I understand it. The common problem of using the geyser say with 2kW element on essential and discharging the battery can easily be overcome with a remote timer like the Sonoff by paying attention to LS times and a weather APP. The reason I mention this is we see a lot of timers for geysers say with a 2kw element on a 150L geyser being switched on for long periods that actually exceed the time required to heat water up to 60 degrees from say 20. Edited June 20, 20233 yr by Scorp007
June 20, 20233 yr 56 minutes ago, Scorp007 said: No the law states no power can go to the non essential without going to the grid when power is down. This applies to all grid tied inverters. The essential side would work. I'm wondering if it can support the non-essentials during a load shed, but not push back to the grid. I know it still has to do the islanding. I've sometimes sat during a day time load shed and been frustrated that it's a nice sunny day, my battery is charged, but the pool pump isn't running. 56 minutes ago, Scorp007 said: The common problem of using the geyser say with 2kW element on essential and discharging the battery can easily be overcome with a remote timer like the Sonoff by paying attention to LS times and a weather APP. The reason I mention this is we see a lot of timers for geysers say with a 2kw element on a 150L geyser being switched on for long periods that actually exceed the time required to heat water up to 60 degrees from say 20. 20! Am I doing well or something? I don't think I ever see much below 35, according to the display for the heat pump. The geyser is inside the roof. Edited June 20, 20233 yr by Bobster.
June 20, 20233 yr One can always add a changeover switch to the geyser input. This will allow you to change the supply manually from essentials to non-essentials on overcast days and have much more control over it.
June 20, 20233 yr 22 minutes ago, Bobster. said: I'm wondering if it can support the non-essentials during a load shed, but not push back to the grid. I know it still has to do the islanding. I've sometimes sat during a day time load shed and been frustrated that it's a nice sunny day, my battery is charged, but the pool pump isn't running. 20! Am I doing well or something? I don't think I ever see much below 35, according to the display for the heat pump. The geyser is inside the roof. PowerUser has given the answer how to get power to a load that is normally on non essential to connect to essential. The same one can do with say the pool pump. One can also use a change over relay to switch loads from the 2 sides. Just wire the common to the load. Via Sonoff the relay can be remotely switched for if not at home. You are indeed lucky to see 35 as the low. After running a normal bath and not even full then my geyser in the roof goes down to 26. 150L geyser.
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