Hi All

Sure you have heard these questions before however here goes. We installed Solar system live 15 June 2023. First weekend, the long weekend the battery reads 99% at 6pm but 14% by 6am and I did not know what was draining it. in the mornings. The installer came out and said two things needed.

1. We must install geyserwise and change form 4kW to 2kW element and

2. He needs to adjust setting so that battery does not discharge so low, but accesses ESKOM to keep charged when it needs to. All done at additional cost and the battery now never drops below 90%. Draws on Eskom fortunately Eskom has also played along with no or less load shedding.

My question here is what should that setting be to prevent total drain. I believe 90% is an overkill and maybe should be 40 or 50% . Only wife and myself at home. We are in our 60's and daily units used before installation was between 6.5 and 11.5 average 9.1. We have a 5kVA battery.

A further question is the geyser temperature according to the geyserwise display gets to 55, and I am finding 40s is comfortable enough to shower. My wife however is complaining that it is not hot enough when she wants to do dishes and has taken to boiling a kettle of water to top up temperature for dishwashing . Some advise please from the longer term system users.

Thanks

GregM

Hard to answer exactly exactly without knowing exactly what system, panels, inverter and battery you are having. But in general,

1. A geyser timer of some type coupled with a lower-wattage element can help you to make better use of daytime sunshine to heat up your geyser, instead of doing it from the battery. Geyserwise is an option, there are other solutions also.

2. If you have a Lithium battery it can make good sense to cycle it deeper than 90%. Depends on how much reserve you want to keep for loadshedding, and there's not a one-size-fits all solution. It depends on what you want and need out of the system.

3. Be careful with dropping the geyser temperature to in the 40's permanently. You need the water temperature to go over 50 degrees to kill off harmful bacteria, eg. Legionella.

13 hours ago, GreenFields said:

Hard to answer exactly exactly without knowing exactly what system, panels, inverter and battery you are having. But in general,

1. A geyser timer of some type coupled with a lower-wattage element can help you to make better use of daytime sunshine to heat up your geyser, instead of doing it from the battery. Geyserwise is an option, there are other solutions also.

2. If you have a Lithium battery it can make good sense to cycle it deeper than 90%. Depends on how much reserve you want to keep for loadshedding, and there's not a one-size-fits all solution. It depends on what you want and need out of the system.

3. Be careful with dropping the geyser temperature to in the 40's permanently. You need the water temperature to go over 50 degrees to kill off harmful bacteria, eg. Legionella.

Good day thanks for the reply.

We installed 8 panels, Lux Power 5100 Inventor and Vestwood 5kVA Battery. It was suggested that we should get a 2nd battery at start but I opted to first see how long this one would hold in load shedding. Our intention was never to exist the grid but to survive load shedding.

6 hours ago, GregM1 said:

Good day thanks for the reply.

We installed 8 panels, Lux Power 5100 Inventor and Vestwood 5kVA Battery. It was suggested that we should get a 2nd battery at start but I opted to first see how long this one would hold in load shedding. Our intention was never to exist the grid but to survive load shedding.

Your power usage is fairly low - let's say 10 units per day, or less than half a unit per hour on average.

The battery can store 5 units max, and according to the spec sheet you've got over 6000 cycles, for which you can discharge 80% out of the battery each day. Call it 4 units available to cycle out each day.

Basically if you use plan to use up 2 units each evening (discharge down to 60% left), and keep a reserve of 2 units to carry you through loadshedding from 60% down to 20%, and then recharge the battery the next day from the panels, I'd think that would be prudent, a fair mix between surviving loadshedding and cycling the battery to reduce daily purchases. Just keep the geyser running from solar panels, or from the grid if the sun is not shining, ideally not off the battery.

As a start, and then after that you can always tweak it again.

Great information thanks. Just looked at invertor on app at 10h49 today and see the below:

1. Solar Yield - 1kWh today 

2. Battery Charge - 3.1kWh today

3. Import (from grid) - 3.1kWh today 

4. Consumption - 3.5kWh today

 

and believe we are able to optimize further.

 

Greg 

 

 

21 hours ago, GregM1 said:

Hi All

Sure you have heard these questions before however here goes. We installed Solar system live 15 June 2023. First weekend, the long weekend the battery reads 99% at 6pm but 14% by 6am and I did not know what was draining it. in the mornings. The installer came out and said two things needed.

1. We must install geyserwise and change form 4kW to 2kW element and

2. He needs to adjust setting so that battery does not discharge so low, but accesses ESKOM to keep charged when it needs to. All done at additional cost and the battery now never drops below 90%. Draws on Eskom fortunately Eskom has also played along with no or less load shedding.

My question here is what should that setting be to prevent total drain. I believe 90% is an overkill and maybe should be 40 or 50% . Only wife and myself at home. We are in our 60's and daily units used before installation was between 6.5 and 11.5 average 9.1. We have a 5kVA battery.

A further question is the geyser temperature according to the geyserwise display gets to 55, and I am finding 40s is comfortable enough to shower. My wife however is complaining that it is not hot enough when she wants to do dishes and has taken to boiling a kettle of water to top up temperature for dishwashing . Some advise please from the longer term system users.

Thanks

GregM

Something that many folks go through is moving loads into the sunlit hours. That makes maximum use of PV, and allows you to run longer on the battery after hours.

You have a 5kVA battery. Now usually you can discharge a lithium battery to 10% remaining, so you effectively have 4.5kVA. You average about 0.5kWh per hour. So on a fully charged battery you could go 9 hours. Now that's some way beyond surviving a load shed, but sometimes the power doesn't come back on when it should. Sometimes, especially in cold weather, overloads occur and things go pop. Anyway, there's no rule about this, but it's worth thinking about. 

Try to do as much as possible during the sunlit hours without overloading the inverter. The reduces your after hours consumption below that average, and you can then stretch the battery further, or reduce the percentage you reserve. The big thing to control is the geyser, your installer is on the money there. Sometimes this can mean changing your routines. From experience I have concluded that to make the most out of any system that uses solar, you do as much as you can whilst the sun is up. 

The 90% that is currently reserved seems to be playing safe to me. If you can drop that, you will make better use of PV and reduce your draw from the grid. But do that thinking I mentioned, we all have different comfort levels (and different trade offs of comfort V budget).

You may find you have to do some tweaking early on. This is normal. You will get yourself into a happy zone where you don't worry about load shedding whilst you're at home.

Water temperatures: Our water is heated to 55 degrees. We find that quite adequate, but we only turn the hot tap on. 

If I may ask, why is your wife so worried about the sink? Do you have dishwasher? Read the manual rather than just run it in the default mode. I found ours has an "eco" mode with claimed 9l of water and 0.9kWh for a full load (takes 3 hours, but so what?) When I tested it the power consumption was actually just under the claimed figure. We now run the dishwasher 5 or 6 times a week, putting everything we can in it. So our primary concern about water temperature is if it's high enough to shower.

Some great guidance in the replies. Based on the figures estimated by @GreenFields I would agree you can get a long way to counter LS even with only 1 battery. Good judgement to take a few months before you decide on that 2nd battery.

If you are prepared to limit your loads during the LS period you can even discharge the battery to 40-50% by the time PV kicks in. 

Your 1kwh from PV up to 13h00 shows a low yield day and on normal sunshine that could be quite a bit more. 

If your battery is still set to 90% SOC that could be another reason why PV yield is low today. 

Edited June 30, 20232 yr by Scorp007

Thanks for this response. I have now started asking those tweaking questions and appreciate all the feedback being given. I have communicate with installer today to ask if he will set the discharge to stop at 60% not the current 90% and I will be changing the geyserwise settings to heat between 10am and 4pm when sun is peaking. Still testing looking forward to more value adding tips thanks

 

1. We must install geyserwise and change form 4kW to 2kW element - this is spot on. 

2. He needs to adjust setting so that battery does not discharge so low, but accesses ESKOM to keep charged when it needs to. All done at additional cost and the battery now never drops below 90%. Draws on Eskom fortunately Eskom has also played along with no or less load shedding. - not sure why your installer charged you additional here, this should have been his stance from the get go. Your battery has a SOC and discharge limit, once you hit the limit that equals 1 cycle (in some cases with certain batteries the cycles differ) cycling your battery more often reduces battery life. But at your rate and the adjusts you should be fine for another 10 years at least. 

My question here is what should that setting be to prevent total drain. I believe 90% is an overkill and maybe should be 40 or 50% . Only wife and myself at home. We are in our 60's and daily units used before installation was between 6.5 and 11.5 average 9.1. We have a 5kVA battery - this should be set on the inverter as per the battery manuals, should not go lower than 20% I would suggest. 

A further question is the geyser temperature according to the geyserwise display gets to 55, and I am finding 40s is comfortable enough to shower. My wife however is complaining that it is not hot enough when she wants to do dishes and has taken to boiling a kettle of water to top up temperature fordishwashing . Some advise please from the longer term system users. - comments by the the other  forum members is spot on 55 degrees is a good temperature, also look into installing a geyser blanket to keep the water warmer for longer.