8 minutes ago, Tariq said:

Hi guys, I will be the first one to apologize, I did not want to create any ugliness on this forum, I am truly sorry, let us all be friends.

We are still good friends but that doesn't mean we can't argue to get to the bottom of the things! 😀

Nothing wrong with having different opinions and still being friends 😉

On 2021/10/18 at 11:25 AM, ASH_JHB said:

Howdy, 

been lurking on here for some time trying to learn as much as possible. been a steep learning curve. About to pull the trigger on an installation but want want to get some ideas around my requirements.

Some background.

The main idea was initially to beat loadshedding but that has turned into trying reduce my reliance and cost to Eskom. I started with an energy monitor to get a good idea of my daylight and night time usages. currently averaging around 30kw per day, mostly split between daylight and evening, (20kw daytime and 10-15kw nighttime) Seems a bit lower in summer now.

Got 2x2kw geysers which are both on solar tubes, gas hob (electric oven) and LED's throughout. so most of the groundwork has been done already. Got a fish pond which is 0.75kw which needs to run 24/7, borehole pump (0.75kw) and pool pump. all of which are connected to smart switches and automated with Home assistant so will be able to control which appliances turn on based on availability of solar generation (except for the pond of course).

Interesting, I noticed if I left my one solar geyser on permanently it used less kw than turning off/on with a timer, initially was set from 05h00-07h00 and back on in the evening from 17h00-20h00. Guess now in the summer its only topping up the water rather than going from cold to hot

Thinking of the following:

8kw Sunsynk 

16 x 535 JA solar panels

3x +-5kw plyontech or hubbles (need some help here)

wont being doing a DIY but got a few companies I am looking at.

Any recommendations to the above will be appreciated especially on the battery front.

 

I've read some of the responses here and don't necessarily agree with all them, BUT I also admit that I'm not an expert.

What I think you are lacking in your considerations of the scenario above is that you have (using water as an example) calculated how much water you need in a day, but not the pressure at which the water needs to be supplied. So in your example you have advised that you need 35KW per day, but not what your average and peak consumption would be.

Is there ever a time that you need the full 8KW for any period of time? You need to answer that question in order to determine the minimum number of each battery required. You can add more batteries to hold more electricity, but you also need to keep in mind that you may need more batteries to get more electricity at a higher "pressure". 

In oversimplification, you will need minimum 2x Hubble to get the full 8KW (as one can provide max 5,5kw due to 1C rating) or (probably) 4x Pylontech batteries (as I think they're rated 0.5C).

I trust others here will point out if I'm wrong somewhere, but the crux of my comment is that you need to consider your peak load requirement too.

 

11 minutes ago, EugeneS said:

I've read some of the responses here and don't necessarily agree with all them, BUT I also admit that I'm not an expert.

What I think you are lacking in your considerations of the scenario above is that you have (using water as an example) calculated how much water you need in a day, but not the pressure at which the water needs to be supplied. So in your example you have advised that you need 35KW per day, but not what your average and peak consumption would be.

Is there ever a time that you need the full 8KW for any period of time? You need to answer that question in order to determine the minimum number of each battery required. You can add more batteries to hold more electricity, but you also need to keep in mind that you may need more batteries to get more electricity at a higher "pressure". 

In oversimplification, you will need minimum 2x Hubble to get the full 8KW (as one can provide max 5,5kw due to 1C rating) or (probably) 4x Pylontech batteries (as I think they're rated 0.5C).

I trust others here will point out if I'm wrong somewhere, but the crux of my comment is that you need to consider your peak load requirement too.

 

Thanks that makes a lot of sense. If I look at my daily usage over the last month, I don't tend to pull more than 5kw which is between 4am-7am (peaks at 6am) when 2 geysers turn on (2kw each elements) and then again around 5pm when they turn on again. I have recently starting adjusting the times based on the anticipated solar install to maximize sun usage rather than grid/battery but with the +-13 kw of battery I am thinking it should be enough to handle as well as get me through the night if the household complains about about the water not being at 100 degrees for midnight showers.  

 

 

18 hours ago, YellowTapemeasure said:

Exactly who are Onecharge, who owns them, and perhaps most important of all, what products do they sell?

I was actually looking forward to @ASH_JHB response though, because he expressed concern and I wanted to understand his reasons.

The concern stemmed more from zero knowledge around it but what was mentioned on here by @Nexuss. Wasn't aware there were different chemistry make ups of batteries and assumed it was inferior. Immediately went to the notion of products claiming to be one thing and they not but use the general wording of a product such as lithium batteries. But reading into it more seems its common amongst manufactures. 

Edited October 20, 20214 yr by ASH_JHB

With that kind of usage and peaks you can easily get away with the 5Kw Sunsynk and +-6,5kw solar . My usage is very similar to that .  At the moment running 2 US3000C and my purchased power is about 2-5kwh a day. So with 4 of them i would be very nearly using no grid,except for winter ofc.

During cloudy/rainy/drizzling winter in Cape Town, with having to heat two geysers ( using essentially pv only), sometimes I cant even charge my small 4.8 kWh battery to 100 % and I have 6.4 kWp of solar array

    In summer I can generate up to 34 kwh of pv a day ( depending,of course, on how many appliances the wife uses that day )

Edited October 20, 20214 yr by Tariq

10 minutes ago, ASH_JHB said:

Thanks that makes a lot of sense. If I look at my daily usage over the last month, I don't tend to pull more than 5kw which is between 4am-7am (peaks at 6am) when 2 geysers turn on (2kw each elements) and then again around 5pm when they turn on again. I have recently starting adjusting the times based on the anticipated solar install to maximize sun usage rather than grid/battery but with the +-13 kw of battery I am thinking it should be enough to handle as well as get me through the night if the household complains about about the water not being at 100 degrees for midnight showers.  

This goes back to a point that @Sarelwas making earlier. You KNOW that your geysers are going to turn on at 6am. You know that they are 2 kw each. So that's 4kw/h right? Maybe. 6 am your geysers turn on, 6:30 you feel like some coffee so you turn the kettle on. Now you're drawing 6kw/h for a short while. Turn on the toaster or the microwave and we're really having fun.

So a couple of things
1) Leave some headroom in terms of power. Because something you hadn't built into your plan will get turned on. Not every day, but enough to cause some inconvenience
2) Decide what loads you MUST have and back up only those. EG at my house when there's a load shed the main house stays up, but the pool pump and the outbuildings (including 2nd geyser) are not backed up and don't run (and don't increase the load on the battery).
3) A thing that people don't consider is that to get the best out of any alternative power system, you have to change your routines to make the most of it. You have your geysers turning back on at 5pm. It's unlikely you'll have much solar available by then, so they are going to draw from your batteries that you would like to get you through the night. So think of showering, shaving, etc earlier in the day. Same with kitchen appliances. You don't want to use your microwave or electric oven a lot during the night because that's taking juice out of the batteries.

Consider turning your geysers on at 7 rather than 6. You'll be getting some solar by then, and on a clear day it will be increasing. Turn them on at 6 and they are going to have nothing but battery to draw from. Turning then on at 7 gives the sun a chance to shoulder some of the load.

13 minutes ago, Nexuss said:

With that kind of usage and peaks you can easily get away with the 5Kw Sunsynk and +-6,5kw solar . My usage is very similar to that .  At the moment running 2 US3000C and my purchased power is about 2-5kwh a day. So with 4 of them i would be very nearly using no grid,except for winter ofc.

Agreed I probably could get away with a 5kw but looking at more futureproofing and go slightly bigger on the inverter to cater for future. Also want to avoid the education process with the household and what can and cant be used as much as possible. That's the plan atleast

 

Edited October 20, 20214 yr by ASH_JHB

6 minutes ago, ASH_JHB said:

So with 4 of them i would be very nearly using no grid,except for winter ofc.

just remember will you be able to charge the batteries fully in winter

 

No you will not be charging the batteries fully in winter regularly i suspect , in order to do that consistently through winter you would have to have a massive pv array lol . Currently i have 7,3kw East /west array. Sizing the system to be very grid independent through winter will substantially influence the payback period i suspect , so if you do the calculations and are happy with it by all means go for max solar your roof/inverter can handle ! 

13 minutes ago, ASH_JHB said:

Agreed I probably could get away with a 5kw but looking at more futureproofing and go slightly bigger on the inverter to cater for future. Also want to avoid the education process with the household and what can and cant be used as much as possible. That's the plan atleast

 

You can still go with the Pylon Batteries, don't let the 1C issue discourage you. Good thing is that, you can still add on more batteries in future if the need arise. I personally would chose a battery that has 95% DoD and more cycles or life time over a 1C one. At the end of the day, it is all about individual preferences. I prefer my Pylons 😁

2 minutes ago, Nexuss said:

so if you do the calculations and are happy with it by all means go for max solar your roof/inverter can handle ! 

Agree with @Nexuss, and to add, spend the money on panels versus batteries

43 minutes ago, ASH_JHB said:

Agreed I probably could get away with a 5kw but looking at more futureproofing and go slightly bigger on the inverter to cater for future. Also want to avoid the education process with the household and what can and cant be used as much as possible. That's the plan atleast

There's almost certainly going to be an element of this.

An example from my life. 

My system provides 20A on the backed up side. It can "burst" to 30A for 10 seconds.

My water heating on the main geyser is a heat pump. This is on the backed up loads.

Now go to the kitchen. We have a gas stove, but also a microwave, a kettle, a dishwasher, and I know there's a toaster that's being kept away from my prying eyes. 

So now early AM the heatpump is running, the housekeeper comes in and turns on the dishwasher. Everything is fine. Then she turns on the kettle. Now we are fine, but only just. Then she turns on the microwave.

Now the draw exceeds that 20A and does so for more than 10 seconds. Result: The inverter trips. It starts up again, but in the meantime the dishwasher has stopped wherever it was in the cycle and will not resume when the power comes back up in a few seconds time, the same will have happened for the microwave, and I'm annoyed because I was watching something very important on TikTok and now my monitor isn't working any more.

So we have a rule now. It is impossible to be in the kitchen and know if the heatpump's compressor is running. But one can see the dishwasher, the kettle and the microwave and whether or not they are running. So the rule is if one is running you can turn on one more. If you want another one of these three then you must wait for one to finish or turn one off. 

Like you, I want people to just be able to get on with their lives, but with the system I bought it's not possible. So in my house we have to make some adjustments or I have to dig into my savings and buy a whole lot more solar gear.

Edited October 20, 20214 yr by Bobster

12 minutes ago, Tariq said:

Agree with @Nexuss, and to add, spend the money on panels versus batteries

@ASH_JHBThis is a perfect example of personal bias. It is no use you have enough panels to generate power for a small country, but nowhere to store it. Nor is it of any use to have storage space for enough power for a small country without having a way to generate power. And the third, my point above, it is no use you have enough power generated or stored to power a small country, but only 1 length of 3mm copper wire (and batteries have this limitation too in terms of the amount of power it can supply at any given time).

I would argue that the first consideration should be what your peak requirement is and ensuring that the system (inverter and batteries) can handle that, then you can start deciding how much power you can generate and how much of it you want to / can store. 

Your average consumption seems to be around 2,5KW per hour, with peaks around 5,5KW and lows around 1KW. So if your panels could generate 3KW, then during idle times when you're consuming 1KW, the balance can be stored to battery. If you have 1x 5KW battery with a 1C rating, you can pull 5KW from the battery, however if you have 1x 5KW battery with 0.5C rating then you can only pull 2,5KW from battery. Thus why I said you will need 2x Hubbles or 4x Pylontech in order to pull the full 8KW through the inverter from battery. 

So now you can decide, do you want to generate more power from panels to fill the batteries faster (increasing the 3KW in above example) or do you want more batteries to store more power for use during the night. (assuming that you've taken care of peak requirements)

On 2021/10/20 at 2:09 PM, EugeneS said:

@ASH_JHBThis is a perfect example of personal bias. It is no use you have enough panels to generate power for a small country, but nowhere to store it. Nor is it of any use to have storage space for enough power for a small country without having a way to generate power. And the third, my point above, it is no use you have enough power generated or stored to power a small country, but only 1 length of 3mm copper wire (and batteries have this limitation too in terms of the amount of power it can supply at any given time).

I would argue that the first consideration should be what your peak requirement is and ensuring that the system (inverter and batteries) can handle that, then you can start deciding how much power you can generate and how much of it you want to / can store. 

Your average consumption seems to be around 2,5KW per hour, with peaks around 5,5KW and lows around 1KW. So if your panels could generate 3KW, then during idle times when you're consuming 1KW, the balance can be stored to battery. If you have 1x 5KW battery with a 1C rating, you can pull 5KW from the battery, however if you have 1x 5KW battery with 0.5C rating then you can only pull 2,5KW from battery. Thus why I said you will need 2x Hubbles or 4x Pylontech in order to pull the full 8KW through the inverter from battery. 

So now you can decide, do you want to generate more power from panels to fill the batteries faster (increasing the 3KW in above example) or do you want more batteries to store more power for use during the night. (assuming that you've taken care of peak requirements)

Thanks, nice summary of things to consider. I think I have my peak loads covered with the 8kw. Even with the geysers on I don't pull more than 5kw and on average 3-4kw being the highest with my base loads around 1kw on average. I decided to go with the 4x pylons US3000 and an extra 2 panes (as suggested by someone on here) to give me 9.6kw array which are mostly north facing. Will make some shifts to higher energy consumption to the day time and see how it goes, sure there will be a lot of tinkering to try and maximize solar vs my consumption.

 

 

Very nice system, I have found that if i heat my geyser to 65 at about 10-12ish in the morning ,the sun then builds the temp up to 70-80 by sundown, this then allows me not to have to heat the geyser at all the next morning ,or very little heating  at most. 

1 hour ago, Nexuss said:

Very nice system, I have found that if i heat my geyser to 65 at about 10-12ish in the morning ,the sun then builds the temp up to 70-80 by sundown, this then allows me not to have to heat the geyser at all the next morning ,or very little heating  at most. 

@Nexuss, when you say the sun heats your geyser up to 70-80, are you referring to solar geysers ?

3 minutes ago, Tariq said:

@Nexuss, when you say the sun heats your geyser up to 70-80, are you referring to solar geysers ?

Correct , Its a vac tube geyser.

2 hours ago, Nexuss said:

Very nice system, I have found that if i heat my geyser to 65 at about 10-12ish in the morning ,the sun then builds the temp up to 70-80 by sundown, this then allows me not to have to heat the geyser at all the next morning ,or very little heating  at most. 

Ya have found the same. I have 2 vac geysers and been playing around with different timers vs usage. Now in summer, I do find that leaving the geyser on permanently uses less energy overall. I did adjust the temp to 65 degrees and for the most part needs very little eskom to keep it there overall. Trying to avoid the morning and evening spikes that would ultimately eat into battery. Sure this will change in winter but for now it seems to work well.

 

install finally started today.

Yay!! Glad your on your way with this! 

Keep us posted. 

Installation finally done but got a fair amount of tweaking to do. Figured will run everything as is for the next week and then start adjusting things like battery COC etc at different times of days. Also got to figure out the geyser situation to get it on remotely when production is strong. Considering been mostly cloudy since the install was quite interesting to see production relatively good considering. during the day still got my batteries charged and kept up with the current AC loads. Had some decent sessions of sun today and production holds nicely at 7-8kw

Went ahead and ordered the solar Assistant as couldn't have been bothered to wire up a cable, Solarman seems pretty limited and slow and seems like a headache to get it into homeassistant.