RichardZA

I'm still thinking that a very dark shadow cast by a chimney or tree branch cast cuts out my panels more than diffused light in overcast conditions, where you can't get a heavy, dark shadow. Or am I on completely the wrong track?

I've discovered that when the sun is really bright in the early morning, my panels perform much worse. Must have something to do with casting "hard shadows" on the panels. I live in Johannesburg and on Wed 20 Dec, 8am, was getting 2kw out of the panels. On Thur 21 Dec at 8am, getting 0.8kw. Anyone else experience this? I guess the mitigation is cutting some branches from the tree

The only thing that nags at my mind is another 4.8kwH battery because load shedding is getting worse and power outages more frequent. Some additional cover would be great - but this is a pure lifestyle purchase because I'm not going to make the money back easily on it! Other than that, start saving for when the inverter packs up. Hopefully in 10 years, and hopefully the tech is even better and cheaper then Unlike some other posters, I started out just wanting to reduce my crazy electricity bill. Load shedding was definitely a secondary consideration (I already had a small batter backup for internet, computers etc). Now I've gone 180 degrees - protection from load shedding is definitely the #1 reason for having solar, and then the secondary benefit is getting some of that money back in reduced bills.

Hi all An update one year on. Please read my original post here: A reminder of the setup 8kW Deye inverter 18 x 540W JA Solar = 9720W 3 x 4.8kW LifePO4 (80% DOD) 4 solar geysers(!!) The 4 solar geysers definitely would affect the performance of the solar system as I need less electricity production to heat water, so please bear this in mind with the stats. In retrospect, I would not have purchased the solar geysers, panels are far more versatile and with proper load management a much better deal in my opinion 4 Solar Geysers R76,253.34 Solar Panels, Inverter, Batteries R212,000.00 R288,253.34 For the sake of this comparison I’m going to leave out the solar geysers. I'm assuming they "break even". I’m also going to assume an interest rate of 9.75% over the full year (can’t be bothered working it out properly) and likewise I’m going to assume the current electricity tariff over the year. Due to the tiered pricing it’s hard to calculate the exact price per KWh, so I’m using City Power Block 2 as a calculated guess (most of the electricity would be saved within this block), so my rate is R2.31 per KWh (incl VAT). The solar system cost R212,000.00. The interest on this is R20,689.50. The production of 10093W @ R2.31 per KWh = R23,361.31 Net gain: R2,671.81 There are a few factors that have prevented me doing better than this. The first is my family is not keen on lifestyle changes and I’ve also got a little more lazy with this over time. Secondly load shedding and other power outages has led me to be super conservative on the battery - I don’t let it go under 40% overnight for instance, so I've been not utilising my full production overnight. Thirdly, we just don’t use a lot of electricity during the day, and seem to use a lot at night (see point #2 lifestyle changes). The positives have been amazing. I’m not sure how people survive load shedding without a solar system. I’ve loved every minute of owning this system and recommend people take any spare cash, any money in their mortgage, heck anything they can find, and buy a solar system, the payback will get better every year with increasing electricity prices and the lifestyle benefit is incredible. If you work from home, it's essential. My break even if I make NO adjustments to lifestyle, interest rate remains constant and electricity price rises 9% a year, is in 11 years, assuming no maintenance costs. My guess is there will be some maintenance costs that may shift the payback to 13-14 years (the compounding effect on even a small net gain is amazing!). I don't really care how long the payback is, the lifestyle benefit and the carbon offset are enough for me to say this is better than the money sitting in the mortgage.

So glad for my investment in solar over the past few weeks - really paying off. Sometimes it helps being a pessimist.

Hi all I've got about 30 staff in our business using this model of inverter. After a couple of years they are starting to fall over (constant loadshedding does not help!). What do you guys recommend as a good replacement battery (lead acid and alternatives?) https://ellies.co.za/product/720w-1200va-inverter-with-trolley-modified-sinewave/

hehe thanks. I don't think they are "wall heaters". Noted on the aircon not a bad idea

Hi all I watched a video recently on this and was wondering if anyone has seen this type of heater in SA. I'm interested in this form of heating as I have a lot of excess solar power during the day that I'd like to use to heat up the walls/floors of the house and that heat can then gently emit after sunset. Currently when the sun goes down I have to turn off my oil heater or pay for electricity - which I don't like to do. My house is just badly designed when it comes to the best form of infrared heating (the sun) and it's ironic that it's hot outside and cold inside in the middle of a winter day.

Wow, well done for taking the plunge. This is my dream as well, but a couple of things need to happen for me. #1 car needs to feed back to the house so the battery pack is dual use - this makes the purchase much easier to justify (a portable battery bank). #2 - SA gov to stop penalising and start encouraging purchase of these vehicles.

If I had the choice again I would go with only solar panels and no geyser EVT. I really think the extra solar panels is more versatile than the tubes.

The BMS should take care of all of this - for instance not charging at very high or low temperatures.

That is why we need the early adopters on this thread so we don't need to extrapolate!

I think a lot of it is marketing. The battery manufacturer looks at the curve and says I will market 6000 cycles @ 80% rather than 3000 cycles @ 100%. They're not saying you will blow up the battery if you take it to 90% or 95% DOD. Nothing on my batteries says the warranty is void if it take it to 95%. I will ask the installers after the break. So basically I think they say do I want to market this at 100,000 cycles at 25% DOD or 3,000 cycles at 100% DOD. Of course there would be minor differences in technology around the battery, but the fundamental chemistry of all these brands is the same. This paper which compares LFP with NCA and NMC cells, gives real world results. Their problem is by the end of the study most of the LFP batteries were still going strong! "Most of the LFP cells had not reached 80% capacity by the conclusion of this study for the NCA and NMC cells, and their longer-term degradation will be reported in a later work." https://iopscience.iop.org/article/10.1149/1945-7111/abae37

Deye 8kW inverter around R30k.

Please see my other thread - we need to start crowdsourcing real world data I think

Following on from various conversations with people telling me to take the manufacturer's warranties and info with a pinch of salt, let's try draw some real world conclusions on the life expectancy / cycle life of Lithium Phosphate batteries. I'm especially interested in the veterans on the forum who've probably been running theirs for a number of years. Please reply to this thread with the following information: Battery Brand/Model: Installation Date: Cycles: Performance: (add your comments here) So mine would be: Battery Brand/Model: Fusion 4.8kwh Installation Date: October 2021 Cycles: 70 Performance: no observable degradation

Thanks @Gnome great detail and very helpful.

I’ve got 3 x 4.8kwh LifeP04 batteries rated at 80% DOD over 6000 cycles - that is over 16 years of cycles and my warranty period is only 10 years. When they were installed, my installer set up the inverter to drain down to 30% DOD overnight before switching to grid and leave 10% in the batteries to cover for load shedding and power outages in the middle of the night. Now nobody likes paying for insurance and I suggest nobody likes leaving 10% of battery on the table every day for the odd occasion that Eskom goes boom while the sun is not shining. So here is my idea. For the odd occasion that I need the extra battery, I’m comfortable draining the battery to 90% while keeping essentials running. I’m not going to be doing this every day - perhaps less than 10 times a year, or 160 cycles in the supposed life of the battery. So I'm rather going with a 80% DOD every night and in an emergency allowing the battery to drain to 90% before switch off. This reduces my payback period from 7.3 years to 6.4 years instantly. What do you guys think? Anything wrong with my logic.

I've got the ja 540w installed. The installers didn't have an issue with them.

I think @Erastusmakes a good point on trade balance. It makes MUCH more sense for us to be feeding in, helping our grid and not buying expensive batteries and exporting precious randelas to China. However this thread is about choices today in either A) sizing batteries to beat load shedding b) sizing batteries to fill up with solar and cycle fully on an AVERAGE day c) oversize batteries knowing you will eventually get the cycles out of them and maximizing your solar input (calendar aging notwithstanding). My understanding is that maybe people have been burnt by bad battery tech in the past but LFP is a much better technology and we shouldn't be so pessimistic about maintenance and lifetime.

I also 100% agree with you that the grid is your best battery. My father in the Seychelles has solar and the municipality allows 1:1 credit for your solar output - e.g. if you put 1kwH into the grid, you get 1kwH in credit on your account (you an only spend the credit on electricity, they will not pay you out). He has a beautiful bell curve of power production every day and a couple of small batteries in case the grid goes out (rare but it does happen). My challenge is City of JHB and most of the country outside of the Western Cape will either pay you nothing for your feed-in or close to nothing 10c-30c per kwh, plus jumping through several hoops. So the question is where do we focus our efforts - do we think there is a realistic chance of persuading City of Johannesburg or others to give us reasonable tariffs. Might be easier to move to the Cape!

@Erastus options for people e.g. in jhb?

@Robbo yep that is super conservative in my eyes. The guys doing the scientific experiments indicate that these batteries can take a beating and you will be able to get through those 6000 cycles. Their studies are done in months though, so I'm not sure how bad the calendar aging factor is... maybe nobody knows because they haven't been around long enough. But if I take your 2880 cycles, that means 11059kwH produced, which means R2.07 per kwH (22,995 / 11059). Still not bad, since I'm paying more than that currently (+- R2.60), and it's likely to go up 15-20% per year over the next few years. The cash outlay is large, but let's say you are in the fortunate position to have an access bond and some spare cash in it, I would guess at 7.25% prime, it's worth it. You get a warm fuzzy mostly off-grid feeling, you're covered for most load shedding scenarios, and you're utilising your excess solar better. As suggested by @Tariq I've got to wait for a winter to really get a sense for whether I need an extra battery.

In summer, yes will definitely be able to use the extra 4.8kWh as people like cooking at night in the house and some geyser activity. In winter, I'm not sure, but does this matter? If the batteries can give me 20,000kwH in their life time, perhaps the payback is a bit longer. I'm looking for a realistic "lifetime discharge" that I can use to make ROI calculations. Yes this is the position I'm in. I have too many solar panels and there are a lot of people on the forum who have oversized solar because it's the cheapest part of their system, so why not (cloudy days, winter etc). But I'm questioning the prevailing logic that you should ONLY size you batteries for load shedding cover, while leaving the rest of your system maximised. Ok but guys let's get back to the original question. Does anyone have a better calculation than I just provided to work out how many watts I can get out of a LifeP04 battery during its lifetime, in optimal conditions (a lifetime kwH). Even if it's not R0.99 per kwH and it turns out to be R2 per kwH, it's still cheaper for me to get more batteries whereas the prevailing attitude on this forum is that batteries are "expensive" and don't provide investment return and should be undersized in a hybrid environment.

Hi all With Eskom going for another 20% increase, I think it's time to revisit battery economics vs using the grid. My problem is I can't seem to find all the info required. I use these batteries https://solaradvice.co.za/product/fusion-4-8kwh-block-lithium-ion-battery/ Let's ignore installation costs for ease of calculation. Let's also assume that you have solar panels that you haven't maximised (e.g. you have excess solar that you cannot or do not want to send back into the grid, and that these batteries will be filled with excess "free" solar that would otherwise not be utilised). R22,995 for 4.8kW / 80% DOD / 6000 cycles. When the manufacturer says it can do 6000 cycles at 80% DOD, what do they mean? Do they mean 6000 cycles x 3.84kW = 23,040kwh throughput during its lifetime? Or do I need to take degradation into account - I assume a "cycle" is 3.84kW as advertised? Because if I can buy R23,040kwh prepaid for R22,995 in today's rands (R0.998 a kwh), that is an absolute steal. I could calculated with interest and eskom projected increases, but ignoring that for simplicity (likely eskom increases will outpace prime lending rate). It would indicate that anyone buying solar panels should size a battery rack to store as much excess power as possible (even oversizing the batteries just extends their life so not a waste to oversize a little?) Please correct me! Thanks, Richard