solar systems

[Isetech]

I have made this mistake of installing these 3.5 kva inverters with 2 x 100 amp/hr batteries (gel/deep cycle/ AGM). I also work on sites where these 3.5 kva systems have been installed.

I have installed (some longer than 5 years) and currently maintain a bunch of 5 kva axpert type inverters with FLA batteries, we use them in factories to support the IT systems during load shedding and at the customers personal properties.

I have also installed a few bi directional/hybrid systems with lithium batteries.

What have I learnt:

It pays to install a bidirectional/hybrid inverter with lithium batteries and solar panels.

What are the challenges I face with the 3.5 kva 2 battery.

The first complaint is "all that money I spent" ( yet its the cheapest option on the market). You get a 3.5 kw system and it should produce 3.5 kw, well that's where the fight starts.

When load shedding kicks in a 10 pm and your system is pulling 2 kw, it will literally switch off in a couple minutes if you are lucky. Yes you can add batteries @R2500 a pop, taking into consideration that you will be required to add 2 at a time thats now R5000, plus the cabling and sparkie to link them.

Then you add a new challenge overload protection and switch disconnectors, most companies who install these little units dont even consider a DC switch disconnect.

In most cases these "small" systems are installed inside the property, now you have a pile of batteries to consider the safety, with a gas that is released during the charging process, which is not even considered with only 2 batteries, now suddenly becomes a consideration, especial if installed in a confined space. You cant just install an extractor fan because it is a highly flammable gas.

In many cases the installer doesnt split the DB or run dedicated UPS plugs and thats where the fight really gets momentum.

Then there is that little extra (sometime more than expected) added to the bill at the end the month, that wasnt there before the "backup" system was installed. the inverter requires standby power to function, the batteries need power to recharge, so now you have to consider losses and efficiencies. Like leaving all your appliances and TV's chargers for phones, gate batteries, alarm batteries etc etc etc, it all starts adding up, multiple that by 30 days then by 12 months, suddenly those silly amounts become a consideration.

[Isetech]

Just when you thought your backup problems were all under control.

You have installed your 3.5kva inverter with your 2 x 100 amp/hr batteries in a safe location, your Db has been split and wired by a person who actually knows what they doing, identified all the circuits in the house, used blue plugs or identified each socket outlet and circuit connected to the inverter and labelled everything accordingly.

Now you have a 3500 watt inverter with only 300-500 watts of power connected to the inverter, if you want the batteries to last for more than 2 hours during load shedding.

You get the news stage 6 load shedding has started with immediate effect, no problem you have a backup system with lead acid batteries, 5 days later you are sitting in the dark again with flat batteries. Why because instead of reducing the load to the absolute min. you added a thing of 2 during load shedding and now the standby time has dropped to below 3 hours.

You call the installer and he tells you that you cannot charge a lead acid battery at more than 10 % of the capacity of the battery. The charge rate of the inverter can only be set to 10 % of the lead acid battery capacity.

But when you installed the system it worked fine, then the installer found out that it is not good to have the cutout voltage at 21 VDC, because that would be draining the battery to 100% DOD and your SOC will be zero, that means his warranty will not be honoured in 8-10 months time (if they last that long with stage 6 load shedding, you might get 6-8 months)

So the installer increased the cutout voltage to around 23.4 VDC to be on the safe side.

If what I am hearing becomes a reality, your 3.5 kva system with lead acid battery is going to become a lead door stop sooner than you think.

You ask why, simple a lead acid battery has 0.02 C rating.

Now I ask myself, was I smart deciding to walk away from 3.5 kva installations, especially if I am installing them under my company name?

I hear it twice sometime 3 times a day, but I cant afford a lithium battery, start adding up the cost of replacing the batteries every 3.5 years (what we are getting out of systems which are setup properly with the correct cut out voltage). Dont let anyone BS about AGM and 50 % and all that, 14 months if you are lucky, is about the limit of AGM's if not setup correctly.

I decided to take the plunge and start installing lithium battery systems, they are expensive, but are they compared to lead acid.

I have tabs at the top of my laptop with all the axpert systems with lead acid batteries and remote viewing and I now have lithium bi directional inverters with lithium batteries.

Heres is why I suggest you install a bidirectional inverter with lithium batteries and a hand full of solar panels.

You are looking for a hassle free system which operates automatically, without having to switch on and off stuff, you want it to last for more than stage 6 load shedding, but the part most people dont take into consideration, the start current of appliances and the charge rate.

The system essential DB we have installed can run for 12 hours (down to 20% SOC), but the important part is that it can recharge the batteries well within the 0.5 C rating with 3 hours.

2 hours of load shedding only drops the battery to around 85 %, which means the battery is recharged and ready for the next load shedding within an hour.

Why waste money on a bidirectional inverter, once the panels are installed, that's when we start saving money and make the system even more efficient with smart switches and controllers.

You may ask why we only drop the SOC to 80%, because once the panels are installed, we dont want to waste power grid charging the batteres in the evening if there is load shedding once the sun goes down. It is also just in case the sub station blows up or the sub trips and it takes a couple hours to reset.

I am living and learning by the day, so feel free to correct anything you feel might feel BS.

[Derlyn]

As things presently stand in SA, vast amounts of money is being spent on solar systems that are gonna help diddley squat when the grid goes down. Take note, when and not if.
The grid IS going to go down sometime in the foreseeable future. That's a given.

99% of the population can only dream about getting off the grid. There needs to be a major mind shift from spending money on something that's gonna make your life a bit more convenient during the hours of loadshedding to surviving when the grid goes down.

This is where I'm at a distinct advantage, having married someone who was raised on a farm without electricity. She grew up not knowing what a hairdryer is.

It still amazes me, the number of people who are so worried about being without power for an hour or 2 or 3, but who are totally unprepared for when the stuff hits the fan.

In my opinion, everyone should try their best to prepare themselves for being without grid power for up to 6 weeks. Remember, no grid, no water. That half a million rand solar system aint gonna quench your thirst when the taps run dry.

Anyway, I don't want to highjack this thread with prepping stuff, but, water tanks before inverters and batteries. Be sure to have at least a bakkie load of firewood.

Make sure you have a jet stove for cooking and a donkey for hot water.

Your priorities in order should be water, food, shelter and lastly, power.

Take note, power is last on the list.

Cheers.

[Isetech]

Where have you been living? I live in Africa, we already have water collection from the gutters, a pool above ground level with a dual purpose which is used to swim in and as a backup water supply. I cant tell you how many time that pool has been a blessing in disguise. You will know what a bucket shower is all about or a sponge bath.

We already have a fully functional fruit and vegetable garden, we have avos, bananas, paw paws, green beans, potatoes, lettuce, onions, carrots, green peppers, etc etc. We are already starting to replace all the wasted space (grass) in the yard with food. You can walk around our garden and pick strawberries, they growing like weeds amongst the flowers.

We have lived in our house for almost a year without electricity and only the 300 litres per day from the restrictor they fit when you dont pay your account, so when we got hit after the floods for a couple weeks without electricity, life just goes on.

We have lots of trees which fell during the floods, our wood pile is getting to a point that its time to get the chain saw and restock.

I just need to find the funds to fit solar panels, to keep the wood workshop operating. One of the reason I did the research into solar and been practising installing them.

During that period without electricity , charging the lead acid batteries became a issue every morning having to take them up the road to a mates house to charge.

What I have since learnt, to keep the lights on, but more important my workshop operating, you need a natural source of producing energy, large enough to charge the batteries which have a high C rating, so that you can charge then within and hour or two. I could use my hand tools to make furniture, shelters etc, but why not use the all the equipment already setup.

I am not wasting all this time and energy on solar systems for a short term solution. I am looking for a long term solution which will cut back my utility bill and keep the machine functioning for extended period of time. Wind power is not an option for me. We have a constant flow of water under our property, I am going to figure out how to tap into it, it runs down the driveway for days after a good rain.

As I get older I have learnt that its not the bank balance or the ridiculously priced car that makes you happy, its more about the experience you share with the people close to you.

[Derlyn]

Wow, it seems as if you are prepared for what's coming. No, not scare mongering, just being realistic.

Your last sentence is the most important. We need to do our best to influence those whose priorities are maybe not what they supposed to be.

Crunch time is fast approaching. I give it another month or 2 at the most.

Have a great day.👍👍✌️