Firstly why the upgrade ... because I have solar panels on the roof and an inverter which can only feed the essential loads ... bit of a waste having solar panels producing power and nowhere to go.

The goal -

1/ To have a system which can charge the batteries so that the essential loads have a backup period of at least 2 hours in the evening when there is no sun.

This is now possible since the AGM batteries (I know I should replace them with lithium ) were replaced under warranty and a few slight circuit adjustments were made.

2/ To feed the excess power back into the grid during the day ... for things like the washing machine ... pool ... aircons etc which are not on the essential supply.

The system still requires a bit of fine tuning ... we have about 4 kw (total) on the essential ... don't wan to go any higher and drain the battery faster during load shedding.

Which inverter would you recommend? ... I like what I see with the sunsynk inverter ... but there are just too many options.

One of the most important factors to consider will be the product support ... which inverter has the best support ? 

I must say ... I had an issue with an RCT inverter (out of warranty) I spent days trying to find someone to repair the unit ... eventually I dropped it off at rectron ... got a call a couple days later to say the damage was bad and they dont do component level repairs ... but the technician said he would see what he could do ... a week later I collected the unit in working order. 

It would be interesting to see a side by side comparison of all the inverter ... what is good about some and bad about others ... there are youtube videos with comparisons but I haven found anything in a XL type format so that you can basically tick the boxes. 

 

 

 

 

 

 

 

 

 

Would upgrading to a hybrid 5 kva be the best option? ... considering everything is already setup or 5 kva ... cabling ... circuit breakers etc ... going up to an 8 KVA would mean infrastructure upgrades ... like cabling ... breakers etc ... and batteries to support the increased load. 

 

 

 

Another consideration when upgrading the inverter on an existing system - voltage ... power and configuration of the panels.

The VOC of the panels compared to the replacement inverter would it be as simple as rearranging the panels ... would I be correct in stating that it is likely that the new inverter will be capable of handling a higher VOC? 

What are the chances of finding the same type of panel - .voltage and wattage  ... installed 3 years ago ?

 

What meter do you have? Are you going to the system approved by the municipality for grid feed in?

We have no intention of feeding back into the grid ... it just seems pointless.

The meter is not a digital meter.

I need to find out more about system approval ... I hear there is talk of all the meters being replaced with digital meters ... for now we do as South Africans do in South Africa. 

One of the reasons I am looking at the sunsynk ... it has the CT which can block any feed back.

First I need to understand the system as it operates at present ... I need to see where we can improve and upgrade ... without replacing the entire system. 

I have been monitoring the charts for 2 days ... looking at the usage ... identified a few challenges with the solar system ...loads and the time the demand is required. 

One of the challenges ... trying to figure out why the solar panels are only producing a max of 600 watt ... 120 VDC ... and around 5 amp in the middle of the day.

There are 12 panels on the roof ... something just doesn't add up ... I understand the 8 are mounted on one side and 4 on the only side ... but at midday surely the system was spec'd for at least 3kw 

The mecer 5 kva can handle:

4000watt ... the charts indicate around 600 watts at their peak. 

80 amps ... the charts indicate the panels produce around 5 amps ... eeeiish. 

60-115 VDC ... looking at the charts ... the voltage seems to be higher than 115 VDC for a large percentage of the day.

Time to get to get the installer back again. 

I have spent the entire weekend doing research into solar systems ... I am starting to wonder if replacing the mecer with a sunsynk is such a good idea.

What about leaving the mecer in place ... its is still fairly new ... to sell it now would just seem such a waste .. it produce an online pure sine wave something to consider when installing an inverter ... I havent had a chance to hook up the fluke 435 ... but the charts indicate a smoother trend than the grid voltage. 

Rather look at installing a grid tied inverter ... that way ... if the power power drops ... we still have the mecer inverter for backup power.

the entire system will need to be replaced over period of time ... I dont have another R100k to piss against the wall thanks to a crap design and installation crap 240 amp AGM batteries ... they have already failed with the 2 year warranty and all 4 have been replaced ... so now we just use them until they fail ... then replace them with what ever is the best technology and vale for money.

 

We know what we want:

A system which will optimize the solar power  ... keep the battery fully charged and set the battery the battery DOD to not exceed 50 % (AGM) 

We want the power to stay in the grid as much as possible to reduce the electricity bill ... so try utilise the power for the washing machine ... pool pump etc which are not connected to the essential load circuits.

Looking at the charts we can increase the essential loads by about 2 kw ... which would mean the peak power  would go to around 5.5 kw for a short period of time.

I have been thinking about ways to maybe add a PLC which could  link non essential loads to the essential loads if the system is running at around 600 -800 watts .. .which is the average power at any point during the day. 

Technology is improving faster then most of us can keep up with.

they talking 3-5 years ... EV's will be cheaper the ICE vehicles ... battery patents expired a tthe end of October ... which means that the Chinese can now distribute their already 3rd generation EV's. 

I am starting to think installing a Fronius primo 5 might be the most sensible thing to do ... Fronius is a premium brand product with an extended warranty of 20 years (the chance the company you purchase from will still be around in 15 years ...is highly unlikely) but the product has a very good reputation and for the same price as a sunsynk.

I can add solar panels as and when required ... if the  primo cant handle the power requirements ... I can always double up.

I need to figue out if I can somehow link the fronius to the existing panels or link it to the mecer king ... that way everything stays the same ... and so the system starts improving to eventually become a top quality system ... when the inverter and AGM batteries are upgraded

 

 

 

Something else to consider before I rush out and replace the batteries ... what happens if I invest in an EV or 2 ... the battery capacity in the EV will hold much more capacity than any battery installed on a house.

If the one vehicle is only used to run around the hood ... dropping kids off at school or the wife going "book club" or if you live on an estate the distance travelled will be a fraction of the capacity of the battery ... so a large  percentage of the EV battery can be use to power the house during the evening. 

If I am only driving to work ... where the vehicle will be be connected to the work charger during the day ... when I get home in the evening the EV is fully charged less the distance from the office ... it can also be plugged into the house and supply the grid with power. 

 

 

1 hour ago, isetech said:

Something else to consider before I rush out and replace the batteries ... what happens if I invest in an EV or 2 ... the battery capacity in the EV will hold much more capacity than any battery installed on a house.

If the one vehicle is only used to run around the hood ... dropping kids off at school or the wife going "book club" or if you live on an estate the distance travelled will be a fraction of the capacity of the battery ... so a large  percentage of the EV battery can be use to power the house during the evening. 

If I am only driving to work ... where the vehicle will be be connected to the work charger during the day ... when I get home in the evening the EV is fully charged less the distance from the office ... it can also be plugged into the house and supply the grid with power. 

 

 

Ha, ha… you want to steal power from the office and use it at home. That’s new… 🤣🤣🤣

Technical I wouldnt be steal power from the company (I own the company) but I would be stealing because the electricity consumed should relieve the tax bill ... could be a nice incentive for employees ... allow them to charge their Ev's at work ... a win for both company and employee.

Think about it ...you given a company EV ... unload 10kwh into your grid ... nobody is going to miss a couple kwh