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My journey into solar


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A little background ... I have installed a few generators/ UPS and inverters purely as backup ... have a bit of experience in the electrical field ... power quality analyzing ... thermography and also been dabbling in alarm systems and CCTV.

I have been following this forum for a while ... reading tons of info ... added a bit of content ... but nothing of value ... and I doubt there will be any until I get a better understanding of how it all works.

Solar was never considered on any our backup system installations ... due to the cost ... now that it has become more affordable ... load shedding disrupts business ... so the demand is increasing. 

I have had so many enquiries about solar installations ... but turned them away due to my lack of knowledge and experience in the field ... Some of my customers have found "highly recommended" installers and blown their money ... Customer are tired of being baffled with bullshyte ... having pretty looking installations installed which lack components which make it illegal or ... not being issues a COC's etc ... it is time to go down this road. 

Let journey begin.........

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The plan is to design and build a system for my workshop/office ... one for my security system and a general purpose one for the home ... its going to take a while due to the cost involved ... I have no plans to borrow money ... increase credit card  or overdraft limits. 

What I have in place at the moment (which requires a drastic improvement) -

A 5 kva contractors generator ... as illegal as it gets ... VOV ... a 2.5 mm extenstion cord from a changeover which gets rolled out when there is load shedding ... no earth bonding at the changeover ... all just quick slap dash install just to keep going ... and never got around to doing it right.

A 600 watt meccer inverter on top of a box with a 100 amp/hr enertec deep cycle ... had it for years ... the battery got old and I never got around to replacing it ... until a couple of weeks ago ... I needed the finish some invoicing and suddenly 14.00 ... load shedding ... I had to get my office back online.

A couple magneto rechargeable LEd lantens  ... by far the best battery backup light I have even used ... we even have them in the van for site work. ( I found a supplier for replacement batteries ... after a couple years the battery packs up ... @ R249 replacement for a complete light ... its cheaper to replace the battery at half that price) 

A tip - take a hammer and hilti handy fix tool and knock in 2 nails above the doorway in locations which provide the most light ... I have 3 ... one in the centre of the main bedroom ... one in the lounge and one in the kitchen .. this lights up the entire house ( I have a small house) 

The alarm systems ... the gate and garage doors all have the standard 7 amp/hr which last for the 2 hours ... but after 5 days of load shedding I swop all of them and recharge them using a smart charger. 

Lastly I have an 18 amp/hr battery in a box with a 5 amp charger ... for routers and alarm peripherals ... which is all going to be upgraded.

 

 

 

 

 

 

 

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I have a 5 kva RCT inverter on my work bench at the moment which I am using to try out remote viewing/recording software ... It has 4 x 100 amp/hr deep cycle batteries in series (48VDC)

This is what changed my view on solar ... I hooked up the inverter ... which has just been repaired.

I connected a power quality analyser to the output to view the "pure sine wave" ... and yes the RCT inverter produces a clean pure sine wave ... a  box ... made up of 6 switched ... 1 kw elements and a cooling fan.

Everything was going fine until I decided to try out remote viewing for the old inverter ... contacted solar assistant ... they gave me a trial version of the software (which I am still using) to try out ... I thought it was going to be an easy plug and play ... SD card ( I supplied) issues ... hardware failure on my side turned it into a nightmare. 

So I decided to rather buy a kit from  solar assistant ... lunch time I ordered and paid for the unit ... I hadnt even finished my breakfast and the box was delivered early the next morning ... I connecte dit to the test unit and tried to set it up ... no thanks to apple ... it didnt work ... sent Pierre an email ... he responded with a contact number ... we discovered that it had something to do with my iphone ... went to my laptop ... with a couple minutes it was displayed live. 

I have since learnt thanks to 87 ... that firefox is a better option when using apple products ... I downloaded firefox and bingo it works.

There has been 2 minor glitches (flat lines) since we installed the software  ... I dont know if it was something on my side or the link.

I have since got the other Pi working ... figued out that it was the WiFI that is not working the Pi ... so I ran a network cable from the switch to the Pi and it working.

I removed the Pi kit from soar assistant to a site and installed it ... it is running without any issues ... linking it to the new site network was literally as easy as step 1-2-3 ... it is live on my office laptop ... I sent an invitation via email to the customer who can now view the information on his inverter. 

 

 

 

 

 

 

 

 

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I switch off the mains/grid power and switch on the fan and 3 elements (3 kw)... I hear the fans in the inverter speed up ... I notice the left fan is running hotter than the right fan ... stop the operation ... get my wifes toothbrush (dont tell her ) and cleaned both the fans ... which were caked with stuff ... now they are running a little quieter.

This is where my outlook on solar changed ... after an hour or so I switch off the elements and switch on the mains power ... holy flippen moly ... I go look at my kwh meter ... the thing is spinning faster than ever :( ... Time to install a couple panels ... but first I need to figue out how many I need. 

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Capital outlay for solar panels ... I would assume they will not be less than R10 000  ... so for now we are going to focus on make the system as efficient as possible.

Now that we can monitor the system ... we can start managing it.

Starting with the chart of the grid power and load power ... straight away you will see that unless you install solar to charge the batteries ... your electricity bill is going to increase ... the inverter is consuming power ... ( note to myself ... dont forget to switch off the display backround light) ... you take out 800 watts ...you gonna be consuming  around 1.1 kw to recharge the batteries.

Starting with the battery parameter setting in the inverter ... the bulk ... the absorption   and float ... I believe if you dont get this right ... you pi$$ing maney against the wall.

The test rig has 4 x 105 Ah (20 hour rate) enertec model 674D 

The operating temperature will be around 27 degreeC.

The inverter is used as a UPS standby power for the computers/servers/screens etc ... I do have a dedicated UPS units at the server ... just in case. 

The settings bulk/absorption/float voltage and charge current.

Consideration should be taken into account that the inverter is in standby mode most of the time ... just topping up the batteries ...until there is a power outage ... w e have been having a lot of those lately. 

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I have 3 tabs open ... one with the the powerforum ... one with the load test I am busy with in the workshop and the other solar assistant of the site where I recently installed a Pi with solar assistant.

The workshop load test is updating every 30 seconds.

I have been comparing the readings on the test equipment to what I see on solar assistant ... the readings are spot on. 

Something to note ... I have an analog 12 volt meter which I use to use on the bass boat to monitor my battery power for the trolling motor ... according to the analog meter (which is still in the green ... indicating just under 13 VDC) ... the battery is still strong ,... the chart is indicating 18 % state of charge.

The load is a 1 kw element ... so it is constant. 

I found for 2 day fishing comps ... it was critical to manage the batteries ...  by using an analog meter you can monitor the state of charge ... as you press the foot control so the needle would drop ... as the state of charged decreased ... so the needle would move further down ... once it started going into the yellow ... it was time to ease of the speed other wise day 2 I would have to idle around on speed 1.

Why is this relevant to this thread ... simple as noted the chart is indicating 18 % state of charge ... but in reality the state of charge is still in the green according to the analog meter. 

The inverter has just gone into low voltage shutdown (set at 45 VDC) ... switched on the power and the state of charge on the chart is already 83 %.

I am going to set the cutout voltage down to 42 volts ... let the batteries charge over night and do the same experiment tomorrow.

It took 1 hour 15 minutes to go from fully charged to cut out at 45 VDC. 

As I switched off the power the voltage dropped from 54 VDC (float voltage) down to 52 VDC and then down to 50 VDC as I switched on the 1 kw element. 

The sine wave displayed on the PQA is clean ... the voltage is stable compared to the grid and the reading on the inverter is .4 VAC out compared to the PQA ... that is even more accurate than most multi meters. 

 

 

 

 

 

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I tried to do a 2 kw load test this morning ... I ran into a minor glitch with the software ... the dashboard was displaying 2 inverters instead of 1 and doubling the values ... I rebooted everything and it seems fine ... I have a feeling it was because I replaced the cable between the inverter and Pi ... or it could have been when I swopped the Pi power supply. 

I want to drop the cutout voltage value to see how much longer the systems runs.

 

Edited by isetech
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23 hours ago, isetech said:

Capital outlay for solar panels ... I would assume they will not be less than R10 000 

Fortunately with some inverters you don’t need all the solar panels from the get go and can start small, on my own installation I started with only 2 x 330W panels, although it took about six hours to fully charge my batteries it was a step in the right direction. That also made me realize every time Eskom increase their power with 10% it in turn bring solar prices down with 10%.

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Test day - grid power switched off 

2 x 1 KW elements and a small = 1970 watts 

Lets see how long it takes for the inverter to switch off and then we see how fast and long the long the kwh meter spins to recharge the batteries.

I might as well start a fire and throw R100 notes into the fire ... comparing what the load power uses to what the grip power consumes to put the energy back into the batteries ... I need solar panels.

 

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Having the remote viewing for the axpert inverter ... just makes life so much easier ... I dont have to sit and watch meters.

I need to find a more accurate way to measure the battery state of charge ... the analog meter does a great job for now ... maybe I should hook up the go pro camera. 

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7.49 am switch on

8.49 am alarm buzzer - switched off at 45 VDC 

The analog meter still in the green.

The battery pack was at 54 VDC (float) as I switch off the power ... it drops to 49 VDC and then drops gradually until it gets to 45 VDC (cutoff setting in the inverter) 

 

 

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2 hours ago, isetech said:

I need to find a more accurate way to measure the battery state of charge .

This probably require a battery monitor with a shunt to measure the actual current flow from 100% SOC. The moment a big load is connected there is a voltage drop that confuses the inverter and it will give alarms.

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Next load test: 

Grid off at 16.50 

1 kw and the small fan to cool the element.

18.50 ... battery pack 47.4 VDC ... testing each battery with a multimeter 11.9VDC 

20.08 switched off at 44 VDC (cutoff setting) ... I plan to change all the inverters to 45 VDC cutoff ... that will give me around 3 hours with an avg load of around 1 kw ... considering these units are being use as backup power and not cycling on a daily basis ... if they were cycling on a daily basis ... I would consider increasing the cut out voltage to 47 VDC ... which would be around 11.7 VDC each battery.

I have AGM batteries (48 VDC) on a site which I plan to do the same load test with the system on bypass at least that site has solar ... so we can run the test early in the morning on a nice sunny day and use the solar system to charge the batteries each day.

Its a pity I dont have any lithium batteries on any of the sites. 

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