Jump to content


  • Posts

  • Joined

  • Last visited

Everything posted by isetech

  1. The last time I read the SANS book ... the regs stated that a lockable isolator can be fitted in the DB ... that why we use the combo breaker/isolator in the DB ... the catch is that most electricians dont even own ... never mind carry circuit breaker lockouts. Then there is the plumbers who replace geyser elements ... but we wont go into that.
  2. Something to note with regards to stoves ... not all stoves are rated to 40 amp ... I have connected floor standing stoves to a plug socket (they are designed for that application). As mentioned already the circuit breaker is there to protect the wire ... the stove have fuses for internal protection ... you can fit a 30 amp on a stove circuit ... it just means that you cannot use all the elements at the same time. In the old days ... we use to install 4 mm wire with 30 amp circuit breakers for geyser circuit ... no we install 2.5 mm wire with a 20 amp combo breaker ( to save you having to install an isolator next to the geyser ... it also helps when you have an earth fault ... you can isolate both live and neutral at the DB ... without having to climb in the roof if you have a neutral fault. Make sure you understand switching loads when using these smart devices ... inductive ... resistive and LED ... in some cases day/night switches are not compatible for LEDs lights ... I thought if a device could work with a CFL's.. .then it would work with LED ... apparently not ... I recently purchased a device for switching LEDs ... there was a label "not suitable for LED" ... you learn something new everyday.
  3. It is interesting to see they are using pictures with copyright solar advice. I wonder if this company is a ware that they are using pics from their site ? https://solaradvice.co.za/
  4. 50 % discount ... stage 8 load shedding ... if it sounds too good to be true ... does this apply here ... or is it just bullshyte ... @R10K for an old axpert inverter 50 % discount sound like someone is gonna get ripped off. https://brightsunsolar.co.za/product/beat-stage-8-loadshedding-with-this-5kva-solar-ready-backup-system-with-21yrs-life/
  5. Yip we live learn everyday ... I have a power quality analyser I should take some screen shots of the terrible wave a generator produces so much for AVR. This is something I have been considering ... using an inverter as a means to clean up the generator wave form ... the axpert inverters I am testing have a clean pure sine wave. The catch is that the inverter is not an "online" device like the more expensive UPS units. when I run the load tests .... it runs smooth ... I have only noticed glitches (spikes) on the wave form when switching loads on and off ... but compared to the grid power its no big deal. I dont change setting 28 to sol when I use the inverters as a stand alone unit ... so that will be a test for the near future ... I will hook up my contractors generator and run a few tests.
  6. 87 - the only concern I have with taking one inverter out a parallel system ... the load capacity ... how would you control the load while one unit is not connected ... that means you would have to isolate the output ... which means you would need 3 output breakers ... if you have a 63 ammp breaker you would have to reduce it to a 40 amp while the 1 unit is not connected ? I am learning as I go ... so any advice or solutions would be appreciated.
  7. Something you need to understand about circuit breaker ... the tripping characteristics. IT is critical that you use the correct breaker designed for the application. Curve 1 or D curve breakers for example are used for motor startup (just an example) Then you get a breaker which is designed for an application like transformer loads ... an example is a magnetic table on a CNC lathe ... or the supply (400/230 V) for CNC machines ... this breaker I assume would be more suitable for big transfomer type inverters. Then you get the standard breaker ... the most common used in domestic applications. Increases the current rating of a circuit might not be the best option ... rahte rbe more specific with the type you install. An example - I have always used D curve/curve 1 breakers for aircon ... to allow for the compressor startup ... however this is not longer a good idea on the new inverter/rotary compressor type aircons ... they tend to hum ... using a standard breaker works better.
  8. A tip - Dont connect your remote viewing Pi to the output side of the inverter ... unless it have a battery backu.
  9. 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.
  10. I would be cautious of looking at the suggestions and connections in the axpert manuals ... when you see a breaker on the neutral wire as per the manual ... eeesih. This is an interesting topic ... circuit breaker protection for inverters ... 1 unit alone ... easy ... you can fit a 20 curve D curve or curve 1 breaker .. .some people use a 32 amp breaker with 4 or 6 mm* wire ... to ease the inrush current. When you start connecting them in parallel ... this is where I am interested to hear how others would do it. I am busy preparing a 3 x 5 KVA axpert inverters ... supplied directly from a 63 amp circuit breaker in the meter .. then out to the main DB rated at 63 amps. I saw an installation the other day ... it had 3 x single phase 63 amp single pole breakers connected to the inverter with 10 mm* wire and a 63 amp single pole breaker on the output. Would using a 32 amp triple pole breaker ... bridged at the top across the 3 poles ... out the bottom of the breaker connected to each inverter using 6 mm* wire (the same length) ... then 6 mm* out the each inverter ( maybe even 10 mm* all the same length wire) to a bussbar at the top of a 63 amp single phase breaker or a 6 mm* wire from each inverter to the top of a triple pole breaker ... with a bussbar at the bottom .. this doesnt sound right ... I did send a email to CBI to query this ... but never got a response. Circulating current to come to mind ... I am interested to hear how other do it.
  11. 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)
  12. 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.
  13. 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.
  14. 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.
  15. A circuit breaker is installed to protect the wire from overload. A general rule of thumb: 10 amp - 1 mm wire 16 amp - 1.5 mm wire 20 amp - 2.5 mm wire 30 amp - 4 mmm wire 40 amp - 6 mm wire 50 amp - 10 mm wire 60 amp - 16 mm wire "mm square" not actually mm in width. Free standing stove - 6 mm wire with a 40 amp mcb Hob - 4mm wire with a 30 amp mcb ELU - 4 mm wire with a 30 amp mcb Geyser - 2.5 mm wire with a 20 amp combo breaker. The installation must be designed as per the SANS regs ... these values are just a guide line.
  16. 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.
  17. While reading the RCT user manual from cover to cover ... I noticed on page 10 - Dry contact signal ... when program 38 is enabled ... you can use the contact as a trigger to link the ground and neutral of the AC output.
  18. 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.
  19. 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.
  20. 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.
  21. 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.
  22. 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.........
  23. Just beware of taking advice on a forum ( not saying the guys are giving incorrect advice) ... not only are the earth systems different around the world ... different provinces have different arrangements. TT TN-S TNC-S TNC .
  24. I got my first taste of an inverter connected in my workshop ... and it didnt look good. I having been looking into ways to remotely monitor old meccer and RCT inverters on some of the sites I look after ... but never really felt the need to waste the money. I had an RCT unit repaired (it took a while to find someone) ... decided to hook it up in the workshop ... and test it ... it worked ... I linked the laptop and used watch power to check a few things ... then got smart and bought solar assistant. They say if you can monitor it you can manage it ... suddenly you realize ... you have to put the energy back into the battery ... every time I flicked 1 -2 or 3 switches (increasing the load by 1 kw) .. .the inverter fans speed increased and it worked like a charm ... then I would switch the grid power back on and thats when it hit me ... watching the kwh meter in the meter spin faster than I have ever seen it spin ... I could see R100 notes flying out the window. This journey into solar is about to get real.
  25. Depending on the type of earthing arrangement ... it is generally not allowed on the consumer side of the electrical installation ... however if you have an inverter/UPS/generator or the like ... there is a good chance you will have the neutral and bonded together close to the system as per the electrical regs. This is something you need to understand before just looking for it ... if you do have it on the consumer side ... you should be concerned because there is a good chance your protective device are either not operating correctly or not installed.
  • Create New...