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meyerwh

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Everything posted by meyerwh

  1. In our area (Ruimsig, South Africa), we "lost" one phase in the grid due to cable theft followed by repairs. Electricians say they cannot synchronize because they do not know where the synchronization point is. What does this mean on a physical level? Can somebody explain this in a simple way, or are there multiple reasons, and it is impossible to say what happened here?
  2. Thanks, Coloumb, for your reply! What do you think about the Eeprom fault message? Everything seems to working fine, you think one can ignore it?
  3. Dear forum members. I have a problem with my setup: 4x330W PV panels in series, Kodak 3kW 24V OG3.24 inverter, Pylontech UP2500 24V Li battery. I made my own communication cable thanks to this forum and HennieB84 who posted a picture of the cable ends necessary for this setup, by connecting a phone cable (4 contacts) and an ethernet cable (8 contacts) through sockets with the right cable connections at the back. It worked and I could load my superspecial-priced Pylon UP2500 (5.5 months on the shelf before sold to me) from 75% state of charge (SOC) to 98% SOC in a few hours, readings according to the Watchpower app. After that, however, the battery showed a fault: overvoltage or overcurrent or so according to the LEDs lit on the battery panel. I did not think much about it though. NOW: I finally got the proper cable (Segensolar) and noticed that the capacity reading is always 100% on the Kodak inverter monitor (4 blocks lit) and on Watchpower app. The battery seems to be working fine, charging, discharging down below 75% and charging again. No further fault was indicated on the battery. The voltage indication on monitor and Watchpower seems fine and goes up and down as one would expect. Same story if I use my old cable again. More worrying, I measured the voltage across the power cables with a multimeter while battery was being charged with 9A (at a battery voltage indication on monitor and Watchpower app of 27V) and got a multimeter reading of 31V. (Can I trust the reading while current flowing through the cables?) Concerned about the high voltage, I switched off the PV supply and back on again, after which the multimeter showed 28-28.2V. The Watchpower app gave a warning of "line fault" and of "EEPROM fault" in the same time frame (I only saw it 30min later, so not 100% sure about the timing of events). Btw, the current also goes down to zero when battery is full and battery LED shows "idle" when no consumer is on. My preliminary conclusion is, that there is nothing wrong with the cable and nothing wrong with the battery. However, the Kodak inverter might have a fault responsible for the constant 100% SOC reading and high voltage of 31V? Any ideas about it and what I should do next? The holiday house is 250km away in the sticks and it is difficult for me to pay constant attention (there is not even a no cellphone signal). I am quite desperate. Kind regards Wolfgang
  4. Thanks, HennieB84. Looking at your post from 31 July, what puzzles me is that you have two cables (blue, brown) on side but three cables (green, brown, blue) on the other side... why is that?
  5. Hi HenniB84. Thanks for your reply. So, then you are using "Pylon" as the battery type in the settings of point 5 of the Kodak menu? Can you confirm, pls. Regards Wolfgang
  6. Hi HenniB84. I just bought a Pylon Ep2500 and a cable pack for my Kodak 3kW inverter and get worried when reading your post. I was actually just searching for advice on the settings of the inverter as the online shop said I must use user-defined in program point 5 as the setting. I like to know what to put in under points 26, 27 and 29. Any advice on the settings? Would appreciate it very much. Wolfgang or meyerwh
  7. I am not an expert in the field and just like to share the info and ask for opinions and views on the problem. I do not consider Li batteries here. I have a Kodak 3kW 24V inverter, and 24V Li batteries are very expensive (about R17,000-20,000 for BlueNova 26V-77-2k and R17,000-22,000 for Pylon UP2500 2.84kWh). Second generation 25.6V Li batteries by e.g. Revov are currently sold with a minimum capacity of 5.2kW and go for more than R30,000. The information in this document is collected and compared with a focus on a low-consumption off-grid scenario. Solar panels (1,320W) supply enough power during the (sunny) day to run all appliances with a minimum energy contribution by the batteries (maybe max. 10% capacity). During the night (14 hours without energy supply by solar panels), a fridge is a major consumer and I like to cater for about 1.2 kWh during this time. I consulted the spec sheets of AGM or GEL batteries advertised (but some not available anymore as I found out) in South Africa. I compared the data on constant power discharge down to a cell voltage of 1.8V. I adjusted the rating of a battery for a 10h constant current discharge to 1.8V per cell (10.8V per battery) since some battery model names refer their capacity to a 20h discharge and/or to a discharge down to a cell voltage of 1.75V (10.5V per battery). As a second adjustment, I multiplied with a factor to “simulate” a 200Ah battery. I assumed that with this approach a common base is created for a better comparison. The second info I compared was the cycle life at different depth of discharge (DOD). It refers to the number of discharging/charging cycles until the battery drops to a capacity of 60% of its original rating. These discharging and charging cycles are mostly laboratory experiments under idealised conditions. I focused more on the ratings up to a maximum of 30% discharge per cycle. To strike a balance between my battery size requirements and acceptable daily discharge, I am considering a battery bank of a minimum of 4.8kWh (4x 12V 100Ah or 2x 12V 200Ah) which would give me 25% DOD at an overnight consumption of 1.2kWh. For a 20% DOD, one would need a capacity of 6kWh which can only achieved by combining four 150Ah or six 100Ah batteries since one or multiple sets of two batteries have to be connected in series to obtain 24V for the inverter. For the two “simulated” 200Ah batteries with a total number of 12 cells and a DOD of 25%, one would require for a constant power discharge of 85.7W per hour over 14h (1200Wh) a discharge per cell of 7.1W per hour for 100% DOD and a possible discharge of 28.6W per hour for 25% DOD. So, the value of 28.6 at a discharge time of 14h is considered here as the minimum requirement per cell of the two simulated 200Ah batteries. Squeezing the power consumption of 1200Wh into 10h would increase the value to 40W per cell at a time of 10h (which is 4.8kW energy). These values are only indications of what kind of performance figures to expect. The constant power discharge graphs are shown in Fig. 1 and the cycle life graphs in Fig. 2. Green circles indicate acceptable performance. Fig. 1: constant power discharge for “simulated” 12V 200Ah batteries given in W per cell Fig. 2: cycle life of batteries according to spec sheets or website information, 60% capacity as end-of-life is not always explicitly mentioned in the source There are a number of other battery companies which I did not include here. Some perform too bad to be considered and others seem to be a rebranded product of another manufacturer. According to one supplier, batteries based on lead crystal technology are not available in the country. The formerly supplied batteries by Betta Batteries are manufactured by GreenRhino, an American company. The Dutch office confirmed via email to me that they do not have an agent in South Africa. One can order from them and a 12-GRGS-200 battery costs €409 excl. shipping. The Narada ICS range seems very good. In South Africa I could only find the NDF-Acme range which does not perform well enough and cost about R7,500 for a 12V 200Ah battery. I could not find a supplier for the lead-carbon battery Ritar DC12-100C. So, the good performers Narada ICS, Betta Lead Crystal and Ritar Lead-Carbon can be excluded since one cannot purchase them in South Africa. The capacity of the Trojan SAGM 12 205 is only 174Ah which requires four batteries for the given scenario. One battery cost more than R8,000. Therefore, this battery can be ruled out. Concerning the Allgrand batteries, the data are inconsistent. There seem to be a CNF and a CNFJ range and some spec sheets available from South African supplier cannot be found on the Allgrand website itself. For the Allgrand Gel 6-CNFJ-150 (12V 150Ah) battery, some data, e.g. a constant current discharge of 15A for all given cut-off cell voltages between 1.6V and 1.8V after 10h, can’t be correct; from the constant power discharge data, the battery might actually have a capacity of 135Ah instead of 150Ah, which means that the adjustment in Fig. 1 would not be correct and the battery would perform better than illustrated. More confusing, Allgrand states “up to 2000 cycles” and “up to 1000 cycles at 30% DOD” in writing which is far lower than the data published as a life cycle graph by the company. While their prices in South Africa are the best of all AGM/GEL batteries, one would like to have a better idea about their performance data. Surprisingly, the expensive Victron range does not feature with noteworthy cycle life. In general, the spec sheets do not give a lot of information. A number of other batteries show a comparable performance on cycle life. With the limited information presented here, the best choices for the mentioned requirements are the Omnipower and Oliter batteries. While the Oliter 12V 200Ah is a “genuine” 200Ah battery, the capacities of the Omnipower OPR 120-12 and 240-12 batteries are not 120Ah and 240Ah but 100Ah and 200Ah for a discharge to 10.8V over 10h, respectively. The Oliter with ca. R5,000 is less expensive than the Omnipower which costs ca. R7,000. I must stress, that I have no experience in the use of any particular battery and merely oriented myself on the available data. Any views on the validity of the analysis? Any real-life experience to share? I would welcome your comments.
  8. The first link looks quite ok. I have attached a trial for a 5kW system with lots of thumbsucking. I basically pay R150,000 for it and use all electricity myself. With a price of R1.1 per kWh i cannot break even within 10 years. The tool is quite crude... i really think it would be better to do it from scratch. export_summary.php.htm
  9. It would perhaps be better to calculate the net present value over a fixed period, let's say 10 years. The period of 10 years should be long enough to include maintenance and replacement of the installation. The "income" would be the cost of electricity from the grid for the time period with one's specific consumption and the fixed monthly cost one pays to the municipality or electricity provider. [Your quotes suck. No offense meant.]
  10. Hi there, I'd think that if NERSA as the energy regulating authority decides you can feed into the grid than ESKOM has to follow. I could be wrong but new building regulation require a green component for new buildings (like solar heating, not sure what else). I refer to an article in Mail&Guardian from 15/01/2015, not sure whether this is already outdated: One can expect a low tarif on electricity sold into the grid, talks are R0.50/kWh. At the same time, an extra tarif is discussed since PV without storage would feed in at the wrong times leading to a steeper demand at peak times in the morning and evening. The drop in supply when the sun goes down would require more power stations to come online at peak times. To summarize: you might get little pay for feeding in and might pay a higher tarif when using grid electricity. In addition a further network charge for PV feeders is also mentioned. That sounds now all pretty negative and maybe there was some exageration by the author. My personal concern would be where to get electricity during loadshedding if my PV system does not have sufficient storage capacity. The fixed fees for network and maintenance make up about R600 of the monthly electricity bill. I would like to save these costs, too. For a new house, i personally would design for off-grid solar power and solar water heating and gas for cooking. Have not done the calcs though but a payback time of about 8 years looks ballpark to me (R150,000 investment and R1,500 monthly savings). I cannot commend on your technical question regarding when to buy what kind of inverter. C u
  11. Hi there, regarding the capacity of a battery, perhaps check out http://batteryuniversity.com/learn/article/how_to_measure_capacity Charge the battery until it is full (13.8V ?), disconnect from charger, connect a constant load using 12V (maybe a set of lights?), should need a decent power value (250W?) otherwise the test will take forever. According to the website, you wait until the battery is down to 10.5V. I don't know whether is defined as empty or 20% full or whatever. Let's asumme it means empty. Then full to empty at e.g. 250W takes e.g. 4h.... the capacity of the 12V battery would then by 4*250/12 = 83 Ah (any losses neglected) I have never done it, so rather check with others.... Don't measure the current between the battery poles with a handhold meter, i blew my meters fuses. Hope that helps a bit Wolfgang
  12. Hi Wetkit, hehehe, you are right about the cheap crap solar stuff. It is rated at 30A 12V DC load but battery loading only 10A at 12V and 20A at 24V. Actually, i only want to use it to power my garage doors and roller shutter doors: power consumptions are 450W, 300W, 3x200W. These roller shutter doors only work with pure sine wave. A 1kW sine wave inverter would be to small, and i got also a rather cheap (R10,500) 12V 3kW pure sine converter from AC/DC. So, actually, i would not need to worry but if i like to add a 24/7 load, i found it just disturbing that the solar charge controller stops loading if the inverter drawing more amps from the battery than 10A. It does not matter for opening/closing garage doors as this takes only 30s. Connecting the panels in series (and then also the batteries, right?) is a good idea, thanks. Just wondering what to do then with my 12V inverter? (it cannot handle 24V) Can is just connect it to one battery instead of the two which are connected in series? My other idea, forgive my ignorance about electronics...: can one not get a 9A relay which switches then a new circuit from controller to battery with a higher resistance??? In this way, even if the inverter draws >10A, the controller will only "see" much less and continue loading... any comments? Lastly, maybe i should not waste my and your time and just buy new equipment... just not happy about spending lots of money again. Regards Wolfgang
  13. Hi Regie, thanks for your reply. the inverter is connected to the batteries. I think the problem is, that the charge controller is, too. So, when the inverter draws +10A from the batteries, it will also draw it from the charge controller through the wire from battery to charge controller. Regards Wolfgang
  14. Hi David, don't know the company either... I usually approximate the needed amps from the power usage specified by the appliance... e.g. if it is 300W at 220V (meaning then 1.4A) it would then be 25A at 12V to get to 300W. (I hope that is the right approach!?) Considering you want to drain your batteries only to 50% capacity, you have 220Ah available meaning a 300W appliance could run for 220/25 = 8.8h. If your charge controller could do 10A for 5h (very genereous), it means that you replenish only 50Ah in one day, so your set of batteries will never be fully loaded at a constant usage of 300W. If one sticks to loading the batteries with 50Ah per day, an appliance switched on 24/7 should not use more than 25W constantly. Your limiting factor for your setup is the amount of solar panels... Hope that makes sense. Wolfgang
  15. Hi everyone, i have recently started with my own PV installation and searched the components via internet and helpful websites. I figure out now, that i am learning it the hard way by combining components without being aware of the consequences. Ok, enough intro. I have two 12V 120W solar panels connected in parallel (directly on the terminals) and routed one set of cables to an 30A 12V Ecco solar charge controller. The controller has one set of terminals for the solar panel(s), one for the battery/batteries and one 12V 30A for DC loads (which i am not using). I connected two 12V 120Ah batteries in parallel to the controller and to a 12V 3000W pure sine wave inverter. I put a 16A breaker between the controller and the batteries it is loading. I also put 2 breakers after the inverter (63A earth and 16A load) before connecting to a set of 220V plugs. The problems: the inverter draws constantly 2A on standby (no load). It is not written in the manual and i found it eventually on the internet. I have an Owl ampere meter which works via induction (don't ask me more) via magnet placed around the live wire (it is very useful and saves data every minute which can be downloaded). The Owl confirmed 2A usage at no load. Considering no solar power for 15h at night, i am loosing 30A of my battery power. I checked with the Owl the amps going from the charge controller to the batteries and found and average of about 6A (depending also on state of batteries and whether the inverter is on or not). Well, that means i would use the whole day meaning 5h sunlight just to recharge what the inverter used at night! Ok, i can switch it off but that is not the idea of the setup... Next surprise (another praise for the Owl): the controller shuts down the power supply to the batteries when a load on the inverter exceeds 10A (including the usage of 2A of the inverter itself) drawing from the batteries! This means roughly, a constant load of 120W would prevent the controller from loading the batteries while the load is on! I could check this with a desk halogen light with two settings, one below 100W and one of about 150W: while the controller keeps on charging at the lower light setting, it stops loading the moment i switch to the brighter light setting. Finally my question: Can one 'trick' the controller by letting him 'see' never more than a 10A load on the inverter? How can one manipulate the live wire from controller to battery to achieve this? Is there a way to bypass this function maybe by changing settings? Or is the controller not functioning the way it should? Something wrong with my setup? This is utterly frustrating... i hope someone has an idea. Cheers Wolfgang
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