March 4, 20179 yr 34 minutes ago, Richwost said: 1. Plonkster I have been shopping around for Victron and I find that a "Victron Energy Multiplus Compact 12/1200/50-16 230V VE Bus" I can get for R!2,767 whereas the "Phoenix" 12/1200 I can get for R8,650. There must be a difference, but what is it? I am not saying that I will get that particular model, but I do like 12V, because I want one 12V Victron Lithium battery. I would like a 12/1600, 12/2000 or 12/3000. I think that most of you would disagree with 12/3000, but why? (Anyway I don't think is available in this country) The Mulltiplus is an Inverter/Charger/Transfer switch. The Phoenix is just an inverter. In other words, the Multiplus can work like a UPS, charging the batteries from the grid, powering appliances from the battery, and switching seamlessly from grid to batteries (< 20ms, most appliances don't notice it). That's the difference. I'm a fan of using 12V for small systems. The nice thing is that the equipment is easy to resell when you want to get rid of it, or you can chuck it in the back of the bakkie as an emergency power source while on the road. The trouble is that above certain power levels the cables just get too thick. a 3000VA at 12V is 300 ampere (slightly less, but I'm too lazy to fetch a calculator). The kind of battery you'd have to put down for that kind of current and the size of the cable usually rules it out. BUT... if you're going Lithium, which can handle the large currents, the 3kva should be okay. You'd only be able to use it for short peaks, but it would be fine. Not with lead-acid though :-) 43 minutes ago, Richwost said: The generator would be used twice a day for a total of about 3 hours and during that time it would (hopefully) recharge a 50% used Victron Lithium battery. Typical setup most farmers used when I grew up. The battery is there to tide over the low-energy stuff until the next time you start the generator. 44 minutes ago, Richwost said: The cost of power thereafter is R1.16 per unit (excl). I regard R1.16 as cheap(ish) power. Am I wrong? That is very cheap yes, especially if the line rental is unavoidable. 45 minutes ago, Richwost said: I am now Victron and I really don't want to look at anything else. Of the two inverters that are always battling it out, I think most people will agree it is a battle between "cheap, but good enough" and "excellent, but darn expensive". If you have the stomach to shell out for a Lithium battery, you should feel right at home :-)
March 4, 20179 yr 2 hours ago, Richwost said: I would really like to have just one 12V Lithium battery of 160 or 200aH and if necessary Hi Richwost, It seems you have decided on the battery you want and now want to make everything fit the battery. It actually works the other way round. Your load determines the size of your inverter and the size of your batteries. On 3/2/2017 at 6:16 PM, Richwost said: Total ….. say 960w per hour - or 4 Amps per hour Your load is 960 Watt. (Keep in mind the 4 Amps you referring to is at 230 Volt, not 12 volts) 2 hours ago, Richwost said: Once on, I would expect the system to be able to stay on for 12 hours without being charged. Let's call your load 1000 Watts. At 12 Volt, that is 83 amps x 12 hours = 1000 ah required. With lithium batteries You can probably go down to a DOD of 50%. Therefore if you make use of the 200 Ah batteries and willing to take them down to 50% DOD, that is 100 Ah. To cater for your load, you would therefore require 10 of them. The only thing that 200 Ah lithium battery can power for 12 hours is 1 x 100 Watt globe. In my opinion, 12 Volts discharging at 83 amps is not the way to go. 2 hours ago, Richwost said: Victron Energy Multiplus Compact 12/1200/50 The maximum rated power output on that unit is 1000 Watt. You therefore actually plan to run it at 100% capacity for 12 hours? Also not the right choice. It is fine to have a 12 Volt UPS to keep your PC going for an hour or two when there is a power outage, but 12 Volt is not the way to go to power the loads you are talking about for 12 hours. Anyway, that is just my gut feel. I might be wrong. I personally think you have to have a re-look at your requirements.
March 4, 20179 yr Rule of thimb: 0-1000w = 12v 1000-2000w = 24v Above 3000 = 48v I see where @Richwost is coming from. You get in SA Victron 3000va 12v inverters. Edmund and I started to play with smaller off-grid systems, systems for specific uses like just for lights. Or maybe lights and TV. Cheap and easy to use. Is this an option before I type a lot?
March 4, 20179 yr 2 hours ago, Don said: In my opinion, 12 Volts discharging at 83 amps is not the way to go. So 3000VA probably 2400 Watts. So you want to push the amps up from 83 to 200 Amps now? The minimum requirements for this system is 2400 Watts @ 24 Volts.
March 5, 20179 yr Author Plonkster, many thanks for your help with understanding the difference between Multiplus and Phoenix. Now I think the price of R13k odd for the Multiplus is not bad. I would like something a bit bigger - say 1600 or 2000, but that does not seem to be available in 12V - that I can find at the moment anyway. Don, you are right in a way - I do tend to start at the wrong end and work backwards sometimes, but yikes - please tell me that your workings are incorrect. Surely!! My sums go as follows: 1000W (absolute maximum) used by the LED lamps, TV, Security system and the inverter. Usually half that. The 1000W divided by 240V = 4 Amps. So my usage would be 2-4 Amps per hour. Call it 3. One Lithium battery holds 160Ah. We discharge it 75% so 120 Amps. Divided by 3 = 40 hours available. I am using energy at 240V, not 12V. Is there something wrong with my workings? TTT, this is certainly an option that I would really appreciate looking further into. Maybe that would demonstrate whether (or where) I am going wrong with my thinking and my workings. Many thanks to you all...
March 5, 20179 yr 3 hours ago, Richwost said: please tell me that your workings are incorrect No, unfortunately not. Let me explain it this way. The load is constant throughout (1000 watt) The Output voltage is constant throughout (230 Volts) , but the Input Voltage is different, and therefore different discharge rates. Load on Grid 230 Volt : 1000 Watt 230 Volt 4.3 Amps Load on 12 Volt Inverter: 1000 Watt 230 Volt 83 Amps (Discharge Amps) Load on 24 Volt Inverter: 1000 Watt 230 Volt 42 Amps (Discharge Amps) Load on 48 Volt Inverter: 1000 Watt 230 Volt 21 Amps (Discharge Amps) 3 hours ago, Richwost said: We discharge it 75% so 120 Amps. You really want to hammer those batteries? That is a state State of Charge of 25%. That is low even for Lithium batteries. They are not going to last long, but that is fine by me. So you have 120 Ah available. 3 hours ago, Richwost said: One Lithium battery holds 160Ah. We discharge it 75% so 120 Amps. Divided by 3 = 40 hours available. You cannot divide it by 3, that is for the Amps you pull on 230 Volt System when you are on grid. You have to divide it by 83 Amps (the discharge amps), because you want to run it on 12 Volt System. Therefore 120/83 = 1.5 hours, not 40 hours. So in this case, you need 8 of those Lithium Batteries, taking into account you are going to hammer the batteries. You go wrong where you divide the Grid Amps into the Battery Amp Hours available. Look at the table above, select the inverter voltage and divide the corresponding Inverter Discharge Amps into your available Amp Hours.
March 5, 20179 yr @Richwost No matter how you look at it, you need 8 x 160 Ah Lithium Batteries for a load of 1000 watts: 12 Volt system (2 Stroke System - High Revving System) - High Discharge Rates, Thick Cables, Lots of Heat to Dissipate: 8 Batteries: 8 x 12 Volt batteries in Parallel = 960 Ah / 83 Discharge Amps = 11.6 hours 24 Volt System (4 Stroke System - Moderate Revving System) Moderate Discharge Rates, Moderate Cable Sizes and Moderate Heat to Dissipate: 8 batteries: 2 x 12 Volt in Series = 120 Ah 4 x 24 Volt in Parallel = 480 Ah / 42 Discharge Amps = 11.4 Hours 48 Volt System (Diesel System - Low Revving System) Low Discharge Rates, Smaller Cable Sizes and Lower Heat to Dissipate: 8 batteries: 4 x 12 volt in Series = 120 Ah 2 x 48 volts in Parallel = 240 Ah / 21 Discharge Amps = 11.4 hours The choice is yours. By dropping the load to say 650 - 750 watts will make you batteries last longer, but you will not be able to reduce the number of batteries required.
March 5, 20179 yr 12 minutes ago, Don said: 12 Volt system (2 Stroke System - High Revving System) - High Discharge Rates, Thick Cables, Lots of Heat to Dissipate: 24 Volt System (4 Stroke System - Moderate Revving System) Moderate Discharge Rates, Moderate Cable Sizes and Moderate Heat to Dissipate: 48 Volt System (Diesel System - Low Revving System) Low Discharge Rates, Smaller Cable Sizes and Lower Heat to Dissipate: That is a wonderful analogy! (Even better than your cricket analogy - which was pretty damn good).
March 5, 20179 yr 850rpm, now that is slow revving, and at 48V and fits right in with Don,s analogy..
March 5, 20179 yr The thing that worries me about the 1200VA 12V Multiplus is that it is really a small inverter and not the best value in the range. Being a multiplus it comes with all the nice features of a transfer switch and full hybrid capability, but because it is really a 900W inverter the value to cost ratio really isn't as good (like a bar fridge costs almost as much as a full size unit, cause the guts are essentially the same). Also, 1kw constant is a LOT. Even by city standards that is a lot. 500W constant is too much imho.
March 6, 20179 yr 12 hours ago, plonkster said: Also, 1kw constant is a LOT. Even by city standards that is a lot. 500W constant is too much imho. I agree Plonkster. I have the same problem. I switch off everything I can before going to bed, I still sit with 500-600 watt load. 2 x fridges, water cooler, security cameras, 2 x gate lights, DSTV, ADSL modem, 2 x cell phone chargers and 2 x laptop chargers plugged in, not charging anything (only little green light is on). That is all I can think of. People see most of these as insignificant. Well I tell you, those insignificant items all add up. Everything a family member wakes up, the load meter bumps up to a higher level. That is reality and you have to cater for it. Unless you want to run around the house the whole day shouting if someone leaves a light on and unplug everything you see.
March 6, 20179 yr 8 minutes ago, Don said: I agree Plonkster. I have the same problem. I switch off everything I can before going to bed, I still sit with 500-600 watt load. 2 x fridges, water cooler, security cameras, 2 x gate lights, DSTV, ADSL modem, 2 x cell phone chargers and 2 x laptop chargers plugged in, not charging anything (only little green light is on). That is all I can think of. People see most of these as insignificant. Well I tell you, those insignificant items all add up. Everything a family member wakes up, the load meter bumps up to a higher level. That is reality and you have to cater for it. Unless you want to run around the house the whole day shouting if someone leaves a light on and unplug everything you see. Do you need the water cooler on during the night? Perhaps the fridges temperature can be adjust a bit? I found that, the difference between 4 degrees and 6 degrees on my fridge is quite noticeable - in terms of electricity usage. At 6 degrees everything is still cold enough not to spoil or go rotten. The security cameras could possibly run from it's own 12V battery, powered by it's own smaller solar panel? w.r.t. lights, I have 3W and 5W LED lights, and don't mind if the passage, bathroom or even night light is on, since, as you say, if my 2 year old wakes up, there's light for her. The outside security lights are 10W so it's not that much draw either. But I have two security lights on their own solar panels as well, helps bring the load off from the main battery bank.
March 6, 20179 yr I would suggest @Richwost should be looking at the Victron Multiplus 48V 3kVA-2.4kW Pure Sinewave Inverter/Charger. The inverter will be sitting at 25-30% most of the day and maybe 50% load for short periods during the day. Yet sufficient capacity should someone inadvertently plug in a toaster, kettle or hairdryer. I consider 3kVA entry level, size wise. I installed one in my moms flat. She lives alone and has 1 light on during the day and the TV, DSTV decoder, ADSL modem and PC. If she switches on a small little vacuum, the inverter alarm goes of to warn that she is running close to maximum power. With a load of 1000 watt and say 1400 watt spare power for flexibility, that is not a lot. There are very little appliances the uses less than a 1000 watt to operate.
March 6, 20179 yr Author Hmmm... I thought I knew a bit about Solar. I now discover that I knew very very little. I've learnt more yesterday and today than I have learnt in the past 2 years. Thank you Don for clearing up the mess in my head and putting me on track to do something approaching intelligent!! I loved your 2-stroke / 4-stroke / diesel analogy - that really does bring it home to me. That is complete news to me. I wonder how many people "out there" understand all this? One of the reasons that I became a Solar Atheist was because of precisely that. The first Solar installer I went to - a year ago (a recommended installer) - gave me a quote. He then refused to tell me what make inverter, what make of battery and what make of panels - nor any specs. Said that was privileged information and that he was selling me a solution, not components. Can you blame me for buying a generator? Your list this morning of items drawing power was very interesting too and it forced us to go through ours. Exactly the same and you're quite right, you can't run around turning things off the whole time. We do live in the 21st century after all. Plonkster thank you for your support on this too. I am not quite sure where I go from here, but I am looking forward to see what TTT has to say and to see if there is an economical way of bridging the gap. Otherwise I have a choice it seems to me... Either I do what I wanted to do and treat the 1200 12V with the lithium battery as a one hour stop gap, OR I get a 3kW 48V with Trojan batteries and panels and have a real system that could last for several hours.
March 6, 20179 yr 3 minutes ago, SilverNodashi said: Do you need the water cooler on during the night? No, but if I switch it off, I forget to switch it on again. It runs minimal during night time and uses very little power. 5 minutes ago, SilverNodashi said: Perhaps the fridges temperature can be adjust a bit? I found that, the difference between 4 degrees and 6 degrees on my fridge is quite noticeable - in terms of electricity usage. At 6 degrees everything is still cold enough not to spoil or go rotten. I agree, but I don't want to drink a glass of milk with ice cubes. Beer is in the same fridge, so that is not an option for me. I have Bosch fridges, they really impress me. 7 minutes ago, SilverNodashi said: The security cameras could possibly run from it's own 12V battery, powered by it's own smaller solar panel? Now that start to complicate things for me. More gadgets, wires and batteries. That will just clutter things up for me. I only have LED lights in my house. I took out all other light bulbs, stepped on them and threw them away. I appreciate the help @SilverNodashi, but I think I have come to a stage that I have accepted that is what it is and I am happy with it. I went totally off grid for 2 days, and I can do it if need be, as long as it does not rain the next day, therefore I am happy. I actually need more battery capacity, but that is to expensive. So when I run short, I use the grid.
March 6, 20179 yr 10 minutes ago, Richwost said: I thought I knew a bit about Solar. I now discover that I knew very very little. I've learnt more yesterday and today than I have learnt in the past 2 years. We all go through that learning curve. 11 minutes ago, Richwost said: That is complete news to me. I wonder how many people "out there" understand all this? The man on the street, highly unlikely. 12 minutes ago, Richwost said: Your list this morning of items drawing power was very interesting too and it forced us to go through ours. Exactly the same and you're quite right, you can't run around turning things off the whole time. We do live in the 21st century after all. I know, just cater for it. It becomes a mission if you play Power Police in the house and you very quickly become unpopular with the wife.
March 6, 20179 yr 2 minutes ago, Don said: I know, just cater for it. It becomes a mission if you play Power Police in the house and you very quickly become unpopular with the wife. Ain't that the truth brother :-)
March 6, 20179 yr WOW, 2 stroke 12v, brilliant!!! Right, a careful introduction to solar, that you can manage, is lights. If you load is below a certain point, the 2 stroke engine is a perfect fit. The moment you talk fridges or bigger like the entire house, the entire ballgame changes, you have to go diesel. Allegedly lights are off-grid for no matter what you do, you don't seem to use them in the day. So taking just your lights as a starting point, with all the above taken into account ito reduction, work out the EXACT watts of all the lights on for peak usage and how long that could be, and then the lights on for average use during the night when all is supposed to be off, you can then pinpoint exactly what battery bank you need. Then we could add the alarm system, so get the exact usages, and we add that. After you have that we can suggest the right battery AH / controller / panels / inverter to matches the usage to run off-grid. IF you go this route, you learn a hell of a lot very quickly cheaper than trying to go a whole house off the cuff. No matter how good the installation is, taking a house onto solar is quite a journey. Once you understand the system, and it takes about a year to enjoy a summer and a winter, that is when you now can really start to map the route out for your own particular needs, without upsetting the wife, for she then bought into it. Solar necessitates lifestyle changes or a hell of a bank account.
March 6, 20179 yr 5 minutes ago, The Terrible Triplett said: own particular needs, without upsetting the wife, for she then bought into it. Now that would the top point of optimism but hey we are all allowed to dream for a while .
March 6, 20179 yr 24 minutes ago, Don said: should be looking at the Victron Multiplus 48V 3kVA-2.4kW Pure Sinewave Inverter/Charger. The inverter will be sitting at 25-30% most of the day and maybe 50% load for short periods during the day. Yet sufficient capacity should someone inadvertently plug in a toaster, kettle or hairdryer. That inverter really is the pick of the bunch. It can peak over 6kw if you need it to. I would say that the little bit of Diesel you need to bridge the big loads (over 3kw), given that you already have the generator, makes it unnecessary to look at anything bigger. Of course I am now talking future, when in the future you add solar panels and batteries. You can just continue using the inverter. I'm one of the people here with the smallest inverter: A 1600VA Multiplus. That's because my entire use-case is different. From day one the objective was to take the small loads off the grid, all those little loads that add up to 1kw so quickly. We know who the big guys are (geyser, stove, air conditioners), but we don't know where all the small jackals live. I've drawn that picture before, but if you look at a consumption line chart with kilowatt on the vertical and hours on the horizontal, then the area under the line is kilowatt-hours, the bit you pay for (either to the grid or in Diesel). If you can draw a line across that chart around 1kw and say that everything below the line is covered by solar, I need only use the grid/run the generator for the bits that stick out on top... you see very quickly how over half your consumption goes away with a small inverter. But with all that said, there is something to be said about the buy-in from the wife. A certain balance needs to be maintained. I'm sure that when you're out on the farm and the grid is down, the mere availability of some power (even if I cannot run the kettle, or need to push a button before I can) might be good enough. In the city, something as small as telling your wife she cannot run the vacuum cleaner on THAT circuit could be a complete deal breaker :-)
March 6, 20179 yr 2 minutes ago, plonkster said: ... could be a complete deal breaker. 3 minutes ago, PaulF007 said: Now that would the top point of optimism ... Done and done - no hospital bills and no angry wife. SHE now shouts at the cleaners. 5 minutes ago, plonkster said: I'm one of the people here with the smallest inverter: And I am one of the people here with a 375Va and 1600VA Victron inverters off-grid in the city. Neither can take Eskom so I rely totally on panels. I do have changeover switches for i.e. lights to go back to Eskom after day 2 of no sun.
March 6, 20179 yr Just now, The Terrible Triplett said: changeover switches I have those too, but the DSTV has to reboot when you use that one... and I think we've covered how irritating that might be when it involves a soap or a rugby game. Especially my old PVR1... good grief, when that thing reboots you may lose an entire season...
March 6, 20179 yr 6 minutes ago, The Terrible Triplett said: SHE now shouts at the cleaners most important usually that happens AFTER the training phase was completed..
March 6, 20179 yr 33 minutes ago, plonkster said: ... has to reboot when you use that one. That is why I have a online UPS between it all. Three reasons: To keep things on when switching. To blow less things up. Sorry @Energy - you guys know of electrician frying my previous UPS. To protect it all when it runs off Eskom for when I saw how many of my friends started having problems with goed during Eskom failures, when power comes back on. Yes it is inefficient but you know what, it works, things are protected and nothing goes off ever even when "someone" presses buttons. THAT I can tell you, is drama, when the wife's computer goes off. Lately every-time I walk to a specific spot in the house, where I can switch things on/off, the dogs and the cat starts hiding.
March 6, 20179 yr 2 hours ago, Don said: I agree Plonkster. I have the same problem. I switch off everything I can before going to bed, I still sit with 500-600 watt load. 2 x fridges, water cooler, security cameras, 2 x gate lights, DSTV, ADSL modem, 2 x cell phone chargers and 2 x laptop chargers plugged in, not charging anything (only little green light is on). That is all I can think of. People see most of these as insignificant. Well I tell you, those insignificant items all add up. Everything a family member wakes up, the load meter bumps up to a higher level. That is reality and you have to cater for it. Unless you want to run around the house the whole day shouting if someone leaves a light on and unplug everything you see. A lot of these appliances you can put on timers. I have one plug circuit that switches off from 10pm to 5am, where all of the phone chargers, router and other electronics sit, and another one for the fridge and freezer which runs from 6am to 6pm. My overnight load is actually miniscule now, being a few lights and so on, about 100-150W.
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