Green Power

The Voltronic battery I might be able to get in Chile is LIO4810. If I go with Pylontech, there's a chance I may go with two US2000C rather than one UP5000 battery. The total capacity is the same, so I assume it doesn't matter either way. For the smaller US2000C, the reccomended discharge current of 25A looks a bit low for my needs. However if I buy two of them then I will have a recommended discharge current of 50A, right? At the moment the store doesn't seem to have stock, so it may come down to which product comes into stock first this week or next week.

I think I am moving on from the original topic of this thread. I think most likely the problems were the old batteries. My current problem is I'll probably get some new batteries. If problems persist with the inverter, I'll look to fix or replace that later on. I think the batteries will be lithium if possible, so for now I'll set aside lead acid and only consider lithium as first choice. I did start a new thread to discuss which batteries to get if anyone is interested: https://powerforum.co.za/topic/11261-are-pylontech-up500-and-us3000c-compatible-with-axpert-mks-ii-5kw/

Thanks for that. OK, so maybe the shop didn't want to sell me the battery to avoid me coming back with novice issues and complaining...maybe they thought it wasn't worth the hassle. I did actually email Voltronic Power in Asia (coincidentally before you mentioned it as they are the one other manufacturer I found with a reasonably priced lithium battery for sale in Chile) and I did actually get a reply from someone in Taiwan. They said "Yes, it is OK to use it without bms communication." I also asked: "Is it still safe, and will it still work, with normal battery life, and warranty still valid?" and they replied "yes". I also emailed Pylontech but no reply yet. And emailed another shop in Chile that sells the batteries, and they said "si se pueden configurar sin embargo ese inversor no cuenta con comunicación con baterías. Por lo tanto la configuración debe realizarse de forma manual." "Yes, you can configure however that inverter doesn't have communication with battery. So the configuration must be done manually". My friend who did my original solar install for me, who works as a professional installer, also thinks it will be OK. Any thoughts anyone on Pylontech vs Voltronic Power?

I went to the shop today to buy a Pylontech battery and they asked me what inverter I had and when I told them they said the batteries would not be compatible, that it may not work when I turn it on, and that I would need to buy a different battery or change the inverter. They showed me the Pylontech US3000C and I took a photo of it. It has 6 ethernet ports (or something that looks very similar) and they are labelled "Contact" "A/CAN"" "Linkport 0", "Console", "B/RS485" and "Linkport 1". My inverter, the Axpert MKS II 5kW, only has one such port and it has RS232 written on it. I googled that and I see RS485 and RS232 are different communication standards. Coulomb, is that the issue you meant when you said "you can't connect the BMS directly to the inverter"?

Apart from once or twice, every time we had a 5 or 10 hour power cut, the power seemed to come back on miraculously just when the inverter was beeping low battery. I do agree with spreading loads and I do already do that myself with the car, pool filter, electric heaters and watering system. These are usually scheduled/matched to the available PV so we have our demand and supply fairly well in sync compared to most people. We also recently bought a gas kettle. It reminds me of going camping. If I lived alone, this would be very easy. The battery would mostly only be only used in the evening to run low power items. But there are four of us and I don't think people want to be told what hours of the day they can use the hair dryer.

I varied setting 12 quite a lot and sometimes had it at 48V but I think I had it at 46V more than half the time to try and reduce fossil fuel use. It also would go to 44V when there was a power cut in the winter all evening which happened a number of times. So although I hoped the battery would last longer on reflection it's not a complete shock that it died after a year and a half. The trouble was, at 48V the amount of energy you would get in an evening would be really poor.

Thanks for the inverter settings. I would like to do that in between buying the battery (assuming I do go ahead) and installing it, so let´s come back to that topic at that time. If the cable length is a problem, perhaps putting the battery inside the cupboard could work. To be clear, by "tiny heater" I am talking about heating the air in the cupboard, not the battery itself. I wondered if we could put the battery in a closed cupboard and then on winter nights some very tiny (i.e. low power) heater such as perhaps a 40W incandescent bulb in the cupboard to provide enough heat to keep the temperature overnight in the cupboard where the battery is to a better level. And just turn it on when I go to bed and turn it off sometime the next morning. That might mean using 10% of the battery capacity to heat the cupboard though. The office will not be too warm in summer. Have you written about your experience of your Leaf´s battery degradation in 7 years and the battery change. I would be interested to know a bit about that, but just curious (battery degradation after 7 years, costs, what happened to old battery). Good that you managed 98% solar powered, I reckon I`ve manage about 90% for the car. I have a first generation Ioniq 2017 model.

I have been coming around to your way of thinking on lead acid batteries, which is why I´m thinking of going to lithium. The question is whether I can run a lithium battery to support loads during the day AND drain the battery in the evening and still get 5 years. I guess I can´t expect anyone to really know that? I can´t find anything useful from searching for scientific studies online so I´ve given up searching. 500 cycles a year (i.e. more than one a day including daily cycling) would be 2500 cycles compared to the >4500 it´s supposed to be capable of in ideal conditions according to Pylontech. That sounds plausible. Even if the use of daily cycling cuts the total cycles in half it could still be OK. The battery has a recommended discharge current of 50A so for 48V battery I think that should be 2400W. Load is going to be below PV input majority of the time, and nothing we use is >2400W, so only rarely will things go above the recommended discharge current. And you would think the recommended discharge current in the manual ought to be consistent with the >4500 cycles in the manual. However that still leaves your point "You are continuously cycling your batteries, they are so confused they don't know if they are charging or discharging. The batteries will never last." Are you saying that continuous flicking between charging is discharging is bad for a battery? Is that a gut feeling or let me know if there is any evidence to support that. I am concerned also that what I am looking to do would cause in practice the battery to be cycling a lot between 100% and 90%. That is a problem because for lithium 10 times from 100% to 90% is far worse than 1 time from 100% to 0% as far as I know. That means my 2500 cycles above may in reality be like 3000+ complete cycles. Not sure if there´s a way to stop the max charge % at 80% to minimize this issue. My wife bought a gas kettle after the electric kettle caused power cuts several times since the battery got trashed. So that should help. We do not exceed the solar power input constantly during the day. It isn´t jumping all over the place. The electric oven at tea time is extremely frequent for 20 minutes at about 1500W, almost daily. Apart from that, things can be fairly stable and exceeding the input is pretty occasional. For 8 months of the year, we don´t have much changeable weather here. It is either sunny all day or cloudy up to a point then sunny. That helps a bit. The Pylontech UP5000 I am looking at it seems comes with a 5-year guarantee. So there is the argument that either it lasts 5 years which means I´m happy, or it lasts less which means I have a chance to get something on the guarantee. Thanks again for walking me through this.

That sounds about right. Is that "return to batteries" a changeable setting in the inverter menu? I don´t recall seeing that. Or maybe I´m confused again. When the batteries were newer it would usually only switch to grid for everything if the load was more than 1500W higher than PV input or if the batteries were very low in charge. But lately even after 10 minutes of supposed charging it tries to switch back to solar and batteries and doesn´t work and goes back to grid again for another 10 minutes. I actually have the batteries disconnected at the moment.

Thanks again for your help Don. I see the point of switching to batteries at 9pm or 10pm but from a climate change and pollution perspective I suspect it makes more sense to run the battery from sunset onwards because that is a high demand period for electricity grids. If you can avoid using grid electricity until 10pm, that probably helps more to reduce gas and coal, and even get the plants shut down. I suppose if I replace the inverter now at this early stage we´ll have to factor in 3 inverters during the life of the system rather than 2. I´ll likely end up spending US$1000 (??) on the inverter. We`ll also lose some money in spending more on grid electricity during the day - say $100 a year. Maybe $1500 spent after 5 years. (Add on installation cost and a bit of grid spend while the inverter is out of action, that´s another $200, but say I get back $200 from selling the inverter. So let´s say $1500.) Would I save US$1500 in batteries during the say 10 years lifetime of the new inverter? Even financially, without concern about climate change, it´s not clear to me if buying an inverter works at this point. What do you mean by "never last"? Might the daytime and tea time cycling reduce the lifetime of the battery by half? More than half? Less than half? Some data and studies might be out that to help on this. Haven´t found anything so far. Maybe will have another look.

It is an old type turning disk meter. Nothing smart, and the rate is always the exact the same at every hour of the day.

On the temperature, I can think of three options. 1 Just put the battery next to the inverter and get on with it, and accept some performance reduction and degradation over time. 2 Put the battery in the cupboard next to the inverter. Means leaving the battery in an enclosed space, no air flow. Could its own heat production heat up a cupboard enough? Or try and rig this up with an incandescent bulb or some other tiny heat source in there. Or maybe this is just a mad idea. 3 Put the battery in my office next to the outside area. Temperature would rarely be below 10C and would be on average 5C higher than the outside in winter, the same for the rest of the year. Requires drilling a hole in the wall of the office and putting 5 - 10 metres of cable/wire between battery and inverter. I´m guessing some small efficiency losses fro the length of cable/wire but not as much losses as leaving the battery in the cold?

Again, feel out of my depth here. Don´t know what that monitoring program would mean, or even whether that means some additional hardware to be purchased or whether it´s just software. If it´s very easy for an amateur to do, and cheap, I could learn more about it. Otherwise maybe just plug and play and see what happens? And maybe revisit this topic if I get disconnections later?

Now replying to an earlier post in the thread that I hadn´t gotten round to replying to yet. The trouble is that making your batteries last longer by just using them as a power backup or to a lower depth of discharge is also kind of a false economy because you aren´t getting much value out of them. I am thinking that the bottom line is that batteries don´t work as a truly good financial investment. If you care about climate change, or need power backup, they make sense. I actually prefer that the inverter uses the battery to supplement high loads because this is very likely a better thing to do from a climate perspective (35% coal and >50% fossil fuel here in Chile) and I´d rather avoid more grid electricity use, even at the expense of a shorter battery life, as long as the sudden heavy zapping when things are turned on isn´t actually damaging any part of the system. If it just means the lithium battery lasts say 5 years instead of 8 I´d settle for that as long as it functions fairly well for that time and doesn´t have issues. As long as the lithium battery lasts 5 years+ we will get enough value out of it to justify the cost. I may only recoup half the cost of the battery in that time in electricity savings, but the other half I am happy to spend to have a good backup as we have regular power cuts, and to reduce our family´s carbon emissions. At the moment I´m still leaning towards replacing the battery first and hoping for the best but I am dithering and you might all be able to convince me. The inverter is expensive but it´s also the heart of the system. I don´t even know how to take out the inverter and connect the house back to grid. So I either have to pay a professional to come to the house and evaluate it here or pay another professional to take out the inverter and connect to grid and then someone else to evaluate it in their store and factory.

LoodPyp, Did your system have lead acid batteries? Would it be fair to say that with lithium batteries the better cycle life, and perhaps better ability to withstand heavier demands, might mean that this inverter might work Ok with lithium batteries?

Thanks for that explanation, in which case it could mean that the power cuts were due to my system´s problems rather than the cause of them.

Would appreciate any assistance. I have had solar for 1.5 years now but I didn´t install it myself and still feel very much a beginner. The lead acid batteries I bought seem to be almost junk after 1.5 years of regular use and some hundreds of cycles. I was thinking of replacing them with a lithium Pylontech UP5000; 4.8kWH (or maybe a Pylontech US3000C; 3.5kWH). It seems to be a good beginner´s option, as well as one of the very few lithium batteries available here in Chile. With 3.25kWP Risen panels (10 panels), does it seem to be an OK choice? Would the UP5000 (and the US3000C) be compatible with my inverter Axpert MKS II 5kW. It looks like it might well be, but I couldn´t confirm for certain? (EDIT February 16th: Bought 2x US2000C instead of 1 x UP5000 due to the UP5000 being unavailable at time of purchase. However total capacity is same/similar.) Batteries would be in an unheated area; average winter minimum daily temp is about 4C, about 0C can happen on a minority of days. How big an issue is that?

I have been disconnecting the battery for days at a time and I noticed that when I did this grid use in the day is reduced. I think when there are high loads the inverter goes to the battery and when the battery doesn´t respond it goes to grid. I also noticed that when the battery is disconnected things work smoothly and there have been no power cuts so far. I am fairly confident that grid and solar is being mixed and simultaneously used when (and ONLY when) the battery is turned off, as shown by the picture on the inverter. I also took a bunch of meter readings and compared to load and PV input and this seems to confirm this. It looks like the battery may be in need of replacement. I thought it would last longer than 1.5 years but after using daily to provide power in the evening and some hundreds of cycles I suppose it´s plausible that the battery is pretty much dead. That seems to be the best explanation for now. I had my friend who installed the system come over, and that is what he thinks as well. I still have a small doubt...it could be the inverter after all that is the problem, but that looks less likely.

I am afraid things just got more complicated and confusing than ever. Yesterday (after my last post) I had someone in our gardening doing some soldering work and they kept causing power cuts but when this happened they just kept trying over and over again. I went out and suggested he stop but he insisted it worked fine in other houses and it was nearly finished so he kept trying and the power cut out several more times - either that circuit or the entire house. I then had a look at his tool and had an amperage dial that ranged between 30 amps and 200 amps and he had it set to about 50 or 60 amps I think. The circuits of my house are 10,16 and 25 I believe amps and the whole house is I think 32 amps, and the inverter can only deal with I think 5000W or 5500W. So I then insisted he stopped. However, after he left, we have had about 5 or 10 more power cuts that evening and today, all when we try to use something that uses a lot of electricity like a kettle. It wonder if the soldering tool may have damaged the inverter, the battery, or some other part of the system. It seems likely to me the use of that soldering tool did something as we have had as many power cuts in the last 20 hours as we had in the previous several months. At the moment we seem to have stable power as long as we don't plug in anything that uses 1000W+, if you do we sometimes get a power cut, sometimes it works but only on grid, and sometimes it works normally. On the other hand we already were having power cuts occasionally before then, perhaps once a month or once a week, due to what I thought was an error on the inverter as they happened randomly at night. I found this old thread about that months ago which might be relevant: Most of the power cuts either give the error code 58 "Output voltage is too low", the code 8 "Bus voltage is too high" or, just now, BP "Battery is not connected". That last one didn't make sense at first when I saw it last night as the pictures on the inverter show the battery being charged. However, now I think about it, it may make sense. That could explain why the grid electricity is being used too often. It would also explain why in the last few days I happened to notice on one day the battery had a low charge just after sunset when it would normally be high, and other day this week I noticed the house running off grid electricity as early as 9pm at night, when it would usually be battery. At the time I just assumed we had used more electricity in the day that usual, or due to clouds. At this point it may make sense to fix the battery connection issue first, and then see what issues remain after that? Re your last post, I just set it to 44V and plugged in the car and it went over to grid. It should have been possible to provide the electricity with solar + battery, even just solar alone without battery should almost certainly have covered it, and it still went over to grid. Before going over to grid there was a few seconds when it was trying to provide the energy without grid and showing error 4 "low battery" before giving up and going over to grid.

Will changing to CSO stop it flicking over to grid/utility, and if so will this only be because the battery is fuller/voltage is higher? What I really want is to use less grid/utility electricity overall. Should CSO (rather than (OSO) achieve that? I don't want the grid/utility charging the battery after sunset so I'll have to check if it does that now I made that change. I currently have setting 12 on 46V on setting 13 on 48V. Would it make sense to set 12 to 44V during the day time when I have had high loads - would that help it stop depleting the battery. And then change it back to 46V in the late afternoon to protect battery life? What do you mean by LS? I'll probably need a few days or a few weeks to try out changes and see the result, there is no huge hurry here...

Thanks for helping out. Yes, the batteries are connected. The batteries will step in and add a few hundred watts or maybe a thousand watts if needed. For example, with a load of 2300W might see 2000W from panel and 300W from battery. But when the difference is larger such as a load of 4000W vs 2000W from panel the batteries don´t provide the difference. It just uses grid for everything. The battery bank is connected. However it is fairly small (four 100Ah batteries). In some cases, that may explain why the batteries don't provide the difference because they may not be capable. Setting 1 in SBU, setting 16 is OSO (only solar). I can try setting 16 to CSO later and see if that helps.

Hi, this is my first post. Thanks for reading and I hope some of you can help. Sometimes someone turns on the microwave, or kettle, or oven, or hair dryer, or some other appliance briefly for a short while. When this happens the load, previously say 2000W, will increase to 3000W or 4000W vs solar power of maybe 2500W. The inverter, Axpert MKS II 5kW, will then use grid electricity to provide ALL this power, even if the batteries are full and there is 2500W solar power, which is just shut down and wasted (I can't sell to the grid). This is causing unnecessary climate change and pollution, not to mention throwing money away. Once it switches over to grid power it will then persist with using grid power for everything for some minutes (I timed it a couple of times and it looks like it's on a clock for ten minutes) even if the load has fallen down to what can easily be handled by the solar panels. E.g. if someone turns on the microwave for 30 seconds grid power is used for everything for the next ten minutes. At first I ignored it since the losses were small and it only happened about once a day but lately we are using more electricity in the day and it now happens constantly (5-10 times a day) and is starting to get annoying as well as probably pointlessly wasting probably between about 1KWH and 3kWH/day. When the solar is 2500W and the load is 4000W I want the grid to provide only the difference of 1500W not the total of 4000W. I know it's possible to combine solar and grid because I've seen the inverter do it, but for some reason only when the batteries are disconnected. Is there a setting in the program that I can use to make it do this? The setting 23, overload bypass, is set to BYD (bypass disable) but I also tried changing it to BYE (bypass enable) once and it made no difference. I couldn't figure out for sure whether this setting was relevant or not but I thought I'd try it. In fact, it was finding some threads on this topic that brought me to this forum. Is there a good reason why the inverter won't combine solar and grid? Is there any downside to trying to make this happen? I am a novice pretty much so please keep it simple. Thanks for your help.