Tinbum Posted March 31 Share Posted March 31 (edited) 22 minutes ago, Scorp007 said: We all seem to be on the right track. It's just a matter of a faulty BMS and not the inverter that cased this problem based on what we know. No a cheap inverter. The inverter did not get the correct instruction from the BMS. Most BMSes in the battery has no means to apply the right settings. That is as far as I have seen. Their settings are set by the factory. We just need to look at how many of a certain make of battery never switches off or stops charging when over voltage. This is also the reason the cells bulge but the manufacturer always blames the inverter and hardly ever accepts responsibility that it is the BMS that did not action its own protection before damage. Yes, generally in off the shelf batteries their is no way to change the settings but if they are wrong then the manufacturer should be informed and the battery returned. I sniff the CAN communication in my setup and I also alter some settings before passing them on to the inverter. My Pylontech batteries do control the inverters very well but two settings I do change, one because I think it's too high and the other because of my application. The battery charge voltage request is 53.2v, which I change down to 52.5v on 6 days of the week. The other is the charge current. I have 2x US3000C batteries on a PV setup with 8kW of panels on a 4kW inverter. The BMS would request a max of 74A but I limit it to 20A as that's enough to charge them during the daylight hours and will hopefully increase longevity of the batteries. Edited March 31 by Tinbum Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted March 31 Share Posted March 31 1 hour ago, Tinbum said: Yes, generally in off the shelf batteries their is no way to change the settings but if they are wrong then the manufacturer should be informed and the battery returned. I sniff the CAN communication in my setup and I also alter some settings before passing them on to the inverter. My Pylontech batteries do control the inverters very well but two settings I do change, one because I think it's too high and the other because of my application. The battery charge voltage request is 53.2v, which I change down to 52.5v on 6 days of the week. The other is the charge current. I have 2x US3000C batteries on a PV setup with 8kW of panels on a 4kW inverter. The BMS would request a max of 74A but I limit it to 20A as that's enough to charge them during the daylight hours and will hopefully increase longevity of the batteries. Your settings do seem very well indeed. But I would think the average user does not even look at the battery voltage. Members here will know but most won't. While it's working all is well. Just like "as die wiele draai moenie worry nie" Quote Link to comment Share on other sites More sharing options...
Beat Posted March 31 Share Posted March 31 8 hours ago, Tinbum said: The BMS normally incorporates protection features to shut down the inverter if something is wrong before the BMS has to activate its own protection. Everyone is free to believe what he wants. My observations show me another picture. In this forum we can read of many user having problems with BMS communication to the inverter. It looks like there are more batteries mismanaged by BMS than saved by them. On the other hand inverters are well designed to manage batteries correctly on their own if settings are according to battery specs. Read also my thread "Are BMS reliable?". GreenFields, tigger_na and Antonio de Sa 3 Quote Link to comment Share on other sites More sharing options...
Tinbum Posted March 31 Share Posted March 31 (edited) 48 minutes ago, Beat said: Everyone is free to believe what he wants. My observations show me another picture. In this forum we can read of many user having problems with BMS communication to the inverter. It looks like there are more batteries mismanaged by BMS than saved by them. On the other hand inverters are well designed to manage batteries correctly on their own if settings are according to battery specs. Read also my thread "Are BMS reliable?". I have read your thread before. I disagree, nearly all problems are user error or bad inverters. Inverters don't manage at all. They set a voltage and that is it. They wouldn't have a clue if the battery had a problem and would just keep pumping out the Watts no matter how dangerous it was. They wouldn't even know to reduce the current if the battery was too hot or cold. Using without communication is a bad idea and potentially dangerous. Manufacturers wouldn't put it in their batteries if it wasn't necessary and in some cases it is a requirement of the warranty. Edited March 31 by Tinbum Quote Link to comment Share on other sites More sharing options...
GreenFields Posted April 1 Share Posted April 1 Said this somewhere else as well. I'm not in favour of disconnecting the BMS, but also think if the inverter is able, then manually set the battery's recommended charge and discharge parameters on it, or just within. Analogy being, even if your car has a rev limiter, you still don't floor it all the time, and neither do you disconnect the limiter. To each his own. Quote Link to comment Share on other sites More sharing options...
tigger_na Posted April 1 Author Share Posted April 1 On 2024/03/31 at 6:57 AM, Nexuss said: You are comparing Lipo to LFP chemistry ,they are very different. LFP need to be charged to 100% regularly to keep cells balanced. See, There it is, the obvious expertise. Considering the answers on the forum, the fact that the guarantee is destroyed anyway, and the fact that the charging algorythm is obviously wrong, I will disconnect the communication between the BMS and the inverter. I have my Solar Assistant, so I can monitor and see whether I'm making the wrong choice or have the wrong settings. I can see one problem though, the inverter will disconnect when my battery is at less than 30%SOC, but without the inverter knowing the SOC, I will need on the BMS to disconnect, but that will probably be at a much lower SOC than I prefer. What voltages do you recommend I program the inverter for? Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 1 Share Posted April 1 (edited) 47 minutes ago, GreenFields said: Said this somewhere else as well. I'm not in favour of disconnecting the BMS, but also think if the inverter is able, then manually set the battery's recommended charge and discharge parameters on it, or just within. Analogy being, even if your car has a rev limiter, you still don't floor it all the time, and neither do you disconnect the limiter. To each his own. A spot on answer. Just like @Beat I am running lithiums with their own BMS no comms but using inverter settings. This way I still have protection. Then I also have a external JK BMS managing a DIY bank. The inverter oversees all the charging/discharging settings. I do belief the JK BMS is doing a better job than a number of internal BMSes while having no comms. Edited April 1 by Scorp007 Beat 1 Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 1 Share Posted April 1 11 minutes ago, tigger_na said: What voltages do you recommend I program the inverter for? Use about 3-3.1V per cell for stopping discharge. Bulk charging set at 3.55V where balancing might already be switched on. BMS specific. The JK BMS is a active balancer and work much faster than passive. You can also set is to start at any level per cell. Quote Link to comment Share on other sites More sharing options...
Beat Posted April 1 Share Posted April 1 (edited) 24 minutes ago, tigger_na said: What voltages do you recommend I program the inverter for? For 15 cells LiFePo packs: Bulk charge 52.5V, float charge 51.5V, low voltage cutout at 1 to 2V above the BMS cutout. For 16 cells packs add 3.5V to the values. My LEOCH 48100TB specs mention BMS low voltage cutout at 40.5V. I set the inverter to 42V. Edited April 1 by Beat Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 1 Share Posted April 1 38 minutes ago, Beat said: For 15 cells LiFePo packs: Bulk charge 52.5V, float charge 51.5V, low voltage cutout at 1 to 2V above the BMS cutout. For 16 cells packs add 3.5V to the values. My LEOCH 48100TB specs mention BMS low voltage cutout at 40.5V. I set the inverter to 42V. My lithiums can also go down to about 2.5V per cell but once one hits 3.2V you have around 10-20% of capacity left. Also I would rather switch off than to have the inverter draining the battery after switch off up to the point that the BMS switches off. To much effort to wake a lithium up once the BMS has operated. Quote Link to comment Share on other sites More sharing options...
tigger_na Posted April 1 Author Share Posted April 1 Thank you, Scorp007! So, if I want to charge to 100%, but allow the batteries to keep at 95%, going down to 30%, I would need: Bulk charge: 56.8V Float charge: 54V Disconnect: 51.5V and monitor and adjust as needed? Quote Link to comment Share on other sites More sharing options...
Antonio de Sa Posted April 1 Share Posted April 1 (edited) 9 minutes ago, tigger_na said: Thank you, Scorp007! So, if I want to charge to 100%, but allow the batteries to keep at 95%, going down to 30%, I would need: Bulk charge: 56.8V Float charge: 54V Disconnect: 51.5V and monitor and adjust as needed? I charge to 56.3 and float at 54.3 disconnect 49,3 and it works 100% for my battery. LBSA 5,1 KWH and battery temp very seldom goes over 34 degrees C also only charge the battery at 20 Amps. Edited April 1 by Antonio de Sa tigger_na 1 Quote Link to comment Share on other sites More sharing options...
Beat Posted April 1 Share Posted April 1 (edited) 14 minutes ago, tigger_na said: ulk charge: 56.8V Float charge: 54V Disconnect: 51.5V Consulting the recommendations of my 15 cells LEOCH 48100TB that would be way too high. Coulomb also recommends the values I mentioned. However if you have 16 cells those values may be ok. Disconnect at 51.5V? That would make the 15 cells pack unusable. Practical operational voltages are: back to grid bypass: 48V, back to battery mode 50V. Edited April 1 by Beat tigger_na 1 Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 1 Share Posted April 1 (edited) 15 minutes ago, tigger_na said: Thank you, Scorp007! So, if I want to charge to 100%, but allow the batteries to keep at 95%, going down to 30%, I would need: Bulk charge: 56.8V Float charge: 54V Disconnect: 51.5V and monitor and adjust as needed? More or less. The problem with most BMSes are that once the 1st cell reaches the upper voltage charging would stop. It does not mean all cells are fully charged. Thus one uses a trigger from the highest/lowest cell but that is a false indication for the battery as a whole. Also we might balance at 2A while charging at 40A. This high current causes a cells or 2 to run away and charging stops. The same during discharge. One just needs to check the values on the APP to do fine tuning. AFAIK even keeping lithium at 3.5-3.55V will get them to 100%. You just have to see what the 95% level might be but bear in mind the charge and discharge currents affect the voltage seen by the BMS. I placed the picture of the per cell volts to take care of 15 or 16 cell batteries. Edited April 1 by Scorp007 tigger_na and Antonio de Sa 2 Quote Link to comment Share on other sites More sharing options...
Tinbum Posted April 1 Share Posted April 1 (edited) This tread started off all about the batteries getting too warm and here we are recommending that the batteries be connected to an inverter without communication. This is crazy. The batteries are already getting hot due to the location. All inverters are dumb. You can set a charge / discharge voltage and a max current and that is it- that does not make them intelligent. They have no idea what the battery is doing. Below are the temperature settings for a Pylontech battery, presumably your going to set your inverter for the charge and discharge worst case temperatures or risk destroying the batteries again. As I said before the best coarse of action, and safest, is to swap out the BMS. Edited April 1 by Tinbum Quote Link to comment Share on other sites More sharing options...
tigger_na Posted April 1 Author Share Posted April 1 31 minutes ago, Tinbum said: This tread started off all about the batteries getting too warm and here we are recommending that the batteries be connected to an inverter without communication. This is crazy. The batteries are already getting hot due to the location. Hang on, you have to see this in pespective. The batterioes are getting warm because the BMS isn't correctly programmed. With no way to program the BMS, and with inverter control either on or off (as in BMS communicating and overwriting inverter settings, or not), disconnecting the BMS is the only and cheapest short-term solution. I cannot see how the battery will be destroyed, as the BMS is still there to protect it, albeit with limited control? Now, should EnerSol remain mute, and once you start getting on my bad side, I'm normally able to get the dead to speak, so there's little chance of that, I will consider swapping the BMS. A technical question: The existing BMS has two largish heat sinks. The JK BMS recommended by @TaliaB is a closed box. Where are the heat sinks? And without heat sinks, I ASSume that the original BMS does something that the JK BMS does not? A big shoutout to this forum. It reminds me of a time long gone, before the world moved onto Facebook, where the Internet used to educate, which enabled dimwits like me to develop and deploy knowledge we wouldn't have normally had. Quote Link to comment Share on other sites More sharing options...
Scorp007 Posted April 1 Share Posted April 1 47 minutes ago, Tinbum said: This tread started off all about the batteries getting too warm and here we are recommending that the batteries be connected to an inverter without communication. This is crazy. The batteries are already getting hot due to the location. All inverters are dumb. You can set a charge / discharge voltage and a max current and that is it- that does not make them intelligent. They have no idea what the battery is doing. Below are the temperature settings for a Pylontech battery, presumably your going to set your inverter for the charge and discharge worst case temperatures or risk destroying the batteries again. As I said before the best coarse of action, and safest, is to swap out the BMS. Most lithium battery specs are save up to 55 deg C. Have never really looked at the Pylontech. Also the temp graphs were not as high as this. You have identified something very valid then. All I can say is LifePo4 are normally specced to 55 and the JK BMS has 2 temp probes. Cut of temp is set to any temp decided on. Also the reset temp is adjustable as well as the lower minimum temps for stopping discharge and release temp. It also has the MOSFETS temp setting to stop charging. The great plus is user selectable and can be viewed on the APP. Also switch ON OFF and BALANCE via the APP. Quote Link to comment Share on other sites More sharing options...
Tinbum Posted April 1 Share Posted April 1 (edited) 27 minutes ago, tigger_na said: Hang on, you have to see this in pespective. The batterioes are getting warm because the BMS isn't correctly programmed. A technical question: The existing BMS has two largish heat sinks. The JK BMS recommended by @TaliaB is a closed box. Where are the heat sinks? And without heat sinks, I ASSume that the original BMS does something that the JK BMS does not? A big shoutout to this forum. It reminds me of a time long gone, before the world moved onto Facebook, where the Internet used to educate, which enabled dimwits like me to develop and deploy knowledge we wouldn't have normally had. I do see it in perspective. The batteries will get warm even if the BMS has no fault. You have already said your ambient can be 35 degrees regularly so you are not far off where the batteries should be limited to say 0.2C. Your inverter won't do that by itself. The BMS's I've seen tend to send settings to the inverter to limit current. As to whether your bms has the ability to limit current, I don't know. It may well just shut down when the batteries get too hot, but at what temperature. You've already had temperature problems on a big scale and I am looking at this from a safety perspective. What value you put on safety is your decision. Yes forums are great as is the internet and I've learnt a hell of a lot myself. But their is a lot of misinformation and you have to be able to sort out what is what. My son doesn't see the point in going to school and said he could just ask ChatGP for anything he needed. My reply was yes you can but you have to have the knowledge to know what it is telling you is a) feasible and then b) correct. I tried an AI bot the other day and it shocked me. The answers were often taken from a forum comment (not this one) and they weren't right!! Edited April 1 by Tinbum Quote Link to comment Share on other sites More sharing options...
Tinbum Posted April 1 Share Posted April 1 1 minute ago, Scorp007 said: Most lithium battery specs are save up to 55 deg C. Have never really looked at the Pylontech. Also the temp graphs were not as high as this. You have identified something very valid then. All I can say is LifePo4 are normally specced to 55 and the JK BMS has 2 temp probes. Cut of temp is set to any temp decided on. Also the reset temp is adjustable as well as the lower minimum temps for stopping discharge and release temp. It also has the MOSFETS temp setting to stop charging. The great plus is user selectable and can be viewed on the APP. Also switch ON OFF and BALANCE via the APP. I have some JK-BMS with the active balancers and they are indeed good. Quote Link to comment Share on other sites More sharing options...
Tinbum Posted April 1 Share Posted April 1 (edited) 24 minutes ago, tigger_na said: A technical question: The existing BMS has two largish heat sinks. The JK BMS recommended by @TaliaB is a closed box. Where are the heat sinks? And without heat sinks, I ASSume that the original BMS does something that the JK BMS does not? The case is the heatsink. Can you show a photo of your BMS then we may be able to identify it? Edited April 1 by Tinbum Quote Link to comment Share on other sites More sharing options...
Tinbum Posted April 1 Share Posted April 1 (edited) On 2024/03/28 at 2:21 PM, tigger_na said: You can see from your graphs that where the voltage is high the current is actually very low , as you would expect. Normally heat will be generated at high currents. Your temperature graph is not for the same time period- do you have one for the voltage / current period? Edited April 1 by Tinbum Quote Link to comment Share on other sites More sharing options...
tigger_na Posted April 1 Author Share Posted April 1 10 minutes ago, Tinbum said: Can you show a photo of your BMS then we may be able to identify it? Not without opening the battery case and destroying the guarantee all over again. I think the battery specs of 55°C max temperature are just something to get you worried about the whole setup going up in flames, not the lieftime of the battery being cut much shorter than it has to be. My temperature problem is sorted. We've had some cooler weather lately, but even before that I saw mcuh better values, after I installed my 7 fans. The issue now is a super-high bulk charging voltage, and, if I look at the readings, I have to wonder where the float voltage is in all of this. That nice voltage drop at the end is where I disconnected comms between inverter and battery. Let's see where this goes. Quote Link to comment Share on other sites More sharing options...
Tinbum Posted April 1 Share Posted April 1 (edited) 15 minutes ago, tigger_na said: I have to wonder where the float voltage is in all of this. My Pylontech shut off the inverter charging once at 100% SOC, so no float. (Float, absorbtion (and equalise) are terms really carried over from lead acid). Is this now a warrant replacement battery? If so I would go back to them and ask for your money back. It shouldn't be staying at that high a voltage for so long assuming its got to 100% SOC. Or ask for a firmware update. Is when the voltage drops only occurring when the battery is discharging? Edited April 1 by Tinbum Quote Link to comment Share on other sites More sharing options...
tigger_na Posted April 1 Author Share Posted April 1 It is a warranty replacement from my supplier, who gave me a EnerSol instead of the Akkutech I fried, or which fried itself, depending on how you look at it. The BMS does indeed report that the SOC is at 100%, so this shouldn't be happening. I can't return the battery now, since, yeah. And it doesn't really matter what I ask, these's only silence from EnerSol. Quote Link to comment Share on other sites More sharing options...
Tinbum Posted April 1 Share Posted April 1 (edited) 3 minutes ago, tigger_na said: It is a warranty replacement from my supplier, who gave me a EnerSol instead of the Akkutech I fried, or which fried itself, depending on how you look at it. The BMS does indeed report that the SOC is at 100%, so this shouldn't be happening. I can't return the battery now, since, yeah. And it doesn't really matter what I ask, these's only silence from EnerSol. So is it the same over voltage with 2 different types of batteries? This is my voltage for one of my sets. It stays at the high voltage for a few minutes only. They are now just sitting their waiting to be called to discharge. No charging no discharging. Edited April 1 by Tinbum Quote Link to comment Share on other sites More sharing options...
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