April 6, 20242 yr Good evening all, I purchased 2x100ah 12v lfp batteries around 8 months ago. They are connected in series with battery balancer for my 3kw system used in the visitors cottage. All is working well but have a concern about the 1 battery cell difference. Both where balanced up to a week ago when i noticed cell 1 was charging up faster than the other 3 cells and discharging faster. My system: *2 x 100ah 12v Revov batteries in series. *RCT 3kw 24v VMIII inverter. 4 x Seraphim SIV 460 Wp Mono Silver Frame Solar Panels. Below screen print of Bms. Help would be appreciated. Regards Derek.
April 7, 20242 yr 11 hours ago, Derek3 said: Good evening all, I purchased 2x100ah 12v lfp batteries around 8 months ago. They are connected in series with battery balancer for my 3kw system used in the visitors cottage. All is working well but have a concern about the 1 battery cell difference. Both where balanced up to a week ago when i noticed cell 1 was charging up faster than the other 3 cells and discharging faster. My system: *2 x 100ah 12v Revov batteries in series. *RCT 3kw 24v VMIII inverter. 4 x Seraphim SIV 460 Wp Mono Silver Frame Solar Panels. Below screen print of Bms. Help would be appreciated. Regards Derek. May be @TaliaB can give his view on this behaviour of cell 1. It does not look good.
April 7, 20242 yr 14 hours ago, Derek3 said: Both where balanced up to a week ago when i noticed cell 1 was charging up faster than the other 3 cells and discharging faster. What is your Bulk charge voltage (program 26) and float(27) set at. Cell 1 seems to be problamatic but the complete pack is out of wack. What you can try. 1. Go to Parameters in the Bms app then click on Balance settings then under Balance Method activate Static Equilibrium. 2. On the same page check the Equalization Voltage mine is set to 3.55V. You need to do this when the battery is fully charged and leave it for a few days without discharging. Otherwise this battery needs to be replaced under warranty. See screenshots for process.
April 7, 20242 yr Just something else I would do is the switch off the PV side. Use grid charging. Also in the settings no 11 on my inverter is to set the lowest charge rate. Most times while charging is taking place the balancer is trying to do it's work cannot while there is say 4-50 times more current coming in and charging the high cell than what the balanced can discharge. This will be BMS and balancer specific. One just needs to monitor it and keep the voltage high enough to keep balancing active. Another point would be what are the 2 x 12V battery voltages like.
April 7, 20242 yr Author Many thanks @TaliaBand @Scorp007 for the assistance. Sorry for the delayed reply. What an approvement to the balancing of the pack cells as i followed the procedure @TaliaBsuggested. I will leave it to balance for the next 2days or when the average is at or below 10mv. Below screen print of the balance. From 285mv to 30mv in 7hours. Again thanks guys.
April 7, 20242 yr Hi @Derek3 glad we could assist i would like to know what your absorption voltage(26) and float voltage(27) is set at on the Vm3 inverter as this could be part of your cell balance problem. I also see that cell 1 that was the highest is now the lowest it might indicate the cells was not matched or top balanced properly. Let see how it goes and @Scorp007asked what is the voltage diffrence between your 2 batteries if you could measure each battery and let us know. Also remember before you put the system back in service change back from static to charge balance.
April 9, 20242 yr Author On 2024/04/07 at 9:31 PM, TaliaB said: Hi @Derek3 glad we could assist i would like to know what your absorption voltage(26) and float voltage(27) is set at on the Vm3 inverter as this could be part of your cell balance problem. I also see that cell 1 that was the highest is now the lowest it might indicate the cells was not matched or top balanced properly. Let see how it goes and @Scorp007asked what is the voltage diffrence between your 2 batteries if you could measure each battery and let us know. Also remember before you put the system back in service change back from static to charge balance. My absorption voltage is 28.2v and float is 27.4v as per Revov specs 14.1v and 13.7v. Below nicely balanced pack, hope it stays that way. Again thanks guys @TaliaBand @Scorp007. The 2 batteries in series voltages is spot on and balancer between batteries is off. Battery 1=13.82v and battery 2= 13.84v half an hour after full charge. Cycled the batteries down to 50% and charged up to 100% then took the screen print below. Edited April 9, 20242 yr by Derek3
April 9, 20242 yr 7 minutes ago, Derek3 said: My absorption voltage is 28.2v and float is 27.4v as per Revov specs 14.1v and 13.7v. Below nicely balanced pack, hope it stays that way. Again thanks guys @TaliaBand @Scorp007. The 2 batteries in series voltages is spot on and balancer between batteries is off. Battery 1=13.82v and battery 2= 13.84v half an hour after full charge. Cycled the batteries down to 50% and charged up to 100% then took the screen print below. Good to read your results are as desired. Nice and balanced and they stayed that way after a discharge and recharge. For some reason I cannot see the picture included.
April 9, 20242 yr Author Just now, Scorp007 said: Good to read your results are as desired. Nice and balanced and they stayed that way after a discharge and recharge. For some reason I cannot see the picture included. Have very weak signal tonight just refresh and see again @Scorp007 i can see it on my side.
April 9, 20242 yr 8 minutes ago, Derek3 said: Have very weak signal tonight just refresh and see again @Scorp007 i can see it on my side. Good I can see it now. Could just be a weak signal on my side as I looked when moving to the furthest point from my router.
April 9, 20242 yr 23 minutes ago, Derek3 said: My absorption voltage is 28.2v and float is 27.4v as per Revov specs 14.1v and 13.7v. Below nicely balanced pack, hope it stays that way. Again thanks guys @TaliaBand @Scorp007. The 2 batteries in series voltages is spot on and balancer between batteries is off. Battery 1=13.82v and battery 2= 13.84v half an hour after full charge. Cycled the batteries down to 50% and charged up to 100% then took the screen print below. 🤞 Yeah looks good keep an eye out and see if it stays balanced.🤞
April 15, 20242 yr Author Good evening all, The Revov battery seems to be behaving. Now for a question relating to the graph on solar assistant. Why is the grid power so much higher than the load power when in utility mode(sbu). I am running essential load only on the 3kw inverter. See graph below from SA. Help would be highly appreciated.
April 15, 20242 yr 59 minutes ago, Derek3 said: Good evening all, The Revov battery seems to be behaving. Now for a question relating to the graph on solar assistant. Why is the grid power so much higher than the load power when in utility mode(sbu). I am running essential load only on the 3kw inverter. See graph below from SA. Help would be highly appreciated. I would say about 240W is used to charge the battery. The rest of the grid power is used to drive the load. One can see when the load is zero it uses about 240W from the grid. From this one can perhaps deduct 30W as the power is used to power the inverter itself.
April 15, 20242 yr Author 15 minutes ago, Scorp007 said: I would say about 240W is used to charge the battery. The rest of the grid power is used to drive the load. One can see when the load is zero it uses about 240W from the grid. From this one can perhaps deduct 30W as the power is used to power the inverter itself. Hi @Scorp007 initially i also thought that but i have solar only selected will only charge battery when solar is available will not charge from grid.
April 17, 20242 yr Author On 2024/04/15 at 10:34 PM, Derek3 said: Hi @Scorp007 initially i also thought that but i have solar only selected will only charge battery when solar is available will not charge from grid. Anyone that could explain the graph i am seeing where is the extra 250w grid power used by the inverter. It is clear on the battery power chart it is not used for battery charging. The grid power should ride close above the load power. What am i missing?
April 18, 20242 yr On 2024/04/17 at 4:07 PM, Derek3 said: Anyone that could explain the graph i am seeing where is the extra 250w grid power used by the inverter. It is clear on the battery power chart it is not used for battery charging. The grid power should ride close above the load power. What am i missing? While using a 3kW inverter that might not be able to measure and report the difference between W and VA as I have found on my 3kW Axpert I would follow the route of actually measuring Watts with a power meter and not a clamp meter. There can be a large difference between the 2 values depending on what the load is. Also worth your while to test the power meter against a grid power meter. This applies for the load and grid power values. This way one can be sure of the values seen. Edited April 18, 20242 yr by Scorp007
April 18, 20242 yr Author 47 minutes ago, Scorp007 said: While using a 3kW inverter that might not be able to measure and report the difference between W and VA as I have found on my 3kW Axpert I would follow the route of actually measuring Watts with a power meter and not a clamp meter. There can be a large difference between the 2 values depending on what the load is. Also worth your while to test the power meter against a grid power meter. This applies for the load and grid power values. This way one can be sure if the values seen. That is the only scenario that makes sense. What i will do i will disconnect the load and then connect a kettle or heater to the output of the inverter as this should then be watts and no reactive power present. Thanks for the suggestion i will try that as soon as my guests depart.
April 19, 20242 yr Author On 2024/04/06 at 9:12 PM, Derek3 said: My system: *2 x 100ah 12v Revov batteries in series. *RCT 3kw 24v VMIII inverter. 4 x Seraphim SIV 460 Wp Mono Silver Frame Solar Panels I want to add 3 x Svolt 24 v batteries in parallel with the existing 2 x Revov 100ah batteries to give me a total of 10 kwh. Then add 4 x Seraphim 460wp panels all in series 8S1P. The idea is to run off grid. The inverter is set to SBU work mode and solar only charging. Any problems you foresee doing it this way. Always grateful for your professional advice 😉
April 19, 20242 yr 3 hours ago, Derek3 said: I want to add 3 x Svolt 24 v batteries in parallel with the existing 2 x Revov 100ah batteries to give me a total of 10 kwh. Then add 4 x Seraphim 460wp panels all in series 8S1P. The idea is to run off grid. The inverter is set to SBU work mode and solar only charging. Any problems you foresee doing it this way. Always grateful for your professional advice 😉 The only problem I see is the Revov charges at a higher voltage so they might not charge to 100% when the SVolt is fully charged. Every 2 months I will just disconnect the SVolt and charge the Revov to 100% and keep it there for at least 24hrs in order to balance. I take it you not using comms to the batteries but voltage? Not professional advice but my own opinion.
April 19, 20242 yr 2 hours ago, Scorp007 said: The only problem I see is the Revov charges at a higher voltage so they might not charge to 100% when the SVolt is fully charged. Every 2 months I will just disconnect the SVolt and charge the Revov to 100% and keep it there for at least 24hrs in order to balance. I take it you not using comms to the batteries but voltage? Not professional advice but my own opinion. @Derek3 I have some experience with the Revov drop in batteries. The reason Revov states a higher absorption voltage(14.1) is due to the fact that the default setting on the bms for balance is set to 3.525v/ cell but this can be lowered via Bluetooth app to accommodate the Svolt absorption voltage. I have set the Revov 200ah to start balancing at 3.425v/cell and then schedule equalization once a month to bulk charge up to 3.5v/cell. The system on test is set to Bulk- 27.4V and float to 27.2v. Very little capacity above 3.5v/cell. Edited April 19, 20242 yr by TaliaB
April 19, 20242 yr 1 hour ago, TaliaB said: @Derek3 I have some experience with the Revov drop in batteries. The reason Revov states a higher absorption voltage(14.1) is due to the fact that the default setting on the bms for balance is set to 3.525v/ cell but this can be lowered via Bluetooth app to accommodate the Svolt absorption voltage. I have set the Revov 200ah to start balancing at 3.425v/cell and then schedule equalization once a month to bulk charge up to 3.5v/cell. The system on test is set to Bulk- 27.4V and float to 27.2v. Very little capacity above 3.5v/cell. Not knowing what settings are on the Bluetooth APP it is great for the guys in the know to help us out. Go for it @Derek3
April 19, 20242 yr Author 1 hour ago, Scorp007 said: Not knowing what settings are on the Bluetooth APP it is great for the guys in the know to help us out. Go for it @Derek3 Thanks so much guys is this below the balance voltage per cell am i at the right place? Equalization voltage?
April 19, 20242 yr 17 minutes ago, Derek3 said: Thanks so much guys is this below the balance voltage per cell am i at the right place? Equalization voltage? Yep right place change 3550mv to 3525mv see procedure below. Also SVolt 24v 106ah manufacturers charge voltage. Change Balance Method to "Charge Balance"
April 27, 20242 yr Author On 2024/04/19 at 7:23 AM, Derek3 said: I want to add 3 x Svolt 24 v batteries in parallel with the existing 2 x Revov 100ah batteries to give me a total of 10 kwh. Then add 4 x Seraphim 460wp panels all in series 8S1P. The idea is to run off grid. The inverter is set to SBU work mode and solar only charging. Any problems you foresee doing it this way. Always grateful for your professional advice 😉 Good evening all, Received the 4 x Seraphim 460wp panels and the 3 x 24v 106ah Svolt batteries today, so Monday i will add the panels and batteries and see how it goes. Also got 2 x Victron 250A 4p busbars and 4 x 150A mega fuses for each batt pos to the busbar. Existing fuse disconnect between batt and inverter. Have a great evening.
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