ojeysky

What would you like to know? Maybe you indicate your components and I will confirm if I have them or not

Yup

Cool, I have just gotten a BMV 712 as well, will be installing that soon.

My 200AH battery pack was coupled by a local seller, he has prismatic cells and Daly BMS in it. How are you checking the state of charge?

I just had grid last week after almost a year of no-grid, but behaviour is still the same. As I understand it, "back to grid" is only useful when you are connected to grid and your battery is charging via solar. If at some point battery voltage dips to BTG voltage then it starts charging via grid. I don't think that have any effect on the float bug. Apart from the voltage spikes, I noticed my battery does not discharge below 25v before BMS kicks in, I think that is probably a cell balancing issue unique to my battery.

I use 28.2/27.2 bulk/float

When charging, the battery voltage displayed on the inverter is more than what is measured on the battery terminals. Usually between 0.2 and 0.5v When discharging the battery voltage on the inverter is less than what is measured on the battery terminals. Usually between 0.1 and 0.3v

Did you eventually resolve this? Am lockdown so can't get battery bank to seller, will like to see if I can balance from my end. Am considering floating at 28.2v overnight while on utility to see if the BMS will be able to balance up the cells.

My setup is similar to yours (though mine is an already coupled 5.4kwh Lifepo4 with BMS) but it behaves similar to yours. I think mine is because the cells are unbalanced and will be sending it back to the seller to fix. One way to test this is for you to attempt to discharge the battery and see if the BMS trips at higher voltage (mine tripped at around 25v which wasn't normal) That said, am considering a DIY to increase my bank capacity, and gathering the ingredients, yet to decide on the BMS to use, are you able to see/manage individual cells with the Daly BMS? Regards

While I still figure out how to setup Node-RED on my RaspberryPi, I do have a tool that I use to change float/bulk settings (it's called solpiplog). However I have reduced and increased the voltage before without the reset, until I restarted the inverter.

@weber so am back on the float bug workaround....tweaking the max charge settings either gets me to early float or continuous bulk (thereby ending up with not eventually having a well charged battery by sunset). So i remove max charge limit and today when i got an early float, i restarted the inverter and the system boot back into bulk mode which was great. The question now is whether there is a way to reset the inverter charging algorithm without having to restart the inverter?

Lol..... Yes resistors/wire guage 😀

I intend to do exactly this but @weber suggests that paralleling old Lifepo4 batteries with a new one will kill the batteries. Have you done this before and what was your experience?

Thanks @weber I had thought the negative effect of paralleling batteries is much lesser with lithium compared to lead acids. From your comment it seem even if I get a new 200Ah lithium to add to my existing 200Ah lithium, I will still have a challenge. About a real life scenario, LFPs are quite pricy and for a battery that will last 5 to 10 years, it's natural the power needs may increase within the same period hence the need to increase battery bank. If one will need to decommission existing bank and get all new cells of total capacity needed then that will significantly increase the overall cost of LFPs.

So far i still get bounces between 28.4 and 27.6v though not as much as before, i guess that was because i usually reduce the charging rate once the initial charge drops to zero. I also tried to deplete the battery and noticed the BMS kicked at 25v so i am guessing that would explain the possible cell imbalance that you were referring to. I am going to be having it checked by the seller. Meanwhile i am intending to increase my capacity and found a good deal of unit cells, but they are 150Ah, will there be any major issue if i parallel a 150Ah lithium with 200ah , and both of them are 24v?

I think it will be 38hours versus 12hours since we should be working with a 48v Lead Acid as well, though it still does not remove the fact that lithium is much better and preferred. I have been using lithium for a month now and can say the experience is quite better....just like you noted, it reacts better to high load (high current draw)

It should be up now, and yes I see battery voltage but the inverter does not report battery current Cool that's good to know Perhaps mine is patched "to some extent" because I hit float as fast as few minutes after sunset and my voltage is still at 26.3v by then. You can look at my dashboard here Earlier shared the battery voltage log. I do not have that of current but I do log charge current which can be found in the URL I earlier shared if that helps

Hello, so far so good with LFP. I like to get clarification about a behaviour I have observed. Here is the link to my battery voltage log. Between 2pm and 4pm I noticed that the battery voltage would spike up to 28.3v and then come down almost within few minutes to around 27v... This happened for quite a while. Is this a normal behaviour? Perhaps the BMS was trying to balance up the battery or is this a symptom that I should be worried about?

Oh my bad....sorry about the confusion created

It's documented on the GK manual. The error is due to lack of communication between remote display and inverter. I have no idea what caused it. I reached out to MPP staff since it's still within warranty. They will be sending me replacement boards for the remote/com display (at my own shipping cost). Hopefully that resolves the problem.

It was quite sunny today and I didn't hit float all through the day. Do you think I should still change the charge current to 30A or I should just maintain the 40A currently set? I will look for it. Though I bought the inverter to serve as stop gap while I receive replacement part for my PIP-3024GK which suddenly threw up error 32. I know the float bug affects that as well, do you by chance have the patch for those? as it will be useful when I finally get to put my GK back online. Edit: It's almost 6pm and now the inverter has a float indicator. Thanks @weber

@weber here is my battery charge current log, and here is my PV harvest log. I started using LFP in the last 3 weeks, so you may only correlated figures within the last 2-3 weeks

It's an Axpert variant(clone?) specifically felicity IVCM3024 here is the link to the inverter. Will I still be able to do the update? Noted with thanks I am off-grid so i may not be able to always ensure that charge current remains high as it depends on the weather condition but my PV array(2.25kw) on a sunny day does up to 50A Okay I have set the max charge to 40A Settings 02 was on default of 60A but i have just changed it to 40A. Settings 11 is at default of 30A but its not applicable as i am offgrid Done and i have reduced the float to 26.9v as well This is not applicable I only have one 200AH Thanks a lot for the support @weber

I think my challenge is similar to this and it seem my LFP battery is not getting well charged. How do i work around this? my current settings is now 27.8/27.6 (bulk/float)

Thanks @Coulomb but what i have noticed is that once it gets to 27.6v on the inverter after a while the battery voltage drops to 26.9 and the inverter float status gets indicated and it does not leave float thereafter and charging current goes to zero. I am concerned that it seem my battery is not getting adequately charged (i like it to be up to 90% full). I have just tweaked the settings to 27.8v for both bulk and float and now the battery voltage indicator on the battery stays between 27.4 to 27.6v even though the voltage reading on the inverter is between 27.6v and 27.8v. It seem there is si 0.2/0.3v difference between the meter on the inverter and that of the battery Is my new settings of 27.8v(bulk and float) still fine or will i be killing my battery earlier than latter? If i disconnect the charging source, battery voltage drops rapidly from 27.6 to 26.6 hence it seem i am yet to achieve a 90% charge on my cells?