Ed S

@meetyg So glad I found this thread! I have pretty much the exact same inverter, it's just an Esener which is a rebranded Must in my opinion, model number is pretty much the same, ES-3024VPM. I am experiencing the exact same thing after moving to a LifePO4 battery when my lead acids died. I am indeed also using the Li battery type as instructed by the sticker on the inverter, and I am also seeing what you describe with the Utility/mains charger. After discharging the battery and putting in back into charge, the voltage will eventually go to the float voltage(mine is set to 27.2V) and will sit there for a while before moving up to the bulk voltage, mine set at 28.4V for now(I'm still toying with the voltages, more on that later) The issue, mine just seems to sit at the bulk voltage when reached, when charging with Utility. It does not come back down to the float/resting voltage. I don't know if this is by design, as the battery's bms will stop charging when the battery is full, but my concern is leaving the battery at that voltage? Also not sure if the battery's bms internally will perhaps go a resting voltage, which if so, I guess it's ok? Because once the battery is fully charged from Utility, and when measuring the voltage at the terminals with a multimeter, I only see fluctuations of small voltages constantly jumping around all over the place, i.e, 1.2, 0.6, 3.4 etc.. . I would hazard a guess as to say that's probably the BMS being shut off from charging and perhaps just balancing the cells? If I drop the bulk voltage lower to say 27.2V, I get a static voltage reading at the terminals. BUT, with PV, it seems to be charging as expected. When discharging and letting it recharge, it will again reach the float voltage first as pointed out earlier in this thread, will sit there for a while, move on to bulk voltage, and eventually comes back down to the resting voltage(float voltage setting) of 27.2V. My inverter readings versus actual at the terminals also differs by 0.4v on Utility, and about 0.2v-0.3v on PV, i.e. inverter at 28.0V actually means 27.6V at the battery and so on. So you can see what a tricky balance it is to reach a compromise with the charge voltages when charging from Utility vs charging from PV.. Other people who do not have the Li battery type on slightly older Axpert inverters for example, are happily using the USE mode with float and bulk set to the same i.e. 27.6 with no issues. (Thanks @Flouw and @GMAC) I just want to understand why this behaviour occurs with the LI battery type mode, when charging with Utility where the battery voltage stays in the Bulk setting and not coming down to the float value.. (I've even left overnight and was the same the next morning until PV takes over.)

Thanks @Flouw I'll look into the smart shunt and solar assist guides. How did you connect the Smart Shunt into the Pi? Just USB? Are you using CSO as charge source priority? Actually, would you mind sharing your settings with me? Just the important ones like Source priority(SBU, SOL etc), charger source priority, back to grid voltage setting, back to solar/battery voltage setting, cut-off voltage etc Many thanks

@Flouw Thanks for your reply! Good to know the Esener has an active balancer! Big plus 1.) Do you use the "USE" battery type? 2.) How do you go through the night with only a 2.56kwh battery? What is your base load at night? 3.) What's the reason for setting float the same as bulk? To overcome the float bug? Is it fine to float at 27.6(3.45V per cell) when resting voltage is said to be 27.2V(3.4V per cell) @GMAC Thanks, I have tried the Li mode, but when in that mode, it seems to stay at the bulk voltage despite the battery being fully charged, it does not honour the setting for float and does not come down to that voltage, i.e. bulk set at 28V for example, float set to 27.2V. It will just stay at 28V on in the inverter. I know the battery's BMS will cut current and stop charging when full, but is it safe for it to just hang at 28V?? Thanks again all, tricky business this!

Thanks for the reply I don't have the timed bulk charge function on mine, but do have the Equalisation feature which can be run periodically according to a set schedule. Is it safe to run that with these lithium batteries? Just to ensure that the BMS balances the cells from time to time.. I do have an app for mine where I can monitor and even set certain parameters, strangely I can't set voltages remotely, only source and charger priorities(and a bunch of other things I don't want to mess with) How are you cycling your battery? Do you run off solar and when PV fades you use the battery until a certain cut-off point? What if load shedding gets in the way, and not leaving enough capacity to get through a load shedding schedule? Also, what made you decide on running bulk and float at the same voltage?

What is your battery type set to in your inverter settings? On my Esener, I do have a "Li" mode(lithium) and the manual encourages to set it to that when using a lithium battery. However, the problem with this mode, is that the inverter will ALWAYS stay at the set bulk charge voltage and won't ever come down to float, it's as if it ignores the float voltage setting altogether. Note that my inverter does not have comms for BMS, nor does my battery. I have since been advised to use "USE" after which it does indeed come down to float voltage(aka resting voltage for lithium, as it won't trickle charge like it does with lead acids). If using the "Li" mode, would it be safe to set the bulk and float at the same voltage? I'm just worried that with "USE" mode it is a charging profile more aimed at lead acid batteries, and wonder if the charging algorithm could have an adverse effect on the lithium iron phosphate battery? Many thanks!

Thanks very much! It sounds like that is a good compromise :)

Hi all, I have this same Esener 25.6v lithium battery paired with a 3KW Esener inverter(a MUST rebrand it seems) anyway, seems there is a lot of variance in the recommended bulk and float voltages. I purchased mine from GeeWiz - Esener 25.6V 2.56kWh 100Ah Lifepo4 Lithium Wall Mount Battery - GeeWiz, and on that page it specifies the following recommended voltages, which according to them came from the manufacturer: Recommended User Settings When using a Esener Inverter • Bulk Voltage 29.2V • Float Voltage 27.3V • Cut-off Voltage 20V versus what the manual says: • Bulk Voltage 27.6V-28.4 • Float Voltage 26.4V-27.2V • Cut-off Voltage 22V I am mega confused as to what to use and don't want to damage the battery!? Which ones are right? Also, do you guys also notice a discrepancy between the battery voltage reading on the inverter versus at the battery terminals? Thanks in advance