gertc

Chris, what is a battery balancer?

Thanks. Will try this tomorrow morning when the reading is closer to 70%. I do not have the midpoint reading installed, but are thinking of doing it now.

Hi all My system is about 3 months old with the following specs: - 3x 5 KVA Axpert inverters in parallel, 48v system - 840 ah battery bank (Sonic Gel batteries) - 7 KW solar panels I use AICC to monitor and record the system together with a BMV 702 battery meter. I have set the inverters to go to grid on 44v and back to batteries to 46v, both the lowest possible settings, with the idea that AICC will control the system and kick over to grid at 55% SoC. What worries me is that the inverters kicks over to grid at between 65-70% SoC. Compared to what I remember just after installation, the battery voltage much faster from the 54v fully charged state. Today, as an expample, I let the house run on grid and charged the batteries with solar energy to 100% (it went through both the bulk and absorption phases). But right now the BMV shows 99.2%, the current load is 867w / 17.3 amps and the battery voltage already shows as 50v. Should I be worried?

Thanks all for the help. I set my back to grid setting to the lowest possible (48v) and now it responds immediately.

Hi Viper Batteries are 800ah. So if I understand you correctly I should set setting 13 to a lower voltage? Any suggestions?

Jaco, In this case the inverters went to grid when the SoC dropped to below 50% juts after sunrise (07:00). The PV output was not big enough yet at that moment, but shortly afterwards it was more than enough to power the house and recharge the batteries. I saw this and tried to manually change the inverters to go back to battery and also tried to change the setting in AICC to go back to battery mode at 60%. Eventually it went back to battery mode around 11:00 when the batteries were almost full again. Battery settings are at 44v (setting 12) and 54v (setting 13). I attach the AICC graph to illustrate the situation.

Thanks. Which setting are you referring to for solar only?

Hi all I have 3 Axpert 5 kva inverters in parallel with a BMV702 battery monitor. I use AICC software to monitor and control them. On the odd occasion the SoC dips below 50% and AICC switches the inverters to grid. But for some reason I cannot them switch them back to Battery mode. I have tried to change the settings in AICC, click on the manual battery mode button but all without luck. Is there a way to force the axpert (on the inverter itself) to go back to battery mode? Thanks!

Thanks all @Chris - it is only the one CB that trips For now I am guessing that it is a faulty CB which I will get the installer to replace. I will also check the combiner boxes with him. Thanks again for the help and will post back once resolved.

Thanks for all the quick and detailed responses! To all: - Apologies, I made a mistake on the voltages (getting older so the memory is not that good). I am looking at it now and (for one set of 3x3) the voltages are around 78v with reported amps of 33 amps and 1715 watts. So given Chris' explanation the real amps are around 22 which makes senses. Apologies again about the incorrect voltage readings. - So the question remains - why do the circuit breakers trip? Some further information as requested - Circuit breakers are Noark Ex8BP-N K 40A (photo attached) - Installation was done about a month ago by an installer - Only one of the strings trip (but that string also produces slightly higher watts) - but I guess that this points to something wrong with that string or breaker - One other thing to note - initially the installer made a mistake and setup one string as 4 x 3 and another as 2x3, instead of both as 3x3. So this of course resulted in higher amps that tripped the circuit breaker (although it should have still been under 40 amps). Although this has been corrected now, it is still this string that causes the problems @viper_za: pardon my ignorance but what is a combiner box? @TTT - the panels are fairly new (1 month old) but I will get on the roof this afternoon and check. But all 3 strings are producing roughly the same watts / amps / volts - so seems a bit less likely that all 3 strings will have a faulty panel Thanks a lot for the help! Gert

Hi all Would appreciate your help on this. My setup: 3 Axpert 5 Kva inverters in parallel 27 Yingli 260 Watt panels (3 sets, a set for each inverter, of 3 series by 3 parallel) 800 ah Gel batteries @ 48v The Yingli panels' spec at 1000 w/m2 solar radiation: - Voltage at maximum power = 30.3 - Current at maximum power = 8.59 - Open circuit voltage = 37.8 - Short circuit current = 9.09 What happens during the peak sunshine hours of the day, when the panels are reaching their max output is that current climbs to over 12 amps (40 amps per set of 9 panels) while the volts stay well below their max, at around 20 volts (60 volts per string). When the solar radiation and resulting power output is lower, the volts are between 25-30 volts, but as the solar radiation increases the volts drop and the amps increases above the max. Overall the power output in Watt is still close to spec, but the amps and volts are not what I expect. This in turn causes issues with the 40 amp circuit breakers I have for each set of solar panels, causing them to trip in the middle of the day. Would appreciate any help PS Yingli panel specs attached - I have the 260 Watt panels DS_YGE60Cell-29b_35mm_EN_v04.pdf

Thanks - fixed it.

Thanks - appreciate everybody's help. In summary, for future readers of this post, the Axpert went into line mode in the morning if the battery SOC was too low. I am not quite sure what the formula is that it uses, but it happens even if the battery volts are above the 'back to grid' setting (46v in my case). My solution was to use jdp's software with a Victron BMV 702 battery meter to more intelligently manage the batteries. Next step will be home automation integration to also manage the load.

jdp - in AICC is there a reason that I cannot use both the time and SOC setting to change the mode, i.e. between 5pm and 8pm and otherwise when reaching 50%?

Thanks Gustavo Appreciated the feedback - I will try the settings on 12 & 13. On 26 & 27 - I have Sonic Gel batteries and if I look at their manual and it seems like these are the values for their cycle and and float values - any reason why you are suggesting different values here?