October 18, 20223 yr I just need some advice on the panels, I got 21x250W panels on the roof, is there a way to ad higher output panels combined with the existing panels. regards
October 18, 20223 yr You didn't specify how many MPPTs you have,or inverters/or batteries,so i'll assume what you have is full and you have a battery/bank If that's the case,you need to either 1) upgrade/parallel the inverter to allow extra string(s) 2) Replace 1/all string of panels with upgraded ones 3) Add a busbar,extra charge controller and join the new set of panels/old set to this to charge the batteries direct You can probably find a buyer for your used panels easy enough should you want to start replacing
October 18, 20223 yr Author Thanx, Used to have 12x 200ah led acid gel batteries, but they just don’t last, with 2x Axpert 5kva inverters. I am replacing the inverters with a 8 kva Sunsynk inverter and 3x5,1Kwa lithium batteries, maybe a fourth one. But it is getting very expensive by changing the panels as well
October 18, 20223 yr The Axperts can't be that bad necessarily? 1/2 MPPT per inverter? You would get some cost on the panels back by selling and upgrading some rather than convoluting by adding extra cost for a MPPT and busbar setup + new panels
October 18, 20223 yr On the other hand, if you're getting the 8kW Sunsynk, you wouldn't necessarily have to sell your 250W panels. Just looking at the PV input specs: PV String Input Data Max. DC Input Power (W): 10400W. PV input Voltage (V): 370V (100V-500V). MPPT Range (V): 125-425V. Start-up Voltage (V): 150V. PV Input Current (A): 22A + 22A. No. of MPPT Trackers: 2 No. of Strings Per MPPT Tracker: 2+2. If you've got 21 x 250W panels already in place, why don't you combine 2 strings of 10 panels in parallel on one of the MPPT's? Assuming your panels are oriented in the same direction. Okay, that way there's one panel left over that you can sell, but if you're anywhere near PE I'll gladly take it off your hands for a fair price. With this solution you will have installed 5000W out of the maximum input of 10400W that the inverter can handle, but you've still got the second MPPT free to install another 5kW or so of whatever other higher-output panels you want. Assuming you've got panels with a Voltage (open-circuit) of around 38V, Vmax around 30V and 8-9A max current, I think you should be safe, but let it be checked out by whichever installer you've got lined up. Edited October 18, 20223 yr by GreenFields
October 18, 20223 yr 2 hours ago, GreenFields said: On the other hand, if you're getting the 8kW Sunsynk, you wouldn't necessarily have to sell your 250W panels. No. of MPPT Trackers: 2 No. of Strings Per MPPT Tracker: 2+2. Good catch,just confirm the voltages on the panels and party hard!
October 19, 20223 yr @Peet Welthagen why are you replacing your axperts? If you don't mind me asking? Edited October 19, 20223 yr by MKRandburg wrong word
October 19, 20223 yr Author I was told, that the canbus, on the 16 cell lithium batteries and the Sunsynk management system, work better together. Hopefully I will get better service from the new system. It is the second time in 5 years that I need to replace the batteries.
October 19, 20223 yr 1 hour ago, Peet Welthagen said: I was told, that the canbus, on the 16 cell lithium batteries and the Sunsynk management system, work better together. Hopefully I will get better service from the new system. It is the second time in 5 years that I need to replace the batteries. Surely lots of people must be successfully running lithium ion batteries on Axperts using the voltage parameters, and the expected lifespan should still be much higher than for the previous lead acid batteries. Just not sure if that is the right reason to be replacing inverters if they are perfectly functional and serving your needs. The lead acid is just a technology with a lower expected lifespan, and that's not the fault of the inverter.
October 19, 20223 yr 1 hour ago, Peet Welthagen said: I was told, that the canbus, on the 16 cell lithium batteries and the Sunsynk management system, work better together. Hopefully I will get better service from the new system. It is the second time in 5 years that I need to replace the batteries. Not to discount the advice,but this does sound kind of like "Buying a new car because the old one's tyres are old" Better inverters can squeeze a bit more out or read more accurately,or have better apps,but if your sole reason is batteries that's not a good reason to upgrade I'm also running dual Axperts on Voltage-mode with Hubble batteries in a bank,so not a dissimilar architecture to the suggestion above
October 19, 20223 yr 22 hours ago, Peet Welthagen said: Thanx a lot, I appreciate the advice and help a lot👍👏👏 Great advice from @GreenFields No need to change the panels. Even if 1 MPPT is working at say 18A instead of the 22A maximum it is a major saving retaining those 250W panels. There will always be someone interested in the 21st panel. Also although newer inverters have a lot more bells and whistles and extract more energy I would also not change the working Axperts just to get comms to work. Although voltage settings don't work as well with lithium I am also using lithiums this way and works well for me. There might just be a bit of estimated SOC instead of getting the exact %.
October 20, 20223 yr 22 hours ago, Peet Welthagen said: I was told, that the canbus, on the 16 cell lithium batteries and the Sunsynk management system, work better together. Hopefully I will get better service from the new system. It is the second time in 5 years that I need to replace the batteries. It might be worth checking if your inverters suffer from the premature float bug, that might be your problem if batteries are not lasting. If that is your problem there are various workarounds before replacing them completely.
October 20, 20223 yr 21 hours ago, GreenFields said: Surely lots of people must be successfully running lithium ion batteries on Axperts using the voltage parameters, and the expected lifespan should still be much higher than for the previous lead acid batteries. Just not sure if that is the right reason to be replacing inverters if they are perfectly functional and serving your needs. The lead acid is just a technology with a lower expected lifespan, and that's not the fault of the inverter. My 2 cents, I am running the Hubble AM-4 with the RCT VMIII (Axpert) using the cloudlink the battery BMS passes the data to the inverter via the CAN conversion in the cloudlink. The inveter is set to "user" under the battery type selection - some screen shots below: Spoke to Hubble tech support they confirmed that all is good!
October 22, 20223 yr Author Thank you Drew, I have bite he bullet and change the batteries and the inverter. Enormous costs😢😢😢
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