Hardekool Posted February 23, 2021 Posted February 23, 2021 Good day everyone, Recently had a 10kw system installed by Romic Consulting. They used 2x RCT 5kw inverters with 2x Narada 48NPFC100 batteries. They had the inverters in parallel setup but had each inverter charge it's own battery. Started getting a fault code 72 which after checking everything and getting info online realized the batteries also had to be in parallel. They came out and connected the batteries in parallel (Why they did not do it from the beginning is a mystery?). After the first night in the parallel setup (completely off grid with the system, no connection to eskom) the one battery showed 0% SOC and the other 50% SOC on the batteries LED indicator the next morning. Why? Shouldn't they be on the same SOC because of the parallel setup? So my question is, does the batteries need to be connected to each other with a BMS cable to communicate their SOC and balance effectively? If so, what is the correct way to do it. As there is hardly any info on Narada batteries online and the manual isn't exactly 100% clear on the correct procedures. Quote
excitedphoton Posted February 24, 2021 Posted February 24, 2021 Does Romic Consulting not know? Surely the installer, and presumably supplier, of your solar equipment should know what's going on? Please post some pictures of how they connected the system in parallel. Quote
Hardekool Posted February 24, 2021 Author Posted February 24, 2021 Their technicians are clueless! And to get them to come out to site.....don't even want to go there. That's why I joined this forum to get help from people that actually know what's going on and guide me in the right direction. Will upload pics now. **Update** Today at about 7am (second morning after they connected batteries in parallel) the one battery would show 50% SOC and the other 0% SOC with no LED indicators on (according to the battery manual this means the battery went into Dormant Stage). Then after about 3mins the battery that had no LED indicators on would then all of a sudden show 50% SOC and the other one then had no LED indicators on. They alternated between this states a few times until I decided to reset batteries and the inverters. This is confusing the heck out of me.... Quote
Kalahari Meerkat Posted February 24, 2021 Posted February 24, 2021 So, looking at the piccies, both inverters are trying to charge//discharge the batteries, but no actual DMS comms between batteries and inverters exist... that seems dumb to me, also, if you *actually* need 10kW peak power, I'd say that you should probably have 2 batteries per inverter and no DC interconnect between the inverters, but certainly BMS's from the batteries talking to the inverters. Based on the last piccie, is the left hand battery claiming 0% SOC? its got the shortest cable and would probably be required to deliver more of the power... Quote
Hardekool Posted February 24, 2021 Author Posted February 24, 2021 We would never require 10kw peak power. Maybe 5-6kw max. The inverters are setup in parallel mode and connected to each other with their parallel communication cables & current sharing cables. I've tried to get information on the internet to determine if it's possible to have the inverters connected to the batteries with a communication cable....no luck with that so far. The only way the inverters can determine the SOC of the batteries at the moment is through the charging/discharging cables, and ja that is quite unreliable I reckon. 14 minutes ago, Kalahari Meerkat said: Based on the last piccie, is the left hand battery claiming 0% SOC? It's at 50-75% SOC based on the LED indicators according to the manual supplied. It really is a pain in the butt to get info on the Narada batteries. Tried to get in touch with them directly, but seems only the suppliers can make contact with them and hopefully get any info. The only communication ports the inverters have are 1x RS-232 and 1x usb port. The batteries have 1x RS-232 and 2x RS-485 ports. I have connected the batteries to each other with the supplied RS-485 cable according to the manual, but there is no effective way of telling if they are indeed communicating to each other....if that would help the situation at all?? Here is a link to a supplier where the battery manual can be downloaded. (Bigger than 3mb, so cannot attach sorry): https://suministrosdelsol.com/en/lithium-batteries/869-bateria-litio-narada-48npfc100-48v-de-48kwh-.html Quote
Kalahari Meerkat Posted February 24, 2021 Posted February 24, 2021 1 hour ago, Hardekool said: We would never require 10kw peak power. Maybe 5-6kw max. I would have suggested a Sunsynk 8kW or 2 Sunsynk 5kW units... don't know the Axpert, but the Narada spec sheet says the battery has RS232 and 2 X RS485 ports, so , presumably you'd plug the RS485 from the 1st battery into the 1st inverter and the 2nd battery's RS485 into the 1st battery, not sure about how the power is paralleled up between the inverters, presumably one would need to also plug the RS485 from the 2nd battery into the 2nd inverter, but which inverter charges both batteries? etc. that setup could get interesting. Also I'm assuming the inverters have RS485 for BMS connection to them... Quote
CCSA10 Posted February 11, 2022 Posted February 11, 2022 I cannot really see clearly, but it looks like your dip switches are not correct. the "master" must be set to 0000 and the "slave" to 1000. Then you use the cable that came with to connect the 2 batteries to each other using the RS485 ports. I have 3 x Narada Batteries and they work well together. Load Balancing and all that. Another thing, I would take positive off the one battery and negative off the other. Then of course also connect them in parallel. Quote
Beat Posted February 14, 2022 Posted February 14, 2022 (edited) I strongly suspect the problem lies with the BMSs. Parallel tied battery packs as required by the Voltronic manual, physically cannot have significantly different SOC, assuming all cells are in good condition on new batteries. They equalize themselves without help from BMS. The fact that the troubling displays alternate between the BMSs confirms it. Imagine two tanks of water interconnected on the bottom with each other with a good size pipe. If the level indicators on each tank show different levels you know they are wrong. In my opinion the supplier should exchange the batteries under guarantee. Edited February 14, 2022 by Beat Quote
Frik Abek Posted February 10, 2023 Posted February 10, 2023 On 2021/02/24 at 11:07 AM, Kalahari Meerkat said: So, looking at the piccies, both inverters are trying to charge//discharge the batteries, but no actual DMS comms between batteries and inverters exist... that seems dumb to me, also, if you *actually* need 10kW peak power, I'd say that you should probably have 2 batteries per inverter and no DC interconnect between the inverters, but certainly BMS's from the batteries talking to the inverters. Based on the last piccie, is the left hand battery claiming 0% SOC? its got the shortest cable and would probably be required to deliver more of the power... Quote
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