jetlee

Awesome, got it now .. thx

Hey, can you please elaborate on that current calculation with an example .. its not making sense to me ? I assume this could be negative (discharging) or positive (charging) ? But I cant follow your logic ? Thx

The inverter will surge to utility, in short tests, I have seen it go to 8kw.. I haven't tried much higher than that, and do not intend to. It moans a bit by beeping, but it will do it. I feel like we are debating semantics though. My inverter very seldom even gets to 3.5kw, and if it does, its there for a few seconds and then back to a regular load of around 500w. My statement is really just, that while the inverter is under 5kw (its rated load), it SHOULD be able to handle switching between solar / utility / batt without asking the battery for more than 100A, which it appears is not 100% the case.

Thanks Ill give a firmware update a bash, and monitor for a bit. I was hopeful this was a more common problem with a simpler solution like an inverter setting, but it appears a new battery will be in my near future.

Thanks for this. I just want to comment here. I am not off-grid, I (mostly) have a grid (bar loadshedding, which is not when I am experiencing this problem). In the event that I have a utility failure, I agree 100%, the inverter must supply, and should the demand exceed the 100A limit on the battery, yes, I expect a trip or some sort of drama. But, my expectation when utility is available is not the same, and perhaps this is where I am off with my expectation. If I have a fully functional grid, my expectation is that when the inverter is asked for more than its rated power (5kw / 100A at 48v), it should ask from utility, not try to pull the additional load from the battery, and that switch should be handled gracefully.

awesome, glad its working .. good luck

I feel like maybe I havent been very clear, so just to be super clear.. I am not exceeding the 100A draw .. I havent ever gone over about 60A according to my logs. BUt when the inverter switches between battery / utility / solar, its sometimes going into protection mode with a short circuit protection, which I am assuming is due to the capacitors suddenly requiring current when switching. I just want it to be clear, that I am not getting close to 100A yet .. but once or twice a day, even at lowish loads, I can see the battery behave as if it detects a short. No need to answer if thats been understood, I just got the feeling from the replies that there was an assumption that I was getting over the 100A limit on occasion

I used an old straight through cable, and it was wired as follows Orange (pin 2) -> A / D+ Green and White (pin 3) -> B / D-

I didnt search for the files, when it was unrecognized, I just told it to search online for a driver and it installed no problem

OK, had a minute so git my wife to release her laptop driver : ftdi (2.12.36.4) (2021/07/05) driver files ftser2k.sys, serenum.sys, ftcserco.dll, ftserui2.dll worked fine with my batt, did a quick software connect to be sure Hope that helps

Just as an FYI, my linux machine sees it as "Future Technology Devices International, Ltd FT232 Serial (UART) IC"

LOL .. isnt that amazing .. TBH I dont use windows, except for the Narada software .. and thats inside a VM .. My current setup is ubuntu 22 desktop -> virtualbox windows 10 vm with serial passthrough -> Narada software = working Also working, is ubuntu desktop -> cutecom direct to battery .. The other adaptor I had was not a usb -> rs485, it was serial -> rs485, so not the same .. If you like, I can plug it into my wifes windows 10 laptop and run some tests and feed back when I get a gap on the weekend, but the adaptor def works via linux

Just a note for anyone who finds there way here and has a similar problem with the Narada and the older (5KW) Axperts. The error I was getting was the BMS going into short circuit protection. This is most likely due to the instantaneous current draw when switching powers source if the capacitors discharge slightly. So .. running a single Narada is a bit hit and miss it seems .. probably going to order a second one to get it going properly

Sure .. bought this one https://www.robotics.org.za/RS485-MINI , all the others I found were like 300 rand plus, this one with shipping (95 rand in SA) was still cheaper even with ludicrously expensive (proportionally) shipping .. Hooked up to a homemade RJ45 .. Good luck

Hi Coulomb Thanks for the advice, I have read MANY of your responses on this forum, and appreciate that you took the time to reply, I'm sure you spend many hours helping people on this forum. I have a follow up question / comment that could use some clarity. I have yet to update my firmware (current - 74.31) and I know there is an updated version (if I recall 74.40 with the lithium slant), I assume that has no extra bits to soften the cutover? Additionally, there are no settings I can tweak to force the capacitors to stay "more charged" when switching back to battery? This is a little frustrating when I spent 4 years running flawlessly on 100ah of AGM, and after spending the cash, now need to spend more .. so just trying to exhaust as many options as possible, before selling my soul for another Narada 😉 Again, thanks for your reply

Hi All I have been having some intermittent trouble with my migration from AGM to lithium. I have recently purchased a single Narada 48npfc100 to run on a quietish Axpert 5kw inverter that powers my home along with 2kw of canadian solar panels. The new lithium battery has been going into protection (short circuit by my recent investigations .. thanks rs485) a few times a day, which due to my model of inverter, results in a power outage in my home, till I restart the batteries with an AGM 48v jump start to the inverter. I manage my loads with a homebrewed raspberry pi app that I wrote that monitors the inverter over serial, and turns off loads like my heat pump and pool pump if my inverter use goes over 2.5kw, so it VERY rarely exceeds 3.5kw and if so, only for seconds at a time and this sends the draw back to utility for a few minutes until the offending kettle or iron use is over. So I suspect, unless I can find a way to limit the current draw to 100A, the intermittent ms surges, will continue to drive me mad.. so I have a few options, and I'd love some additional opinions - Buy a newer inverter with a softer start - Buy more batteries to limit the draw per battery (not 100% sure this will solve my problem .. not sure how many I would need to be sure it would work ?) - find a way to limit current and rather brown out the inverter, than draw too much current Thoughts ?

OK, so after all that .. the rs485 just wasnt great, replaced it, and now the Tian Power software is working, next is to figure out why its shutting down / Alarming, and then if I can fix it, on to writing code to read the protocol now that I am getting valid responses

No, but Ill have a google .. thanks for the heads up

Yes, I monitor the voltage every 10 seconds, and log it, and it seems like theres no pattern, it can go at 49 volts or 48.5 volts or 48 volts .. I am not getting anything looking like a sane response from the BMS, so the next step for me, is going to get a different rs485, in case mine is faulty or just not compatible. Then I'll run through the Tian Power commands in the hope that I can get something looking like a correct response, even if I have to run tests on every wire combination. Once I have that, as you suggest, I'll use the provided app to read the error... if it still doesnt help, then either I'm swapping the BMS or buying an inverter .. will have to see which ..

So I voided my warranty and took it apart to find out. Mine is using Tian Power. I unfortunately have an older Axpert 5KW (RCT Brand) .. which every 2 or so days, completely shuts off due to some BMS condition. I monitor my inverter with a homebrew app on the PI, and it is definately not over current / voltage related, so the only way I can see whats actually going on, is to read the BMS to find out why it goes into protection. Switching my inverter back to my (very old) AGMS works a treat and also happens to force the Narada back to good health, until it shuts off again. Disconnecting it from the inverter instantly also results in it working .. so I have a wierd issue, I'm hoping the BMS will tell me what it is... Worst case, Ill buy another BMS and swap it .. but Id prefer to get the original to work ... Going to try another rs485 adapter and new cable before I completely lose my mind, but at least now I know I have the Tian Power

Just in case you didnt see it, the post by ziva on June 4th, includes a zip file. In that zip is a doc file that has commands similar to yours. It also includes the software, so if you want to reverse engineer, I'm sure that would be useful (If you havent seen it already obviously), and looks like it will work with your battery

Hi Am having some similar trouble just trying to read data from my Narada 48npfc100 and could use some help / insight I have made up a cable for testing purposes that uses a usb -> serial then rs485 -> rj45. Incidentally a homemade rs232 cable seems to provide zero response at all. I have obtained the Narada software mentioned previously in this thread, but it cannot connect, it gives comms errors. Using cutecom I am able to send commands and see responses, but they dont make sense, so could use some eyes if I am missing something obvious. I have also noted I get different responses if I set to baud 1200 vs baud 9600 .. so am a bit at a loss. below see some examples, and hopefully someone can give an opinion, (dip switch 1 is up, all others down, and it is a single battery) baud request response 1200 27040FFF000105E8 00 6f 77 ff ff ff eb df 9600 27040FFF000105E8 fc e0 f0 1200 7e010100fe0d fd fd ff fb 7d 9600 7e010100fe0d f0 e0 None of those look close to what people where getting from either BMS ? or am I just not seeing it ? I have also noticed on the supplied battery rj45 cable, the end labelled battery has wires only on pin 3 and 5? Any direction would be helpful.