Jonny Posted May 19, 2022 Posted May 19, 2022 Hey there, I have a RCT Axpert 2k inverter and it is bugging me because it has the premature Float bug. It wont even hit the programmed float voltage. I want to update the firmware to fix this bug. Where can i find this fix ? ALSO I dont have an idea how to do this. Is there a guide you guys can recommend??? Quote
Coulomb Posted May 20, 2022 Posted May 20, 2022 14 hours ago, Jonny said: I want to update the firmware to fix this bug. In an ideal world, the manufacturer or their distributors would have them listed on web sites. indeed, they did until the first clones started arriving. Alas, 2 kVA firmware is hard to find, and there isn't a patched firmware available. So there is no firmware fix for the premature float bugs in these models. 14 hours ago, Jonny said: It wont even hit the programmed float voltage. It should reach within about a quarter volt of the float voltage for 24 V systems, or your issue isn't the premature float bug. (Half a volt for 48 V systems, and I don't know about 12 V systems). Does your inverter have timed absorb or equalise settings? If so, they can be used to work around the problem. But the lower power versions tend not to have these. Low power models also tend to have very low power Solar Charge Controllers, like 600 W (25 A x battery voltage). If so, that could be why you struggle to charge the battery. Perhaps consider an external MPPT, connected directly to the battery. You might still want to use the internal SCC as well. Quote
Jonny Posted May 20, 2022 Author Posted May 20, 2022 (edited) @Coulomb - Thanks for the response again. It did finally reach the float voltage. Is there a way i can factory reset the inverter to set it back to "normal" ? The other irritating thing is that the fans spin every 30 min even with no load. This was not the case before this issue. If i have to get an external MPPT them maybe it would be better just to return/refund the @#$% thing and get a Growatt/whatever ? UPDATE : I managed to get it to not stop at float by doing the following. 1) Removed AC and PV power 2) used 20% of by battery capacity. 3) Disconnected battery then reconnected battery 4) While off added the PV again 5) added load 6) added AC Now if is charging without "is_charging_to_float" true and is charging to bulk voltage.... BUT when the SOC reeds 100% it goes to float and does not go to user defined voltage Edited May 20, 2022 by Jonny Quote
Coulomb Posted May 20, 2022 Posted May 20, 2022 7 hours ago, Jonny said: Now if is charging without "is_charging_to_float" true and is charging to bulk voltage.... BUT when the SOC reeds 100% it goes to float and does not go to user defined voltage I'm finding this hard to follow. You say it's charging to bulk voltage, good. The SoC reading is based entirely on battery voltage, as measured by the inverter. For a 24 V model, it's something like 2% for every 0.1 V in excess of (setting 29 plus 0.1 V). I don't think it triggers anything from a 100% SOC reading. But if it does, you can adjust what it thinks is 100% SoC by fiddling with setting 29 (low DC cutoff voltage). When you say "does not go to user defined voltage", what voltage does it go to, and what voltage are you expecting it to go to? It can take a battery some time to change voltage, depending on charge current, load, temperature, and internal state. Is it lead-acid, LFP, or other battery chemistry? Quote
Jonny Posted May 22, 2022 Author Posted May 22, 2022 Let me try again (please remember this was not the case until i connected PV)... My settings are Bat_voltage = 24V Float = 26.8V battery_bulk_charge_voltage = 27.8V cut off voltage = 24V Even with these settings, as soon as the inverter reads 100% SOC (this is not correct when it comes to lifepo4 because you can not determine this purely on Voltage). it instantly goes into float state .... It never even hits the bulk/absorption voltage of 27.8. Note: i have a balances that balances the 2 batteries at 27.3 v. This never happens because the inverter never hits high enough voltage. This is the issue. Before it adhered to the setting and when it would go into float it would maintain (without fans) the voltage with no issues, now the fans spin up every 20 min. Quote
Coulomb Posted May 22, 2022 Posted May 22, 2022 (edited) What version is your main firmware? It's slightly possible that I've already patched it. Edit: re the change in behaviour: have you changed the maximum charge current (setting 02) between when it was working and now? Edited May 22, 2022 by Coulomb Quote
Jonny Posted May 22, 2022 Author Posted May 22, 2022 (edited) 6 hours ago, Coulomb said: re the change in behaviour: have you changed the maximum charge current (setting 02) between when it was working and now? No i have not. My current version : U1 09 52 U2 03 39 6 hours ago, Coulomb said: It's slightly possible that I've already patched it. That would be really awesome. Thanks for the assistance. Is there not a way i can "factory reset" the unit to get it into the previous state? Just for ref: https://www.rctzone.co.za/power-solutions/inverter/off-grid-inverters/rct-axpert-vm-2k-24v Edited May 22, 2022 by Jonny Quote
Coulomb Posted May 23, 2022 Posted May 23, 2022 14 hours ago, Jonny said: Is there not a way i can "factory reset" the unit to get it into the previous state? Yes, with WatchPower or other monitoring software, there is a facility to reset to factory defaults. That defaults all the user-accessible settings to defaults, so that might work. It uses the PF (Put to deFaults) command. There is a stronger command that resets nearly everything, but I think you might lose all voltage and current calibrations, etc. So that's really only for the factory to use. Quote
Jonny Posted May 26, 2022 Author Posted May 26, 2022 On 2022/05/23 at 10:59 AM, Coulomb said: It uses the PF (Put to deFaults) command. There is a stronger command that resets nearly everything, but I think you might lose all voltage and current calibrations, etc. So that's really only for the factory to use. @Coulomb - thanks - please share how i can do that. I dont mind loosing the calibration. Quote
Coulomb Posted May 26, 2022 Posted May 26, 2022 4 hours ago, Jonny said: please share how i can do that. I dont mind loosing the calibration. Sorry, I'd rather not. I don't know what the full implications are, and I suspect that they would be severe. I suspect it would not help with your situation anyway. Quote
Jonny Posted May 26, 2022 Author Posted May 26, 2022 @Coulomb - make sense, thanks for the wisdom. Ime going to have a call with their tech and will give feedback. Quote
Jonny Posted June 6, 2022 Author Posted June 6, 2022 @Coulomb - have the opportunity to to get rid off this inverter, upgrade to 3kva or add some cash and get the Growatt... any suggestions ? Quote
Coulomb Posted June 6, 2022 Posted June 6, 2022 22 minutes ago, Jonny said: any suggestions ? Sorry, I don't know much about the smaller models, and nothing about Growatts. Quote
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