Beta Patched Firmware version 74.40e for some 48 V PF1.0 58.4 V 5 kW models
This is the first version of our patched firmware based on factory firmware version 74.40 for the Axpert MKS 5K-48 (non
64 V), Mecer SOL-I-AX-5P (not
SOL-I-AX-5P64), and equivalents. I note that MPPSolar don't sell an equivalent PIP model at this point. There were no patched firmware versions 74.40a-d. We jumped straight to "e" so that "e" (and later) would indicate the presence of the kettle-compensation feature, as in 73.00e for PF0.8 models, and 72.20e for PF1.0 64 V models. See the first post of this topic
for these and other patched firmware versions.
This patched firmware has all the same patches as both 73.00e, 72.20e, and earlier patched firmwares, including Dynamic Charge and Load Control
, AussieView™, and KettleKomp™
. This includes fixing the infamous premature float bugs
It's been a while since all the patched firmware features were listed, so here is a summary:
LFP† and Lead Acid Patched Firmware
LFP patched firmware only
- The repaired voltage criterion for transitioning from absorb stage to float (main premature float bug fixed).
- For non-automatic absorb stage timing, only time when the battery voltage is near the CV setting counts as being "in absorb" (second premature float bug fixed).
- "Font" improvements, and HS -> MS for Master units.
- Firmware revision display screen contains patch revision.
- Fixed "change a setting twice", and "limited steps" bugs in factory firmware.
- Improved the accuracy of all charge and discharge current readings.
- AussieView™ improved display of data.
- Dynamic Charge Control (DCC): vary charge current by commands without wearing eeprom and without delays.
- Dynamic Load Control (DLC): switch inverter-proper on and off by commands to save idle power drain.
- KettleKomp™ (load/charge compensation for important battery voltage measurements).
- The bulk/absorb to float transition occurs with a different current threshold: (sum of maximum charge current settings) divided by 12, minimum 3 A.
- Low battery cutoff voltage range changed from 40-48 V to 44-52 V.
- Back to utility voltage range changed from 44-51 V to 46-53 V.
- Float to bulk charge stage transition occurs at 1.2 V under the float setting.
- The battery low warning occurs at the cutoff voltage plus half a volt, and returns at cutoff plus one volt.
More details on the features can be found here
, and in the manuals linked near the top of this post.
Testing to date
The patched code has been thoroughly checked by eye (a multi-day process), and has been running for several days in my two paralleled PF0.8 machines. Yes, I'm taking a risk (see below), but soon I'll be reverting to 73.00e patched firmware, so that my hardware is fully protected.
Paralleling PF0.8 and PF1.0 58.4 V machines
Unfortunately, there is no proper way to do this, unless your PF1.0 machine(s) all have factory firmware version 74.10; then you can parallel with factory firmware 72.70 in the PF0.8 machines. Failing this (there would only be a handful of machines with firmware version 74.10, and I don't know of any firmware update files for that version), then the following is a RISKY possibility. You could flash 74.40e into all machines, PF1.0 and PF0.8. Note that this will make the PF0.8 machines think that they are PF1.0 machines, so the fans won't work as hard, and the firmware will let your power loads up to 5 kW without triggering an overload. This is likely very bad for your PF0.8 machines. However, in a paralleled situation, it may be possible to guarantee that the total load when shared amongst all paralleled machines will very rarely if ever exceed 4.0 kW, so the PF0.8 machines should be safe. If you do this, you do so AT YOUR OWN RISK!
This patched firmware is intended for: some genuine 48 V PF1.0 58.4 V (i.e. NON 64 V) 5 kW models.
Do not attempt to use with clones
, workalikes, or 64 V models. Check setting 26 before you flash: if you can choose values higher than 58.4 V, then you have a 64 V model, and this firmware won't work. This patched firmware is not for any model with a 450 V MPPT, or PWM Solar Charge Controller; only for models with a Solar Charge Controller limited to 145 V Voc at the PV input. It is not for any model with a removable display, or for 24 V or 12 V models, or for any apparent power rating less than 5 kVA.
The 'B' initial letter indicates a beta version (tested in-house, now available for testing by all, but not yet proven as "release" quality).
The 'F' second letter indicates the LF
P flavour, or 'C' for Lead AC
id / C
The '1' third character indicates that this is main (DSP) firmware, not SCC / display / Bluetooth firmware.
For lithium ferrous phosphate (LFP)† (16S or 15S) or lithium manganese oxide (LMO) (14S).
For lead acid (24S), lithium cobalt-blends (LCO, NMC, NCM, NCA) (14S), and lithium titanate (LTO) (21S or 20S)
For reflashing instructions see the 72.70b reflashing instructions
, but ignore the zip files there.
It should go without saying that you use this at your own risk. Please report any problems to this thread.
† "Lithium ferrous phosphate" and "LFP" are the preferred name and abbreviation for what is sometimes called lithium iron phosphate or LiFePO₄.
[ Edit: added DCC and DLC features; added Axpert and Mecer model numbers. ]
[ Edit: removed a chunk out of "Testing to date", which we suspect would happen with factory firmware anyway, as we didn't touch the battery calibration code. ]
[ Edit: replaced original zip files with versions that contain a minor update to the KettleKomp™ manual. This mentions more directly how the maximum charge current of paralleled inverters affects the strength of battery voltage compensation. Thanks, Weber! ]
[ Edit: replaced zip files with ones that have slightly corrected .txt files. The error was quite minor, and has no effect on the final dsp.hex file. ]