Hi. First time I switched on MAX II 11kW and can't really believe how loud (fans noise) is that model. Is it normal? Also what means H5 indicated on a screen?

VIDEO

 

Edited November 10, 20241 yr by Bocian

OK I found what HS/H5 issue is all about. Whether output 230V is turned on or off from the button, I cannot change it from PAL to SIG with #28 (tried with only 48V DC connected, only AC in, both connected still I cannot change).

Edited November 8, 20241 yr by Bocian

On 2024/11/08 at 11:41 PM, Bocian said:

I cannot change it from PAL to SIG with #28 (tried with only 48V DC connected, only AC in, both connected still I cannot change).

All I can suggest is that this is a poor clone that somehow isn't sending the right commands from the display processor to the main processor.

However, what little I could see from the video suggested it is a genuine Voltronic. Can you post a photo of the sticker on the side?

Also, what is the main (U1, DSP) firmware version? There is a small chance that this is fixed in later firmwares.

Hi Coulomb. Thanks for reply. Here are photos already taken. I will add photos of control board and main processor soon.

6 hours ago, Coulomb said:

All I can suggest is that this is a poor clone that somehow isn't sending the right commands from the display processor to the main processor.

However, what little I could see from the video suggested it is a genuine Voltronic. Can you post a photo of the sticker on the side?

Also, what is the main (U1, DSP) firmware version? There is a small chance that this is fixed in later firmwares.

 

 

 

 

 

 

 

 

 

 

Edited November 10, 20241 yr by Bocian

Also I will try to change original very loud fans with better quality Sunon Maglev 92x92x25mm fans.

https://www.digikey.com/en/products/detail/sunon-fans/PF92251V1-1000U-G99/7927803

BTW. You may think that 0,37A fan as a replacement to 1A will have not enough power to cool the components inside but You need to know that current declared on a sticker is twice to the real one. This one was measured 0,51A at 12V DC voltage.

Edited November 10, 20241 yr by Bocian

6 hours ago, Coulomb said:

All I can suggest is that this is a poor clone that somehow isn't sending the right commands from the display processor to the main processor.

However, what little I could see from the video suggested it is a genuine Voltronic. Can you post a photo of the sticker on the side?

Also, what is the main (U1, DSP) firmware version? There is a small chance that this is fixed in later firmwares.

Photos attached.

14 hours ago, Bocian said:

Photos attached.

Thanks.

Interesting that  it uses a '28069, I'm not familiar with that variant. It seems to be a two core version of the '28066. It's not clear if they just could not obtain the single core chip, or if they are using both cores.

Unfortunately, I've not seen any 75.xx Axpert Max II 11kW '2806x Twin firmwares at all.

The label strongly suggests that it's a clone, so it's compatibility with Voltronic firmware is unknown.

So the quieter fans sounds like the only option until a suitable firmware turns up.

3 hours ago, Coulomb said:

Thanks.

Interesting that  it uses a '28069, I'm not familiar with that variant. It seems to be a two core version of the '28066. It's not clear if they just could not obtain the single core chip, or if they are using both cores.

Unfortunately, I've not seen any 75.xx Axpert Max II 11kW '2806x Twin firmwares at all.

The label strongly suggests that it's a clone, so it's compatibility with Voltronic firmware is unknown.

So the quieter fans sounds like the only option until a suitable firmware turns up.

Thanks

On 2024/11/11 at 3:17 PM, Coulomb said:

Unfortunately, I've not seen any 75.xx Axpert Max II 11kW '2806x Twin firmwares at all.

I have recently come across firmware version 75.85.

This is main (U1) factory firmware version 75.85 for the Axpert Max II 11kW '28066 Twin. Do not use with any other model or version.

Use at your own risk. The hex file is dated 02/Jun/2025.

Firmware upload instructions for models with a removable or colour display.

This firmware processes the QDOP command, so with suitably recent display firmware, it should support SoC% for settings 12,13, and 29 when connected to a suitable battery's BMS.

MAXII11K_TWIN_DSP75.85.7z

[ Edit: Added "or colour" before "display" ]

Edited June 17Jun 17 by Coulomb

On 7/15/2025 at 7:30 AM, Coulomb said:

I have recently come across firmware version 75.85.

This is main (U1) factory firmware version 75.85 for the Axpert Max II 11kW '28066 Twin. Do not use with any other model or version.

Use at your own risk. The hex file is dated 02/Jun/2025.

Firmware upload instructions for models with a removable display.

This firmware processes the QDOP command, so with suitably recent display firmware, it should support SoC% for settings 12,13, and 29 when connected to a suitable battery's BMS.

MAXII11K_TWIN_DSP75.85.7z

What specific firmware version is this, and will it work with the Max 2 11kW inverter model?

On 2026/06/12 at 10:01 PM, Atac777 said:

What specific firmware version is this,

It's version 75.85. It should work with your inverter.

Hi! I'm looking for a patched firmware for Axpert Max II 11kW Twin, MCU TMS320F28069, my current factory version is U1 75.01.

Are you sure this firmware will work?

3 minutes ago, Atac777 said:

Hi! I'm looking for a patched firmware for Axpert Max II 11kW Twin, MCU TMS320F28069, my current factory version is U1 75.01.

Are you sure this firmware will work?

15 hours ago, Atac777 said:

Are you sure this firmware will work?

Yes. The MAX firmwares are designed for either the '2809 (older) or '28066 chips; the 75.xx firmwares (those designed for MAX models, not the ones for rack mounted Kings) are for the '28066 chips.

You have the '28069 chip, which is the same as the '28066 chip except it has a bit more RAM and two extra accelerator modules (not needed or used in the inverter firmware). My guess is that there are occasional shortages of the '28066 chip, so they use the '28069 instead. Or maybe Texas Instruments' fabrication is maturing to the point where the '28069 has the same yield as the '28066, and the '28069 is completely backwards compatible, so they just concentrate on producing the highest spec version, simplifying inventory.

I've heard of other '28069 chips in Voltronic inverters.

That said, nothing in this crazy world is completely certain, but this one is very close to completely certain.

On 6/25/2026 at 3:29 AM, Coulomb said:

Yes. The MAX firmwares are designed for either the '2809 (older) or '28066 chips; the 75.xx firmwares (those designed for MAX models, not the ones for rack mounted Kings) are for the '28066 chips.

You have the '28069 chip, which is the same as the '28066 chip except it has a bit more RAM and two extra accelerator modules (not needed or used in the inverter firmware). My guess is that there are occasional shortages of the '28066 chip, so they use the '28069 instead. Or maybe Texas Instruments' fabrication is maturing to the point where the '28069 has the same yield as the '28066, and the '28069 is completely backwards compatible, so they just concentrate on producing the highest spec version, simplifying inventory.

I've heard of other '28069 chips in Voltronic inverters.

That said, nothing in this crazy world is completely certain, but this one is very close to completely certain.

Thank you, everything works. I replaced the firmware u1 75.85. Does it make sense to change the firmware u2?

On 2026/07/06 at 6:14 PM, Atac777 said:

Does it make sense to change the firmware u2?

Since your U1 (DSP) firmware is so old, your U2 (display comms) firmware is probably also quite old. So I'd say yes, but there is no great need if you're not having problems.