Axpert 5kVA Cooling Fans

[VaughanT]

Folks - please could I pick some brains about the cooling fans inside the Axpert 5kVA (unit was purchased circa 2015/16) - and noted the two internal fans run constantly at slow speed (i.e. not dependent on load or on the unit temperature. I have the 3kVA model in which its fans run at two speeds (seem to be dependent on unit temperature and/or load). 

Would appreciate your comments.

Vaughan

 

[Coulomb]

13 hours ago, VaughanT said:

could I pick some brains about the cooling fans inside the Axpert 5kVA

I'm not sure what your question is, but I can tell you that the fan speed algorithm in firmware version 73.00 takes into account the inverter load, total charge current, temperature (from 4 sensors), and has a minimum PWM level of 30%, which is enough to have the fans barely ticking over. From the factory, the fans such the air downwards, against the natural tendency of hot air to rise. Changing the fans to blow upwards has been shown to keep the electronics cooler.

73.00 blows the fans harder, compared to earlier firmware versions, by a factor of 5/3, based on SCC charge current. 72.20 (for PF1 models with the 64 V option) also does this.

[VaughanT]

Coulomb - thanks for your valued input. I don't think this unit is a PF1 model (the rating plate states the unit is 5kVA/4000W. If I multiply out the max current x DC voltage I get 4,464W - which I note doesn't equate to the maximum current of 22A as stated. This model also has the large heatsink right at the top (presumably where the FETs are mounted onto). I installed the unit for my folks - its in an cupboard (as this was the closest point I could get to the existing DB board). This does cause the unit temp to rise somewhat and I've further added in vent holes to improve air-circulation around the unit. I will likely have to get some 48VDC fans and build a small temp sensor circuit to control these automatically. Given the horrific state of SA's grid - these units are becoming increasingly popular. My PF1 3kVA unit runs the fans much harder - in fact these run much of the time even with the inverter lightly loaded. 

How do I determine the firmware version of the 5kVA unit? Is it a pain to upgrade the firmware? The 3kVA model I have also provides for a contact-closure output (to drive external relays, etc.) - the state of which can be determined via the sub-menu setup. The 5kVA doesn't provide a contact closure when the unit is running - does the firmware upgrade address this?

Vaughan

 

[Coulomb]

27 minutes ago, VaughanT said:

I don't think this unit is a PF1 model (the rating plate states the unit is 5kVA/4000W.

No. PF1 means the same W as VA, so 5 kW and 5 kVA.

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If I multiply out the max current x DC voltage I get 4,464W - which I note doesn't equate to the maximum current of 22A as stated.

Losses mean you need more than 4000 W from the battery to send 4000 W to the load. Total losses are of the order of 10%.

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This model also has the large heatsink right at the top (presumably where the FETs are mounted onto).

You'd think that. But in fact that's where the Solar Charge Controller is.

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How do I determine the firmware version of the 5kVA unit?

Simply press the up or down buttons until you come to a screen with "U1" at the left (or top on more modern models). Then the other two sets of digits tell you the version number. For example, if you see "U1 72 61" then your main (DSP) firmware version is 72.61.

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Is it a pain to upgrade the firmware?

It depends on your skills. I've done dozens of updates; it's no trouble for me at all. But you need to find a suitable USB to RS-232 adapter, find its COM port number, re-assign that COM port if it's COM10 or higher, that sort of thing. It's also a bit of a hassle figuring out what version you want. I wrote a post about this: Can I update my firmware, and if so to what?

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The 3kVA model I have also provides for a contact-closure output (to drive external relays, etc.) - the state of which can be determined via the sub-menu setup. The 5kVA doesn't provide a contact closure when the unit is running - does the firmware upgrade address this?

 

Yes. Firmware versions 72.70 and later for the PF0.8 models have this configuration setting (setting 38).

[VaughanT]

I've recently hacked a three-wire RS232-to-USB interface for my Texecom Alarm panel using the FTDI-RS232RL development board - this I understand is a Chinese clone and it seems to work ok. I've done a few firmware upgrades and it shouldnt be an issue - provided as you say I identify the correct version to upgrade the unit to. 

Best regards

Vaughan

 

 

 

[willem12345]

@Coulomb, Hi,

On the topic of these fans.
Is there a way that I can switch them on permanently? I'm getting a 51 error on my 5kw-48dc inverter. so I want to see if this makes a difference.

And I see this topic is quite old, is there an updated way to upgrade the firmware version, and is there an advantage to updating the fw with regards to the 51 error?

[Coulomb]

37 minutes ago, willem12345 said:

Is there a way that I can switch them on permanently?

Not easily. It might be easier to arrange an external fan, though the fans likely run backwards (sucking air down) so you might need one on each side.

37 minutes ago, willem12345 said:

I'm getting a 51 error on my 5kw-48dc inverter. so I want to see if this makes a difference.

I highly doubt it.

There are several posts about fault code 51 on the repairs and hardware modifications topic. The link is to the first post of the repair (fault code known) section, which has links to various posts, sorted by fault code. Most of these seem to involve capacitors.

37 minutes ago, willem12345 said:

is there an updated way to upgrade the firmware version, and is there an advantage to updating the fw with regards to the 51 error?

Yours is a clone (the fourth warning is a giveaway), so it may not even be possible to update the firmware. But a firmware update is unlikely to help in this case.

[willem12345]

@Coulomb, thanks again for the speedy reply.