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Axpert error code 09


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Unfortunately, it usually means shorted IGBTs, either in the 230V inverter, or the high-side of the DC-DC converter. 

It"s a Bus Soft Start error. There is a small power supply that charges the DC bus capacitors to about 8x the battery voltage (some 400 V), which is switched on very soon after powering on. If there are no paralleled machines, it has about 15 seconds to reach that voltage, or a bus soft start is asserted. A friend and I had one recently (after a repair), and the first time it took about a minute before it came up. Probably the IGBTs were OK at that point. Next startup, the error came up quickly, possibly in just over 15 seconds. There was a dead short across the DC bus. 

It's possible to check this with a multimeter without removing the main board, but it's tricky on some models. Measure on a voltage range first in case there isn't a short. The 2x 470 uF capacitors can hold a wallop, so care is advised. If no voltage, it's safe to measure on ohms. A working inverter should measure in the megohms, slowly changing. 

Edited by Coulomb
230 V inverter
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10 hours ago, jussclay said:

Coulomb thank you a lot how possibly can i get the schematic diagram or better still a comprehensive service maual

Have a look at the AEVA forum (lounge if I can remember). There is a PIP thread which is invaluable with schematics and there's other info. Unfortunately the thread is 70 odd pages long but there is a index on the first page.

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  • 1 month later...
22 hours ago, saif1985 said:

fault still is 09 this time soft starter ic 3845 is faulty

That would be U16; there is more than one UC3845 chip in an Axpert.

Soft start partial schematic trace.

Fault code 09 means that when the Axpert attempted to pre-charge the 400 V bus, it failed to reach its target voltage in 15 seconds. The target voltage is usually battery voltage × 8 but always 336 V  to 480 V and it can depend on grid voltage. That could be because failed capacitors or IGBTs are shorting the bus (either the inverter IGBTs or the high-side full-bridge of the DC-DC converter), or something failed in the soft-start circuit itself.

Edited by Coulomb
Clarify bus voltage target
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  • 2 months later...
  • 2 weeks later...
On 22/02/2018 at 3:12 PM, Kobus van der Watt said:

what cause error 08 to come up now and then...

As mk12 says, error 08 is bus voltage too high. This is the internal ~400 VDC bus that drives the inverter IGBTs. The electrolytic capacitors on this bus are rated at 500 VDC. They can take a voltage overload for some minutes, but it will not be good for them to do this long term.

The firmware measures the bus voltage continuously. You get error 08 if the bus voltage exceeds 500 VDC without exception for 10 seconds, and in addition, if the bus voltage is at least 10 VDC higher than the measurement at 1 second of over-voltage. The instant the bus voltage falls to 500.0 V or below the counter is reset to zero and the whole thing starts again. So it's pretty tolerant.

The bus voltage is generally close to 8.0 times the battery voltage, because the high frequency transformer has an 8:1 turns ratio. So a very high battery voltage could possibly cause this. [ Edit: or possibly a poor (high resistance) battery connection, perhaps a bad crimp etc. ]

However, I think it's more likely to happen during utility (mains, AC input) charging. At this time, they do something I don't yet understand to the inverter, such that it pulls power from the AC input to the DC bus. I think it's a bit like regeneration in an AC electric vehicle, except that there is a "DC transformer" with an 8:1 turns ratio between the inverter "input" (now really an output) and the battery. There is a buck stage to buck this bus voltage to whatever is needed to push power back into the battery at the desired current. I think that sometimes they get the dynamics wrong and the inverter (running in reverse, so now a battery charger) puts too much charge into the bus capacitors, and you get the occasional error 08. Perhaps this can happen if the utility or generator voltage increases suddenly, perhaps due to a big load coming off (it might not be your house, but someone down the street or the next farm or whatever).

Edited by Coulomb
Sentence re bad battery connection
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  • 5 months later...
On 10/2/2017 at 8:04 AM, Energy said:

Heya Guys. Hope well  . I dropped this to 5. Do have a look see.



Im working on axpert inverter 5kva Is it possible for U16 to be bad even if the resistor R245 is good. I've checked everything on the board yet im still having error 09


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