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Parallel Axpert not charging from generator


PeterGutti
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My installation:

  • 2 x 12 panels, 24 batteries à 1500Ah, Gel, 48v.  
  • 2 Axpert inverters 5kVA, configured as Master and Slave, running in parallel mode.
  • 1 Generator à 7,2kVA
  • 1 Victron Battery Monitor BMV700/2 
  • No utility connection, stand-alone/island solution

Expectation: Whenever batteries drop below 46,5v the Battery Monitor should start the generator to charge the batteries. 

Problem: The gen starts (manually to test) but does not get connected although the inverters recognize the generator input (wave icon). 

The technician says, that this is a design failure by the Axpert inverter. He has other clients with the same problem.  He recommends to install a charger between generator and batteries.

Does anybody have a similar installation that works? Or prove that this is indeed a design bug?  

If there is a design bug: Who should i contact?

I live in Spain, Costa Blanca.

 

Plano sistem fotovoltaico v2.pdf

IMG_6113_13564.jpg

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welcome,

I think it is a design flaw in the product. I am aware of a few folk in S.A with the same issue. You could try getting in contact with www.voltronic-power.com

 

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I also know of a bunch of UPS'es that got damaged when they where powered from generators during the dark times out of desperation.

So I would add that most generators are not that dependable ito clean power, I think Plonkster at one stage gave a good description of power generated, then more is needed and the flywheel being to small and the engine not being able to respond fast enough for increased loads and all that.

Generating clean power consistently yet provide for power peaks in between, is an art form of note. Cudo's to the engineers at Eskom and all other grids in the world.

 

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Yeah I had a big old ramble about how small petrol generators (that's basically everything under 10kva) generate islanding events with a little bit of power as a side-effect :-P

Torsional vibration. You have a 4-stroke engine, usually with a single cylinder, so you have a power stroke only 25% of the time, the rest of the time it runs off momentum and it actually slows down a tiny bit. So what the engine is doing is speeding up and slowing down 1500 times a minute (assuming 3000rpm, which is 100 revolutions a second, which gives you 50hz). In addition, the crank shaft is made of steel and it can actually bend, it;s somewhat elastic. So if you think about this in the angular/rotational sense the crank shaft actually shakes itself like a wet dog.

Now you stick that jittery rotational energy into a generator and you're expecting a clean 50Hz out? Dream on :-)

In addition, whenever the engine takes a load, the governor has to respond and push more fuel into the engine to keep the speed up, but since it spends 75% of the time unpowered (on exhaust, intake or compression stroke) and it generates a full one and a half cycles of AC in that time, it's going to generate badly misformed waveforms whenever something heave is turned on or off.

Moral of that story, you want a big old Diesel running at 1500rpm, 4 pole alternator (I hope I have my terminology right here).

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10 hours ago, PeterGutti said:

Does anybody have a similar installation that works? Or prove that this is indeed a design bug?  

If there is a design bug: Who should i contact?

I live in Spain, Costa Blanca.

HI Peter

As explained some small petrol generators have difficulty achieving a clean wave. I know that certain firmware, 52.30 I think,  just would not accept generator power. You must make sure  Program 3 is set to Appliance and check that you have the latest firmware I think that is 72.40. Firmware update available http://forums.aeva.asn.au/forums/pip4048ms-inverter_topic4332_page1.html  (Australian Electric Vehicle Assos.)

I powered my 4kW Axpert/PIP with a large diesel generator and even it needs the Axpert to be in Appliance mode.

 

I lent a very cheap Chinese generator to a neighbour who has one of the smaller Axpert's and it powered it successfully.

Hope you solve your issues 

Chris

 

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Thank you folks for your support!

What makes me a bit shaky is that in the first stage i only had one inverter. That configuration worked fine with the generator.  Problem started when adding the second Axpert with a second set of modules. 

The source of the problem must be in the communication between the two Axperts.

The generator is a Yanmar GBW10 diesel with an  alternator MeccAlte ECP3, 7,7kW

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2 hours ago, PeterGutti said:

How can i find out the firmware level without a monitoring software??

 

Using the LCD screen you can scroll through various screens. Inverter firmware is U1 and SCC is U2. Make sure both units have the same firmware. Those Yanmar generators are good and I think you should not have hassles with clean sine wave. Definitely hassles with combined Axpert units.

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I was always wondering what U1 and U2 mean. The manual doesn't mention it.

Firmware levels:

  • Master: U1: 5230  U2: 0124
  • Slave: U1: 5230  U2: 0400

What means SCC?

The firmware seems to be on the same level.

On the Voltronic web page (support/download) i could not find firmware files or any other information. Shouldn't they inform about the updates and current levels?

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SCC is your solar charge controller.

I think the latest version of the firmware is 72.4 if I remember correctly the one you have did have some issues with generators.

Unfortunately the don't notify clients of this 

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Yes. That's the Australian Electric Vehicle Association, and I've posted copies of firmware that was available for a while from one of the distributors, MPP Solar. I know it's a bit off topic for an EV site, but there is overlap of interest.

Edited by Coulomb
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OK - i downloaded the firmware and will try to install it. Hope nothing goes wrong. 

What can happen in worst case? Damaging the device?

When running parallel mode: Can one install through the connected inverter to the others?  Or does one have to connect directly to the target device?

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2 hours ago, PeterGutti said:

What can happen in worst case? Damaging the device?

¨The worst that can happen is that the flash process might start but never finish. You'd have to be pretty unlucky; you'd have to have a serial interface that was reliable enough to start the flash process but unreliable enough to fail repeatedly. My understanding is that in most situations if the firmware update fails, it stays in firmware upload mode, so you can keep trying again until you succeed. If that kept failing, the unit would effectively be "bricked", like a mobile phone that has had its firmware updated incorrectly. Not really damaged as in parts burned out, but not functional.

If that were to happen, you could just get the controller board repaired or replaced. It's a plug-in board; it may cost less than R2000 to replace, if you can source one. But if that's not an option, a ~~R1000 development board from TI with a few mods can rescue it. I have the hardware and software to do this, and hopefully I could guide you through that process through this forum if necessary, but it's most unlikely that it will be needed.

A final desperate last resort might be to post just the control board to me or someone closer who can do the update. The control board is only about 250 x 75 mm, so it's a lot easier and cheaper than the main board or entire unit to ship about.

Summary: there is little chance of anything going wrong, and there are various options in the unlikely event that something does go wrong.

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Doesn't the flash process use some kind of checksum? The stuff I work with is pretty similar, it remains in the bootloader if the flash fails... but if you power cycle them at this point it will attempt to load the incomplete firmware and crash... and then you are in big doodoo. This is because our esteemed engineers are still working on a checksum implementation... :-) Once you have that, the device will simply remain in the bootloader (aka the flash part) if the firmware does not pass the checksum verification.

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  • 2 months later...

Reviving this thread... Would love to know if you managed to solve the issue via the firmware upgrade Peter?? I have the same issue at a friend's installation. Would try it if it seems to do the trick.

At my own place the only way I was able to use a generator through axpert eventually by buying an inverter-generator. but these are small and expensive...

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(TTT smiles broadly and says nuthin')

 

No seriously, Axpert cannot take the shots. Know of cases last year where 3 APC online UPS'es, top of the range, got damaged when they where powered from a cheap Builders generator, over time. Oaks thought they hit the jackpot, APC picks up the load for 5 minutes till gennie is running. Worked well till the APC's chargers started failing one after the other. No-one saw that one coming.

 

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I also had a gennie about 2 years ago when Eskom started becoming unbearable, UPS'es never stopped beeping despite the gennie running. Was as if power was still off. They were not happy. All APC BTW.

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