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Thank you for the great forum, Safe Driving over the weekend. Sincerely Jason
SilverNodashi

portable Generator not working on Axpert inverter

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The better solution is to sell the Axpert and buy a Victron *hides* *flamesuit on*

There's actually a setting on the Victron to allow it to accept power that is a bit more dirty :-)

Re the AVR, I believe all that does is regulate the current in the field of the alternator, thereby regulating the voltage. In the old Hoffberg alternators you had a big old rheostat in the box on top that you used for that :-) The frequency generated by the alternator depends on the engine RPM, and that's controlled by the governor on the engine.

 

Nevertheless, I think the explanation that an unloaded generator makes noisier power is accurate, I just don't think the AVR has much control over frequency, only over voltage.

So when I think about this a bit more, there is this thing called torsional vibration, which is basically how the crank shaft of an engine speeds up and slows down with each power stroke of the IC engine. The crank shaft literally shakes itself like a wet dog.

 

Also been reading up on how anti-islanding switches work. What lots of these devices do -- and I highly suspect the same thing happens with inverters -- is run a phased locked loop at the same frequency, and then they contiuously measure the "vector shift". So basically, the vector shift is related to the number of milliseconds that you're signal is out of sync with what it was supposed to be, so when the engine slows down or speeds up it misses the mark by a few milliseconds.

 

(Anti-islanding devices will trip out if you have two consecutive cycles where you miss the mark, that is to say, in 0.04-0.05 seconds.

 

So given a single-piston unloaded petrol engine with a smallish flywheel... well you're going to be permanently out of sync with the PLL :-)

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One possible way around this, is to use an inverter-generator. The "raw" ac from the genny is rectified, filtered and fed to a proper sine wave inverter (part of the generator). These don't care for variations in speed or voltage of the generator, and will synchronise easily with another inverter or inverter-generator.

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On 2015/08/27 at 9:58 PM, SilverNodashi said:

As confirmation, my Axpert firmware are as follows:

U1 - 52  30

U2 - 01 24

U3 - 01 03

As a point of interest, SilverNodashi, what does your manual tell you that U3 display setting is about?

 

Quote
So, the question is, where does one get the older firmware? I don't see if on the Voltronic website. 

 

They used to be available from the MPP Solar web site, but they seem to have moved. Either they were deleted, or moved somewhere, and no web crawler has come across them as yet.

 

I happen to have 52.30 and 72.40 saved away. and they can be downloaded here:

 

http://forums.aeva.asn.au/forum_posts.asp?TID=4332&PID=59274&title=pip4048ms-inverter#59274

 

You might be interested in my patched version to fix a different bug:

 

http://forums.aeva.asn.au/forum_posts.asp?TID=4332&PID=59884&title=pip4048ms-inverter#59884 (intro) and http://forums.aeva.asn.au/forum_posts.asp?TID=4332&PID=59908&title=pip4048ms-inverter#59908 (download, lead acid version). People on this forum don't seem to be using LiFePO4 batteries much, it seems. The lead acid patch is untested, so treat with caution, and please report back any results, good or bad. The original 72.40 firmware is int the download, just in case it's bad and you need to revert to factory firmware.

Edited by Coulomb

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> ...  The Axpert doesn't recognize the power from the genset. The "AC icon" flashes and it beeps, but there's no error.

 

> While looking for the other topic on this matter, I found this one: http://powerforum.co.za/topic/215-infini-axpert-firmware-solarpower-pro-software/?hl=generator#entry1481 where Chris Hobson quoted another forum:

 

So Solamahn says that 52.25 was good (for generator tolerance), and 52.30 is bad. Someone else reported that 72.40 is good.

 

I was surprised that 72.40 would fix this, since there seem to be so few differences between 52.30 and 72.40. But now I think I've found two instructions that are present in 52.30 and not in 72.40, and not in 52.02 (the only version I have prior to 52.30). It's a test for non-zeroness of eepromOutputMode (name will be different) after a test of non-zeroness of eepromModeSelect . Confused? Me too. Firmware is complex, so it's not surprising to see something like this slip in. It may also be that I have not found the significant difference at all, but it sure looks that way to me at this point in time.

 

So there you have it: seemingly a bug introduced between 52.25 and 52.30, and fixed by 72.40 (perhaps well before, I don't know their version numbering system).

 

Thanks for the Christmas day puzzle guys; it was a good one B)

 

[ Update: there is evidence that this puzzle isn't (completely) solved yet. ]

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Hi all, I see this tread is pretty old but I am having the same problem with the latest Axpert / Voltronic inverters.  I am running U1 72 70 and cannot get it to hang on to the generator AC input.  With the one generator it latches on but drops it after 10 seconds or so.  With the other it actually does latch on but as soon as battery charging goes up to 28 amps it drops charging to zero and slowly builds up to 28 amp again.

No problem with grid power so obviously it does not like the not so perfect generator power, but one would expect inverters that are sold as off-grid capable to deal with it.  I have no such issues with Microcare or Victron inverters.

Has anybody found a cure for the Axperts?

Thanks

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Hi Hannes

I run @Coulomb's 72.60 firmware which I installed over vanilla 72.40. I have not had trouble with either firmware versions.I presume you have program 3 set to APL rather than UPS. I know that there was a problem with firmware 52.30 and generators. On the Aussie site there have been recent reports of exactly the same issues.

http://forums.aeva.asn.au/pip4048ms-inverter_topic4332_page1.html

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The storm we had on the West Coast this week had more benefits for me than the much needed rain it brought. We had a blackout for around 37 hours so my 2 x Axpert 4Kw inverters and Trojan T105 battery bank of 450AH got a good workout. After 24 hours the batteries were down to 53% and I decided to use the Makro Chinese 5.5 Kw generator with AVR. My Axperts have been reprogrammed with @Coulomb 's Ver 72.70b firmware. The Axpert setting 3 is usually set to UPS but at that setting the Axperts showed the voltage and Hz but did not charge the batteries. I remembered that @Chris Hobson had commented on the issue some time in the murky past and just changed the setting to APL without turning anything off. The Axperts started charging right away at my setting of 30A each and some 4 hours later the batteries were at 95% which I thought would be plenty to go on with. Fortunately Eskom managed to restore power at 2:30 the next morning according to ICC graphs. So I am very pleased with with the performance of the Axperts and @Coulomb 's firmware for lead acid batteries. Hopefully this will help those with generator problems and my recommendation is to program your Axperts with that firmware and use APL for setting 3.

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12 hours ago, Chris Hobson said:

 On the Aussie site there have been recent reports of exactly the same issues.

http://forums.aeva.asn.au/pip4048ms-inverter_topic4332_page1.html

Yes, starting with this post:

http://forums.aeva.asn.au/forum_posts.asp?TID=4332&PID=64717&title=pip4048ms-inverter#64717

It seems that charging at about 30 A is fine, but 60 A is not. Somewhere between these two, it will hiccup. 

I have a theory that it might be the first same inductor that gets hot (like 100°C), and may get hotter when utility charging. If so, one of the several thermal sensors would cause the power to back off, and this might explain the problem. But "no problem with grid power"  ( @Hannes7212)  would seem to disagree with that. 

It's good to know that 60 A total (two Axperts charging at 30 A each) is not a problem. (Thanks, @ebrsa).  That eliminates some theories about what is going on.

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Yes I can most definitely confirm I have no trouble with charging at full power from grid power.  I have a 24kWh LiFePO4 bank hooked up with two new Voltronics in parallel running firmware version 72 70.  I can charge the bank with 120A combined between them and have even gone as far as pushing it to 80A per inverter with PV added (so 160A).  I never have a problem (the inverters sound like they want to take off but everything works as advertised...).  

The moment I try to charge from generator power the problems begin.  With the one generator I could not get the inverter (I took a fresh one that is not in parallel but standing on its own) to latch on to the generator AC for longer than 20 seconds or so.  I was running in Utl mode and it would take the input, go to bypass and (come to think of it) just as it starts charging, drops the AC in and go back to batteries.  I also set the charging amps to very low (10A) to test but that made no difference.

Then, with another generator, it would latch on to AC in and start charging but when it gets to 28Amp (yes, exactly 28A every time), it would drop the charge amps to zero and slowly start ramping it up again.  In the end, out of desperation, i set the charge amps to max 20A and now it is happily doing what it should with the generator on but I can only get 1kW into the batteries which is not enough for the setup.

Generator: Chinese special HAOMAX KDE8500T (with AVR, Chinese style).

My electronics knowledge is very rusted and I should be legally prohibited to touch firmware code so I am in the hands of the clever guys.  What I can offer is to get a scope on the generator and see what it looks like and if the inverter has any excuse for not taking it.  

Any help or advice will be very much appreciated. 

cheers

 

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I know my portable gennie that I rarely use is absolutely cr*p and yet it gaily carries on. 

I have just had a thought.I wonder if you just try and charge with one inverter. 28 Amps is about 1500W and you cannot charge without supplying load too. Depending on the load you may be physically taxing your gennie too much. The charging slowly ramps up and the revs drop due to dirty filters poor governor etc, the Axpert drops charging because it is way out of even the wide tolerances allowed by the APL mode. 

One of the Aussies who was having problems was using a Kubota 8kW which is a good gennie but I wonder if dirty fuel or a filter may have been influenced the Axpert's behaviour. He did report the fuel was on the old side.

A sure sign would be if it drops the load too.

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@Hannes7212 perhaps you should try @Coulomb 's 72.70B firmware which I have on my 2 Axperts. This week I used the about 8 year old Chinese cheapy generator with AVR for the first time with the Axperts. Setting 3 had to be set to APL and I charged at 30A per inverter as explained above. It would seem that @Coulomb 's firmware solves a bunch of snags encountered with the factory version. Reprogramming is not a big deal if one follow the instructions carefully. Once you have drummed up the courage, you may want to try it. I also was very apprehensive and concerned that I may end up with expensive paper weights but all went well and also did when @Mike and I reprogrammed 2 Axperts for a client of his in the village.

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While it's true to say that the patched firmware addresses several issues with the official firmware, there is nothing that addresses the generator issue. Certainly not directly, and I can't think of any way that it would help indirectly. OffgridQld, the AEVA forum user that started the topic over here, is running patched firmware. 

So by all means use the patched firmware if you need it (in my probably biased view, every Axpert user with solar panels needs it), but don't expect it to solve this particular issue. The patched firmware is better than official firmware 52.30, but only because it's based on 72.70, which is based on 72.40, which has a bug introduced between 52.02 and 52.30 reversed (fixed). 

Edit: it's gratifying to hear about successful installations of the patched firmware. Of course, it would be even better if the manufacturer listened and made the minor changes to their source code, so that all subsequently manufactured machines would benefit. 

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Thank you for all the comments and suggestions.  Yesterday we put a scope on the generator to see if we could spot a pattern and I can confirm that it is not due to under or over voltage that the inverter drops the AC in.  The generator stayed within 208V - 240V which is not great but not the cause of the issue.  The frequency was a bit all over as well but the Axpert seems to be OK with that (we go up to 3Hz variance from 50Hz on both sides).

If you look at the waveform of the generator it looks pretty bad (I know, I should have taken screenshots) but still the Axpert accepted it.  As it started charging the wave did not change but as we got to about 23A you could see distortion starting to form and this gets progressively worse and true to form at 29A it drops the charging to zero.  This is where my knowledge of electronics start to fall short but I am considering sticking the AC in through a big, heavy transformer to see if that (apart from introducing losses) will have a stabilising effect on the waveform under load.

One other thing, as expected, putting a resistive load of 2kW on the generator did not result in the distortion we saw when the load is applied via the inverter charger.

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22 hours ago, Chris Hobson said:

I have just had a thought.I wonder if you just try and charge with one inverter. 28 Amps is about 1500W and you cannot charge without supplying load too.

Have you tried switching of all loads while charging, as an experiment not a permanent solution.

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1 hour ago, Hannes7212 said:

I am considering sticking the AC in through a big, heavy transformer to see if that (apart from introducing losses) will have a stabilising effect on the waveform under load.

A 2kVA 1:1 transformer will set you back a bundle and I doubt it will make a difference as it will faithfully transmit the input waveform to the output.

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17 hours ago, Hannes7212 said:

If you look at the waveform of the generator it looks pretty bad (I know, I should have taken screenshots) but still the Axpert accepted it.  As it started charging the wave did not change but as we got to about 23A you could see distortion starting to form and this gets progressively worse and true to form at 29A it drops the charging to zero.  This is where my knowledge of electronics start to fall short but I am considering sticking the AC in through a big, heavy transformer to see if that (apart from introducing losses) will have a stabilising effect on the waveform under load.

One other thing, as expected, putting a resistive load of 2kW on the generator did not result in the distortion we saw when the load is applied via the inverter charger.

Interesting; thanks for the data. Would it be possible to check one more thing? Can you check the power factor at the AC input of the Axpert when generator charging? Perhaps just a clamp current meter would do. Record the power factor or AC current into the Axpert near the point where the waveform starts distorting. 

The Axpert is using phase control to cause the inverter to draw power from the AC input to the battery. It needs to adjust the amplitude of the inverter output to control the power factor, or equivalently, to control the reactive power. If it's not doing a good job of adjusting the amplitude, the power factor can be very poor, and many generators won't like that. They might be heading towards their current limit way before they reach their rated power, and that could cause distortion of the waveform. When the waveform is distorted enough, the Axpert will find it hard to stay synchronised, and this would be why it drops the charge current.

With utility charging, the mains will generally not be affected by poor power factor much, so the charge current doesn't drop.

One weak data point: when the Axpert is powering loads and AC input is present, the inverter locks phase with the AC input. I believe that this is because it can perform a bypass transfer (utility replaces inverter for powering loads) much cleaner that way. But it makes no attempt to follow the amplitude of the AC input. This is a bit of a stretch now: perhaps it generally doesn't care much about the amplitude of the inverter output. Maybe they even leave it at 230 V all the time. 

Would it be possible to adjust someone's generator output to 230 V to see if they can get more charge current from their Axpert that way? 

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On 6/12/2017 at 6:25 AM, Hannes7212 said:

If you look at the waveform of the generator it looks pretty bad (I know, I should have taken screenshots) but still the Axpert accepted it.  As it started charging the wave did not change but as we got to about 23A you could see distortion starting to form and this gets progressively worse and true to form at 29A it drops the charging to zero.

What would be interesting is a shot of the current and voltage waveforms overlayed. I assume you only looked at the voltage waveform?

The overlaying is to get an idea of what kind of power factor is involved.

The easiest way to get a current waveform is to install a small resistance in line and place the scope probes across that resistance. A long length of wire might be sufficient so that you don't have to use an actual resistor (which would have to be correctly rated, etc).

Also, I assume the scope is rated for 400VAC peak and that it's either the nice handheld Fluke scope or you are aware that the ground clamp is tied to earth and how not to blow up a scope when measuring two things :-)

Edit: Or you can use a current transformer... I have ten of those in a box somewhere...

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On 6/12/2017 at 7:43 AM, pilotfish said:

Have you tried switching of all loads while charging, as an experiment not a permanent solution.

Jip did that too.  In fact, tried to dedicate one inverter for charging only as in parallel mode it wont even take the generator at all.  Have tried multiple firmware versions.  Now on 72 40.

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Hi all, thanks again for showing in interest in my problem.  Let me give a quick update:

Three inverters in parallel all running 72 -70 wont take generator.  Added filter to AC in, no change  (all the older, heatsink at the top type)

Took one out of parallel config and tested.  Takes AC in, but only charges to 27A before starting from 0A again.  Downgraded software to 72 40 (some user somewhere said that solved his problem).  This made it better - could hold charge at 47A without dropping so not too bad.  However, needed to run 3 in parallel due to clients requirements of over 10kW usable from time to time so put that one back after downgrading other two to 72 40 as well.  But sure as Bob, will not take AC in in parallel configuration.

OK, ever prepared, took out a new Axpert (no heatsink visible on top - the 4kW MPPT version) to act on its own as AC charger.  But this hardware, running same 72 40 software will not go over 27A again.

So this is where my level of gatvolness exceeded patience and I took out a 5kW Microcare inverter and stuck it on the battery bank to act as AC charger which is does without any complaints.  Now my client is sorted while I can try and find a solution to the Axpert generator charging issues.  

This has turned into a serious issue now to the point where I point it out to clients as a definite problem and can't recommend them if you want to go fully off grid.

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There is a user in Australia with a very similar problem, who has contacted his supplier over this issue:

http://forums.aeva.asn.au/forum_posts.asp?TID=4332&PID=65020&title=pip4048ms-inverter#65020

Would that be you? If not, it might be worth keeping an eye on developments there. As you can see, they haven't progreed past the "must be idiot user" stage yet. But sometimes things do get fixed via that route. 

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As a point of interest, what version of firmware did the older models with the heatsink on top come with? 

Can you remember when they were bought? Do they perhaps have a manufactured date tag? (Perhaps between the DC input terminals inside the cable cover? 

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Hi Coulomb, yes they were bought in June 2016 (and my supplier brings then directly from Voltronic so would have been fresh off the line) and the version was 52 30.  Not close them now to spot the manufacture date tag.

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I have a Mercer 5 kva inverter.a 16kva ss kipor generator.could not get the inverter to take power from the geni.untill i changed setting for ups to apl (appliance).also changed battery charge setting to solar and utility.seems to work ok now.the inverter will accept a wider imput voltage on apl then on ups guess there is a "voltage lag"with geni as its AVR adjusts for demand

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