Axpert MPPT vs Victron MPPT

[Guest]

I have said that IF it is proven that a Axpert MPPT is similar or same as a Victron MPPT, arranging a test 150/35 for this purpose, the results are in.

Not at all what was expected. Seems to me I need to keep my promise. 

I leave it now to Paul to give a detailed feedback in the next post.

[PaulF007]

Keep in mind that was done by me and I tried to be as impartial as possible. I asked @Chris Hobson just to verify that what I wrote was what I meant (Thanks Chris for the help) Also it should be noted that @The Terrible Triplett arranged through Victron SA for the SCC and we should give that man a Bells for his bravesness. Lastly the guys from SP Powerunits who was kind enough to give the SCC for testing. If you are in the Pretoria area it will be well worth your time to go by them. In the short time that I spoke with them I realised that there is still a massive amount if info that I don't know and I could have saved a fair amount of money have I took the time to chat to them beforehand.

As for the report here is what I came up with:

The System:

My current setup consists of the following:

·         12 x 260 w solar panels set in 3 panels per array

·         8 x 6-GFM-170F batteries

·         Victron BMV 702 Battery Monitor

·         1 Axpert 5000 VA – Firmware 72.80 Loaded

·         Victron 150/35 SCC (Test Unit)

First Method:

I have been testing the two SCC’s over a period days alternating between them to see how they perform under my day to day conditions. Now the consumption on a day to day basis does not stay consistent as this is a running household, but it does give you a reasonable idea as to the performance of the different SCCs.

First is the Axpert on a normal day starting from a 89 % SOC

By the end of the day the the battery monitor showed that the batteries was charged to 99 % and overall there was no real problems that I could see.

 

Second was the Victron SCC also starting on 89 % SOC

By the end of the day the the battery monitor showed again that the batteries was charged to 99 % and overall there was no apparent difference that I could see bet tween the two days.

Second Method:

I then decided to put the two SCCs next to each other and see how they would perform in exactly the same conditions. This meant that I would need to split the system in half having 6 panels on each SCC, and 4 batteries that was discharged to the same level. As my batteries do not get discharged very low at night I also decided to push them lower than what they have ever been discharged in order to give the SCC enough time charge. The batteries were discharged overnight to 70 % SOC and then the whole system was switched off, split and wired to the two SCC. As I only have one BMV I decided that I would not use it for any comparisons as it would only be able to measure the Axpert’s output.
Both the Axpert and the Victron do report battery Volts solar Amps and solar Watts and these readings were compared.
(As a side note when I tested the Victron SCC I did notice that there was a slight difference between the Victron SCC battery volt reading and that of the BMV so there would be some deviation between the two SCC’s , the  Axpert’s readings were very close to the BMV)

EmonCMS was used to log the data from the two SCC and there was no other load on the Axpert.

First graph is the Panels watts outputs from the two SCC.

Panel amp output

Battery Volts

Linear comparison between the Watt output of the two SCC’s

Personal Notes on the tests :

Apart from the one battery bank that took a bit more charge than the other I could not see any real apparent difference between the two SCC’s outputs. It was also noted that the Axpert’s data is not as refined as the Victron’s. The step pattern of the Axpert’s Amp feed indicates  reporting of Amps in whole numbers oppose to Victron more accurate readings in decimals. There was also a small variation in voltage reported by the Axpert and this can either be ascribed to again the coarser scale of its voltage readings or an inability to perfectly maintain absorb or float. Since there is a small amount of variation in the Victron voltage feed and the Axpert Voltage line is nearly linear I suspect that the case  is the former and the scale is too coarse to truly record the voltage. Occasionally it is rounded up or down resulting in peaks and troughs. In my opinion there is no real difference between the two SCC’s outputs as the data confirms it.

Some Extra notes:

Now there could be a host of other tests that one could do to compare the two SCC’s, but I attempted to run them in normal and side by side tests. The only thing that I would like to see is how they would compare under a cloudy day where the SCC would need to adjust as clouds passes over the system but then I would need to run the system in parallel over a time or hope that you time the weather perfectly and then split the system again. As this is a running household and not a test bench site it would be impractical to do so.

One last comment, when you handle the Victron SCC you do feel that there is a big difference between the two units. The Victron feels solid and well built and I would say the Victron would be able to handle a lot more hammering than would the Axpert but considering the price tag I am not prepared to push either one of them but my money would definitely be on the Victron to be on top of that one . 

The Victron gives you a host of options so that you could configure your system to be as automated as possible but it comes at a price.  The Axpert is more of an off grid “Inverter/UPS with a SCC” that does not give you many options so you would need to build your own setup to make it work fairly well within a grid system. In my case I have a remote triggered switch on the Axpert that will switch to grid under certain conditions and the family needs to be constantly aware as to what the system is currently doing before something is switched on or off. Where as if you have a Victron you could setup it up as a grid tie and then there would be no need for checking the system all the time.
Also to consider is the future value of your property. If you have an Axpert, you have had to grow with the system and learnt as you went on. In my case I had to setup up all sorts of things to make the system work. Now if I would like to sell the system with the property will I be able to get a buyer that will be able to understand the system and will he be able to get every thing going again if the R-Pi were to fall over? If not the system would become a liability and not an asset.

All in all money talks and the Axpert gives real good value for money as long as you know what you get and you are happy to live with it else consider saving a bit longer get your baseload lower and maybe consider getting a smaller Victron system. 

Best Regards

Paul

 

 

[Mark]

Many Thanks @PaulF007

This test took time and lots of effort which few would been able to spare.  Much appreciated!!

Regards

Mark

[Weasel]

Big super thumbs up for the post. Really aweaome stuff keep it coming. I did simmilar stuff testing panels and dirty panels effects cleaners and so on. 

Few things you could take into considderation. Swopping out strings of the two and swopping the banks. I.e. 4 days of testing averaging out the variables. Then comping a 60A and a 35A isnt really apples to apples In terms of the efficiencies that the units will experience, it will differ based on the load percentage . See the smaller one will heat up more as its running closer to its limits, heat = efficiency loss. Someone out there will likely think what about efficiency claim and yeah it doesnt quite work that way. each mppt will have its own sweet spot in terms of efficiencies. Dropping x volts at y current... bringing me to my last note. Viccy is at a disadvantage here from a design perspecive. It caters for 150v to charge 12 24 and 48v systems. Anyone with some switch mode converter experience will know the tighter you can define the in and output voltages the higher efficiency you can design in. Axie only needs to drop 60-145v into 48v sys. 

Ps. Im a victron fan in case its not obvious.

 

[___]

Looking at the volts/amps charts, it seems that the Victron controller ran at a slightly higher voltage most of the time, and as a result at slightly lower current. The proof is in the power-chart though, what you are interested in is the area under the graph (watt-hours), and it seems pretty conclusive that the Axpert won this round.

From the first test however, it seems that the same amount of charge is put back into the batteries by both controllers, which contradicts the area-under-the-graph observation. There seems to be some variables unaccounted for.

My gut feeling is to suggest that you need a BMV on both battery banks and compare the SoC at the end of the day. Because of voltage inefficiency (working at too high a voltage), it's possible that the controller with the lower throughput might have done the same work.

Other things I would be interested in is things like the ripple voltage and the ripple current, the kind of thing that stresses capacitors.

Overall though, credit where credit is due. The Voltronic SCC seems to be a fairly decent bit of kit (at least compared to some others... which I've already done today).

[___]

18 hours ago, PaulF007 said:

I would say the Victron would be able to handle a lot more hammering

I ran a 100/15 controller with a 50% oversized array for several weeks in the middle of summer. That thing got so hot I could smell it, and it was doing 14.3 ampere almost all of the time. I can vouch for the ability to take a hammering. Granted, that was just weeks... not years, but these things to have a warranty that is not too shabby.

[Chris Hobson]

3 minutes ago, plonkster said:

Looking at the volts/amps charts, it seems that the Victron controller ran at a slightly higher voltage most of the time, and as a result at slightly lower current. The proof is in the power-chart though, what you are interested in is the area under the graph (watt-hours), and it seems pretty conclusive that the Axpert won this round.

Hi Plonky if you look at the watt hours the Axpert does appear to "win". I think it is just due to Paul splitting his battery bank and there being a slight difference between the two strings. The Victron got the string that went to absorb first introducing a difference since the Axpert was able to continue with a higher charging rate. That small difference is then maintained for the rest of the day. If both SCCs were to charge the SAME battery bank based on what I see from this test I would expect no difference.

So my summation is that on a sunny day there is no difference in output between an Axpert SCC and a Victron SCC. On a day with intermittent cloud the Victron may still have the upper hand.

So is an Axpert a good piece of kit. "You betcha". It is comparable in some respects to top end kit and is ½ the price. Do Axperts inexplicably fail? The answer is yes to that question too. However, failure is not the exclusive domain of the Axpert as we have seen in recent days .

I try not run my Axpert at more than 80% of it capacity and therein maybe the reason for my Axpert's trouble free existence.  (Watch there is nothing like Murphy to make one eat humble pie ).

[pilotfish]

5 hours ago, Chris Hobson said:

On a day with intermittent cloud the Victron may still have the upper hand.

It would be great if @PaulF007 is able to hang onto the borrowed kit for a while longer until he has an opportunity to put this to the test - I have read some comments about the slow response of the Axpert SCC, I would just like to see the comparative effect of this on a cloudy day.

[Guest]

@pilotfish any more test / ideas / plans that one can test before the kit has to go back?

A test I am interested in, Paul is looking into it, seeing as a lot of people here push their panels for max ROI, is to see what the differences are over a period of time, between the 2 controllers under constant max use. Will the one make really be that much more than the other make to justify the price?

The next test I want to see, if someone can do such, is compare the 2 inverters. I suspect oscilloscope is required?
We all know the Axpert uses a bit just being on, but how good is the actual sine wave compared between the two? 

 

@Chris Hobson - the banks where identical, as each batt was load tested before anything was started to ensure apple for apples.

 

I am sending a email to the relevant parties to explain to me, with these test results, why should one pay so much more for Victron equipment. We can argue the level of built quality / reliability but then getting a new Axpert every X years would not only cost the same(?), the newer model will have more features, so that is a win. I don't think one can add more features to Victron controllers, they have all if not most in like complete configurability, auto equalise etc.?

 

Nope ... drink the coffee before it spills ... I am NOT switching alliances @Chris Hobson. 
I want my controller separate from the inverter.

[viper_za]

7 minutes ago, The Terrible Triplett said:

The next test I want to see, if someone can do such, is compare the 2 inverters. I suspect oscilloscope is required?
We all know the Axpert uses a bit just being on, but how good is the actual sine wave compared between the two?

Not both but Axpert vs Eskom
https://mybroadband.co.za/vb/showthread.php/808222-Axpert-MKS-5Kva-inverter-firmware-upgrade?styleid=42
Linked this somewhere before but cant find it now

[Guest]

46 minutes ago, viper_za said:

Not both but Axpert vs Eskom

Nope. Eskom varies all over the country.

Want to see outputs compared between Axpert / Victron inverters - maybe the Victron is less stable, maybe they are on par.

We also must also be fair here, as the post you noted Viper, if it was not for Coulomb and kie, there would not have been firmware upgrades to solve that problem. BUT, it is now solved, so lets not dwell on that shall we. Lets hope the newer Axperts are now sorted.

[Chris Hobson]

32 minutes ago, The Terrible Triplett said:

 

@Chris Hobson - the banks where identical, as each batt was load tested before anything was started to ensure apple for apples.

 

The two banks are the same make, age and in all respects identical. There is however a small difference is their ability to accept charge. If there is not it becomes very difficult to explain the Victron going to absorb early.

[Guest]

6 minutes ago, Chris Hobson said:

If there is not it becomes very difficult to explain the Victron going to absorb early.

Why? When I saw that I thought the one sees all is done and dusted on the bank so go to float.

If it is sooner than the other, it meant to me it was happier quicker. 

[___]

16 minutes ago, Chris Hobson said:

The two banks are the same make, age and in all respects identical. There is however a small difference is their ability to accept charge. If there is not it becomes very difficult to explain the Victron going to absorb early.

This test looks good on the Axpert's CV, but not necessarily bad for the Victron controller. It is simply too close.

Small variances might easily account for the difference seen. It could be as simple as temperature compensation. The Victron Controller, for example, has a BatterySafe thing in the algorithm where it deliberately charges a bit slower to keep the temperature down. If you didn't account for that, it might fully explain the small difference. But we don't know, so all we can safely conclude is this: That the Axpert SCC is at least in broad strokes, at face value, as good as the Victron controller. We cannot yet conclude that it is better because of things unaccounted for.

To be certain you'd have to put a BMV on both. It's possible they both got the same job done, and the Victron cooked the battery less in the process... (note, watch the nuance in my language... I said it is POSSIBLE... we don't know).

Also, DC ripple has to be tested before you can declare victory. Those fried DC-bus capacitors, there is some speculation that it might be DC-ripple, so you don't see it with a multimeter but in reality there's a nice little voltage ripple peaking at 63V... which is okay until the caps get on in age.

As I said, this is good for the Axpert's CV, but not necessarily bad for the other one.

1 hour ago, The Terrible Triplett said:

why should one pay so much more for Victron equipment.

Support. Support makes up a significant part of the price. It also has a 5-year warranty. I'm not defending, just stating fact.

1 hour ago, The Terrible Triplett said:

The next test I want to see, if someone can do such, is compare the 2 inverters. I suspect oscilloscope is required?
We all know the Axpert uses a bit just being on, but how good is the actual sine wave compared between the two? 

I have an oscilloscope. There's two things I need to sort. The first is that I cannot power the scope from the inverter while testing it because the ground clamp is connected to system ground and doing so will either create a big spark or trip the ELB. So I need an isolation transformer or use some other trickery. There is a way of using two inputs and telling the scope to show the difference between them, or you can just use the one probe and leave the ground clamp disconnected (using the fact that neutral is already bonded to earth), but that might cause noise in the signal that isn't the fault of the inverter and would not be fair. Also (second point), the scope's max voltage is 250V (peak) and grid voltage peaks at around 350... so can't measure it directly. I am unsure if using a step-down transformer would distort it. But I do have a scope...

The more interesting test would be to test THD (total harmonic distortion), but for that you need a really good storage scope with FFT functions. IE, something that costs at least as much as a 3kva axpert itself (for a cheap one), but ideally a piece of kit that costs around 10k. There might be a cheap way of using normal sound recording hardware and analysing the THD using DSP software, but once again, that would involve a step-down transformer and I'm unsure how that might affect things.

 

[Chris Hobson]

50 minutes ago, The Terrible Triplett said:

Why? When I saw that I thought the one sees all is done and dusted on the bank so go to float.

If it is sooner than the other, it meant to me it was happier quicker. 

To use an analogy it is like filling two sets of bottles with water at the same rate (we know this since the watt output of the two SCC is for all intent purposes is the same) and the one set made that funny noise to say it was nearly full sooner than the other. Our bottles are not identical - we thought they were but they not.

28 minutes ago, plonkster said:

It could be as simple as temperature compensation.

Paul switched that off to make as close to comparing apples with apples.

 

34 minutes ago, plonkster said:

This test looks good on the Axpert's CV, but not necessarily bad for the Victron controller. It is simply too close.

Very true - reminds me of your quote a couple weeks back of a debate between a biologist and a philosopher if memory serves me correctly.

 

38 minutes ago, plonkster said:

The Victron Controller, for example, has a BatterySafe thing in the algorithm where it deliberately charges a bit slower to keep the temperature down.

If it had charged slower then the Axpert would have transitioned to absorb first. It is about 15-20 min and probably 1A so not a huge difference. 

[___]

1 minute ago, Chris Hobson said:

If it had charged slower then the Axpert would have transitioned to absorb first. It is about 15-20 min and probably 1A so not a huge difference. 

I don't think one can infer too much about the timing of when it switches to float. The BlueSolar also has adaptive charging whereby it times the absorp phase relative to how long the bulk phase was. The Axpert does something similar I'm told, but even here, minor differences between the controllers might mean that one switched at a real SoC of 85% and the other at 86%. This isn't an exact science :-)

[Guest]

12 minutes ago, Chris Hobson said:

Our bottles are not identical ...

Aha, I see where you are going.

To be fair, why not ask the question: Why did the Axpert take longer?

As Plonkster says, BlueSolar has adaptive charging.
And was it on exactly the same SOC?
EDIT: As I said, one was happy with what the batts could take faster than the other one is what I took away from that.

 

We have to try our very best here to be impartial - look at both sides equally hard. 

I was NOT impressed with the results I tell you, but that is an emotional response. 
And IF my equipment was to fail today ... it would be an emotional debate going on in my head. 

[pilotfish]

58 minutes ago, plonkster said:

Also, DC ripple has to be tested before you can declare victory.

Could the DC ripple not be tested to a reasonable degree with an RMS multi-meter set to AC, which would give a figure for the amount of AC ripple on top of the DC voltage.

Obviously an oscilloscope is preferable, but the multi-meter should give an answer enough for comparison purposes.

[___]

1 minute ago, pilotfish said:

Obviously an oscilloscope is preferable, but the multi-meter should give an answer enough for comparison purposes.

It could indeed provide some kind of idea. A pure DC signal would then register as zero? And a lower AC-bit would be preferable? I would love to have a meter that can measure RMS instead of assuming it's sinusoidal as most of the cheaper ones do :-) Can't quite justify it, I'm a code jockey by trade, and amateur electronic engineer at night :-)

[___]

6 minutes ago, The Terrible Triplett said:

And IF my equipment was to fail today ... it would be an emotional debate going on in my head. 

Oh I doubt it. If I crashed my Toyota today... would I seriously be looking at a Ford tomorrow because it does the same thing for less money... or would I be buying another Toyota? :-P

[pilotfish]

1 minute ago, plonkster said:

A pure DC signal would then register as zero? And a lower AC-bit would be preferable?

Correct.

I have 2x Fluke RMS multi-meter but may be a bit far from the test lab (Randburg), I am sure that there will be someone in the vicinity with the correct equipment for a loaner.

[pilotfish]

10 minutes ago, The Terrible Triplett said:

I was NOT impressed with the results I tell you, but that is an emotional response.

I dont think there is any reason to be grumpy with Victron because it seemed to do a good job, it is just that the Axpert was equally good!

I still think that carrying out the same test in less ideal conditions might swing things in the blue direction.

[Guest]

20 minutes ago, pilotfish said:

I dont think there is any reason to be grumpy with Victron because it seemed to do a good job, it is just that the Axpert was equally good!

I still think that carrying out the same test in less ideal conditions might swing things in the blue direction.

Wanted to see a 20-30% improvement.
Wanted to see the batts are better treated by V and A.
Wanted a justification for the more expensive SCC.
Wanted to give all non-Victron users the chance to say: Aaaaa, now we understand why.

What is in blues favour is the robustness, the auto firmware updates, the support, the not rusting, the plug and forget. But is all that the difference in price worth it?
Not for a Axpert user no, never. That is why I am grumpy. (sad face)

 

29 minutes ago, plonkster said:

Oh I doubt it. If I crashed my Toyota today... would I seriously be looking at a Ford tomorrow because it does the same thing for less money... or would I be buying another Toyota? :-P

Ag ok ... but I will still have the debate ... a quick one. 

But ja, there is something with what we have that just works, like Toyota and Isuzu 280TD's. Not cheap but they do give you a feeling of don't stress ever.

[Guest]

Bottom line: There is no "cheap easy" way to compare the inverters that leaves little to the imagination then?

 

For if the two inverters are on par like the MPPT's, then I have nothing more to add for or against Victron. It boils down to:
- How technical are you? (No support from the manufacturer. Read: Is Coloumb around still? PowerForum still around?)
- Are you a tinkerer? Yes, get Axpert. No? look at Victron.
- Best you make sure if your area are prone to things rusting - get Victron. If not, Axpert.

Or what is your budget?

[Chris Hobson]

1 hour ago, plonkster said:

I don't think one can infer too much about the timing of when it switches to float. 

I not that concerned about the transition from absorb to float but the transition from bulk (CC) to absorb (CV). That transition is voltage based and is the best we have in terms of feedback from the batteries.