54 minutes ago, The Terrible Triplett said:

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:

I have about 12x Axpert 5k units out in the field operating as grid backup systems (so no PV input) and can report that the the inverter section has surpassed my expectations and are quite hardy units. I have had no failures at all and no problems reported regarding quality of the output.

The output is hard wired into the DB supplying selected loads only so they are quite well looked after - supplying all lights, fridge, security equipment, computer/internet, entertainment systems and then a couple of plugs in the kitchen for small appliances and charging etc.

I think that Voltronic have been in the UPS/Inverter business for quite a while and have that side of things pretty sorted. If you look at the Mybroadband test report pointed to by @viper_za above, it shows a waveform clean enough for anything other than the most sensitive scientific equipment, and certainly much cleaner than your regular Eskom supply.

I still have some questions regarding the quality of the SCC section which these tests above have not yet entirely allayed.

@pilotfish I should be able to test the RMS as I have a Fluke 177 but you will need to explain how and what to look for . 
If all goes to plan and the weather hold I am going to run a test with only one array of panels on the SCC this should "simulate" running the system at max then I will run the Victron under the same conditions. I suspect that the victron will produce a little more energy than the Axpert , from what I understood the victron's MPPT is quicker than the Axpert and should result in better yields... 

From my view the first bunch of tests show that they are on par with each other and I would not call a winner on either one of them the fact that the one went to flout quicker could be a host of things and would not make any difference at the end of the day so it would be splitting hairs. Depending on how much more energy one could get out of either of them could make a difference and that is why I would like to see what they do. 

 

3 hours ago, The Terrible Triplett said:

Wanted to see a 20-30% improvement.

LOL, the space between the best and the worst controllers is only about 10%, maybe 15%. The difference between PWM and MPPT is about 33%. Victron claims a 10% edge specifically on faster tracking, but that is a generic claim, one of those "up to X%" type marketing claims. We already know the BlueSolar tracks faster because it doesn't drop to zero when it needs to do a rescan, but this wasn't tested. Even if it was, it is possible that the difference will be single digits.

3 hours ago, The Terrible Triplett said:

Wanted to see the batts are better treated by V and A.

The jury is still out on this one. The BatterySafe stuff with the temperature compensation -- which was turned off -- does actually mean it's treated better. Better ripple does mean your batteries and the rest of your equipment is treated better. Of course we don't yet know, and even if true, is it enough to justify the price? That remains the eternal question.

3 hours ago, The Terrible Triplett said:

Wanted a justification for the more expensive SCC.
Wanted to give all non-Victron users the chance to say: Aaaaa, now we understand why.

Yeah, "I told you so" can be very satisfying. Not today though... :-)

3 hours ago, The Terrible Triplett said:

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)

Our perpetual car analogies is not far off. I remember some 8 years ago when I got rid of the BMW... one of my colleagues thought I was crazy. How on earth could you prefer a Japo-box over the German smoothness? It turns out we value different things. I want a car that doesn't come begging for money every other month, even if the ride is a little harsher. He on the other hand doesn't mind paying for the pleasure of a nice car.

3 hours ago, The Terrible Triplett said:

- Are you a tinkerer? Yes, get Axpert. No? look at Victron.

I disagree on this point. The Victron stuff is like Lego Mindstorms. Expensive, yes... but the ultimate tinkerer's toy.

Edit: Really, what other manufacturer has a mailing list where people can subscribe and participate in the development of the firmware, where they make software that you can run on hobbyist boards (Beaglebone Black and Raspberry Pi) so you don't have to buy everything from them, where you can control their stuff using ModBus TCP, where you can download an SDK to write addon software... and you want to call the OTHER guys tinker-friendly? More like tinker-needy :-)

1 hour ago, plonkster said:

... the ultimate tinkerer's toy.

True true ... but it is also plug and forget if that is your thing ... like in my thing. 

Of the 1577 users here, the tinkerers are in the vast minority I would bet.

43 minutes ago, The Terrible Triplett said:

tinkerers are in the vast minority I would bet

I think an inverter like the Infinisolar or the Goodwe even really shines if you're a non-tinkerer. I mean, not much that can be adjusted, but once properly set up it really just works. The Multiplus can be somewhat overwheming (look at @9xsolar's tribulations on another thread :-) ), and the Axpert needs a little external help (from a BMV and an Rpi), so it does seem as if these two are the rich- and the poor man's tinkerkit respectively.

11 hours ago, plonkster said:

I think an inverter like the Infinisolar or the Goodwe even really shines if you're a non-tinkerer ...  The Multiplus can be somewhat overwhelming.

You make a very good point. I stand corrected.

14 hours ago, PaulF007 said:

I should be able to test the RMS as I have a Fluke 177 but you will need to explain how and what to look for

The tests required are simply DC voltage and then AC voltage at the output terminals of the SCC (and then if you have a DC clamp tester the DC current at the time of testing), the Fluke 177 meter will read RMS values there is nothing special required. We are interested in comparing ACv values between the two SCC's under similar conditions with the lowest AC component being the winner. So the tests are dead simple, it is setting it up and getting it done which is going to be a PITA, so thanks in advance for your effort!

• Each SCC should be tested entirely on its own with no external influence - so no load on batteries while measurements are being taken and only the SCC being tested should be connected to the bank at time of testing,
• Carry out 3 times during the day if possible (early, mid morning, just before float) with the last test being the most important,
• This is the biggie If possible test at various charge currents (min/normal/max).

If there is going to be a significant AC ripple component it would normally worsen as power output increases. If AC ripple is low at 20amps, manageable at 40amps but sky-high at 60amps then that is important information for Axpert owners.

To carry out all the above tests will take time and be a significant disruption to the household, so it would be perfectly understandable if you cut it down to just one test on each SCC, at your charge current, preferably just before float.

 

5 minutes ago, pilotfish said:

AC voltage at the output terminals of the SCC

Am I correct to say that I will need to set the Fluke to ACv and then measure the DCv of the SCC output?

Yes, first DC volts and then flick over to AC volts. Both values are informative.

Sent from my SM-N910C using Tapatalk

Also, just as an explanation about this whole RMS thing, check out this old knulgnar video, starting at around 4 minutes, the DC ripple bit is at 5:15. What you have is a DC component with an AC component on top of it. You want to know how large the AC component is.

The cheap meters measures the peak AC voltage, and then assuming that its a sine wave, it shows a value that is 70.7% of that (which is the average of a sine wave). 9:35 in the video.

The RMS meter measures the actual average, which is important when you're not dealing with a sine wave, or where the duty cycle of the waveform varies. But more importantly, it is AC coupled, which means it filters out the DC component and measures only the remaining AC component.

An MPPT, being a buck converter, will use a square wave of varying duty cycle, usually in the range of 40khz to maybe 150khz (high enough that humans cannot hear it, low enough that skin-effect doesn't become a problem). But a buck converter also has a capacitor that has to smooth it out, and depending on the size of this capacitor, the ampere range of  the converter, the voltage ratio of the input vs the expected output, and the size of the inductor, there will be a DC voltage ripple (a slight up and down variation in the DC voltage) on the output. Lower is better.

The reason why you want to measure it a few times during the day, is because the duty cycle is going to vary depending on how full the batteries are, and the voltage ripple will be worst when it the duty cycle is low (as it goes to float)... it's like trying to fill a test tube using a high pressure hose by opening the tap for a REALLY short period... that is the kind of spike you deal with at that point :-)

On 6/21/2017 at 5:44 PM, pilotfish said:

I have about 12x Axpert 5k units out in the field operating as grid backup systems (so no PV input) and can report that the the inverter section has surpassed my expectations and are quite hardy units. I have had no failures at all and no problems reported regarding quality of the output.

The output is hard wired into the DB supplying selected loads only so they are quite well looked after - supplying all lights, fridge, security equipment, computer/internet, entertainment systems and then a couple of plugs in the kitchen for small appliances and charging etc.

I can testify to this as well. These inverters work quite well. Even comparing them to Microcare and Victron's in the field, I think it's a good piece of equipment for the price. The InfiniSolar range is also quite surprisingly good. 

14 hours ago, SilverNodashi said:

These inverters work quite well

It's like being a Stormers-supporter while the Bulls are having a winning streak! :-)

On 21/06/2017 at 2:56 PM, plonkster said:

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 :-)

I have a Fluke 179 ( http://en-us.fluke.com/products/digital-multimeters/fluke-179-digital-multimeter.html) and both quattro and Axpert - I will try this weekend . I may be able to lay my hands on a THD scope also by August end . 

Something I've been thinking about recently, after I learned something of the internals of the BlueSolar: Does anyone have details about the Voltronic MPPT (perhaps @Coulomb), is it a sync or async buck converter (I'm guessing sync), and how many inductors/switches and is it interleaved? I ask because I learned that the BlueSolar is essentially two synchronous buck converters running interleaved (better output ripple). In other words, it is quite a step up from the other MPPT I know well, namely the Microcare MPPT.

3 hours ago, plonkster said:

Something I've been thinking about recently, after I learned something of the internals of the BlueSolar: Does anyone have details about the Voltronic MPPT (perhaps @Coulomb), is it a sync or async buck converter (I'm guessing sync), and how many inductors/switches and is it interleaved? I ask because I learned that the BlueSolar is essentially two synchronous buck converters running interleaved (better output ripple). In other words, it is quite a step up from the other MPPT I know well, namely the Microcare MPPT.

Hi Plonky I think it is an asynchronous interleaved buck converter. I base my observation solely on the presence of diode rather than a MOSFET in the diagram below.

I was lead to believe it should be a Schottky Diode rather than an ordinary diode. Perhaps I should just stick to sheep farming.

Yup, that's an interleaved sync converter. Notice how Q and ~Q drives the two FETs in each stage (ie the free-wheel side is done with a FET rather than a diode, that is what makes it synchronous), and also note how the two buck converters are driven with an out of phase square wave.

So it's the same kind of design as the BlueSolar then.

16 hours ago, plonkster said:

Yup, that's an interleaved sync converter. Notice how Q and ~Q drives the two FETs in each stage (ie the free-wheel side is done with a FET rather than a diode, that is what makes it synchronous), and also note how the two buck converters are driven with an out of phase square wave.

So it's the same kind of design as the BlueSolar then.

Back to buck converter 101

Yeah my visual "water flow" idea of a buck converter is this: It's like having a low pressure tank, you know the kind you put on water heaters. You have a ball valve at the top, and you fill it quickly using a high-pressure feed, reducing the high pressure to a lower one. Same with a buck converter, it reduces a higher voltage to a lower one. The inductor is the "tank", the FET is the ball valve. The only difference is that unlike water, electricity needs to flow in a circle, so you need a "reverse valve" on the input side to catch the back-EMF (that's where you normally put the Schottky diode). If you replace the diode with another FET (because FETs have lower RDSon than a Schottky), then you need to manually open that valve, ie operate the two valves alternatively (that makes it synchronous). And if you have two tanks and two ball-valves and you operate the two tanks alternatively you get a more even flow out of the two combined tanks and you say that it is "interleaved". :-)

49 minutes ago, plonkster said:

Yeah my visual "water flow" idea of a buck converter is this: It's like having a low pressure tank, you know the kind you put on water heaters. You have a ball valve at the top, and you fill it quickly using a high-pressure feed, reducing the high pressure to a lower one. Same with a buck converter, it reduces a higher voltage to a lower one. The inductor is the "tank", the FET is the ball valve. The only difference is that unlike water, electricity needs to flow in a circle, so you need a "reverse valve" on the input side to catch the back-EMF (that's where you normally put the Schottky diode). If you replace the diode with another FET (because FETs have lower RDSon than a Schottky), then you need to manually open that valve, ie operate the two valves alternatively (that makes it synchronous). And if you have two tanks and two ball-valves and you operate the two tanks alternatively you get a more even flow out of the two combined tanks and you say that it is "interleaved". :-)

Nice explanation