15 minutes ago, Mark said:

And they are BLUE   I have a 40A MPPT - solid build an looks robust...

I took one of these apart and repaired it. It's a simple design, asynchronous buck converter, PIC microcontroller, drives an N-channel MOSFET on the high side (ie, the proper way), good components, uses an actual issolatedhigh-side supply to drive the FET (no bootstrapping or other tricks), ie simple simple simple. It is of course nowhere the same quality as my little blue box, but it is half the price. It's double the price of the WRND... and worth every cent of that! :-)

Downsides, as I said, quality of construction not quite up on the top shelf (though miles better than the WRND!), after some years the metal case may show a bit of rust. Company is close by and will repair. Communication with them is a bit hit and miss though, or it was with mine (which is why I repaired it myself the second time round).

12 minutes ago, Noobie said:

Awesome, thanks for sharing. Looks like those models have a fan?

Ja... I have the older plain MPPT... not the geyserwise model the guys are drooling over...

1 minute ago, Mark said:

Ja... I have the older plain MPPT... not the geyserwise model the guys are drooling over...

Indeed, new models might be better even :-) Although I'm silently hoping they kept it simple.

The fan on mine would run at all times of the day without it even getting hot. I didn't see any temperature sensors inside, so I think it predicts in software when the fan might be necessary. It could very likely run just fine without the fan, even the original. Might even modify mine to have an actual temperature sensor (which I can scavenge from the WRND lying in a box, unrepairable).

Just found these videos on YouTube 

It seems as though he had the failure as I did, I hope I don't have to repair my Axpert every couple of months!

 

 

Dockarl (chap in the video above) is knowledgeable and had one of the earliest PIP's for evaluation for his communication business. He was running them using a separate MPPT from Voltronic stable which did not make sense to me as the Axpert has its own MPPT. A lot of water has passed under the bridge since then. PIPs and Axperts have gone through a phase when they were quite stable and unfortunately seem to have become less stable with the more recent updates. TTT and Plonky will be pleased that he is an avid blue supporter.

Solarmahn based in Papua New Guinea has installed lots of PIPs and has had failures but has some tricks up his sleeve to improve reliability in what is a very hot humid environment.

@edmundp mentioned to me in a private conversation -- I hope he is okay with me sharing this bit -- how amazed he was at the speed at which the BlueSolar tracks. In turn, I was amazed that that is "fast", I thought all MPPTs are at least that fast. My MicroCare was at least that fast (visually). So to hear that the Voltronic MPPT is slow to back off (causing overvoltage on the DC bus) is somewhat of a surprise. You know, much as my Blue fanboydom wants to take over and celebrate... I'd think that should be easy to fix and would have been done a long time ago?

Also, rating caps just slightly above expected working voltage is done all over the place. In TTT's small Victron, I commented that I found it odd that the caps were only 16V. In the same way, I'm always amazed how car radio makers get away with 16V caps... cat batteries easily go that high on a cold morning, especially if the battery is a bit worse for wear. So a 63V cap on that bus -- though a little cheap-ass -- isn't too odd. Swinging the bats over 63V though... what the heck? :-)

11 hours ago, Noobie said:

Just found these videos on YouTube 

It seems as though he had the failure as I did, I hope I don't have to repair my Axpert every couple of months!

 

 

It's such a pith these cheap inverters don't last. I wonder if the more expensive stuff will last longer than 3 months?

1 hour ago, plonkster said:

I'd think that should be easy to fix and would have been done a long time ago?

Will this be a firmware fix or is it hardware related?
I know a new firmware for the SCC was posted on the forum just the other day.

38 minutes ago, SilverNodashi said:

It's such a pith these cheap inverters don't last. I wonder if the more expensive stuff will last longer than 3 months?

Like Chris said, those videos were made with the earlier revision of the inverter. If you look at the Aus forum you will see they did upgrade the DC side a bit later on.

Still curious about two things though: That 2000 hour capacitor, and the slow reaction times from the SCC. How slow is it really (for interest sake), eg when you snap off a load like a kettle, how badly and for how long does it spike? The spike is unavoidable, I think even the best controller is going to take 100ms (at the very least!) to start adjusting, possibly much more. On the more elaborate hub systems just the comms will take 100ms :-)

Anyone have an open unit they can use to check the caps?

On the way to work I thought about something else. The 48V 3KVA Multiplus is about 1600 Euro, if you bought it in Europe today, directly from HQ. Through a bit of research, and just as a general rule I learned over the years, I know that the cost of making it is bout half of that, so in terms of physical components it costs around 800 Euro, or R12000 Ex vat. That's still about double what the Axpert costs, after markup and import costs, in other words these inverters come with a "free" MPPT, delivered all inclusive for just over half the manufacturing cost of the other one. Granted, some of it is going to be down to labour costs (China vs Europe), I'm not sure where these units are built, but it does rather feel to me like something has to give.

With that said, cost isn't always an indicator of quality, I know and all, just having never had the privilege of working with one, that is one of the few yardsticks I have. It might in fact be so that these comparison fights we get into is entirely unfair to both inverters.

1 hour ago, viper_za said:

Will this be a firmware fix or is it hardware related?

To answer that (missed it first time round), I think it is at least partially hardware related. Slow comms. The inverter speaks to the SCC to open up the taps if there is a kettle on in the house (for example). When the kettle turns off, it takes some time for the inverter to back off the SCC. In that time, the extra 30 amps (at 48V) that was going towards running the kettle is now going into the batteries... which even for the recommended 200Ah bank is an extra 15% on top of the safe 15% you likely had configured. If the batteries were already quite full, that's going to push them to 64V easily.

There has been a post on this forum asking about the MPPT's and the spikes that was seen monitoring them. I think it was @edmundp who asked, but it derailed.

Edmund, what was the question you had? Maybe it is related to this chat?

29 minutes ago, plonkster said:

Anyone have an open unit they can use to check the caps?

From the service manual

Thing is, voltage is not the only measure. A better quality capacitor would be able to withstand the odd abuse at 64V. I still don't like it. Just way too close. You should have 10% space at the top, which means put in 100V capacitors dammit! It doubles the cost of those caps of course... I think that is why they do it. That's my point though...

11 minutes ago, plonkster said:

Thing is, voltage is not the only measure. A better quality capacitor would be able to withstand the odd abuse at 64V. I still don't like it. Just way too close. You should have 10% space at the top, which means put in 100V capacitors dammit! It doubles the cost of those caps of course... I think that is why they do it. That's my point though...

From the Aus forum these are Jamicon caps.
What would you suggest as a good replacement for them? (limited to 18mm diameter caps  because of the board layout)

So I realised I know little about capacitor lifetime.

A 2000h capacitor will have 80% of its capacitance left if you run it at its rated temperature (in this case, 105 Celsius). I don't think a 2000h capacitor is necessarily a bad one. The "voltage derating" is much more important (for caps running close to their maximum). Viper makes a good point though, uprating might not be that simple. Has to fit on the board. Can't find a single one that will fit so far.

Point is, it remains a weak point when you have 63V caps and battery banks (such as the Trojans) that equalize at 62V and will easily go there with a little extra current. Also another reason not to run these with small battery packs :-)

4 minutes ago, plonkster said:

So I realised I know little about capacitor lifetime.

A 2000h capacitor will have 80% of its capacitance left if you run it at its rated temperature (in this case, 105 Celsius). I don't think a 2000h capacitor is necessarily a bad one. The "voltage derating" is much more important (for caps running close to their maximum). Viper makes a good point though, uprating might not be that simple. Has to fit on the board. Can't find a single one that will fit so far.

Point is, it remains a weak point when you have 63V caps and battery banks (such as the Trojans) that equalize at 62V and will easily go there with a little extra current. Also another reason not to run these with small battery packs :-)

This design is quite common in just about any electronics today! Car radios are much worse, but since they generally draw much less current, it's not so bad. Until you fit custom sound and quickly realize why a "competition deck", even from the same manufacturer is so much more expensive than a normal one. 

This is one recommended on the Aus forum

'Caps: United Chemi-con EKZN800ELL 182MM40S, 1800uF 80V radial
Digikey part 565-4129-ND

Capacitance, voltage, ripple, impedance, endurance (at 100 kHz and 105°C)
Original          3300 uF, 63 V, 4.57 A, 15 mR,   2,000 h
Replacement 1800 uF, 80 V, 3.86 A, 17 mR, 10,000 h

Hopefully the 5 times longer endurance more than makes up for the 15% lower ripple current rating."

Man, don't get me started on design. When a computer motherboard pops the caps because they were placed too close to the hot CPU... that just irritates the crap out of me.

1 hour ago, plonkster said:

Man, don't get me started on design. When a computer motherboard pops the caps because they were placed too close to the hot CPU... that just irritates the crap out of me.

The 350 VA little issue I created, Edmund put in better ones ... so it is a common issue and as Silver pointed out, if you go top notch, so does the price, on sound systems also.

But yes, on computer motherboards, that is just bloody stupid, even if you have fans and all that.

And then I think, the designer, maybe he had an issue to deal with ... or maybe they where just lazy or maybe designed it so that it must fail over x hours of operation.

It's simpler than that really. They make it as small and as cheap as they can. Sometimes they overshoot. Then someone from Bean Counter central walks down into the basement and tells the engineers that they are getting too many warranty returns. The engineers then move the Cap one millimeter away. This process is then repeated until the Bean Counters are happy with the warranty return rate. The result is that you literally optimise cost vs life to the point where everything fails just outside of warranty.

:-)

Had the little Victron open this morning to blow out the dust. It has a big 50V capacitor on the bus. With a 24V inverter, if you were being cheap, you would have gone with a 35V capacitor... :-)

is it so big difference in their prices!?

 

I think I am officially at my wits end with this Mecer inverter.

Following the failure Mustek replaced the main PC board, I reconnected the inverter and found that the solar charge MPPT was not working.

I returned the unit to Mustek again and they replaced the MPPT board.

I connected the inverter up again and set it to UTI so that it would use solar to charge the batteries when Eskom was available and feed Eskom through to the house.

Its been running for two weeks and the solar has been keeping the panels on float and Eskom has been supplying the house.

This morning we had a power failure, the inverter started pulling power from the PV panels and used this to charge the battery and supply 220v to the house.

After about 15 minutes I went to go and check the load the house was pulling and found that the inverter was showing no solar input, like the panels had been disconnected! 

I measured the voltage coming from the PV panels and found it to be 98v.

Im not sure where to go from here, as far as I can tell my install is in good order and the max PV voltage does not exceed the MPPT's 145v Max input?

Could there be something wrong with the PV panels which is causing the MPPT to stop working?

When the PV was charging the batteries only it pulled about 20watts with no issues, when Eskom failed and the load was increased to 400watts it seems to have killed the MPPT???

My PV array is 1500w, 2 strings of 3 series connected 250watt panels?

Do you have any fuses between the MPPT and PV? Put some 10A fuses in-line and see if they blow? That could indicate PV voltage spikes.