Anyone with experience with the Huawei range of inverters? I haven't seen the smaller units for sale in South Africa, but only the bigger ones.

http://solar.huawei.com/eu/products

Certainly looks impressive, or am I missing something? SUN2000L.pdf

Their products in IT, has always been good. Same as their phones.

Their prices are always very good for the reliable products I have used of theirs over decades.

If they now enter this market, and get their stuff approved by say CoCT and others, it could become very interesting. 

I was impressed by specs so was following release date since a year. Guess they had some production problems. Huawei always had service problems before.

Heard they will start in Australia market first. I am very curious if anybody knows about pricing over there ?

Also i thought HV LG fade on SOH quickly due to absence of cooling , so not the best combination.

 

I am about to install a 36kW unit. It does derate above 45°C but I think that is a minor issue.

 

Sorry i thought CJW mentioned about FusionHome , which is fro 2kw-8kw , similar to StorEdge without Boost DC converters in Huawei optimizers.

For larger ones , have no idea.

10 hours ago, Chris Hobson said:

I am about to install a 36kW unit. It does derate above 45°C but I think that is a minor issue.

 

I saw Bonanzatech have 3 different 3phase models in stock, but none of the smaller ones nor the 36kW unit. They do seem to be competitively priced for units with a 5 year warranty. Would be interesting to see what the smaller single phase units sell for in SA.

 

I'm still a newbie and what I do not understand is the fact that the smaller units can handle batteries of 350Vdc - 450 Vdc. Would this mean that you need to use some sort of specialized battery?

26 minutes ago, CJW said:

batteries of 350Vdc - 450 Vdc

That might in fact be due to them being "smaller". Small engineering lesson coming up... :-P

A modern inverter works like this: First it takes your low DC voltage, and converts it into high-frequency AC. Then it pushes that AC through a transformer to turn it into a higher voltage AC. The reason for using a high frequency is it allows you to be more efficient and use smaller transformers. Then it turns the high-voltage AC back into DC. At this point it typically generates around 400VDC. This first phase of the inverter is called the "boost stage".

The second phase then turns this 400VDC into 230VAC. You may wonder why does the DC have to be so much higher? Because the 230VAC figure is an RMS value. The peak voltage is over 300V.

Now you get some inverters that use a high voltage DC input. Those inverters don't need a boost stage. Usually they are PV inverters (SMA makes some nice ones), but the same thing can be done with batteries.

In addition, the boost stage of an inverter is the more stressed part of it. A high voltage input unit will be less stressed and less likely to fail.

So this "smaller" unit likely relies on the high input voltage for exactly that reason. And it may well require a special battery.

The Tesla battery is a high-voltage battery as far as I know. Perhaps that is what they are aiming for.

Thanks for the lesson plonkster!

It would indeed seem that they are aiming for a specialised battery in the form of a “LG Li-ion” battery which is already available in SA, but quite expensive.  

 

On 2/20/2018 at 10:53 AM, plonkster said:

This first phase of the inverter is called the "boost stage".

plonkster ; so by logic those 400VDC inverters which doesnt need boost would be cheaper ? We can connect series of solar panels to supply 400VDC with no extra cost. And if battery supplier just connect cells in series 400VDC will be even cheaper becuase of low current BMS cost.

Correct ? 

14 hours ago, Mars said:

by logic those 400VDC inverters which doesnt need boost would be cheaper ?

Could be... though I cannot say I see it play out in practice.

14 hours ago, Mars said:

series of solar panels to supply 400VDC

Long series strings have other problems too :-) Probability of a failure point goes up linearly the longer that string gets.

14 hours ago, Mars said:

cheaper becuase of low current BMS cost

Way way more cells to keep an eye on though, so I'd think it would get more expensive, not less. And same long-string issues. One cell in the middle of a very long string, with high currents and all that... you're swapping one kind of problem for another one.

Truth be told, I'm speculating, postulating. If it is cheap, I can guarantee you it is not because they are being nice. The money is being saved somewhere. And the high input voltage is like a big flag: No boost stage. That could be it... or not :-)

On 2/20/2018 at 9:53 AM, plonkster said:

That might in fact be due to them being "smaller". Small engineering lesson coming up... :-P

A modern inverter works like this: First it takes your low DC voltage, and converts it into high-frequency AC. Then it pushes that AC through a transformer to turn it into a higher voltage AC. The reason for using a high frequency is it allows you to be more efficient and use smaller transformers. Then it turns the high-voltage AC back into DC. At this point it typically generates around 400VDC. This first phase of the inverter is called the "boost stage".

The second phase then turns this 400VDC into 230VAC. You may wonder why does the DC have to be so much higher? Because the 230VAC figure is an RMS value. The peak voltage is over 300V.

Now you get some inverters that use a high voltage DC input. Those inverters don't need a boost stage. Usually they are PV inverters (SMA makes some nice ones), but the same thing can be done with batteries.

In addition, the boost stage of an inverter is the more stressed part of it. A high voltage input unit will be less stressed and less likely to fail.

So this "smaller" unit likely relies on the high input voltage for exactly that reason. And it may well require a special battery.

The Tesla battery is a high-voltage battery as far as I know. Perhaps that is what they are aiming for.

The high pv voltage usually feeds the mppt. The MPPT works like a DC step-down Transformer and this lower voltage matches the battery voltage for which the inverter was designed. With a system like that, there is a lot more flexibility in that the input voltage may change significantly without affecting the output voltage of the MPPT.  E.g., to charge a 48V battery with a low PV voltage, would mean a change in Mppt output a lot quicker than if the PV voltage was higher. In general the efficiency improves with a high PV voltage. A further advantage of high PV voltage, is the fact that the current is low and the cables can be thin.