coffeedogsjujitsu

My apologies, I was busy at the time, I didn't have the capacity to respond in full.
Axpert inverters typically work well if all you want is a UPS, keeping essential loads going during a power failure or load-shedding utility. That said, there are losses in efficiency with any inverter, charging batteries from AC (AC -->DC conversion), storing the DC charge (standing losses), and then converting it all back from DC to usable AC again. These efficiency losses means that It becomes expensive to just keep the lights on.
So you add some solar panels, thinking that it would be great to offset some of these losses using sun power. And it is, solar panels charge the batteries, and but when they are charged, they just sit there in the sun. So you decide that you want to use them directly to service loads, and they can, but the problem with most axperts is that they either use 100% Eskom power, or 100% battery power or 100% solar power, there's no in-between. This means that if you have a 5K Axpert inverter with panels capable  generating say 2500W DC, and your load is 2000W, all is good, the inverter will convert and use solar power to power loads. The problem is when a cloud happens along, and solar generation drops to 1500W. The axpert-type inverter will switch 100% from solar to grid, and if not grid, 100% to battery. This is true for most axpert-type inverters, although I have heard of some that can do limited "blending" of sources. The Sunsynk, by contrast, will blend any source depending on how it is set up. In the above scenario, it will still use the 1500W from the panels, but supplement it with 500W of power from the grid, battery, aux, genny or wind turbine. So it is far more efficient.
Another difference is that it is a true bi-directional hybrid inverter ( Sunsynk uses the term "Super Hybrid Parity Inverter"). The Grid and Aux input is bi directional in the sense that it operates as both an input and an output. So it can draw current from the grid or aux, and it can send current back to the grid / aux. It can also limit the load of the current flowing in either direction too, to a pre-determined wattage. This significant because, due to budgetary contraints, most homeowners cannot afford to put in a 20kW inverter, and so they split their db into essential and non-essential loads. Essential loads are usually quite light, and allow homeowners to reduce the size of the inverter to say 5kW. The non-essential loads are usually big current hogs (like water heating and pumping), and they are placed before the inverter, on the grid side, effectively being served directly by the grid before grid power even reaches the inverter. This also means that they are down when the grid power goes, but hot water is quite stable and doesn't change its temperature in four hours, and the pool won't go green immediately if there isn't any pump working, so this kind of works well from a functionality perspective. The problem with this is that it does not result in much efficiency gains or electricity savings, because the biggest current hogs are also the ones that are still serviced by the grid (when it is there). So homeowners either have to buy a bigger axpert type inverter, or get a smaller hot water installation, or change the element to a smaller one, or get a soft starter for the pool pump, and/or shift the load to the essentials side. The Sunsynk hybrid can safely export power to the grid side though, using a Current Transformer or CT coil to measure directional load (when the grid is up).
So if you have a 4000W hot water heater element, it can still be on the grid or non-essentials side, but the Sunsynk can pump 4000W of excess solar to it. The CT coil measures the power and the inverter will reduce power when too much power is detected going to the grid. Even better, if the Sunsynk inverter only has 2000W of excess solar, the element will receive the other 200W from the grid. So it is efficient. The same with the Aux port, it is bi-directional, so it can be configured to take a genny input, or act as an output or "Smart Load" as Sunsynk calls it, and you can dump excess solar power towards it.
Here is a video which explains it:
Also important is battery support, the Sunsynk manual lists over 3 pages of batteries that it supports, most with CAN or RS485 communications.
Another difference is the wide range of capacities that it supports. In addition to the ability for it to parallel (up to 16 inverters), it comes in 3.6K, 5.5k, 8.8K, and a whopping 16K for single phase installs, and there are 12 and 50K 3phase units available. Not even Victron makes such a wide range of self-contained units, their biggest is 5K.
Pricing is a little more expensive than axpert-types, but it is nowhere near the pricing of Victron, which is a whole lot more.
This probably covers the most pertinent differences between the majority of Axpert and Sunsynk Hybrid inverters, but it is certainly not all, and other forumites are welcome to supplement it with their favourite ones. There are many others, from its easy to use interface, to the warranty and support in South Africa, that are equally important. It's simply in a different league.
Please note that I am not affiliated to Sunsynk in any way, I am just an enthusiastic owner who discovered this brilliant piece of kit under two years ago. 
                 
   
 

Master installer forgot battery fuse disconnect. 

"Low Frequency" is an older design that first uses MOSFETs to create an AC signal then drives it through a transformer to up the voltage.
"High Frequency" first boosts the voltage the voltage to > ~400v RMS AC (very high frequency AC), rectifies it (usually with MOSFETs for higher efficiency than a diodes) to 400v(ish) DC, then smoothes it (using capacitors) then uses MOFSETs again to create an AC signal (the same as the low frequency design but at much, much higher voltage so much lower current, so fewer MOSFETs required so higher efficiency)
If ever "low frequency" had an advantage that has long since disappeared.  Its most significant advantage is simplicity of design (so easier at the design phase).  The higher frequency designs have higher efficiency, lower inductance (and can thus respond faster to transients), lower weight (50/60hz transformer need to be huge).
Another big factor against low frequency is your design phase is cheaper but your manufacturing costs will be higher because it is dominated by the HUGE cost of that transformer.  And because the transformer is so important, it plays a huge role in your efficiency.  For example, if you look at a Voltronic 5kVA inverter's transformer, it is actually pretty small for the 5kVA rating.  I know this because I bought a toroidal transformer for lab purposes and the cost of a 5kVA toroidal transformer is so high that I considered actually buying a Victron inverter JUST for the transformer.  So they are sacrificing some efficiency to save cost and weight during manufacturing.
The high frequency inverter has a transformer in its boost converter stage but it is relatively tiny in comparison, so they don't need to cheap out on the transformer.
In theory and practice high frequency designs have lower impedance and lower losses.  In the early days before electronics were so good as now, maybe.  But these days there is no way a company can compete with the most expensive high frequency designs.
Unless your design criteria is simplicity, then, yeah sure.

This thread should be taken down

This thread should be taken down

You made one hell of a scene , that's gossip for you

@PowerUser In your opening post you ask battery (singular) to inverter, but then later posts pictures with batteries is parallel. Surely you can see have that could've led to people misunderstanding your question.
In the scenario of a single battery and inverter, the positive and negative cables can be of different lengths. The longer the length of the cable (Pos and Neg cables summed), the higher the resistance and the higher the voltage drop will fall over the cable (it doesn't matter whether this is on the Pos or Neg cable). As the Pos cable, battery and Neg cable form a closed, serial circuit the current will flow through all the components, equally.
Voltage (V) = Current (I) x Resistance (R)
 

 
If you are using 35sqr welding cable, the voltage drop over the cable will be ~0.8 milli-Volt per Amp per metre.
Example 1 - Equal cable:
Voltage drop over Pos will be = 0.8mV x 50 x 2 = 80mV = 0.08V
Voltage drop over Neg will be = 0.8mV x 50 x 2 = 80mV = 0.08V
Therefore, the Battery will "see" 50V - 0.08 - 0.08 = 49.84V
 
Example 2 - Unequal cable:
Voltage drop over Pos will be = 0.8mV x 50 x 1 = 40mV = 0.04V
Voltage drop over Neg will be = 0.8mV x 50 x 3 = 120mV = 0.12V
Therefore, the Battery will "see" 50V - 0.04 - 0.12 = 49.84V
 
So, both scenarios are the same (electrically) from battery and inverter point of view.
 
Side note:
However, the both cables should be kept as short as possible to reduce lost energy which is dissipated as heat by the cables. The power (W) lost can be calculated as P = V x I.
The higher the loss over the cable, the higher the temperature due to heat dissipation. The thinner the cable, the higher the voltage drop over the cable = more loss = higher heat, which in a worst case can lead to burning if underspec'd.
 
 
 
 

No.
The combined positive and negative cabling length of parallel batteries should be the same so that voltage drops over cabling is the same.
Which in turn means that parallel batteries are equally charged/discharged at the same rate.
The same logic would apply to other parallel devices that are likely to draw high current during operation.

No naughty person, you will create a potential difference between earth spikes if they are not bonded. Let's blow the roof off ,jump ,jump
 

No naughty person, you will create a potential difference between earth spikes if they are not bonded. Let's blow the roof off ,jump ,jump
 

No naughty person, you will create a potential difference between earth spikes if they are not bonded. Let's blow the roof off ,jump ,jump
 

I think for big commercial installations we must really change to HV batteries and high voltage inverters ,this idea of using quattro's and big bus bars and cute 48v batteries is an outdated idea . As an electrician who has worked with 11kv and 6.6kv i always have to laugh when i see 6 Quatro's and 15 mppts  on the wall to get a cute 90kva ,ridiculous and unimpressive. The installs can be way easier and efficient using high voltage batteries and inverters.

This answer is a non sequitur. I have been to the Victron repairs and its chock a block and not just Inverter controllers ,gx devices ,etc. The 8kw Sunsynk is a beast and there is nothing on the market that can compete for that price. Have done 20 8kw installs no problems, also when you start using smaller panels you can have 2 strings per Mppt and have something like 32 panels on your roof, if you have the space. Nothing comes close. In sunny areas i have taken people off grid with that 8kw and 20kw batteries.

Master installer forgot battery fuse disconnect.