Hi 

I was asked to review quotes for a  friend for an off-grid install . It is a true off-grid - no munic or eskom power . 

Both of the quotes propose a Sunsynk inverter . Now just to state it up front I like the Sunsynk and is my go-to in case of normal installations . But in this case I would propose an Axpert or Clone as an adequate inverter . It will be cheaper , you can still power it from a generator , and you could use the saving to get extra panels or bigger battery . The true hibrid features will be waisted in this case . Am I missing something ? What alternatives could also work ?

Sunsynk is a more reliable design. For completely off-grid you don't want any downtime. I would probably go with something even more reliable, but it depends on the customer.

Most installers will not even consider Axpert because of time lost to support.

For the sake of service reliability in an isolated area I suggest to install 2 off-grid inverters in parallel such as Axpert, but not clones. If one fails you can still operate with the remaining until the failing is repaired.

P1000 - I have installed a number of the Mecer branded Axperts and only had one case where I had to take the inverter for testing and it then turned out that the battery was the problem - You have any other experience ?

Must say that the battery supplier said it was the inverter that caused the issue - but in the end that was also false - just a overstated ability of a lead acid to work in a cycled environment . 

Seven years ago a lot of statements was made by people that this is chinese crap and Victron is the only option but 7 years later they are still operating and I am not aware of an enmass failure of that design - yes it is not an Hibrid and a Hibrid is now my choice for a normal house install with a eskom/munic supply because mostly you can still use your solar panels during loadshedding , you can cycle your batteries in a intelegent fasion , you have a good app etc. But I must say that most of the original Axperts is probably still operating if it was installed with adequate protection . Or am I on some other planet?

Edited June 24, 20222 yr by 1ougat

The only other design related issue is the lower voltage limit on the MPPT's of the Axperts - but I think there are some that have a 450V in stead of the 150V limit?

They are available in the high voltage mppt's. Some even have 2 mppt's. Nothing wrong with a real(non clone) Axpert inverters.

With the lower price get 2 and run in parallel. If any problems arise you can run on the remaining one.

Edited June 24, 20222 yr by Jacques Ester

Reliability wise - both are a transformer less design - and usually these will not make it is if the designs are not good to deal with the inherent issues related to trfr less designs . 

The other option that would make sense is the Microcare offgrid inverters - but then you then have seperate MPPT's etc. - still also a good inverter with a transformer based design .

4 hours ago, 1ougat said:

The other option that would make sense is the Microcare offgrid inverters - but then you then have seperate MPPT's etc. - still also a good inverter with a transformer based design

What is the application for the inverters? Is it for a holiday home? Is it a farm house that will need to power welders and pumps? How big are the inverters. Sunsync is brilliant for your average city home where most people run the geyser and work from home (that need a install and forget inverter)

10 hours ago, Beat said:

For the sake of service reliability in an isolated area I suggest to install 2 off-grid inverters in parallel such as Axpert, but not clones. If one fails you can still operate with the remaining until the failing is repaired.

I would go with you on this one. I do fancy the Sunsynk a lot but for the price of a 5.5kw you can nearly get 2 Axpert or the Kodak OG King. One needs the model that can run in parallel. The Luxpower could also be considered but not sure how well they parallel if at all.

Just make sure they(Axpert/Kodak)are housed outside the house area as they are noisy. 10kW could be a good start.

Yes please no clone if you want it to operate as designed and want to upgrade software going forward.

Edited June 24, 20222 yr by Scorp007

On 2022/06/24 at 3:17 PM, iiznh said:

What is the application for the inverters? Is it for a holiday home? Is it a farm house that will need to power welders and pumps? How big are the inverters. Sunsync is brilliant for your average city home where most people run the geyser and work from home (that need a install and forget inverter)

Retirement home in a Eco development - no Eskom / Munic power supply - Only solar and generators . Gas stove and gas geyser . 

There is a R100 000 provision in the house build for Solar .

Edited June 28, 20222 yr by 1ougat

Seems that the King has  a low voltage mppt - any reccomendations for high voltage versions?

Id recommend it. The main reason is that you can make a long string with the high voltage MPPT charger. This will save you also on DC switch gear. One string requires one set of DC breakers, fuses & Surge protectors. This all adds up with the King. Because the same PV wattage will require a DC combiner with 2 maybe 3 inputs & the same number of switches and fuses. All the major manufacturers have opted for the higher DC voltage. For residential use that is usually <500V. In the commercial levels that goes to 1000v. 

As an installer less hassle for me to install & uses less DC PV cable & connectors. Overall makes for a cheaper cost of installation for the customer. 

You are spoilt for choice & there are sizes & scalability options for everyone's budget. The 5.6kW, 7.2kW & 10kW versions. The best brand to buy is the kodak simply for the walk in support should you ever need it. So that's a 2 year warranty & the fact the boys at Segen have a technical department with spares & technicians locally. The other outfits I'm afraid are just not as jacked up. The other suppliers are glorified postboxes from China. So if you need assistance or help they will revert to China again. This all the while takes a lot of time.

The simple truth with anything electronic & especially as complex as an inverter is that things can & do go wrong & it's pretty possible & normal. But all you as an end user or installer want is the piece of mind that you have local support of people who know the product & stock spares. 

The same must be said for FreedomWon & Livoltek Lithium batteries. You want a tangible local presence and support. 

10 hours ago, 1ougat said:

Retirement home in a Eco development - no Eskom / Munic power supply - Only solar and generators . Gas stove and gas geyser . 

There is a R100 000 provision in the house build for Solar .

Just out of interest. Will the generator be run for certain hours a day - every day of the year or only during low PV periods?

On 2022/06/29 at 9:01 AM, Scorp007 said:

Just out of interest. Will the generator be run for certain hours a day - every day of the year or only during low PV periods?

Dont actually know - but that is the ultimate back up - low solar , battery flat -only option - so sizing and use and learning how to live with what you have is important . My recommendation was 6kw PV, 5.2 kW inverter and at least 8kWh battery installed at 35+degrees. You need to optimise for the winter months .

3 hours ago, 1ougat said:

Dont actually know - but that is the ultimate back up - low solar , battery flat -only option - so sizing and use and learning how to live with what you have is important . My recommendation was 6kw PV, 5.2 kW inverter and at least 8kWh battery installed at 35+degrees. You need to optimise for the winter months .

This is an install where you need to look at the lifestyle. If people at home during the day training and management can get you far. For R100th I feel one can get quite a bit in storage and PV power during the day to keep batteries charged.

Some time ago I measured a 5 room granny flat LED lights and it used only 8kwh per month. This with normal use for 2 people so it is assumed that most of the times 2 lights would be on.

For 2 people using a heat pump running it 1.25h in the early morning and 1.5h during the day takes care of the geyser. Yes add to this heating the geyser is heated after a bath as the 150L geyser is at 27deg after running a full bath.

If the lifestyle is such that cooking takes place in sun periods and just heating in the evening then your estimate is spot on. It is just bad weather that can be a challenge.

We get through LS with a 2.4kw Axpert and 3kwh storage during sunshine days. Only because we have grid so the low bypass when grid is on is not a problem as loads can be fed above 2.4kw from other plugs.