Hey guys.

Been lurking for a while now. Really informative stuff here, and lots of it! So here's my thread and hope you can point this noob in the right direction

My goal :

I would like to go off grid.... Eventually. Funds not even close to where it should be so I'm looking at just getting into it for now and adding on to the system and upgrading when needed. For now I'd like to see how far I can get with the proposed setup below. I currently use an Axpert 5kva unit with 8 x 105ah lead acids at my shop for load shedding purposes. Very happy with the setup so looking at starting off that way.

I would propose running on solar during the day with battery/eskom at night.

Proposed System :

• 1 x Axpert 5kva Inverter
• 2 x Pylontech/Leoch Lipos or 20 x 105ah Lead Acids (or 8 x 230ah Lead Acids)
• 8 x 335w Solar panels (to start off with). I currently have 6 x 30w panels (new) but would rather sell them in favour of higher output panels

Additional info :

I have already done a lot in terms of energy efficiency to my home.

• Running whole house on LED's
• Gas stove
• Gas geyser in kitchen
• Heat Pump (1600w)
• Inverter fridges and washing machine.
• 5kva Generator

The biggest power sappers are :

• My giant Speedqueen tumble dryer (almost 3000w)
• Dishwasher (2000w i think)
• Oven (3500w at max)
• Aircons (lots of them and yes inverters)

Attached my Efergy graph of a fairly average day and excel file of daily consumption for February.

Facing reality :

I get that the proposed system won't be adequate for my need but it's a start right? And I can build on the system to where it's stronger and close to going off grid. I get that I'll have to schedule large appliance use during peak sun hours and maybe even have my air cons run off eskom until the system reaches "maturity".

Questions :

1. I see there are various different models of the 5kva Axpert. The one that caught my eye is the Trio model with the 9000w MPPT (3 x 3000w 60a). The reason is to future proof the system as far as possible. Am i looking at this from the right angle in that I can add 8 x 335w panels now and whatever battery setup i choose, and then later on "double up" and later on add more panels to boost daytime supply and charging before night time? Or should I save R2k and just get the standard 5kva unit and add on another 5kva unit later on in parallel?
2. Also the axpert is marketed as off grid. How will it perform in conjunction with eskom and solar use?
3. It seems like lipos are the way to go if they can be afforded. Unfortunately I'll end up going for the "cheaper" brands to suit budget. My question is hoe the dark horse (Lead Acids) will stack up in, lets say, the first 8 years? Would it be viable to go lead acid now and lipo later on when they need to be replaced?
4. Are there good and bad solar panels? Or are we looking at "ball hair" differences? Would it be worth wile to invest from the start in so called "better" panels or would any brand suffice?
5. What pitfalls will I face?

 

I know its a lot but thanks in advance for all comments!

Usage - February 2019.csv

Edited March 5, 20197 yr by TheoG
Added excel file

5 hours ago, TheoG said:

I see there are various different models of the 5kva Axpert. The one that caught my eye is the Trio model with the 9000w MPPT (3 x 3000w 60a). The reason is to future proof the system as far as possible.

Be aware that these models are a sort of "orphan"; they have their own main firmware series (used to be 75.XX), and can't parallel with any other model. There is patched firmware for them, but it's version 75.31a (based on factory firmware 75.31). This is for the 4 kW model (PF0.8),  new models seem to be 5 kW (PF1.0). So the available patched firmware won't be compatible with new models.

Besides that problem, it only fixes the premature float bugs, and nothing else. There isn't even an LFP-friendly variant. Even if you can only afford lead acid now, you will likely want some form of lithium battery in the future, and right now by far the most popular lithium chemistry for home storage is Lithium Iron Phosphate (LFP, or LiFePO₄). These have a very flat voltage curve, and the Axpert firmware as it comes from the factory doesn't work well with that flat voltage curve.

The MPPTs in these are only 60 A (at the battery) each, so that's a total of 180 A. Two ordinary Axperts in parallel, which have 80 A MPPTs each, will give you nearly that much: 80 × 2 = 160 A total. With all those large loads, you might want to end up with paralleled machines. I don't know if you can parallel a triple MPPT machine with a dual, but certainly you can't parallel it with a single MPPT model.

The dual and triple models don't seem to be all that popular, so there is less support from the community. They also pack a lot of conversion hardware into one box, so cooling may be an issue, and the fans might be roaring all day. They also come in a physically deeper box, which may not suit some installations.

Finally, you will be limited to 145 V MPPT max. This is a good thing in a way, as the high voltage MPPT models (450 V MPPT max) don't have patched firmware. But it means that you will be limited to 2S or 3S panels, and I seem to be the only user in the world running 2S. With your proposed eight panels, you'd have to go to 2S 4P and have four pairs of wires down to a combining box, or get another panel and go 3S 3P.

If you don't want to re-wire your roof and stay 3S, then you'll have to run a model with the high voltage MPPTs; see PIP-5048GE, PIP-5048GK and PIP-5048MG inverters (with unsafe SCC). (The PIP models are equivalent to Axperts).

Arguably an even bigger resource than this fine forum is the Australian AEVA topic PIP-4048MS and PIP-5048MS inverters. It is so large (105 pages at 25 posts each) that it has its own index, and it's now too big to read in total. But there is a lot of information there, including partial schematic traces, links to manuals, etc.

So: lots to consider, even just in inverter-charger selection. The triple MPPT model may not be the most future proof after all. Good luck with your planning.

Edited March 6, 20197 yr by Coulomb
8 existing panels -> proposed 8 panels

Wow...... Information overload!

Thanks for the reply @Coulomb. I'll have a read through as much as possible before deciding.

Your experience with the VM III?

Edited March 6, 20197 yr by TheoG

10 minutes ago, TheoG said:

Your experience with the VM III?

Zero personally. I note that it's a Value model (hence the V in the name), so it's a little cheaper, but not parallelable.

It's also a 450 V MPPT model, with all that implies: no patched firmware, may not be approved since it doesn't have insulation monitoring, yet easier wiring on the roof.

The model with many of the features of the VM III but with 145 V MPPT and parallelable is the Axpert King (= PIP-5048MK). But I haven't seen any firmware for it, so there is no patched firmware as yet.

 

Inverter:

For someone with grid access I wouldn’t recommend the Axpert.

Rather look at Hybrid inverters like the Goodwe or similiar. The additional R13k in capital over the Axpert will be recouped.

The installation is also actually simpler with a Hybrid inverter and you will be able to maximize the energy generated by the solar panels.

Read the manuals for the Goodwe from here :https://thepowerstore.co.za/collections/inverters/products/goodwe-em-5kw-hybrid-inverter-2-3kw-backup

Let me know if the advantages between the Axpert and Goodwe is not evident.

Your consumption is low so you will probably get away with a smaller unit than the 5 kW, but the price difference between them does not really  warrant going smaller.

 

Battery:

Pylontec or similiar is the way to go for systems that are planned to run for 10 years or longer.

__________________________________________

A while ago I spotted a system advertised and in my opinion the way to go for now:

 

https://solaradvice.co.za/product/lithium-storage-3-92kwh-solar-power-kit/?utm_source=Click&utm_medium=Channel&utm_campaign=Google_ZA&SFDRREF=SFDR_299055705&ptcid=9226_617_401969991&gclid=CjwKCAiA2fjjBRAjEiwAuewS_WZfe2cU-maUpMcfhq-XfmKtQ1nQlGiIVHdNYvoDfCfQvCPblFAUvBoCyuEQAvD_BwE

 

 

 

 

Edited March 6, 20197 yr by Jaws

5 minutes ago, Jaws said:

Your consumption is low so you will probably get away with a smaller unit than the 5 kW, but the price difference between them does not really  warrant going smaller.

Be aware though that you might not be able to legally connect it because of the 3.5kW limit on a single phase 60A main switch supply.

14 minutes ago, Fuenkli said:

Be aware though that you might not be able to legally connect it because of the 3.5kW limit on a single phase 60A main switch supply.

Very good point for the Cape Town guys ....... 🙂 

For the OP - Although the Goodwe is capable of exporting to the Grid, at this stage it would be better to configure the inverter not to.

 

Edited March 6, 20197 yr by Jaws

11 minutes ago, Jaws said:

Very good point for the Cape Town guys ....... 🙂 

My feeling is that unless you plan on buying another inverter in the next 10 years, this pretty much applies to everyone. The good news is that if you start with an Axpert, you will very likely buy another inverter in the next 10 years anyway, so you'll probably be fine, at least legally 🙂

Edited March 6, 20197 yr by plonkster

56 minutes ago, Jaws said:

Inverter:

For someone with grid access I wouldn’t recommend the Axpert.

Rather look at Hybrid inverters like the Goodwe or similiar. The additional R13k in capital over the Axpert will be recouped.

The installation is also actually simpler with a Hybrid inverter and you will be able to maximize the energy generated by the solar panels.

Read the manuals for the Goodwe from here :https://thepowerstore.co.za/collections/inverters/products/goodwe-em-5kw-hybrid-inverter-2-3kw-backup

Let me know if the advantages between the Axpert and Goodwe is not evident.

Your consumption is low so you will probably get away with a smaller unit than the 5 kW, but the price difference between them does not really  warrant going smaller.

 

Battery:

Pylontec or similiar is the way to go for systems that are planned to run for 10 years or longer.

__________________________________________

A while ago I spotted a system advertised and in my opinion the way to go for now:

 

https://solaradvice.co.za/product/lithium-storage-3-92kwh-solar-power-kit/?utm_source=Click&utm_medium=Channel&utm_campaign=Google_ZA&SFDRREF=SFDR_299055705&ptcid=9226_617_401969991&gclid=CjwKCAiA2fjjBRAjEiwAuewS_WZfe2cU-maUpMcfhq-XfmKtQ1nQlGiIVHdNYvoDfCfQvCPblFAUvBoCyuEQAvD_BwE

 

 

 

 

@Jaws thanks for the reply. Do I understand correctly that the Goodwe inverters can only supply 2300va off grid? (Backup mode) Meaning at night with no solar input I'll only have 2300va (max) available?

37 minutes ago, Jaws said:

Very good point for the Cape Town guys ....... 🙂 

For the OP - Although the Goodwe is capable of exporting to the Grid, at this stage it would be better to configure the inverter not to.

 

I believe that our local municipality doesn't allow us to feed back to the grid.

28 minutes ago, plonkster said:

My feeling is that unless you plan on buying another inverter in the next 10 years, this pretty much applies to everyone. The good news is that if you start with an Axpert, you will very likely buy another inverter in the next 10 years anyway, so you'll probably be fine, at least legally 🙂

I was under the impression that the Axpert would last in the vivinity of 5 years so it was always on the cards to upgrade at a later stage to something better 👍

1 minute ago, TheoG said:

@Jaws thanks for the reply. Do I understand correctly that the Goodwe inverters can only supply 2300va off grid? (Backup mode) Meaning at night with no solar input I'll only have 2300va (max) available?

No the Goodwes has two supplies - backup  which one puts ones essential loads on and a gridtie  supply which allows the inverter to supply  geysers aircons and other non essentials if not all the power generated by the inverter is being consumed by the backup appliances.

If we schematically  have the set up with the utility meter on the left and the inverter in the middle then backup is on the right of the inverter and grid is between the inverter and the meter. At night the inverter draws electricity from the grid and supplies the backup (offgrid - poor term in this case) then during the day solar power is prioritised for the backup system and any excess energy is sent to the gridtie supply

 

5 minutes ago, TheoG said:

I was under the impression that the Axpert would last in the vivinity of 5 years so it was always on the cards to upgrade at a later stage to something better 👍

My Axpert is approaching 4 years now. We will see how long it lasts.

4 minutes ago, Chris Hobson said:

No the Goodwes has two supplies - backup  which one puts ones essential loads on and a gridtie  supply which allows the inverter to supply  geysers aircons and other non essentials if not all the power generated by the inverter is being consumed by the backup appliances.

If we schematically  have the set up with the utility meter on the left and the inverter in the middle then backup is on the right of the inverter and grid is between the inverter and the meter. At night the inverter draws electricity from the grid and supplies the backup (offgrid - poor term in this case) then during the day solar power is prioritised for the backup system and any excess energy is sent to the gridtie supply

 

That sounds ideal for my application then.... I can prevent aircons from using valuable battery power and won't have to go so big on the battery side for now.

@Chris Hobson your experience with GoodWe? Is it any Good

GoodWe Link any experience with this particular unit?

On 2019/03/06 at 10:41 AM, Chris Hobson said:

My Axpert is approaching 4 years now. We will see how long it lasts.

Same here. Got it in June 2015. Still going strong.

On 2019/03/06 at 9:41 AM, Chris Hobson said:

My Axpert is approaching 4 years now. We will see how long it lasts.

Hi Chris.

I need advice on a 2x5kva parralell installation.running two separate solar array on each inverter. Grid tied with pylonrech US3000.

In the morning and evening when the arrays start and then stop producing. The slave inverter has fault code 08 and shuts down.

Why would this be?

On ‎2019‎/‎03‎/‎06 at 10:41 AM, Chris Hobson said:

My Axpert is approaching 4 years now. We will see how long it lasts.

 

On ‎2019‎/‎03‎/‎08 at 9:57 AM, SilverNodashi said:

Same here. Got it in June 2015. Still going strong.

Same on my Axpert with no hiccups at all and it's been running an oversized PV array for a while too.
Batteries have also been behaving really well with no equalizing charge ever given to them.

On 2019/03/06 at 10:41 AM, Chris Hobson said:

My Axpert is approaching 4 years now. We will see how long it lasts.

How long did it last....