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First Time Solar Setup - 5kW Sunsynk + 5.5kWh Hubble AM-2


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Salutations Forum Members,

As you are no doubt aware, our lovely country is in a bit of a pickle with its energy situation at the moment. For some time now I wanted to gain some degree of electricity independence since our power seems to off more than on here in Pretoria North (especially so the last month). However each time I look at the prices of solar installations my eyes start to bleed. So I humbly ask the expert forum members for any advice and wisdom they may offer.

My planned system (so far) is as follows:

  • 5kW Sunsynk Hybrid Inverter
  • 5.5kWh Hubble AM-2
  • 6x 365W JA Solar Panels

My inverter and battery is oversized for the amount of solar generation capability a 6 panel string will give, but that is due to current budget constraints. I want to expand on the array later. For now my top priority is surviving the load-shedding. My daily usage averages around 15kWh in the summer (haven't measured the winter yet) so this system definitely won't get me off-grid yet, but I at least want my fridge, freezer, wifi, computer and screens running at all times.

My idea is to power essential loads from the sun as much as possible, then switch to battery during the night, and only if the battery discharges too much I switch to grid power. That way I can have some ROI from a lower electricity bill. As I understand the Sunsynk can use what's left to reduce grid importing for the non-essential side.

From throwing an eyeball around the forum I've come to the conclusion that for a 5kW inverter the Hubble batteries are probably the most economical option that can supply the peak load without issues. (1C vs the usual 0.5C)

Now some questions for those more experienced than I:

  • I calculated my essential load to be around 1kW to 1.5kW with maybe 2kW peak. I went with the 5kW inverter so I have enough headroom for later (and if my definition of "essential" changes). Does the inverter sizing affect it's efficiency in a significant way? (Should I rather use a 3kW, or is it better to stick to the 5kW?) I am reasoning a larger inverter will have to work less to keep the same load running, so it might last longer.
     
  • How do the batteries like it if you discharge them every night and charge during the day? I am assuming they are designed for this, but just want to be sure my plan won't be abusing them.
     
  • Is longevity a realistic concern with the Hubble battery chemistry? I read somewhere they use NMC.
     
  • During the day in the summer it gets stupidly hot outside. I measured the underside of my roof at noon (corrugated iron roof) at around 70 C. I read the solar panels have lower output when their temperature goes up, so will my 6 panel string (2190W rated output) even be enough then? Will sitting in 70+C outside damage the panels? (Are there cooling systems for solar panels? 😉) For reference, the MPPT range is 125V-425V, and the 6 panel string at the testing temperature is rated 204V-247V (Vmp and Voc).
     
  • Regarding the warranty for the installation; I have some experience with electrical systems, but no formal certification. Would it be an issue if I did the installation myself? What would be required for honoring the warranty to prove the installation was done "correctly"?
     

I would greatly appreciate any assistance this wonderful forum can offer. A lot of posts here have been very informative.

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I cannot answer any technical questions but...

Same system going in next week for me. I'm also a little worried about the Hubbles longevity due to the battery chemistry but I really like the dual form factor and the 1C rating. 

So used to Li-Po for RC planes which is over 50c sometimes. RC cars I guess are going to 200C these days. Been out of that game for a while.

 

Anyway I'm sure this system you are spec'ing will serve you well. Once the battery is out of the way you can upgrade to more panels and even later parallel that inverter or sell and buy the 8kw.

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1) don't go lower than the 5 kW inverter, i would even suggest an 8 kW sunsynk, but it is about 10k more, from what i know now, i would have spent the extra money

2) lithium batteries are meant to be cycled everyday, get your money's worth out of them, I even cycle them partly through the day if it is a partly cloudy day.

3)a lot of people mount the panels on a metal ibr roof, as long as there is space between the panel and roof and most panel mounting systems do give you that space for air to flow under the panels.

4) most comapnies do talk about having qualified installers, but a lot of us have installed our own systems, including me, even re-did my db and got a coc for the ac stuff, there is hardly anyone out there that can give you a coc on the dc side.

5) can't give you any info regarding the batteries, Pylontech has been around for a while and Hubble seems to be gaining traction in SA

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Thanks for the advice, @Tariq. I keep being worried the solar panels will melt or something. Is it just my imagination or do metal sheet roofs get hotter than the ceramic tile ones? Anyway, I'll be sure to check that airflow is sufficient.

In the meantime another idea has occurred to me. What if, instead of a hybrid inverter, I get 2x 5kW off-grid inverters? They are basically half the price of a single hybrid, and can be paralleled to provide 10kW output. This is easily enough to connect my whole house on it. If the off-grid inverters can properly combine PV and grid inputs then this would theoretically be a better option? (More output at roughly the same price.) Or am I missing something here?

My concern would be that I saw most off-grid inverters only have a 2 to 3 year warranty, whereas the hybrid inverters (even from the same manufacturer) have 5 years. Does this suggest the off-grid models have a shorter operating life, or give more trouble later on?

Also something I was considering is that the benefit of the hybrid inverter being able to supply loads on the grid side would only work if the grid is on. During load-shedding or other extended power failures it essentially turns into an off-grid inverter anyway.

Does anyone here have such a setup, and would care to comment on how well that works? Also, what would be a good off-grid inverter for this idea? I see Axpert is all over the place, but there is a Luxpower model that looks promising as well.

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Lots of questions there.

 

Different muni's will allow different equipment connected.  

Axpert does not have NRS97 certification so cannot be legally connected in some muni's - eg CPT, and is not on the councils approved inverter list.  More muni's will be enforcing regulations rather than less, so I'd stick to equipment that is certified, vs just cheap.  Not sure about Pretoria, but I'd stick to NRS approved stuff..
(Others - Please update me if I'm incorrect on Axpert certification, its been a while since I last checked).

In summation -  you aren't really saving money buying a cheap inverter that you'll have to replace later.

If you can afford it get something that will scale to your future needs.  The Sunsynk 5k or 8k seem to be in the sweet spot at the moment in terms of product for price, and are legal to use here.

If you can stretch to the 8KW model, I'd do so vs the 5K, as Tariq has said.

Roof temp - I wouldn't worry too much - there isn't much you can do.  Panels will derate a percentage rating for every c above their nominal temperature of 25c.  How much that is will be on their data sheet.  Temps in SA will easily hit 40c on the roof, could be higher.

As an example - if they derate 1% every 1c over 25c, then you'll lose 15% of rated capacity at 40c ( 40c - 25c = 15), so your 400w panel may only output 340W at peak temp.  It's not that bad in real life ratings examples, but do read the data sheets to make sure your panels are suitable for hot climates.

Your roof interior on the other hand will be cooler, as the panels will be taking up the heat and covering your roof, so less a/c bills in summer (assuming you have an aircon!).   You should really paint your roof with a light color to minimize heat (as well as insulate the roof space so you have less heat in summer, keep more heat in, in winter).

I wouldn't worry about panels melting, they're mostly made of glass (front glass), silicon (the panels), silver (the interconnect wires) and aluminium (frame), need far far higher temps to melt those!

If you can stretch to more panels I'd add more first.  6 x 365w is too small.   Why are you looking at those anyway?  Price/ buck sweet spot at the moment are the JA-Solar 405w Mono Perc.

Given that the mounting and labour will cost the most (even if diy) I'd buy more panels, and get that done one time.
Double that 6 panels at least.  I'd recommend 12 panels min, and suggest go for higher watt panels.
 

Double check that the inverter can handle the volt/amp load for the panel strings though.  eg 2 strings of 6 perhaps.  Read the panel specs to work out the numbers, and compare against the inverter manual for its sweet spot.  

Inverter will have an efficiency rating for a given voltage usually, so you want to stick your strings volt sizing or amp sizing in its preferred range.

 

 

 

 

 

Edited by shanghailoz
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On 2021/11/11 at 1:58 PM, Sir Rodgers said:

Salutations Forum Members,

As you are no doubt aware, our lovely country is in a bit of a pickle with its energy situation at the moment. For some time now I wanted to gain some degree of electricity independence since our power seems to off more than on here in Pretoria North (especially so the last month). However each time I look at the prices of solar installations my eyes start to bleed. So I humbly ask the expert forum members for any advice and wisdom they may offer.

My planned system (so far) is as follows:

  • 5kW Sunsynk Hybrid Inverter
  • 5.5kWh Hubble AM-2
  • 6x 365W JA Solar Panels

My inverter and battery is oversized for the amount of solar generation capability a 6 panel string will give, but that is due to current budget constraints. I want to expand on the array later. For now my top priority is surviving the load-shedding. My daily usage averages around 15kWh in the summer (haven't measured the winter yet) so this system definitely won't get me off-grid yet, but I at least want my fridge, freezer, wifi, computer and screens running at all times.

My idea is to power essential loads from the sun as much as possible, then switch to battery during the night, and only if the battery discharges too much I switch to grid power. That way I can have some ROI from a lower electricity bill. As I understand the Sunsynk can use what's left to reduce grid importing for the non-essential side.

From throwing an eyeball around the forum I've come to the conclusion that for a 5kW inverter the Hubble batteries are probably the most economical option that can supply the peak load without issues. (1C vs the usual 0.5C)

Now some questions for those more experienced than I:

  • I calculated my essential load to be around 1kW to 1.5kW with maybe 2kW peak. I went with the 5kW inverter so I have enough headroom for later (and if my definition of "essential" changes). Does the inverter sizing affect it's efficiency in a significant way? (Should I rather use a 3kW, or is it better to stick to the 5kW?) I am reasoning a larger inverter will have to work less to keep the same load running, so it might last longer.
     
  • How do the batteries like it if you discharge them every night and charge during the day? I am assuming they are designed for this, but just want to be sure my plan won't be abusing them.
     
  • Is longevity a realistic concern with the Hubble battery chemistry? I read somewhere they use NMC.
     
  • During the day in the summer it gets stupidly hot outside. I measured the underside of my roof at noon (corrugated iron roof) at around 70 C. I read the solar panels have lower output when their temperature goes up, so will my 6 panel string (2190W rated output) even be enough then? Will sitting in 70+C outside damage the panels? (Are there cooling systems for solar panels? 😉) For reference, the MPPT range is 125V-425V, and the 6 panel string at the testing temperature is rated 204V-247V (Vmp and Voc).
     
  • Regarding the warranty for the installation; I have some experience with electrical systems, but no formal certification. Would it be an issue if I did the installation myself? What would be required for honoring the warranty to prove the installation was done "correctly"?
     

I would greatly appreciate any assistance this wonderful forum can offer. A lot of posts here have been very informative.

I see others have already answered most of your questions. The worry about the Hubble battery is unfounded though. Hubble use BYD cells in there batteries, and as you know the battery is rated at 1C discharge and charge. The fact is the BYD cells are actually capable of 2.5C, but the cost of supplying the battery with a BMS (Battery Management System) of 2.5C would cause the cost of the battery to be prohibitively expensive.

Most of the time you would not be using 1C, but way less, and also not charging at 1C either. But if needs be, you can call on your battery to provide 1C. Therefor with lower usage as normal, the battery life will be 10 to 15 years. But long before the usable life is exhausted, new battery technology will be available, and relatively cheap.

Currently there is already battery technology available with a 45 year usable life, but it's too expensive for most.

The system you mentioned is a good starting point, and can be added too when funds become available. It should easily get you through load-shedding as long as you wire your geyser and stove as non essential loads.

Enjoy your solar journey to power independence.  :)

 

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Personally I'm a bit tentative on the Hubble batteries.

My suppliers keep pushing them, but I'm still wary.

The build quality of the Hubble casing doesn't wow me.  It's not a product I've seen oversea's either. BYD batteries are decent product (as are CATL and CALB), so I'm not worried about that.

NMC isn't the issue, LFP and NMC have their differences - thats much of a muchness - LFP have a longer lifetime, and are safer, albeit slightly lower capacity than other lithium chemistries, NMC higher capacity / upfront cost, lower lifetime.

My concerns are they're knocking together a cheaper BMS + casing with some who knows what lot NMC batteries.
Ideally I'd like to look inside one to see how its built.  

I suspect they're using the 135Ah 3.7v NMC inside, would like to see if its 13S? 14S?  for curiousity sake., and see the wiring / BMS.

[Looks like 15 batteries, given the 5.5KW rating, thats probably a 100Ah 3.7v NMC inside x 15  as 3.7v x 100ah x 15 pcs =   5.5KW]

Build quality wise, I think the PylonTech are likely better internally, but I'd like to see for myself before making incorrect assumptions.

1C vs 0.5C discharge/charge is purely the BMS rating - both *battery chemistries* can support 1C easily.    Its the connectors and other hardware (BMS etc) that need to support 1C.  If you don't need a high discharge / charge eg > 4800W then the Pylontech is fine.  If you need a higher peak rating, then look elsewhere (for now) - i.e at the Bull or Hubble.

If I look at 10 years down the line, I believe PylonTech will be around.  Hubble appear to only be a local brand, so its either a chinese model with their branding on (which is fine), or locally assembled.  My concern with that is will they be around in 10 years.

 

Pricing is reasonable though, even if not the cheapest batteries available on the market here.

 

I'm busy reading the 

 thread so will possibly change my mind once i've finished reading that :)

Edited by shanghailoz
updated with more info on my suspicions
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Just now, PowerUser said:

@shanghailoz As far as I know, the company behind Hubble Lithium is Tescom and they claim to carry spares 10 years after the discontinuation of product lines:

https://za.linkedin.com/company/tescom-sa

 

Personally I have the Revov 2nd life - 10KW.  I got those as the price was great - 10KW for 35k zar.

So far Revov has been good on that for service - I did have 2 bad batteries in mine that were replaced, as they were going off balance, and kicking the system when the coffee machine drew too much current in the morning.  They actually replaced the entire unit so i didn't have any downtime, then brought my old one back once they were rebalanced, and swapped out again.  Nice service :)

I'm currently looking at the hubble for my brother, who's interested in getting off loadshedding.  I was also looking at the Kodak (rebranded Pylontech L1's) for him (and possibly for me).  I need more than 4.8KW peak though, so although the Kodak/PylonTech L1 sizing /price is good, the draw doesn't support my future needs.  It is a far better looking system though - plug and play almost.

For me, I don't really care too much about parts, although I would like some support i.e. for replacing bad bits under warranty - in a worst case scenario, I can rip out bad batteries, replace, or replace BMS.  I'm ok with electronics - I have a background in embedded software, so hardware stuff isn't too much of a mystery, and I'm usually in Asia, and speak/read/write Chinese so no big deal for me to order / ship parts over.  For him, I need/want something more turnkey that can be relied upon for a while.

 

 

 

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Thank you for everyone's replies and advice!

After taking a long, hard look in the mirror, and shedding a tear for my bank account balance, I have decided to beef up the system up-front rather than wait to expand. The way things are looking with Eskom now concerns me. So I eventually decided it was worth it to get as much initial independence as I can afford. Hopefully this will pay off in the future.

My new setup idea looks something like this:

  • 8kW Sunsynk
  • 3x BX51100 Dyness batteries (15.36 kWh total)
  • 12x 470W Jinko Tiger (5.6 kWp)

I went with the bigger inverter after all, with the idea that it would be more future-proof. The batteries I got on a BF special - I couldn't find a better R/kW ratio so I went ahead and bought them already. Some recent threads have made me a little more hesitant to use the Hubble's NMC chemistry. 😅  These BX51100 models have 0.5C recommended and 0.75C max according to their datasheet. The max draw of the inverter is slightly above the recommended 0.5C, but I doubt the small difference will really cause a problem. Especially since I will rarely, if ever, hit the full 8kW anyway.

Now for the panels, does anyone have experience with the Jinko brand? Are they reliable? I found those panels at a better R/W rate than the JA Solar ones I initially thought of, but it's always good to check if anyone has bad experiences with them first.

Since this is turning out to be quite an expensive investment, I want to double check to make sure I am not making any mistakes here. Which brings me to another question - does anyone know reputable solar installers who operate in Pretoria North? I still kind-of want to install the system myself, but a lot of the warranty documents I read mention that you need a qualified solar installer... so I'm not sure what my options are here. Since installers make their business actually installing, I don't know how many are interested in just consulting / checking the installation for certification afterwards.

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