Ted Lassoes the Sun!

[TedLasso]

So I know everyone loves Hubbles because of the 1C and great price.

I've asked for a quote from Power Forum Store for two of them and was checking out Solar Advice too for comparative pricing.

Hubble 5.5kWh 1C – Lithium-ion Battery - Solar Advice

Perfect Size, Perfect Price The AM-2 is our new 5.5KWh 51Volt Lithium pack designed to be easily in a standard rack. Features Wall-Mounted or Rack-Mounted Compact & Stylish Safe and Easy Installation

solaradvice.co.za

Lithium-ion Batteries – Solar Advice PTY LTD

Lithium-ion batteries (LiFePO4 batteries) are the <strong>best solar battery type</strong> available, which is good to know, but what makes them so unique? Apart from <strong>storing your produ…

solaradvice.co.za

So the big difference between these batteries is their life cycle (3500 vs 8000 for Alpha) . I am having brain fade at the moment, but assuming I do use the batteries daily, at night to run the house, is there a much of a muchness between these two? While the alpha could sit on the floor and also be located outside (no i will not do it) ... it offers much better life cycles at same DoD (90%) but probably at 0.5C so longer to charge ?

 

[TedLasso]

New change: Told the SHE-E-O, that I am going for Sunsynk - best to do so the RCT is now out of the picture - woohoo.

There's about 12K difference between 5.5KVA SunSunk and 8KVA - feels like I should just get the 8KVA and be done. But for now 5.5KVA:- I know there have been posts about buying two 5.5KVA for redundancy, etc - so this looks like a good way to bring it in in the future if absolutely required.

 

[RonSwanson]

Hi,

So the garage roof is tiled like rest of house. We have pink insulation in the roof - which hasn't made a difference for this room - maybe it's better but still always warmer than rest of house. In fact the roof over the garage is where I plan to put hopefully 10 solar panels.

Does the garage have a ceiling?
I never had a ceiling in mine and I installed a layer of insulation over some foiled sheet. Also two aluminum turbines. That brought temps down by about 15 degrees. Agreed that installing panels will facilitate a cooler environment (plus less losses for the DC run).

 

[RonSwanson]

Also 2 inverters will give you redundancy...

I'm not convinced on the redundancy thing, for it to be redundant it needs to be there doing nothing on cold standby. Plus the MTBF rating is halved, almost like a self-fulfilling prophecy.

At the most you will have a degree of resiliency with degraded performance.

 

[RonSwanson]

So I know everyone loves Hubbles because of the 1C and great price.

I've asked for a quote from Power Forum Store for two of them and was checking out Solar Advice too for comparative pricing.

Hubble 5.5kWh 1C – Lithium-ion Battery - Solar Advice

Perfect Size, Perfect Price The AM-2 is our new 5.5KWh 51Volt Lithium pack designed to be easily in a standard rack. Features Wall-Mounted or Rack-Mounted Compact & Stylish Safe and Easy Installation

solaradvice.co.za

Lithium-ion Batteries – Solar Advice PTY LTD

Lithium-ion batteries (LiFePO4 batteries) are the <strong>best solar battery type</strong> available, which is good to know, but what makes them so unique? Apart from <strong>storing your produ…

solaradvice.co.za

So the big difference between these batteries is their life cycle (3500 vs 8000 for Alpha) . I am having brain fade at the moment, but assuming I do use the batteries daily, at night to run the house, is there a much of a muchness between these two? While the alpha could sit on the floor and also be located outside (no i will not do it) ... it offers much better life cycles at same DoD (90%) but probably at 0.5C so longer to charge ?

Personally, I would avoid the Alpha. If you want something to compare it with, consider BSLbatt (also 1C), Freedom Won (some are 1C), Pylontech and Dyness.

The biggest difference is the chemistry. They are both Lithium batteries, Hubble are NMC, most other batteries are LifePO4 (but not all). Different characteristics here. Summary table of the differences here.

1C discharge rate is important, for two reasons: Higher discharge rates affect battery longevity, so it's easier for a manufacturer to give a longer term warranty on a battery that only allows a trickle. It also dictates how many battery units you need to place in parallel to get the rate of discharge that is suitable for the load of your inverter.

It's not only price, although this too is important. It's also support if / when things go wrong.

 

[Mike Hoxbig]

I'm not convinced on the redundancy thing, for it to be redundant it needs to be there doing nothing on cold standby. Plus the MTBF rating is halved, almost like a self-fulfilling prophecy.

At the most you will have a degree of resiliency with degraded performance.

That's pretty much what I mean by redundancy, I guess resiliency is a better word. You will at least have half a system rather than no system...

 

[RonSwanson]

Just for clarity sake.
The reason for keeping the cables as short as possible has nothing to do with AC or DC.
Otherwise DC transmission lines wouldn't be a thing....

Also those things on the roof going to the inverter is also running DC current and they are typically 30 to 40m long.


Infact if you consider that with AC circuit power factor comes into play the voltage drop could be considerably higher in AC circuits...

Yes, I should have stated LVDC.

 

[itareanlnotani]

Hi,

So the garage roof is tiled like rest of house. We have pink insulation in the roof - which hasn't made a difference for this room - maybe it's better but still always warmer than rest of house. In fact the roof over the garage is where I plan to put hopefully 10 solar panels.

To something in your post

I am thinking this will then help

Yeah, and given the bloody pricing on rolls of insulation at the moment, I think it might actually be cheaper to put panels on the roof.

 

[RonSwanson]

RCT is now out of the picture - woohoo.

Not entirely. You could give it a good home and get some cash for it in return, to spend on the insulation.

 

[RonSwanson]

Yeah, and given the bloody pricing on rolls of insulation at the moment, I think it might actually be cheaper to put panels on the roof.

I received some great prices from an outfit in Pretoria around 18 months ago. I did one 100mm run and another 150mm run on top of that, didn't cost a fortune. I don't remember the exact details, but I am sure that @wingnut771 does.

 

[AfricanTech]

So informative these threads are.

Also good to be reminded about the importance of 1C - forgot that little. detail.

 

[TedLasso]

Not entirely. You could give it a good home and get some cash for it in return, to spend on the insulation.

I got it as a gift so will pay it forward to another family member if my blesser doesn't want it back

To your other post. Garage roof has a ceiling (and the pink aerolite is above it) . Insulated exactly like rest of house, only it has a huge double door aluzinc garage door - yet still is just so lekker warm .

Walked into garage around 7:30pm last night and considering how cold the house is, with current temps, it seemed a lovely 21&22 degrees.

Gonna put one of my Shelley dw2s in there for a while to track temps . It may have to become permanent - if temp goes to 25 - open garage door 20%

I swear I am using home assistant to create problems that probably never need solving

 

[RonSwanson]

I got it as a gift so will pay it forward to another family member if my blesser doesn't want it back

To your other post. Garage roof has a ceiling (and the pink aerolite is above it) . Insulated exactly like rest of house, only it has a huge double door aluzinc garage door - yet still is just so lekker warm .

Walked into garage around 7:30pm last night and considering how cold the house is, with current temps, it seemed a lovely 21&22 degrees.

Gonna put one of my Shelley dw2s in there for a while to track temps . It may have to become permanent - if temp goes to 25 - open garage door 20%

I swear I am using home assistant to create problems that probably never need solving

That would be good data. Batteries are generally pretty well insulated, and only start absorbing ambient heat after a good few hours, so you would need to take into account the lows as well as the highs.
I also had two 350mm tornados installed, and chose aluminium due to less inertia for startup. They cost me R5,800 including installation.

 

[wingnut771]

I received some great prices from an outfit in Pretoria around 18 months ago. I did one 100mm run and another 150mm run on top of that, didn't cost a fortune. I don't remember the exact details, but I am sure that @wingnut771 does.

Here are 2 links from what I can find. For some reason, I prefer the good old Think Pink stuff as its been around for yonks, SABS approved, fireproof and is made from glass and not some synthetic stuff like the others:

Aerolite Installers The Home Of Aerolite Insulation

Everything you need to know about Aerolite Insulation and the Preferred Aerolite Installers in South Africa. Get the best Aerolite Prices AND save

aeroliteinstallers.co.za

Aerolite Insulation Price – Roof Insulation

roofinsulations.co.za

 

[TedLasso]

Old Lasso was trying to figure this all inverter solar Max V stuff out, looking at the data sheets of the SunSynk 8KVA inverter and solar panels. Why the F is it so complex? ... I know I can apply my mind if I want to , but I would rather not (for now).

As my alter ego, previously said:

"Taking on a challenge is a lot like riding a horse, isn't it? If you're comfortable while you're doing it, you're probably doing it wrong."​

So my garage roof apparently is not big enough to hold 8 panels - could be 6 maybe 8 - I need to climb on to roof to measure. Also realised the other parts of north facing roof is actually going to be complicated due to shading from trees currently in Winter morning (seems to clear around 9am) and a skylight.

So to maximise space: Instead of JA 540W, maybe go for 640W or higher panels (while they exist - can't seem to find anybody in SA who sells them). The question is, which is better in long term :- JA 540W or Canadian Solar 650W (https://www.greenbuildingafrica.co.za/canadian-solar-launches-640-665-w-panel-series/)

Based on my research (on my phone) there doesn't appear much difference in size between the 540W / 640W panels.

For installation:
I think a string of 6-8 540W or 640W Panels could do me right as a start without blowing up the inverter

• 1 string of 6 on the garage (facing north) on MPPT1
• 1 string of 2 (facing west) or north in a different location on MPPT2. Later add a few more panels for a total of 12 altogether which will more than meet our needs for daily production (540w x 12 ) = 6480wp

Any thoughts esteemed Diamond Dogs?

 

[TedLasso]

Oh, I put an temp sensor in the Garage. It's interesting how hot it gets by itself. There is no appliance in the room that generate heats. It's truly magic.

As a comparison, the Equipment monitor cupboard has all my PCs and iOT stuff in it so it's normally always warm.



The scullery is right next the garage and mirrors rest of the house in being normally a bit cold!

 

[furpile]

Old Lasso was trying to figure this all inverter solar Max V stuff out, looking at the data sheets of the SunSynk 8KVA inverter and solar panels. Why the F is it so complex? ... I know I can apply my mind if I want to , but I would rather not (for now).

As my alter ego, previously said:

"Taking on a challenge is a lot like riding a horse, isn't it? If you're comfortable while you're doing it, you're probably doing it wrong."​

So my garage roof apparently is not big enough to hold 8 panels - could be 6 maybe 8 - I need to climb on to roof to measure. Also realised the other parts of north facing roof is actually going to be complicated due to shading from trees currently in Winter morning (seems to clear around 9am) and a skylight.

So to maximise space: Instead of JA 540W, maybe go for 640W or higher panels (while they exist - can't seem to find anybody in SA who sells them). The question is, which is better in long term :- JA 540W or Canadian Solar 650W (https://www.greenbuildingafrica.co.za/canadian-solar-launches-640-665-w-panel-series/)

Based on my research (on my phone) there doesn't appear much difference in size between the 540W / 640W panels.

For installation:
I think a string of 6-8 540W or 640W Panels could do me right as a start without blowing up the inverter

• 1 string of 6 on the garage (facing north) on MPPT1
• 1 string of 2 (facing west) or north in a different location on MPPT2. Later add a few more panels for a total of 12 altogether which will more than meet our needs for daily production (540w x 12 ) = 6480wp

Any thoughts esteemed Diamond Dogs?

2 panels will likely not be enough for the MPPT. So start with just 1 string of 6 or 7 panels on 1 MPPT and then you can later add another string of 6 to 8 panels.

To do a quick check look at the following.

1. Panel Voltage (Voc)
This is crucial. The combined voltage of the string must not exceed the MPPT limit, which is 500V for the Sunsynk. These panels are typically around 49V (check the values for yours) so 7 will get you close to the optimal voltage (370V for the Sunsynk). Leave 10 to 15% headroom for temperature variation.

Also with Voc you can see how many panels are needed to start the MPPT. I think the Sunsynk is around 100V so 2 panels will not be enough.

2. Panel Current (Isc)
Also important but not as much as Voc. The inverter cuts off at 22A for the MPPT. The 540W panels should be around 13A so if you want to put 2 strings in parallel on one MPPT you will lose some power. With the size panels you are looking at this should not be an issue.

 

[TedLasso]

Thank you Sir!

 

[RonSwanson]

For a good guide on solar panel string sizing, have a spreadsheet ready, and take look here:

String Sizing Guide: How Many Solar Panels Can I String Into My Inverter?

Learn how to calculate string size to optimize your inverter's efficiency and get the most production out of your panels.

unboundsolar.com

As @furpile mentioned, the maximum voltage of an inverter's MPPT is important, and it should not be exceeded. Panels usually come with a spec sheet, which specify this as VoC (Voltage Open Circuit) at a specific temperature. The higher the temperature, the less voltage, and the lower the temperature, the more it becomes. So itis important to also take into account temperature, and there are a few factors that affect this, such as the the sun and the wind and the mounting structure. These will increase or decrease the voltage of a string of panels, so it's always a good idea to take them into account, and leave a small margin for error as well as things that are difficult to determine.

About the specific temperature, there are two usually quoted on the spec sheet: STC (Standard Test Conditions as defined by IEC61538) which is usually 25 degrees celsius and NOCT (Normal Operating Cell Temperature) which is calculated differently, based on specific conditions iro irradiance, wind speed, air temperature and air mass. What's important to know is that, when selecting a panel, one with a higher power rating at NOCT is usually better than another with the same STC rating.

On power, when sizing a string, we take note of the inverter's MPPT spec, for Sunsynk 5k it is:

and for Sunsynk 8k it is:


So we can see that for both the 5 and 8k inverters, the maximum voltage is 500V per MPPT. Both have 2 MPPT controllers and they differ in that the 8K can take 22A per MPPT whereas the 5K can take 13A per MPPT.
Important to note the startup voltage, so for the MPPTs to actually do anything it needs 150V plus to start it up. So putting three panels (@ say 49V) in series won't do anything, it needs at least 4 of them.

If you have a 5K Sunsynk, then you would typically want to chooses a panel that is as close as possible to just under 13A. It won't hurt the inverter to be a little over this because current is easy to control and the MPPT will reduce the amps, but we need to remember that this will cost efficiency, anything over 13A will literally be thrown away.

If you have a 8K Sunsynk, you would want to choose panels that are closest to just under 11A, because 2 panels in a parallel string will double the amperage, and whilst being over 22A wont hurt it, it will likewise impact efficiency.

So once you have your spreadsheet, you can insert the VoC, VmP, IsC, and determine the basics: How many panels you can serialise before you reach 450V or so. I say 450V because that's the max figure that Keith (cautiously) mentions in his videos. Then you need to calculate the voltage increase on temperature drop, and the guide shows nicely how to do that using the coldest day for your location, NOCT and the temperature coefficient of VoC. People with lots of wind (think places like CT and kabookie) may want to adjust slightly for this as well. Also important to consider panel tilt and azimuth, and remember that STC assumes perfect, optimal conditions, which don't always translate in practical terms.

Then you have a spreadsheet which you can compare a range of available panels with, and also use it when you decide to upgrade (we all tend to do that after a few months).

As you have mentioned, you have limited space so you also need to consider panel sizes. Solaredge has a very cool 2D / 3D tool here to assist with that:

https://designer.solaredge.com/sites/794695334900479/design/modeling/2d

Happy modelling!

 

[TedLasso]

Thanks Ron and Furpile

Climbing on roof tomorrow to take some pics and measure when gardener is here .

I had built an excel but it was very simplistic. Will definitely use the resources for more guidance.