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Howdy, 

been lurking on here for some time trying to learn as much as possible. been a steep learning curve. About to pull the trigger on an installation but want want to get some ideas around my requirements.

Some background.

The main idea was initially to beat loadshedding but that has turned into trying reduce my reliance and cost to Eskom. I started with an energy monitor to get a good idea of my daylight and night time usages. currently averaging around 30kw per day, mostly split between daylight and evening, (20kw daytime and 10-15kw nighttime) Seems a bit lower in summer now.

Got 2x2kw geysers which are both on solar tubes, gas hob (electric oven) and LED's throughout. so most of the groundwork has been done already. Got a fish pond which is 0.75kw which needs to run 24/7, borehole pump (0.75kw) and pool pump. all of which are connected to smart switches and automated with Home assistant so will be able to control which appliances turn on based on availability of solar generation (except for the pond of course).

Interesting, I noticed if I left my one solar geyser on permanently it used less kw than turning off/on with a timer, initially was set from 05h00-07h00 and back on in the evening from 17h00-20h00. Guess now in the summer its only topping up the water rather than going from cold to hot

Thinking of the following:

8kw Sunsynk 

16 x 535 JA solar panels

3x +-5kw plyontech or hubbles (need some help here)

wont being doing a DIY but got a few companies I am looking at.

Any recommendations to the above will be appreciated especially on the battery front.

 

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i believe you are right on the money, can't go wrong with either battery, Pylontech has a long track record, but I do like a local  manufacturer, so tough choice, maybe start with 2 and invest in panels,

Panel choice is good, only thing I would do is to put in rails for an additional 4 panels, so when funds permit, you can easily add another 4  for a total of 20 panels = 10,700 watts ( essentially maximizing the inverter pv )

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2 minutes ago, Tariq said:

i believe you are right on the money, can't go wrong with either battery, Pylontech has a long track record, but I do like a local  manufacturer, so tough choice, maybe start with 2 and invest in panels,

Panel choice is good, only thing I would do is to put in rails for an additional 4 panels, so when funds permit, you can easily add another 4  for a total of 20 panels = 10,700 watts ( essentially maximizing the inverter pv )

Thanks. Ya at a crossroad between them. Everyone seems quite happy with the hubbles but on the other side like the longevity and name of the other.  On the hubbles, are the Am2 and X series the same and only difference is mounting options?

Also on the plyontechs, keep reading about limited warranties and amount of batteries you need to have with the sunsynk (like 3 or more)- Do the hobbles have any of these restrictions.

Thanks for the advise on the panels, will definitely go that route to try and future proof

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36 minutes ago, ASH_JHB said:

Howdy, 

been lurking on here for some time trying to learn as much as possible. been a steep learning curve. About to pull the trigger on an installation but want want to get some ideas around my requirements.

Some background.

The main idea was initially to beat loadshedding but that has turned into trying reduce my reliance and cost to Eskom. I started with an energy monitor to get a good idea of my daylight and night time usages. currently averaging around 30kw per day, mostly split between daylight and evening, (20kw daytime and 10-15kw nighttime) Seems a bit lower in summer now.

Got 2x2kw geysers which are both on solar tubes, gas hob (electric oven) and LED's throughout. so most of the groundwork has been done already. Got a fish pond which is 0.75kw which needs to run 24/7, borehole pump (0.75kw) and pool pump. all of which are connected to smart switches and automated with Home assistant so will be able to control which appliances turn on based on availability of solar generation (except for the pond of course).

Interesting, I noticed if I left my one solar geyser on permanently it used less kw than turning off/on with a timer, initially was set from 05h00-07h00 and back on in the evening from 17h00-20h00. Guess now in the summer its only topping up the water rather than going from cold to hot

Thinking of the following:

8kw Sunsynk 

16 x 535 JA solar panels

3x +-5kw plyontech or hubbles (need some help here)

wont being doing a DIY but got a few companies I am looking at.

Any recommendations to the above will be appreciated especially on the battery front.

 

That's a beast of a system you are going to have!

I think the battery choice comes down to the price you can get them at. I am very happy with my pylons, know people who are very happy with Freedom Won and have read lots on this forum about people who are very impressed with Hubble. I would see what quotes you can get and then make a decision. Either way you will have a solid battery!

We have similar daytime usage, I tend to over produce(my batteries are full by mid day) with my 5.4kWp array so your solar should be more than sufficient. (A big plus for you during the winter months... my system struggles quite a bit in winter)

 

Edited by Basil Katakuzinos
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The thing I don't like about Pylontech is that i am not sure where to go if I have a problem with my battery, on the other hand Hubble is based in Cape Town ( same as me ), but then they only have been in business about a year ( same reasoning, Pylontech also was a new company a few years ago  )

 I believe the AM2 is the current wall mount battery that is popular nowadays

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Something to consider is the cells they use in the battery that you choose.  What i dont like about Hubble is that they use Lithium nickel manganese cobalt oxide cells . Whereas Pylontech uses Lithium Iron Phosphate. I would advise anyone wanting batteries to research the pro's and cons of both.

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C rating really is not the best thing to look at when choosing a battery IMO and means nothing if you have enough batteries,If you only have budget for one/two batteries then only does c rating play a role,and even then i would strongly opt for LiFePo4 and just limit current until you can afford more batteries . As in my first post,i would suggest anyone interested in buying a battery to research the chemisty used ,the most important thing for me is the lifespan and DOD capability. For this we have to look at the different chemistry's used in the batteries and not the C rating.  The 1C capability of  Hubble is used as a major marketing point but not many people know that it is not a LiFePo4 battery.Go look on the Powerforum store at the Hubble ,they just call it a 'Lithium' battery and dont mention the chemistry at all. I find this kind of misleading as most other batteries are LifePo4 . 

So just a few differences are :

-LiPo4-is much safer chemistry than Li-NMC 

-LiPo4 has a longer lifespan.

-LiPo4 has a higher DOD capability without affecting lifespan as much .

 

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Hmm C rating..... Let's look at the system level here. The inverter needs to draw Current as it is a current source, the thing that makes inverters work. If we have a 5kW vs 10kW inverter and a nominal 48V battery the 5kW will draw about 96 Amps at 5000W and 52 battery Volts. If you installed a 10kW inverter, double that current draw. At 3000W it's 58 Amps and 2000W it's 38 Amps, not a big load and a kettle can draw that by itself. This is not accounting for any system losses, just theoretical mind you. With losses it's even worse.

So C ratings are quite important in sizing a system, especially if you do not want to kill the battery. You have to consider all things battery in terms of what your system is required to deliver and do. C rating will also determine charging time.

Edited by Sarel
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11 hours ago, YellowTapemeasure said:

Could you expand on what criteria you used to determine that? I would probably say that 5-6 US 3000C would be roughly equivalent to 3x Hubble AM2s, but different criteria of course.

Honestly its a bit silly comparing the two as they are totally different .Its like comparing apples to oranges . You have to compare same chemistry to same chemistry.  Just on lifecycle alone its too big of a difference to make a meaningfull comparison.

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This isn'tt helping my decision  🙈

Good info none the less.

I do like the idea of having less batteries as wall space is tight so logically the Hubbles make sense.  But @Nexuss comments about the chemistry make up is concerning. considering pricing isn't convincingly different between the two. What are your thoughts on the 5kw plyontechs. See everyone seems to mention the US3000 only

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2 minutes ago, ASH_JHB said:

This isn'tt helping my decision  🙈

Good info none the less.

I do like the idea of having less batteries as wall space is tight so logically the Hubbles make sense.  But @Nexuss comments about the chemistry make up is concerning. considering pricing isn't convincingly different between the two. What are your thoughts on the 5kw plyontechs. See everyone seems to mention the US3000 only

The us3000C is very popular and many many people use them,they also come with a 7 year extendable to 10 year warranty vs 5 year on the UP5000.

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4 hours ago, ASH_JHB said:

This isn'tt helping my decision  🙈

Good info none the less.

I do like the idea of having less batteries as wall space is tight so logically the Hubbles make sense.  But @Nexuss comments about the chemistry make up is concerning. considering pricing isn't convincingly different between the two. What are your thoughts on the 5kw plyontechs. See everyone seems to mention the US3000 only

What exactly are your concerns regarding the chemistry?

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5 minutes ago, Tariq said:

@Leshen, My inverter will draw from the grid/ pv after it reaches the 50 amp max for my two 2.4 kWh  Pylontech batteries.

 I am willing to learn, please correct me if I am wrong

So what happens when you are drawing 4.8kw from the essential and the grid fails at that instant?

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29 minutes ago, Leshen said:

So what happens when you are drawing 4.8kw from the essential and the grid fails at that instant?

Then you did not plan/manage the system correctly,its really not that hard to avoid that scenario through minor planning. There should also  ideally not be such a large draw on the essential side of the 5kw inverter ,only absolute essentials ,Keith makes this pretty clear in his training videos. 

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An Inverter is a current source, for it to act that way it needs to draw current from somewhere. The design, apart from Grid-tie String inverters, are to work from batteries. Most inverters will not work with no batteries, or should not be connected with no batteries. There are exceptions....

C rate in Amp hours and Watt hours. C rate is the rate of discharge (or charge) over time based on capacity of the battery. The example here, Pylontech US2000C, is 50Ah based on 2400Wh capacity at 48Volts. Design specification is below. The manufacturer indicates a 0.5C (25Amp) normal discharge and charge rate per module. The max rate is 1.0C or 50Amp at nominal voltage, ie 48Volts.

The design capacity of the Inverter dictates its current draw, ie a 3000W inverter is designed to draw from battery or Solar 3kW nominal. from Solar the amps will depend on string voltage, the OEM will specify the max for each. From battery systems the current depends on battery voltage. But 3000W is 3000W at any voltage, ie the current will be determined by the battery or Solar string voltages. The inverter will draw 3000W to supply the 240V 3000W that it's nameplate specs indicate.

The inverter is designed to supply nameplate capacity to its output. Now imagine having to supply 3000W to the output, for whatever reason, from the battery. After sunset, during blackout or someone stole the cable or the Substation blew up or whatever... This will draw 58Amps from said battery at 52 Volts. If the battery was designed to deliver 25Amps at 52 Volts (48Volt nominal), you will overload the battery. You may kill the battery as you are exceeding it's design specs. Pylontech US 2000C specs for a single unit: 

  • Voltage: 48 V
  • Nominal Energy: 2400 Wh (50Ah)
  • Continuous Discharge Rate (Normal Use): 1200 W (Indefinitely until discharged) or 25Amp
  • Maximum Discharge Rate (5 Minutes): 2400 W (The oops I forgot rate) or 50Amp
  • Surge Discharge Rate (15 Seconds): 4320 W (Strictly for startup of an appliance rate) or 90Amp
  • Maximum Charge Rate (5 Minutes): 2400W (1C or 50Amps)

You want to boil a kettle at 2000W you can, but just, as it should boil 1 Liter water in less than 5 minutes. But you are still exceeding the normal use rate and barely fall within the Max discharge rate. Add a few lights, a TV and cell charging, it's already exceeding the Battery design capacity. 3000 Watts, or really anything above 2400Watts, are a no no as it's or startup only.

When you loose Utility grid or mains or loose Solar due to clouds while using the inverter, it will use the battery. Losing any of the other supplies will switch to battery, basically UPS the thing. Designing the system, especially the battery, to cope with Inverter capacity is good practise. It will make the battery last and not endanger the warranty. Even a 3kW inverter needs a battery that can supply 62,5Amp, and then we discount the losses of the system when we should actually include such losses and increase the Battery C rate.

 

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