Home Data Center Build - Solar Guru Guidance Needed

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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby australsolarier » Wed Apr 04, 2018 8:57 am

it depends what country you are based.
if you are in australia check the local codes.
you will find them online.

as i understand it here in australia the panels and rails are not grounded. but they have an earth wire that goes back to the inverter or solar charger. this is not to protect from lighting. but if there is an earth leakage event.
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby GregoInc » Wed Apr 04, 2018 12:51 pm

australsolarier wrote:it depends what country you are based.
if you are in australia check the local codes.
you will find them online.

as i understand it here in australia the panels and rails are not grounded. but they have an earth wire that goes back to the inverter or solar charger. this is not to protect from lighting. but if there is an earth leakage event.


I am in Australia, and from most of the reading I've done it appears the clean energy council mandates earthing the solar panels, panel mounting, and inverter. And the diagrams I've seen show for off-grid (which I am starting with) an earth rod is driven into the ground, and then connected to everything as per above. So I guess it kind of aligns with what you are saying above... in a round about sort of way :)
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby davidg » Thu Apr 05, 2018 1:16 am

australsolarier wrote:as i understand it here in australia the panels and rails are not grounded.

Sorry to say but that would be incorrect. They are most certainly grounded under current regs and have been for quite sometime.
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby australsolarier » Thu Apr 05, 2018 6:37 am

davidg,
just wondering, where does the earth wire from the rails and solar panels connect to?
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby davidg » Fri Apr 06, 2018 2:08 am

australsolarier wrote:davidg,
just wondering, where does the earth wire from the rails and solar panels connect to?

Generally Main Switchboard or Switchboard the Grid inverter wired into, normally via the Grid Inverter and must be labelled inside the switchboard accordingly (Solar Earth).
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby GregoInc » Fri Apr 06, 2018 7:31 am

I am geting close to roughing in the interconnect cabling for my solar panels. So here's my next question... wire size for connecting the on roof isolator and solar panels.

The Trina panels I purchased were the 300 watt Honey M Plus, and they come with 4mm2 cables with MC4 connectors. So my question, what size interconnect cables do I use between the solar panels, roof isolator, and down to the inverter/charger? Would it be 4mm2 or 6mm2... thoughts?

Here's my draft solar design...
fdwnoy0.jpg
Draft Solar Design
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby davidg » Sun Apr 08, 2018 9:15 am

GregoInc wrote:So my question, what size interconnect cables do I use between the solar panels, roof isolator, and down to the inverter/charger? Would it be 4mm2 or 6mm2... thoughts?

Here's my draft solar design...
fdwnoy0.jpg


Forget the CB's an Isolator at the array for compliance and one isolator at the MPPT charger controller on, with only 2 string PV does not require it and it will not do thing. If or when you get more than 2 strings then you install suitable fuses/CB's per string, specifically (As4509).

4mm2 is fine.

Keep in mind PV is a current limited supply, even in short circuit it cannot exceed XX watts/amps. The way circuit protection is done needs to understood properly, at only 2 strings correctly rated CB/Fuses will never "trip/blow" so no point in using them (still complies with regs). 4mm2 wire will never overheat and worst case may get warmer but that's all.

Install shunt in NEG at the batts so you have current IN/OUT monitoring connect applicable units

Personally I'd use a Selectronic in place of the Latronics. You would install a suitable Shunt in the cable to/from the solar MPPT charge controller and connect sense wires to the Selectronic. The Selectronic would take care of automatic grid/generator switching as it's already built-in and with an expansion module it will do a combination of grid and/or generator at once.
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby GregoInc » Sun Apr 08, 2018 12:00 pm

Hi David,

Thanks for the awesome feedback mate, really appreciate it. I just wasn't sure if I was on the right track, so your advice is a huge help.

davidg wrote:Forget the CB's an Isolator at the array for compliance and one isolator at the MPPT charger controller.


The only reason I have 2 isolators is because the pairs of panels are in 2 different locations. So I figured it was best to have 2 isolators. I will take out the CB and add an isolator.

davidg wrote:4mm2 is fine


Thanks, will use the twin core cabling, which will make my life easier.

davidg wrote:Install shunt in NEG at the batts so you have current IN/OUT monitoring connect applicable units


Do you have a shunt manufacturer/model/size you would recommend?

davidg wrote:Personally I'd use a Selectronic in place of the Latronics.


Thanks for the advice, I'll do some research on the Selectronic as I haven't come across them before.

I do intend on adding more panels at a later date, once I've learnt from the smaller setup. The panels I purchased were the Trina Honey M Plus 300 watt, which I managed to get at a really good price.

Another dilemma I have is what size batteries to purchase. I know I need to have 16 x 3.2v batteries (to make 48 volts), and was leaning towards 100Ah cells, but not sure if the panels I have will charge that size?

Thanks again for the help, Mark
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby davidg » Sun Apr 08, 2018 6:37 pm

GregoInc wrote:Another dilemma I have is what size batteries to purchase. I know I need to have 16 x 3.2v batteries (to make 48 volts), and was leaning towards 100Ah cells, but not sure if the panels I have will charge that size?


That's approx 2.4kWh's to 3.0kWh's of usable power for 16 x 100ah LiFePO4 using 50% to 60% of capacity from the batteries allowing for losses, keeping mind that they should only be charged to approx 90% maybe 95% to improve long term life.

You need to workout how much power you need first, for both daylight hours and night (no sun) hours, then system sizing is developed around that.
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SELECTRONIC SPMC482-AU, 8.2kW's of Arrays
Selectronic Certified AC-Coupled Fronius 8.2kW Inverter
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An OTT Genset for a house.
PVOutput Stats

Sparkys light up your life :)
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Re: Home Data Center Build - Solar Guru Guidance Needed

Postby GregoInc » Mon Apr 09, 2018 8:21 am

davidg wrote:That's approx 2.4kWh's to 3.0kWh's of usable power for 16 x 100ah LiFePO4 using 50% to 60% of capacity from the batteries allowing for losses, keeping mind that they should only be charged to approx 90% maybe 95% to improve long term life.


That aligns will my calculations which is fantastic. I used a power monitor over a 24 hour period and it came in at around 2.4 kWh, so to see your comments makes me feel I am the right track. I always wanted to start small, and then build up if the need required it. So it's likely starting with a 48v 100Ah battery pack may be good, and I can add an additional pack later if I increase the PV capacity.
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