New solar installation - need advice

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Solarfan

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Good morning - the installation of my solar power system (5kw hybrid grid tied, 4.8kw LFP batteries) has just been completed and I have a couple of questions which I hope someone can assist with:
- I have 3 phase power in my house, but the inverter is a single phase inverter and only connects to one of the phases. This creates problems as the back-up function is now limited to that phase only. Is there any way to convert from 3 phases to a single phase, but in such a manner that the conversion is reversible? I have checked and don't need three phase power at the moment - a single phase will be more than sufficient to handle my current load profile.
- Does the solar panel array need to be earth grounded for lightning protection - i.e. grounding wire to ground lightning conductor? My installer says this is not necessary but given the cost of the system I would rather take a belt-and-braces approach. I stay in a area with high lightning activity.

Hope someone here can help. Plse - I am a Newbie and apologies in advance if I break any forum protocol
 
I don't understand what you mean by reversible 3/1 phase since it implies phase multiplication/division both sending and receiving to/from the inverter... Your inverter will either be one or three phase output fed by the DC batteries. Your charge controller may take an AC input but that is a different device altogether. There are ways to convert one phase to three phase but it isn't very efficient. You can tell your installer to swap out your one phase inverter for a three phase one. It's just one more wire.

As for the panels it is probably a good idea to earth the common ground. However, if you are afraid of a lightening strike perhaps consider putting in a lightening pole?
 
If you aren't using the three phase the sensible thing to do is probably to have the municipality convert you to single phase.
 
I would earth the panel frames and also install surge protection on the PV side.

Tell us more about the LFP battery. Specs, where di you get them and ... cost. :)
 
Hi - two 2.4kw LFP batteries, DOD 20%, lifespan more than 10 years
I got these directly from my inverter supplier as local prices for similar batteries are ludicrous, and lead acid batteries, in whatever form (sealed, deap cycle, gell etc etc) is an outdated technology with the very low DOD and life span. People should really compare cost per usable kw of batteries over entire lifespan before buying those things.
My supplier is Solax - Chinese solar company, products have all Australian, EU, German, UK certifications, thus far very impressed with inverter and batteries. Have so far provided me with really excellent after sale service - respond to emails regarding installation etc within an hour ofr two (the service levels is why I enjoy dealing with Chinese companies - they actually want your business against SA companies who really couldn't care less)
Batteries cost me about US$ 2 400 (insured, landed in Durban) for 4.8kw (i.e. US$1 200 each). The batteries are quite small - I am fitting them in a 19" standard server cabinet, height about 15cm. I don't have a separate breakdown of the customs duties paid and the transport from Durban to Pta.
 
Solarfan said:
Hi - two 2.4kw LFP batteries, DOD 20%, lifespan more than 10 years
I got these directly from my inverter supplier as local prices for similar batteries are ludicrous, and lead acid batteries, in whatever form (sealed, deap cycle, gell etc etc) is an outdated technology with the very low DOD and life span. People should really compare cost per usable kw of batteries over entire lifespan before buying those things.
My supplier is Solax - Chinese solar company, products have all Australian, EU, German, UK certifications, thus far very impressed with inverter and batteries. Have so far provided me with really excellent after sale service - respond to emails regarding installation etc within an hour ofr two (the service levels is why I enjoy dealing with Chinese companies - they actually want your business against SA companies who really couldn't care less)
Batteries cost me about US$ 2 400 (insured, landed in Durban) for 4.8kw (i.e. US$1 200 each). The batteries are quite small - I am fitting them in a 19" standard server cabinet, height about 15cm. I don't have a separate breakdown of the customs duties paid and the transport from Durban to Pta.
Click to expand...

What is the AH and voltage of these batteries?
 
Apologies - yes, more than 10 years life at 80% DOD.
At the moment the batteries (fully charged) are showing 53V
 
LFP Battery specs:
•Voltage (V): 48
•Capacity (Ah): 50
•Capacity (Wh): 2400
•Height (mm): 132 (3U)
•Length (mm): 442
•Width (mm): 370
•Weight (Kg): 28±0.5
•Operating Voltage: 42~54
•Charge Voltage: 53.5~56.5
•Max. Discharge Current(A) 50
•Max. Charge Current(A) 10
•Network Interface: RS232
•Life (25°C): 10 years
•Life (40°C): 8 years
•Life Cycles (80% DOD): 4000+
•Storage time (25°C): 6 months
•Operating temp: – 25°C~60°C
•Storage temp: – 40°C~80°C
•EMC Standard: IEC61000/EN55022
•Certification: TUV/CE/CCC/TLC5
 
Ok, so how do you get 4,8kw from a 50Ah battery???
What battery controller you using for the LFP?
I see you can only charge at 10Amp. At that rate, how long does it take to get from 20% to 100% capacity?

What size PV did you install?
By law each PV panel needs to be earthed with an earth cable.
The complete solar array needs a surge protector.
If your installer is worth anything they would also issue you with a COC for the electrical work they did.

You have 2 options regarding your 3 phase system.
1. Convert everything to a single phase. This should be easy with just wiring changes.
2. Buy the 10kw InfiniSolar Hybrid invertor. It should be cheaper than the Solax and it's got 3 phase in and out.

Lastly, how about a couple of pics for those of us that can only drool???
 
Hi - thank you, you are obviously a lot more knowledgeable about solar than I am. Hope this answers your questions:
- 4.8kw from 50Ah battery - have 2 batteries each with 2.4kw
- No idea how long it takes to fully charge, maximum usage thus far (past 10 days) have been 10%, which recharges in about 20 mins, from very early morning solar power generated, not full power
- Battery controller is built in to the inverter
- Size of PV - 5kw (20 x 250w Solarworld)
- Thanks - will immediately get earth cable installed
- Array has surge protector installed before inverter
- Thanks - am going to discuss with my installer to get the CoC
- Plse, Plse give bit more input on what wiring changes are required to convert everything to single phase!! This sounds exactly like the solution I am looking for!
- There are so many different inverters out there that it is difficult for a novice to make an informed choice, and each installer tries to sell you his preferred brand (on which they probably make the largest profit). I chose the Solax because it is a all-in-one solution (inverter, BMS, etc) and because it got good review in Australia, UK and Germany
 
wetkit said:
Ok, so how do you get 4,8kw from a 50Ah battery????
Click to expand...

Its a 48v battery, and he has two of them.
Watt hour = Ampere hour * Voltage
100A * 48V = 4800 Wh = 4.8 KWh

So the voltage makes a big difference.

Granted he can only use 80% of that but still not bad :)
 
Sorry - will post pics when I have a chance - first have to find time to climb on the roof to take the pics!
 
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