7 KW Island Residence Installation

[100islands]

Greetings everyone, this is my first solar installation. Im am excited to finally be working with solar and lucky to be doing it on a very nice location oceanfront. (Pics to follow) A little background, I'm a residential builder from California working in the Philippines islands for the past 2 years.

I have spec'd out most of my hardware and received the OutBack inverter already.

My questions are more specifically:

1. Are my number of batteries to solar panels are correct? Should i be able to fully charge the 32 batteries every day and continue to run the residence requirements of 12-16 kwh per day?

2. How best to layout the strings of solar panels, they will be ground mounted on cement slab so its flexible on the space side. There are very high winds at the location to consider as it is ocean front I want to keep the panels low to the ground. (Multiple rows)

3. How to most efficiently wire the Charge controllers, which strings goto which charge controller or just 14 panels to each flex80 to make it even 14x2, as i understand they have 4000 watt capacity each. My length from flex80's = 35 meters.

--Here are my system specs on the project to run by everyone and hopefully get some feedback I really appreciate the input here--

------------
Grid (Stable at 220V - 60HZ Single Phase)
Notes: Outages frequent couple times a week for a couple hours, during bad weather long outages lasting days.

Inverter ( Outback GS7048E ) 240V - 60HZ Single Phase
---------
Input 1 - GRID
Input 2 - Honda EU6500IS Inverter Generator LPG Fuel source
Outback GS Load Center
MATE3 Controller

Charge Controller 1 - Flexmax/80
Charge Controller 2 - Flexmax/80

28 MODULES
---------
PV - SOLARWORLD (Solar Cell Germany, Monocrystalline)
Max Power Voltage Pmax - 250 Watts
Max Power Voltage VMP - 30V
Max Power Current Imp - 8.33A
Short-Circuit Current Isc - 9.99A
Open-Circuit Voltage Voc - 36.6V

32 BATTERIES Running at 48V
----------
12V TROJAN AGM 31
100-Hr Rate - 112AH

Residence Load Schedule
----------
400-500 KWH per month
Basic House loads, No AC
2 Well pumps, Ref, lights


Thanks !
Lou

[sensij]

I am definitely not the battery expert around here, but here is what I see...

32 * 100 Ah * 12 V = 38400 Wh battery capacity.

12-16 kWh / day means that you are potentially discharging 30-40%... plan to keep the generator ready for cloudy days to make sure you don't often discharge more than 50%.

To get 48 V out of that battery, you'll have 8 parallel strings. Good luck balancing them. Generally, for a high capacity system like this one, you'll be better off with lower voltage, higher capacity batteries so you can put more in series and less in parallel, so it is less likely to get unbalanced.

AGM batteries like a higher charge current... 800 Ah capacity at 48 V, at a C/5 rate = 160 A. You suggested a 7000 W array, at 48 V that will produce at best 146 A (if efficiency were 100% and solar exposure was perfect), but usually much less than that... probably lower than those batteries will like.

I would guess (but don't know) that the Phillippines gets decent sun. FLA batteries would not need (or want) such a high charge current, making it a bit easier to size the array... although they may need more maintenance.

[100islands]

Great info, we have the option of going with GEL technology or FLA, however owner did not want to deal with maintenance. Do you think it would be wise to go with 6V or 2V for this size system?

Optional batteries available locally. Other 2V can be ordered via Trojan as well.

TROJAN TE35-GEL 6 VOLT 210AH (GEL)
TROJAN T105-RE 6 VOLT 225 (FLA)

Thanks!!

I am definitely not the battery expert around here, but here is what I see...

32 * 100 Ah * 12 V = 38400 Wh battery capacity.

12-16 kWh / day means that you are potentially discharging 30-40%... plan to keep the generator ready for cloudy days to make sure you don't often discharge more than 50%.

To get 48 V out of that battery, you'll have 8 parallel strings. Good luck balancing them. Generally, for a high capacity system like this one, you'll be better off with lower voltage, higher capacity batteries so you can put more in series and less in parallel, so it is less likely to get unbalanced.

AGM batteries like a higher charge current... 800 Ah capacity at 48 V, at a C/5 rate = 160 A. You suggested a 7000 W array, at 48 V that will produce at best 146 A (if efficiency were 100% and solar exposure was perfect), but usually much less than that... probably lower than those batteries will like.

I would guess (but don't know) that the Phillippines gets decent sun. FLA batteries would not need (or want) such a high charge current, making it a bit easier to size the array... although they may need more maintenance.

[paulcheung]

You should just get 8 of those Trojan IND17-6V batteries. single string with long sun hours in Phillipine Islands you will have enough power to spare.

[100islands]

Thanks for the input! Im having a hard time locating the IND17-6v however they do have L16RE-B in stock. Any suggestions on how to arrange this if we go witht he L16RE-B? Perhaps 16-20 batteries?

Thanks! Lou

You should just get 8 of those Trojan IND17-6V batteries. single string with long sun hours in Phillipine Islands you will have enough power to spare.

[100islands]

Located IND17-6V battery, looks like the client agrees on this route.

Now are we ok with the 7000w solar array to get these IND17's charged properly, on the 2 Flexmax80's ? We could expand the array a bit if necessary any tips on how best to arrange the modules? Per my research we will need a 16 p combiner.

On a side note, we have the opportunity to go with MPTEC Poly 245, or these SolarWorld 255 Mono. From my research Mono is more pure silicon but perhaps some of you might have other feedback on this.

Thanks everyone.
R/Lou

You should just get 8 of those Trojan IND17-6V batteries. single string with long sun hours in Phillipine Islands you will have enough power to spare.

[paulcheung]

Located IND17-6V battery, looks like the client agrees on this route.

Now are we ok with the 7000w solar array to get these IND17's charged properly, on the 2 Flexmax80's ? We could expand the array a bit if necessary any tips on how best to arrange the modules? Per my research we will need a 16 p combiner.

On a side note, we have the opportunity to go with MPTEC Poly 245, or these SolarWorld 255 Mono. From my research Mono is more pure silicon but perhaps some of you might have other feedback on this.

Thanks everyone.
R/Lou

It depend on what is your other load in the day. The Ind17-6V need 80 to 115 amps to charge it properly. 7000 watts should be adequate to charge the bank if you don't have too much day load in your system. make sure it has at least 80 amps available current to charge the battery after it supply the day load.

[100islands]

We ended up going with 33 x 300watt Mono-x LG panels. with the 8 IND17-6v This should give plenty extra power to charge and run the day loads. We will be using 2 x Flexmax80's with the outback 7048 @ 240v system.

Thanks again for your input Paul!

It depend on what is your other load in the day. The Ind17-6V need 80 to 115 amps to charge it properly. 7000 watts should be adequate to charge the bank if you don't have too much day load in your system. make sure it has at least 80 amps available current to charge the battery after it supply the day load.

[paulcheung]

You are welcomed.

[Naptown]

I am confused
Of the power sources you mention one of them is grid power.
That would make this a hybrid system
What are you planning to use to switch from grid it off grid.
Do not use gel batteries. Use AGM batteries such as the Concorde sun extender.
Gel batteries cannot take the charge current of that array.
And lastly try very hard to find 2 or 4 volt batteries and use 1 string unless you want to be servicing this thing forever due to multiple unbalanced battery strings.

[sensij]

I am confused
Of the power sources you mention one of them is grid power.
That would make this a hybrid system
What are you planning to use to switch from grid it off grid.
Do not use gel batteries. Use AGM batteries such as the Concorde sun extender.
Gel batteries cannot take the charge current of that array.
And lastly try very hard to find 2 or 4 volt batteries and use 1 string unless you want to be servicing this thing forever due to multiple unbalanced battery strings.

The OP is using qty 8 of 6 V FLA batteries, true deep cycle meant for RE, in a single string for 48 V. Looks like he has learned a lot from the forum and is putting the knowledge to good use.

[Naptown]

Ok
Did not look up the battery specs
However those are FLA which will require maintenance

[100islands]

Update on this setup, ended up being a 10KVA LG setup. 33x300 watt mono panels. its working perfectly and completely grid free. The system also suvived a major typhoon with wind speeds up to 200 mph.

Note on battery selection ** Perfect ** System charges up the Trojan IND17's in a few hours from 7am- 10am to 100% charge pulling about 7-8k from the array with plenty of daytime load current to spare. Overnight consumption uses only 20% of the battery bank capacity. The Outback Radian handles everything efficiently and has been trouble free. Thanks again for all the suggestions on this I really learned a lot on the forum.

[solar pete]

Update on this setup, ended up being a 10KVA LG setup. 33x300 watt mono panels. its working perfectly and completely grid free. The system also suvived a major typhoon with wind speeds up to 200 mph.

Note on battery selection ** Perfect ** System charges up the Trojan IND17's in a few hours from 7am- 10am to 100% charge pulling about 7-8k from the array with plenty of daytime load current to spare. Overnight consumption uses only 20% of the battery bank capacity. The Outback Radian handles everything efficiently and has been trouble free. Thanks again for all the suggestions on this I really learned a lot on the forum.

Hi 100islands, thanks for giving us the heads up on how it turned out,, nice work, cheers