Setting up an off-grid system

New to renewable energy? Have questions? Here's a great place to ask them and view information about wind and solar power basics.

Setting up an off-grid system

Postby new to solar power » Wed Jul 22, 2015 10:35 pm

Hello my name is Alex.
I am in the process of setting up an off grid solar system and am pleased to have joined this community of people sharing their knowledge.
I am looking forward to posting my questions shortly in the appropriate forum.
At present I am installing my system and am at the trailing stage, with only a couple of components left to be added. My testing has been with mixed results.
a) 24 Mono Panels 250w The solar panel specifications are Max Power Current 8.073A Max Power Volts 31.14V Short Curcuit Current-Isc 8.61A Open Circuit Volts-Voc 37.74 . There are 3 panels per string with 8 strings yielding a maximum of 70 amps but generally between 50 to 60 amps. As yet I don't know if I am getting the maximum performance from using this configuration?
b) I am not sure about the charge controller whether it is PWM or MPPT. Rated Current and Voltage 150A 48V. Rated Battery Capacity 1500AH.
c) 24 PV Gel Batteries - 2v 1200AH OPvZ 94 kgs per battery . (when I was in China last year I purchased these from a battery factory in Hebei Shangdong Provence.)
d) 2 Gen Power Pure Sine Wave Inverter/Charger Combo Model No. PSW7 6048E from eBay. The reason for two inverters is, one for the house supply and the other one for the workshop supply as required. After lots of reading on this forum about this type of inverter maybe it isn't the best choice but one learns from trial and error.
I shall post photos in the forum shortly.
Alex
new to solar power
Solar Fanatic
Solar Fanatic
 
Posts: 45
Joined: Tue Jul 21, 2015 4:36 am

Re: Setting up an off-grid system

Postby Gordon-Loomberah » Thu Jul 23, 2015 12:22 pm

Welcome to the Energy Matters Forums Alex :)

I suspect that with that many panels you will need more than one of those charge controllers, and it does have to be an MPPT CC, otherwise you will be throwing away much of the PV panel output.

Are you sure it is rated at 150A, and not 150V maximum open circuit voltage, which is much more common.

Can you tell us the brand and model?
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Setting up an off-grid system

Postby new to solar power » Thu Jul 23, 2015 11:44 pm

Hi Gordon
Thank you for replying so quickly to my post.
I just checked google maps and see that your not too far away from where I am about 240 klms.
I don't know the brand of the solar charge controller but I have just been chatting to my friend in China and he will get the information to me shortly.
Tomorrow I will take some photos of the controller and also with the front cover removed and hopefully this will give you a clue of what type of controller I have.
This is some of what's in the booklet supplied with the solar controller.

Model TS48S150P-2T
Rated Current 150A
Battery Input
Rated Voltage (Vdc) 48
Min Start Voltage (Vdc) >35
Rated Battery Capacity 1500A*h
Under Voltage (Vdc) <43.2
Under Voltage Recovery (Vdc) >49.2
Over Voltage (Vdc) <60.0
Solar Input
MAX open circuit voltage (Vdc) 120.0
Number of Solar (N) 2
Rated Charge Current 150
MAX single array current (A) 80
First Array protect voltage (Vdc) >53.0
Second array protect voltage (Vdc) >57.0
Protection Function
Battery over-charge, Battery discharge, Battery reversed, Solar reversed, Reversed charge, Overheating.
Cooling. Forced air cooling.
Conversion efficiency 95%
Dielectric strength 3000Vdc
General data
Dimensions (D x W x H) 320mm x 400mm x 170mm
Weight (Kg) 9.5
Protection grade IP20
Noise (db, 1m) <50
Altitude (m) <3000
Working temperature (c) -25 - +65
Storage temperature (c) -45 - +85
new to solar power
Solar Fanatic
Solar Fanatic
 
Posts: 45
Joined: Tue Jul 21, 2015 4:36 am

Re: Setting up an off-grid system

Postby new to solar power » Fri Jul 24, 2015 10:02 am

[attachment=2]DSC_5681.jpg[attachment=0]DSC_5685.jpg[attachment=1]DSC_5684.jpg
Attachments
DSC_5685.jpg
DSC_5684.jpg
DSC_5681.jpg
new to solar power
Solar Fanatic
Solar Fanatic
 
Posts: 45
Joined: Tue Jul 21, 2015 4:36 am

Re: Setting up an off-grid system

Postby Gordon-Loomberah » Sun Jul 26, 2015 11:18 pm

OK, 150A it is then, but at a lower than usual max Voc of 120V, rather than the ~150V which many high power MPPT CCs have.
The pic isn't really clear enough, so I cant quite tell what is going on with those batteries, do they have 6 terminals each? Seems a lot for a 2V cell. Also, what's going on at the right with the thinner black cables on some terminals?

If it doesn't say MPPT anywhere in the specs, then it probably isn't, and I cant see any large capacitors, which normally feature in this type of controller. That means you want your panel string Vmp to be not too much more than your max battery voltage, otherwise you will be wasting potential panel output.
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Setting up an off-grid system

Postby Roundsole » Mon Jul 27, 2015 1:02 pm

How much did you save importing the batterys yourself.?
Roundsole
Solar Supporter
Solar Supporter
 
Posts: 15
Joined: Sun Jun 14, 2015 2:21 pm

Re: Setting up an off-grid system

Postby new to solar power » Mon Jul 27, 2015 1:28 pm

The batteries where USD310 each and the cables, bolts, bus bar and insulators where another USD 460. Total price icluding shipping to Sydney was USD7900-00 in April 2014.Then you need to pay customs GST + 5% import duties, port fees and charges.
new to solar power
Solar Fanatic
Solar Fanatic
 
Posts: 45
Joined: Tue Jul 21, 2015 4:36 am

Re: Setting up an off-grid system

Postby new to solar power » Mon Jul 27, 2015 7:14 pm

With the batteries there are 8 terminals for each battery. Originally we were going to have two rows sitting on timbers on the concrete floor. I changed my mind and built the steel rack so I now need 6 new cables 650mm long. I am getting them in China and will bring them home with me on my next visit in 2016. The cables with the rubber covers cost me USD30-00 and the air freight is USD70-00 for 3kg. For the time being I am using second hand cables.
At present we haven't the time to rearrange the solar panel strings from three panels to two panels per string because of work commitments however this will be done when time allows.
With the solar controller I think you are correct with it being a PWM. I have been observing the controller for a while now and have worked out what it is doing.
There are two inputs, each one is rated at 60Amps continuous, with the two inputs combined to give 120 amps.
As the batteries reach 53v the first input shuts down and then production is then lost until the volts go below 53v.
The second input keeps operating until the batteries are full.
With the way this controller works, would I be able to rearrange the solar panel strings so as 60amps goes to the second input and the remainder of the solar panel production that is less than 10amps goes to the first input? This amperage amount should improve a fair bit when we rearange the solar panel strings.
new to solar power
Solar Fanatic
Solar Fanatic
 
Posts: 45
Joined: Tue Jul 21, 2015 4:36 am

Re: Setting up an off-grid system

Postby Gordon-Loomberah » Mon Jul 27, 2015 8:04 pm

Alex wrote:With the batteries there are 8 terminals for each battery.


That sounds unusual, is each of the 24 batteries made up of 4 cells? I don't think I've ever seen so many connector cables on a 48V battery ;)

As the batteries reach 53v the first input shuts down and then production is then lost until the volts go below 53v.


ahh, that explains this:
First Array protect voltage (Vdc) >53.0
Second array protect voltage (Vdc) >57.0


which I didn't understand. Does that mean it just disconnects the 2nd PV array when it reaches 57V, or does it have a constant voltage Absorb stage, which would need to be at least 3 hours for a 1500AH, followed by a Float stage where the full state of charge is maintained? In any case, it sounds like a very rudimentary form of charge regulation.
http://gunagulla.com Loomberah weather and astronomy including live solar radiation intensity and UV + Gunagulla aquaponics, organic eggs and cherries
User avatar
Gordon-Loomberah
Community Moderator
 
Posts: 5763
Joined: Thu Sep 24, 2009 9:41 pm
Location: Loomberah NSW Australia

Re: Setting up an off-grid system

Postby new to solar power » Mon Jul 27, 2015 9:02 pm

I have just found out that the solar controller is from Sungrow Power Supply Co., Ltd China and I have just emailed them to request a data sheet for this model of off grid solar controller, so when I get a reply I can forward on the info.
It does have a constant voltage Absorb stage and what happens is it shuts off the current for about 20 secs and when the volts drop it comes back on for the same amount of time. This cycle goes on for a couple of hours.
I am still learning what happens as this setup has only been working for a few weeks now.
Your comment of "a very rudimentary form of charge regulation" seems to simply sum up this controller but it works, just need to fine tune the system to get the best performance from it.
Yes each battery is made up of four 2 volt cells
new to solar power
Solar Fanatic
Solar Fanatic
 
Posts: 45
Joined: Tue Jul 21, 2015 4:36 am

Next

Return to Q&A - wind and solar power basics

Who is online

Users browsing this forum: No registered users and 3 guests

new solar power specials