4kWp Stand alone system design help

[dseeker]

Hi,

I am intending to install a 4kWp stand alone system and I am struggling with the price optimization. I heard that the biggest charge controller available in the market is 80Amp. the price of this one is around £600 no problem, however this means that I have to use at a 48V 600ah battery bank which is very expensive (around £5000). do you think these prices are the best I can get!
From your experience if I split the system into 2x2kWp, and consequently had two battery banks with lower voltages, do you think I would benefit from a reduced overall cost?

Any suggestions are most appreciated!

Best,
A

 

[ExtremePV]

Off grid systems are expensive as the bulk of the cost is in the batteries.

I would suggest working out what your expected daily power requirements (kWh's) and peak load is expected to be.

For a 4kw PV system, I would suggest using AC coupling, rather than a DC charge controller.

Have a look at SMA Sunny Island Inverter/Charger along with a SunnyBoy inverter

At the 4kw level, you want to stick with a 48V battery bank. Lower battery voltage just means much higher DC currents.
If you send me some details I can work out some options for you.

Regards,

Ken

 

[nowty]

Hi,

however this means that I have to use at a 48V 600ah battery bank which is very expensive (around £5000).
A

If you use deep cycle fork lift batteries a bank of that spec will be more like £2000. I have a 24v 1000Ah bank which cost me £1800.

If you do enough google searches on renewable forums you will find most hard core off gridders swear by them and some in the UK have been running a bank of them for 10 years.