Energy Matters Forums

[angusjones8]

Gday,
I'm about to build a shed to live in and will have to go off grid (which is what I wanted all along).
I have got a few quotes from local solar company's and thought there must be some ways to save some money.
We are pretty energy efficient in our current house using 4-5kwh per day all year round and in the new place we will have gas cooking, gas or solar hot water, led down lights, small house pressure pump, dishwasher and cloths washer during the day, large fridge and tv.

Everyone seems to be recommending 4-5kw system so that's what I want.

What I'm asking is if anyone can help steer me in the right direction as to what components I need and what money I am looking at needing to spend.
We are in north east nsw so get a good bit of sun.
I have a good mate who is an electrician that is going to do my electrical work for cost of components.

Thanks and look forward to learning all there is about solar!

[Gordon-Loomberah]

Welcome to the Energy Matters Forum Angus

I went for over 2 years with no generator usage, and averaged 12kWh per day over winter, and much more over summer, with under 5kWh of PV panels. If you went for a ~20kWh LiFePO4 battery, then you'd easily get by with 3kWh of PV.

[angusjones8]

Thanks for the welcome.
I forgot to mention I have a 5kva Honda generator too.
Lithium batteries sound great but also sound expensive.

[Gordon-Loomberah]

Certainly a bit more expensive up front, but you only need about half the rated capacity since they can be safely discharged much more deeply than Lead-acid batteries, without compromising their lifetime.
They are also significantly more efficient, so you have much more energy available from your panels. Overall cost per kWh over their lifetime is less than for good quality Lead-acid.
There is a thread covering this - topic 5108

[angusjones8]

The few quotes I have received have been around the 15-20K mark and to be honest the budget is only $15k tops and that's sacrificing a few other things.
Thanks

[Gordon-Loomberah]

Guesstimates for pricing, you can look for them yourself online:

400AH 24V Winston LiFePO4 battery (~9kWh usable) + balancers, ~ $6000
BMS $500
Outback FM80 MPPT charge controller $1000
Latronics LS4024 4kW inverter $4000
4kW PV panels, mounting $4500

Although you probably wont need it if you can restrict yourself to <4kWh/day in overcast periods, battery charger $?

You could look around for 2nd hand panels, inverters and charge controllers to reduce the cost a fair bit.

[Gordon-Loomberah]

Further to my comments re cost of Lead vs Lithium storage, there is a graph today here:
http://reneweconomy.com.au/gcl-slash-pr ... kwh-20557/

Only one Lead battery is listed, but have a look where it is!

[angusjones8]

That sounds very affordable. I don't mind running the generator if I need to anyway but the idea is to use less electricity into the future.
Thanks heaps

[angusjones8]

Having trouble finding those wiston battery's, the supplier has non in stock and hasn't written back to my emails. Has anyone bought them from overseas?
Also what would be a good BMS
Thanks.

[karrak]

Having trouble finding those wiston battery's, the supplier has non in stock and hasn't written back to my emails. Has anyone bought them from overseas?
Also what would be a good BMS
Thanks.

Not sure which supplier you have tried, have you tried EV Works in Perth?

They might not have the 400Ah batteries, but it is not a hassle to Parallel LiFePO4 (LFP) batteries.

Regarding a BMS, this unit looks very good to me
https://www.ev-power.eu/Battery-Managem ... .html#tab3