Why are off grid solar packages so expensive?

[philnsheilaMember]

hi people,

hoping someone can explain why offgrid solar packages are so expensive?

i am wanting to build a 3kw array with mppt controller, couple of small inverters(2000w-500w) and 4x220ah batteries(48v system). may need a diesel generator for back up sometimes.

we have built a large shed that we plan to move into while our house gets built so wanting to mount the panels on the sheds roof(32degrees with good aspect.) this will provide our power needs and hopefully run tradesmens tools for building house.

we are pretty careful with our energy use but never lived off the grid. we likely to run a medium sized fridge, washing machine,(possibly a water pump), led tv, laptop, mobile phone chargers, led or compact fluro lighting.

the location of block is near albany western australia. can anyone tell me if this setup would meet our needs? or if we need to go larger?

i have sourced some prices for individual components which seem alot cheaper then the package deals that seem to be around $30 000!

3kw pv solar array 18x190w mono panels $7200

2x 60amp mppt regulators $700

1500w pure sine inverters x 2 $500

4x220ah $2000

diesel generator $1500

total $11 900

im not sure how much to installation would be but if i am able to help i would expect it would be around $2000? im sure there are a few things i have missed like wiring, panel mounts etc but i would have thought a system of this size would be around $15000.

have i missed something?

if anyone can help with advise or ideas i would really appreciate it or if anyone in the sw of western australia has such a setup or know of installers in the area would be great to hear from you.

Phil

Australia

[chowanParticipant]

I dont think i can help much except that your system sounds huge to me

and you probably have more than enough to run the things you mentioned.

if it were me id probably skimp on panels probably down to 500 watt

and find other ways to do things like a smaller fridge.I would also skimp on the generator and build a home brew charger from a vehical alternator and a 5-8 horse briggs and stratton this could be used to charge your batteries and even as a small welder.

wire is going to get spendy

best of luck

[DustofferParticipant]

I would go to 8 panels and 1 controller with 8 L-16S 410 Ah batteries, and buy a mounting kit. The refer will have to be the high efficiency type and same with the washer.

[elnavMember]

Your list of equipment seems fairly sensible except for the amount of solar panel capacity. How did you arrive at needing 3 kilowatt. Many people fall into the trap of equating capacity of generating capacity with direct instantaneous consumption.ie. peak load.

I know of installations with 470 watt charging capacity that can supply the type of loads you describe. Admittedly contractor tools do use a lot of power but often only in bursts and for short periods. Once construction is done the demand goes way down. Probably the single largest ongoing power user is the water pump if you have a deep well pump. If you use a cisteren or water tank this demand can be scheduled and in fact a petrol generator may be more cost effective than expensive solar panels.

Air conditioning will be another big power user but you can moderate the need for actual air cconditioning with suitable house design and construction.

I am not personally familiar with western Australia conditions but other locations with smilar climatic conditions have found workable solutions.

I was asked to make a proposal for an off grid complex in Mexico that had similar conditions. It can be done.

[Author]

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