Solar power and hot water

Hi,

I have been searching for some ideas around solar power and storage. We lived on a yacht at one time and stored the power generated from solar panels into batteries for later use. Presuming this can be done in a house does anyone know where to research this or may have done this themselves? I have searched on this site but having difficulty I also want solar hot water, no gas available, and wonder how to sort panels on the roof and what our requirements may be for both systems.

Any help would be much appreciated,
Cheers,
Tracey

You may (if haven't already) find some useful info in the Whirlpool Green Tech forum.
We have solar, but gas h/w so can't give much useful info.

Have a look at a product called solax hybrid inverters. I'm not pushing them but found a lot of info to explain hybrid systems.

Yeah, the Homeone forums aren't great for green ideas I must admit. You may be better served by asking at the forums listed below, where you are likely to get lots of advice from people with lots of knowledge on the subject.

http://www.ata.org.au/forums/

http://forums.whirlpool.net.au/forum/143

http://forums.energymatters.com.au

Generally, it's not financially advantageous to go totally "off grid" with a solar PV system. This is because the batteries are still very expensive, & many large batteries are required to store enough energy for all of a energy house's use. I believe that an offgrid setup with sufficient battery storage costs in the range of $20-40k (this is a guess). So at this stage, it's only appropriate for people who live a far way away from the power grid. This will change as battery technology improves & gets cheaper.

There are also "hybrid" systems. These are connected to the power grid, & have smaller battery banks, to try & minimise electricity consumption from the grid at night time, when the PV solar panels aren't producing. These systems are still quite expensive, so not that popular, but should also get cheaper in years to come.

Most people have grid connected systems, without battery storage, as these systems are much, much cheaper to buy.

Lots more to discuss. But check those forums, lots of information there.

edit: Whirlpool's mentioned above, as are hybrid systems. Took me a while to write this.

+1 to the energymatters forum.

The newer Lithium Iron Phosphate (LiFePO4) batteries are far superior to the old lead acid batteries, and people are running totally offgrid on as little as a 400Ah battery bank.

Many options including going hybrid isn't such a bad idea either.

My longer term plan is going totally offgrid in my new home, but initially it will be grid connect, then hybrid later.

Thanks so much for all the replies

Will definitely follow up on those links. Thanks crazyk will look into the hybrid option. I do understand the costing around batteries, we ran 4 x 80 watt panels and 4 x 200 Ah battery bank for a yacht, not a cheap option to set up but very efficient and obviously completely off the grid, very helpful for a boat

ddarroch will do some homework and may pick your brain further, we're hoping to set the wheels in motion during the build so we can add later hopefully when prices become more realistic. Not to mention that we like the off the grid concept, greenies at heart I suppose

Definitely looking into that energymatters forum, thanks bpratt especially for the lithium iron phos battery option, OH very excited to read that one. How are you going with your system?

Thanks again everyone,
Cheers,
TW

Still building the house, and won't be getting solar PV or HW installed until much closer to the moving in time. Don't like the idea of "five finger discounts" to the scum that think I should 'donate' it to them. I'm putting on a Apricus 315l 30 evacuated tube system for hot water, which is mid element electric boosted, which will be cheaper to run than a gas boosted system could ever be.

It'll start off with a Kaco 6600 grid feed inverter and 24 x 250w panels, the later on get a Selectronic SP-Pro inverter, which will then allow me to get batteries (700Ah LiFePO4) so I can then become a hybrid system. I can then add extra panels to ensure I have plenty to keep the batteries fully charged even on less than perfect days.

The SP-Pro controls the system so that batteries won't feed back in to the grid (not allowed to feed back in from batteries), and allows me to use the grid feed inverter.

Hot water domestic systems smaller element draw 1.5Kw(brand dependant) and normal size house draw 2.5Kw.
The real problem is batteries in solar off grid systems and any "true" off grid permanent system should consist a wind turbine too with a "hybrid controller" for both the wind turbine and pv panels.

E.G. for a 2.5Kw domestic hot water electric system it would require 3Kw of panels not 2.5Kw because pv panels for most in "usual" environment conditions only output 75% of their maximum rating(or rating Pmax) and the complexity is to operate it for ten years or more on lead acid deep cycle batteries is to use only 15% battery bank AH capacity makes the required Kw/h consumed for the total job or jobs.

To understand Solar Wind hybrid off grid (particularly battery systems!) go to this DIY site and read the section about batteries.
http://windsolarhybridaustralia.x10.mx/#battoff

Also read "Ensuring battery service life" because they are a fiddly point to "size up" but will be rarely touched in ten years or more after install.

Thanks nicephotog

Yep, had a wind generator on the yacht with the PV's and deep cycle batteries. Will have a look at the DIY site, thanks for the tip. Was thinking though about the wind generator in residential area, hopefully quieter than the one on our yacht!!
Leaning towards heat pump and 5Kw PV's, payback with evacuated tube HWS & PV's not looking appealing, wonder if we could incorporate with wind presuming ok in residential? Off to research, thanks again

Unless you live in an area that it is blowing a gale all the time (well not quite a gale), then wind turbines are a waste of time and money.

To get any real power generation for off grid systems, you will find it far better value to buy more PV panels instead.