Batteries

[Richard1234]

Hi everyone,


I've just had installed at my house a 3.8kw solar system (20 panels), this is a local authority scheme targeting council properties in Waverley to generate revenue over the long term. I'm sure you've all heard of it!
Both my wife and I work during the best of the daylight hours and the kids are taken care of by family when school has finished away from home, and as you probably know any excess electricity generated during this time will be fed back into the grid. So I guess my question is very broad! How can I benefit fully from this installation? We've thought of the obvious like time delaying the washing machine and tumble dryer etc. So, my next line of thought was batteries.


I've been reading over the last few days about Deep Cycle Batteries, and the related inverters Etc. But my electrical knowledge is very limited and I am not sure if this is a viable option!


For example: can I run my TV, Sky, Dvd and Xbox from a battery, or a series of batteries that will be charged during daylight hours from a mains socket, thus utilizing the best of the daylight hours. Even if this kind of setup is not economically viable, I'm still interested out of sheer curiosity.


T.V. = 120 watts
Sky = 50 watts
DVD = 10 watts
Xbox = 203 watts

 

[moggy1968]

2 decent leisure batteries, which cost around £300 for the pair (I know cos I have them in my van to power a water boiler and microwave-well any idiot can be uncomfortable!) would power your TV for about 2 hours. you would need to buy an kit to charge the batteries and an inverter to convert the battery DC power to AC.

the cost/output makes it pretty uneconomic to be honest. you'll benefit more from your current setup in the summer of course when the evenings are lighter. otherwise set you immersion to come on in the day, and ,as you seem to have done, put other items like washer and drier on timers to come on in the daytime.

 

[Earthstore]

Well you could use batteries, but then you would have to invest in an Inverter (DC-AC), oh and the batteries, rewire the sockets that you need to run off that system, make sure that the batteries are charging only when you are producing energy, oh yes and charging batteries has a health and safety issue.
Lots of investment for a little return.
Or invest in a monitoring system, such as Greenlogic, which automatically switch appliances on when you are producing.
Or, a little hit or miss but stick with your timer idea.
Hope this helps

Earthstore Energy
Bit slow there, Moggy had already covered it

 

[daytona600]

you can get on grid inverters with off grid backup via batteries

 

[Richard1234]

rewire the sockets that you need to run off that system, make sure that the batteries are charging only when you are producing energy, oh yes and charging batteries has a health and safety issue.

Help me out here! If i use sealed batteries, then do the same health and safety issues still remain? As i said I'm interested, because i'm interested. How can i set up a system that only charges batteries when i'm producing energy! Remember i cannot modify my electrical system, only from the socket onwards.

Lots of investment for a little return.

I know, this is what i'm interested in.

Or invest in a monitoring system, such as Greenlogic, which automatically switch appliances on when you are producing

I like the sound of this, can you for example set up a system that will charge one battery series before another, for example, the TV in the living room will take priority over the kids TV, or the TV in our bedroom.
Therefore, first, depending on power produced....
1. The living room (until fully charged)
2. The kids room (until fully charged)
3. Our bedroom (and so on...)

Hope i've made this clear enough...

 

[Richard1234]

you can get on grid inverters with off grid backup via batteries

Hi, I can't interfer with the system as it is not my property, hope i've understood you you correctly

 

[Earthstore]

Sorry,I can not find the link for the monitoring system, but will look it up tomorrow for you, you will understand more if you read their blurb, its clever technology.

Personally, I would steer clear of the battery system, although I really can understand your thoughts...

 

[Richard1234]

Sorry,I can not find the link for the monitoring system, but will look it up tomorrow for you, you will understand more if you read their blurb, its clever technology.

Personally, I would steer clear of the battery system, although I really can understand your thoughts...

Thankyou for your help, I understand battery systems will be expensive, but i'd like to know the exact cost involved and how many years it would take to break even. I guess I always like to try and beat the system :tounge_smile:. Thanks again...

 

[Graeme Harrold]

You will always be shelling out for batteries (roughly every 3-5 years), look at the data sheets and take note of the duty cycle and depth of discharge e.g. a 100Ahr battery discharging to 50% will half of the power you are thinking of. Lot to be taken into consideration including inverter efficiency, DC line losses, battery venting (sealed or not), battery storage/safety. Your best bet is to store the energy generated as heat and have something like a Parsons Switch installed to control your immersion (if you have one).....

I personally am looking at having a SMA Backup installed with a bank of 10 150Ahr batts, but this is being done as a business backup system, and a demo for potential customers......

 

[moggy1968]

have a look at the solar electricity handbook by michael Boxwell.
there is a lot of info in there on stand alone, backup and grid tie systems.
your inverter would come with a socket outlet. you could then run an extension lead from that.
The system I have in my van is 2x 120AH batteries, charged from the engine. this then goes to a 700W inverter which powers either the water boiler or 2x standard 240V socket outlets. I run an extension lead from one of these to give us power on site if we have isolated the mains.
basically what you are looking at here is a glorified RV set up. Your difficulty is finding an RV inverter capabale of taking the loads your talking about.
here is the amazon link to the book
http://www.amazon.co.uk/Solar-Elect...sr_1_sc_1?ie=UTF8&qid=1321744882&sr=8-1-spell

 

[Earthstore]

Here you go, have a look at this system, greenologic.co.uk I have not used it myself yet, but it will monitor your export and then switch appliances on when you have enough power. Sorry not sure of the cost.

Hope this helps

Earthstore Energy