Electricity store?

[harry]

So what does the panel make about this one?

they solved the world's big energy problem or snake oil?

[Tim+]

The fact that they don't seem to know the word "battery" would make me suspicious....

Even if it was a humongous battery, I can't quite see the point unless you're intending to be "off grid" a lot of the time.

Do you get your FIT for all the power you generate or just the stuff you feed back to the grid?

Tim

[Andy Burns]

You get all the generation payment and (unless an export meter is fitted) half the export payment, total 47p/kWh pocketed, with no need to actually export a sausage.

[polygonum]

And don't you love the way they have a "solar collector" right in the middle of the house... ?

[Martin Brown]

Looks very much like midnight snake oil. Good name for it though.

Interesting that they avoid specifying a capacity in kWh. (or any other useful technical details for that matter)

[Bob Minchin]

I bet it is expensive. Enough batteries to store 20-30kWh will non trivial.

Say 300v at 100Ah or 25 large car/truck batteries although ordinary car batteries don't like deep cycle use so traction batteries would be needed. Maybe 1 or 2 electric cars worth of batteries would do.

Whilst it might not affect the MCS accreditation for your PV system the leccy board might not be too happy if they knew what you were up to.

You would have to be careful not to use imported power to charge the batteries on days when the PV generation was low. Same sort of control system as the solar dump scheme use would be needed. Similarly care would be needed not to import too much power once the batteries had been exhausted at night

Again to avoid affecting the accreditation, they would have to use a second inverter which would add to the cost.

So a stack of batteries, another inverter, a control system and you have a midnight sun set up costing £4k or so plus installation.

Bob

[The Natural Philosopher]

I think its a big car battery and that's all. Or snake oil

[harry]

You get the FIT for everything generated regardless.

[harry]

Don't you love the way it isn't even "wired up" correctly? Looks like the battery delivers AC. And there are three "wires" to the meter. They had adverts in national newspapers yesterday.

Dunno how they can get away with advertising such s**te.

[harry]

Well a 15Kwh battery for an electric car is =A35,000-=A38,000. I suppose lead acid might be cheaper

[Dave Liquorice]

Big (maybe) battery. Interestingly they say you can have power during a power cut "whilst there is retained power in the solar collector".

I wonder how they deal with any back feeding? AIUI with a normal PV system loss of mains meant loss of all power as the invertor shuts down without mains.

[Bill Taylor]

SMA do a system that lets you grid connect, but run off batteries when mains fails. You need something called a Sunny Island as well as a compatible SMA GTI and lots of batteries. Not cheap though, and probably not what aweenergy are offering.

[metric_trade]

I've seen batteries quoted here in watt hours and amp hours. I think of a battery as a store of energy and the SI unit energy is joules. Watt hours are merely a non-SI way of expressing joules.

I know there are variables such as voltage variation and a duration of discharge and it's often best to use the unit that is less dependent on assumptions.

My impression is that phone and car batteries (for non-electric cars at least) are usually specified in amp hours.

In the weird world of domestic pv: Which unit is more common for battery spec? Which unit is 'better' as a guide to battery capacity? Which unit would the sales people prefer in order to mislead you?

[Brian Gaff]

That page appears to be blank except for a title here. Is it some kind of graphic?

Brian

[Martin Brown]

battery as a store of energy and the SI unit energy is joules. Watt hours are merely a non-SI way of expressing joules.

Mostly you want a particular voltage battery so Ah is a good metric.

discharge and it's often best to use the unit that is less dependent on assumptions.

are usually specified in amp hours.

And that makes sense at fixed voltage. You have to specify discharge rate and derate the battery capacity if you want a high current out.

Vague hand waving with extra smoke and mirrors.

kWh avoids needing to know the battery voltage. It is the preferred unit for mains electricity too which gives you a handle on it.

1 unit = 1kWh ~ 10p (very roughly for easy mental arithmetic)

That is about the capacity of two 40Ah car batteries (although for power storage you need more expensive deep cycle lead acid).

None or failing that horsepower ;-)

[Theo Markettos]

AWE? Midnight sun?

They aren't fitting a hydrogen bomb in your loft, are they?

Theo

[harry]

Brian I replicate the text here:-

The Midnight Sun is a revolutionary product that allows you to maximise the potential of your solar PV system by powering your home

24 hrs a day with green energy generated by your solar system helping you make huge savings on your energy bills. The Midnight Sun is available exclusively from AWE Energy within the UK and Ireland. The Midnight Sun can be retrospectively fitted to existing solar systems or added to new systems at the time of installation. How does the Midnight Sun work? The Midnight Sun is a solar collector. Once installed the Midnight Sun will collect excess energy generated by your pv system and retain it. When the Midnight Sun is fully charged any excess electricity will be returned to the national grid. As the sun sets and your Solar PV system stops producing green energy for your home, the Midnight Sun takes over and the retained power is converted to electricity, to be used in your home. If you use all of the power your pv system has generated then the Midnight Sun will automatically switch back to drawing power from the national grid.

There is a graphic with a dodgy line drawing of some kind of electrical layout that makes no sense.

The question is how can they possibly store much electrical energy and not cost an absolute fortune. ie, be completely uneconomic.

[Grimly Curmudgeon]

And budget for replacing the battery bank every five years, if you're lucky.

[alan]

No need to. The battery just needs the capacity to power a floodlight for a very short time. At night the floodlight is switched on and the PV panels generate enough power for the house and to keep the floodlight burning.

Some people really don't understand this green energy stuff.

[polygonum]

Don't think I get it. Is that a green light?