Electricity store?

[The Natural Philosopher]

Its perpetual motion deary. A sort of green diarrhoea

[SteveW]

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

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

are usually specified in amp hours.

As we rate the power of items that run off the mains (or solar PV) in Watts or kilo-Watts and it is useful to know how much we'll have to pay to run them for a set time or how big an energy store we need and that ties nicely to kWh.

SteveW

[Doctor Drivel]

Harry, they have definitely solved it. Yes they have.

[geoff]

In message , harry writes

What do you think ?

[The Natural Philosopher]

Given the lack of a Nobel prize. Mind you, they gave one to Europe...

[Bt]

It is total snake oil. It was installed during the winter and I very quickly found that if solar generation was too low it recharges on Mains Electricity and then at night replaces mains with its power causing two lots of energy wastage as you will never get out what you put in due to inefficiencies inherent with all electrical equipment. Unit in mid summer takes 10 minutes to charge and 5 minutes to discharge. Have commenced legal action. What a waste of money!

[Chris J Dixon]

Did they state an actual storage capacity?

Their web site is remarkably coy about any numbers or technical detail. Did you ever get sight of any?

Chris

[harryagain]

Hah. I couldn't see how it worked, the explanation given sounded like bullshit. Pity you had to find out the hard way.

I did see a system the other day that would work but it was just (expensive) lead acid batteries. About 4Kwh of storage for K Hard to see any return on it at all.

Please keep us posted on how you go on with them.

[Bt]

They did not state a capacity but implied that it would work all night. The batteries are quite large and occupy a box 600mm *600mm* 800mm and certainly should last more than 5 minutes on a load of about 400w.

The customer service is also poor. They refuse to put me through to the MD and do not return calls. It is obvious that I have a faulty unit as well as the charging on mains issue.

The system is controlled by an astronomical switch and other than that appears to have no intelligence. This means that it charges when the astro switch tells it to and takes no account of solar generation. I described it in my letter of rejection to them as parasitic.

They wired our electric cooker so that permanently works on mains. That again was not mentioned on the sales visit

[Grimly Curmudgeon]

You didn't seriously expect a battery bank to power your cooker, immersion, or anything else that relies on an electric heating element? This is old bullshit - ten, fifteen years ago, it was simply solar, off-grid, battery banks, inverter (if used) and grid-tie (if needed). Cost? Thousands. Only worthwhile for a cabin in the woods and if you were absolutely determined. Anyone in an urban setting with one of these setups is perhaps hoping for a bit of a tide-over when the main grid starts falling apart, but unless you actually have a cabin in the woods, you're kidding yourself on.

[Bill Wright]

You're right of course, although my mobile 24VDC microwave draws only

45A and thus can be used on two 110Ah batteries without any issues for normal defrosting and warming up jobs.

Bill

[Colin Stamp]

There may still be some mileage in using batteries though. This bloke claims to have made an inverter and a set of traction batteries pay for itself by charging on economy 7 overnight and running background loads during the day. He keeps the big loads away from it, of course, and I think he knows where to get the kit cheap.

Not exactly automated though, and I think he has to be careful to avoid switching the inverter directly on to the grid...

Cheers,

Colin.

[Grimly Curmudgeon]

You'd have to get it cheap - in the early days I knew of telecoms, fork truck and even submarine batteries being used, but they were all bought for scrap prices and salvaged good ones made up of parts. Otherwise, budget for a new battery bank every five years or so and if you pay normal prices for that, forget it.