Any electricians on here? Question about wiring my house to run on batteries.....

Surely most things that we use now could be converted to 12v?

Lighting at 12v isn't a problem.
Heating water with 12v isn't a problem (albeit maybe slow?)
TV could be run from either an inverter or I assume LED/LCD now use low voltage?
 
-Mike- said:
Surely most things that we use now could be converted to 12v?

Lighting at 12v isn't a problem.
Heating water with 12v isn't a problem (albeit maybe slow?)
TV could be run from either an inverter or I assume LED/LCD now use low voltage?
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It's simply easier to use an inverter to step up to 240v. A decent 3Kw pure sign wave inverter costs around £850 and is plenty enough to supply my entire house (excluded large items). I could also get modified sign wave inverters for the larger items if I really wanted, but I'd rather not slam 8kw (33Amps) peak load onto the batteries.

5000 Amp Hours is going to be plenty for my house, I could probably cut down to 3000 Amp Hours if I really wanted but I'd rather preserve battery life by onlu draining them to say 60% daily.
 
Got a link to the kind of inverter you plan to run?
You mention not powering down your PCs, but the switch between your supplies isn't magic, it'll be a mini 1 second power cut each time? You can buy really expensive server room grade systems to compensate for this, but not for a house/budget.
 
tigerstyle said:
Got a link to the kind of inverter you plan to run?
You mention not powering down your PCs, but the switch between your supplies isn't magic, it'll be a mini 1 second power cut each time? You can buy really expensive server room grade systems to compensate for this, but not for a house/budget.
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You can get "make before break" switches which make the connection to the second circuit before breaking the first. However the master trip won't have this feature as I don't want current flowing back into the street during a power cut, the risk of electrocuting a technician is quite big. A nice hefty throw switch will have this job, if the grid power cuts out it will completely isolate my house from the line, and then re-engage once current is detected again. Also when the switch over to the charging cycle begins I'm still running off the batteries so there won't be any cuts then either. I do have a desktop UPS (Smart UPS 1000) too if I really wanted to "protect" my PC, but having a massive UPS in a cupboard more than suffices I think :D

And yes, something like this one (the 3kw version):
http://www.orionairsales.co.uk/cotec-pure-sinewave-inverter-12v-1722-p.asp
 
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Electrically it's the same setup as running a backup generator, buy a gen switchover box, £68, wire it in.

Add battery charger, monitoring, protection, timing etc.

Except it won't pay for itself in 3 years or ever in fact, deep cycle batteries are a fortune, ones that last five years cost a fortune plus an arm and a leg, also you don't want to be draining them more than 25% ish anyway, so that's another shed load of batteries to add to the budget.

Add in all the inefficiencies of charging and conversion to 240v via an inverter and the whole thing is ridiculous.

Even getting an inverter to run an air con unit is near impossible.

Btw.
Your PC does not consume 2000 watts and your hi-fi does not consume 300 watts.


Lolkwerk.
 
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^^ He said 850watt for the PC (2x 5970 + CPU folding can easily draw a kilowatt at the socket fully spun up).

Somehow I don't think this is gonna result in any long term savings tho - would be better looking at ways to reduce power usage or make more efficent use of power IMO.
 
So basically your going to be using 240v AC then convert that to 12v DC and then convert it back to 240v AC ?
Once you add all them <1.0 power factors together it's start to become VERY inefficient and any savings made from the cheaper night rate become insignificant or worse it starts costing you more money!!

Large Ah batteries, High Current 12v Chargers and big kW Inverters don't come cheap when buying good quality! I think you need to sit down and really crunch the numbers as it seems to me that the savings to be made once all the costs are taken into account are going to be very small and insignificant!!
Plus the damage to the environment will be horrendous considering you would be chucking out a box load of batteries every 3-5 years!!
 
snedie said:
There is a reason I'm doing this, simply because energy prices are only going up and this system will earn it self back within 3 years, after that I'm just saving more and more wonga.
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That's a flawed assumption - they could go up or down, please don't base any of your budgeting on assumptions of where prices might be in future. I think the whole project sounds fairly risky and probably not a good thing for someone on a budget to be considering - you're having to put quite a lot of capital into this in the hope that it might save you money going forward.

Unless you can get actual costs showing that you'd be making very significant savings at today's prices then I'm not sure it is something really worth perusing. Do you know where the price of batteries will be in 5 years time, 10 years time?
 
dowie said:
Unless you can get actual costs showing that you'd be making very significant savings at today's prices then I'm not sure it is something really worth perusing. Do you know where the price of batteries will be in 5 years time, 10 years time?
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Agree with the doubters here.
If it was that easy, wouldn't lots of people be doing it? If it was that easy, couldn't you buy off the shelf units that are plug and play and do all this for you? I love DIY, I like saving energy, but don't see this as a practical approach.

A home solar hot water system, superinsulating your fridge, looking to upgrade your products to greener versions will reap better rewards. Home wind turbine? The poo munching algae could be an exciting and cheaper product too!
 
I really hope you've done the numbers realistically on this, cos I think you're in cloud cuckoo land! Fora start, your optimistic £700 per year saving takes more than 4 years to pay back 3k - not 3 years. Seems to be a lot of optimistic rounding and guessing elsewhere in your plans. Economy 7 isn't that much cheaper and you're only applying your scheme to some of your usage, not all. I can't imagine once you take into account the losses from the two conversions and the charging process that you will have much, if any, savings at all in reality. Certainly not anything that will pay for the initial installation and regular battery replacements and still leave you with overall savings. Not a chance.

You dont seem like you can afford to make a big financial mistake, so once again I really hope you've done the numbers properly. Ever thought maybe there's a reason this Youtube 'guru' might be cagey about sharing his info?
 
The Halk said:
I'm no expert, but if you're charging and discharging batteries every day they'll be spent by 3 years. As far as I'm aware there's no batteries that will endure that.
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Also charging and discharging batteries is not 100% efficient, so any savings may be offset in terms of wasted electricity from the charger/inverter.

However some people who have solar panels use batteries so it may be worth looking into some sort of solar battery pack for mains use.
 
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snedie said:
I'm going to use something in the region of 6 12v batteries, any more than that and the cost outweighs the return unfortunately.
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oh dear. The correct number of batteries for this sort of setup is "as many as i can fit in my cabinet", you'll frak 6 batteries pretty quickly due to overly draining them so they lose their capacity.
 
Guys I completely agree that this is a long shot, way before I even start to invest in any of the gear I will be getting solid quotes from energy companies and manufacturers/retailers to get the exact figures.

Also, for those commenting on how damaging this will be to the batteries, I don;t think you understand just what these batteries are designed for. They have the specific purpose of being able to discharge almost all of their capacity, again and again without any serious deterioration for a long period of time. Not to mention the fact that I will have nearly double my daily requirement of power storage, meaning the batteries will probably only ever discharge to say 50~60%.

Also not to brag "Liampope" but I'm spending close to £5k on a new rig, plus the £2.5k I need for rent leaves me with around £3.5k left from my years wages (The bulk of which I earn in the next 6 months). I can resell nearly all of the equipment for this project, the batteries especially will hold most of their value so if it doesn't work out I will have only wasted a few hundred bob with any luck....

Thanks for all the tips and suggestions guys :)
 
MikeHunt79 said:
Also charging and discharging batteries is not 100% efficient, so any savings may be offset in terms of wasted electricity from the charger/inverter.

However some people who have solar panels use batteries so it may be worth looking into some sort of solar battery pack for mains use.
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Very much true but that's why I will be spending a touch more for higher performance devices which don't act like mini heaters.
 
tigerstyle said:
Home wind turbine?
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I've looked into them, they provide mere "watts" of power at any one time, unless you manage to grab one for <£200 with a government scheme then it's going to take a life time to earn itself back.

Even these massive ones are incredibly inefficient, but they do give off a fair few kilowatts, doubt I could get planning permission for one of those in my garden, plus the neighbours would have to move so I can knock their houses down, oh and I'd need a huge transformer :D
 
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