DIY Powerwall pack build

We all started somewhere :)
If I was to do a power wall then it would be to do the lighting only in my home so its all off grid run by batterys and charges at off peak times, you could swap the domestic 230/110 light feed out of the distribution board and run it into a separate board with 12v feed for low power lighting all around the house
I would use 4 lifepo4 100ah cells or a 200ah trojan deep cycle cell to run it all no parralels so its easier to balance, small voltage conversion factors so waste heat is minimized.
 
Ianhill said:
We all started somewhere :)
If I was to do a power wall then it would be to do the lighting only in my home so its all off grid run by batterys and charges at off peak times, you could swap the domestic 230/110 light feed out of the distribution board and run it into a separate board with 12v feed for low power lighting all around the house
d.
Click to expand...
^^ yes, with todays LED lighting tech , im surprised that houses re not being built with dedicated 12 v lighting circuits , to eliminate all thes plugs, sockets , transformers, etc etc that are required for code compliance now.
I know i have over 50 sets of transformers, (each with a dedicated socket and plug), just laying around under the insulation in my roof space !
That whole lot could be served by a 12 v , 20amp(max, 5 amp average) supply.
 
True its the old Edison vs Tesla all over again, but contained with in a house with low wattage lighting it would be interesting to work out the transmission losses,Thats a massive voltage drop I'll have a dig out of my formulas and have a play.
18awg 100metres 2 amp 70% voltage drop at 12v dc so 3.6v on the end of the line
Same cable and length at 230v ac and 2amp 3.6% voltage drop or 8.4v my old college tutor would have been screaming at me for that idea wake up and put the ling cigerrete down haha.
So lesson relearned :) ill shorten them battery wires straight away.
Edit.
Even with a 4mm cable 50m long at 12v dc and running just 5amps it would have a 35% drop or 4.1v so thats that put to bed.
 
But you never run a supply 100m from power supply.!
Central PSU on Each floor level, with "ring" main distribution, ....no lamp point need be more than 10m from 12 v supply, and probably no single feed line carries more than 2 amps ( 10 lamp units) ?
It has to be better, cheaper, easier, safer , quicker, than a similar quantity of 230v tranformers , + sockets, plugs, etc. ?
 
With 12vdc 2amp and 18awg or 1.5mm at 10m in a ring you would have a voltage drop of 3.5% or 11.6v at the load so thats much better.
But with the power wall idea it would need to be run through a inverter to send power any greater distance than 10m so maybe smaller power walls on each floor located central with a dc/dc Cc Cv PSU for 12v lighting run from the battery and charged with a 230vac supply off peak sonthey cycle through the day would be the best way of minimizing transmission losses do away with the need for an inverter and its losses and have lighting thats on a backup.
As for general lighting on grid there is a good argument for one efficent PSU per floor specially in a small terraced house only problem would be the switch line would have to be done away with as they would introduce to much resistance otherwise you would have to use a PSU per light to get that light Alone to switch on as industry standard so it would need to be infrared controlled rather than traditional switches on the wall.
If we used the IR controlled LEDs the fittings would always need to be live and even though its low voltage Its not good practice so maybe a multiway IR controlled relay board in each room would be a better choice to get rid of the switch line length and losses then use any 12v fitting of you choice you would need this setup with the battery too for it to be efficient.
 
Ahh ! Life is never as simple as you would like it to be.
In my childhood, i lived in a house that only had 12v electric lighting from rechargeable cells.
I can still remember the name of the man who came a few years later to connect mains power to the house and power points in some of the rooms.
Off topic a bit...
A good friend of mine bought an old house a few years ago.
In checking out some of the many electrical problems, he discovered the lighting wiring in the roof space was installed (many years earlier) by using bare , single strand, galvanised steel wire, strung between nails hammered into the rafters !
..and this was a 240 v AC system !
Needles to say, a rewire was quickly planned ! :mrgreen:
 
I can't beat that I had a mate that used a radiator as a speaker ground but that house circuit would have been more of a heating element than a power circuit haha.
 
you also forgot, that LEDs don't work with 12V. they need something around 3V and a constant current to work. so it doesn't matter if you have a single ac/dc converter from 110/220 to 3V or if you first convert 110/220 to 12V and then STILL have a single dc/dc constant current converter to 3V for every single LED. sure, you could put 4 LEDs in series, and connect them to 12V, but this still will destroy the LEDs as it will pull all current it can get.
the idea WOULD work for 12V halogen bulbs, but it will NOT work in real live, as current is way to high. that's why you have only 2 spots (max 3) for each converter to keep power lines short and voltage drop low.
 
Seems a AC led chip works a bit like a bridge rectifier that half the chips lights with the positive waveform and the other half light with the opposite waveform, I imagine they can suffer stereoscopic problems and wouldn't be suitable for a light by a pillar drill for example with out using two out of phase sequence.
 
izeman said:
Punx0r said:
It seems mains-voltage AC LED bulbs are becoming more common.
Click to expand...
yes. but they need a ac/dc converter as well inside. don't they?
Click to expand...

Yep. Cheap, effective, no transformers, small gauge wiring. Seems to work.

I wouldn't be surprised in the AC bulbs were similar to the DC ones, just with a rectifier on the front incoming end, then similar dc-dc converters to provide a regulated supply to the LED. Anyone know offhand?
 
Izeman you are very practical thinker.
So the best battery backup system is fire escape emergency light with its onboard battery to keep efficiency high as possible ?,
A way of implement something similar in the home would be each light fitting has ita own battery and charging circuit but uses a led rather than a fluorescent that only works when supply is interrupted so old switch lines work fine then.
Would this setup be better than just using an inverter and a large battery at the distribution board that takes over when the power goes out and converting the energy twice from battery voltage to mains for tramnsmission and then back down again for use ?

The charging circuit in each light could be put on a time clock to take advantage of off peak cheaper electric ?
 
Ianhill said:
Izeman you are very practical thinker.
So the best battery backup system is fire escape emergency light with its onboard battery to keep efficiency high as possible ?,
A way of implement something similar in the home would be each light fitting has ita own battery and charging circuit but uses a led rather than a fluorescent that only works when supply is interrupted so old switch lines work fine then.
Would this setup be better than just using an inverter and a large battery at the distribution board that takes over when the power goes out and converting the energy twice from battery voltage to mains for tramnsmission and then back down again for use ?

The charging circuit in each light could be put on a time clock to take advantage of off peak cheaper electric ?
Click to expand...

i'm not sure if you're playing yokes on me. i'm not sure what you're trying to acchieve? maybe i missed that post.
are you

.) trying to use as little energy as possible?
.) trying to safe as much money as possible?

if you REALLY think of adding a battery and charging circuit to EVERY light than you must be quite rich. you won't safe any money with that idea.
if you just MUST HAVE light if power goes out, then it's a reasonable idea to install battery powered emergency lights.

if you want to power your household from a battery pack, then this is a totally different story. and IF power goes down, you won't turn on ALL lights in the house. you will turn on the one/two lights in the room that you are in. and if you have some LED spots there, each with it's on converter, than this is STILL the most efficient light you can have, maybe comparable to the so called neon tubes (which they aren't).
but as light is not all you need if power goes out, you will need a big battery to keep you house up and running. pump for the heating, electric doors and window shades maybe? stuff like that.
 
No I want to achieve a simple battery back up for lights only thats as efficient as possible nothing more the power tools and leccy shower can stay off I'll bath in the pond
 
Ianhill said:
No I want to achieve a simple battery back up for lights only thats as efficient as possible nothing more the power tools and leccy shower can stay off I'll bath in the pond
Click to expand...
:shock: ....But what about the beer fridge and TV ?? :lol:
If you change your lights to LEDs anyway , you are half way there.
Then all you need is a mains battery back up to take over when the supply fails. Simpler and cheaper than putting batteries and chargers on every light unit,...unless you only need one or two converted ?
But if you just want cheap, quick and convenient lighting for rare power cuts,..just get a rechargeable portable LED light stand.
......you could even take that down to the pond ! :wink:
 
Haha no need for torch I got solar lighting :) A big brush and bar of soap waiting for by side of the pond, My newt's are waiting for the power to go out so I can take a bath with them ;).
 
How does he even balance his cells? And with the no nails the day one of them goes bad he's going to have a helle of a hard time getting to it no?
 
As fruit loop as I sound this will give you an idea
http://gb.auroralighting.com/Lighting-Products/Indoor-Luminaires/Emergency-Lighting/Emergency-Backups/230-240V-2W-3-Hour-Non-maintained-LED-Emergency.aspx

This could be emulated so one main light in each room would have a battery backnup of a desiged time and all fit neatly through the hole designed for the light, placed inside a fireproof sleeve it would be the most efficient way of giving a bit of light in eachroom during a blackout or even in a fire if the power fails u could see a way out it would need a dual led to show system status like a fire escape emergency light
With more and more electrical items entering the house I think it will he mandatory eventual just like fire sprinklers are making their way into new rental properties here in wales most fires start with faulty electrics so there's a good chance the power supply will be interrupted and even with a split board there will be at least one floor with out lighting that you would need to navigate full of smoke disorientated.
The circuit to run this would not cost alot it could be salavaged from old fire escape lights converted to run a 1w led.
 
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