Re-wire a house to use 24v LEDs ?

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ng.sa

Member
Joined
Apr 4, 2017
Messages
88
G'Day Guys

We have to replace our roof as the tiles are well worn out now and while the roof is off I'm thinking of wiring in LEDs as 'backup' lighting.

We already have desk lights using USB plugs into 240V or power banks when the lighting goes off, which happens regularly even though we have the biggest battery installation in the southern hemisphere close by thanks to Elon !!!

I don't want to 'recycle' the old electrical system wiring etc. because in Oz I will lose my high feed-in tariff if I add any more panels to the current 6 panels, I am a victim of my foresight having install solar very early and locked in a very high return on the power we gen. from these panels.

I have got a couple of these "5-24V RF Wireless Remote Switch Controller Dimmer for Mini LED Strip Light" running a mock up prototype, but they are not really 12Amp, get very hot very quickly, so have a 6 x channel controller on the way 'slow boat from .cn' that I can wire up myself :)

The family really likes the remote controls and I expect to dev. an app to put on Droids ( I have 40 years exp. as Soft Eng ) in version 2px of the install.

Anyone got any suggestions about

- Wire gauge
- 24V LED lights for domestic
- Remote controllers for DC lighting
- Easy way to install cabling, I'm a OG -:)
- COTS for this type of sys.

TIA

NG
 

cak

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Joined
Mar 14, 2021
Messages
53
I live off grid and am wiring my cabin with mostly 24vdc. One word of caution from what I have run into is that voltage drop (and the associated energy lost) grows quickly so I recommend you calculate the power and amp needs of your lights to make sur you are okay with the power loss of whatever guage you go for. When I did the math using a free online calculator I realized that for the back rooms of my rather small cabin I really needed 10AWG wire to handle the load of some strip LEDs and phone/computer charger plugs.
 

ng.sa

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Joined
Apr 4, 2017
Messages
88
G'Day cak
Thanks for the prompt reply.
I was concerned about this originally, but I went and talk to truck drivers of the B-triples ( 3 x trailers ) or road trains, the largest in the world.
Typically 50Mtr. long
They do not have batteries on each trailer and run the cables from the cab to the very back for their 24v LED lights.
This is why I'm asking about wire gauge first, because I will have no cable run that is 50Mtr.
NG
 

Solexx X

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Nov 16, 2017
Messages
53
Use the original wiring. Separate the wires at the panel if you really want just low voltage for lights. as an added bonus you can power all the lights from a separate AC/DC transformer if you don't have DC available. Really the easiest solution is to replace the fixtures with LEDs. They have their own low voltage control circuit. Re-wiring is pointless since the 240 volt system can easily carry low voltage.
 

MBF Dan

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May 14, 2021
Messages
35
G'Day cak
Thanks for the prompt reply.
I was concerned about this originally, but I went and talk to truck drivers of the B-triples ( 3 x trailers ) or road trains, the largest in the world.
Typically 50Mtr. long
They do not have batteries on each trailer and run the cables from the cab to the very back for their 24v LED lights.
This is why I'm asking about wire gauge first, because I will have no cable run that is 50Mtr.
NG
I wouldn't be surprised if the application you speak of uses AC power and simple rectifiers at the lights to get their 24vdc or the lights are depending on the LEDs to be the rectifier as that circuit is basically just diodes.
I installed a manufacturing production line once that someone else had done the controls design for. Long story short there was a 50 foot run between some 24vdc proximity switches and the controller. On install I had to over voltage the power supply upwards to 30vdc or a little higher just to get about 20vdc at the sensors at the end of the run. It was about 15 years ago so forgive me the details being hazy. But you simply can't push DC very far without addressing the line losses. You can get low voltage AC and eliminate the line losses. I would have been shocked that the orginal controls engineer overlooked this obvious peoblem when he designed the system but honestly it was very typical of the problems I was brought on to resolve at the end of the build.
My advice is check the calculators and believe then it is simple math. But in general I don't push DC much more than 20 feet without expecting losses or really big cable or both.
 

ajw22

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Nov 16, 2018
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641
truck drivers [...] They do not have batteries on each trailer and run the cables from the cab to the very back for their 24v LED lights.

If they were talking about the brake lights... those are typically just 25W incandescent lights, so red LED equivalents are probably just a Watt or two. Not really comparable if you want to light up your family house with hundreds of Watts of white LEDs.

You'll have to list up all the LEDs you want to install, and any other appliances, measure how long the wiring is, then use a calculator such as this to see how thick your cabling needs to be:

Note that 24V DC wires can overheat and burn down the house just as well as 240V AC, or any other type of electricity. Fuses/breakers should definitely be installed to prevent the wires from overheating.
 

cak

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Joined
Mar 14, 2021
Messages
53
In my experience here in my cabin lights are working fine with longer small guage wires but I believe that there is still the losses it just is not very noticeable to the lighting because of how non linear human perception of light is. For reference I have 24vdc led strip lights (the kind that comes in 5m rolls with tap on back) with one run using 5A in total at full brightness and probably around 35-45 feet at the longest point and mostly using the light strip (rated for 10m runs) and 16 guage speaker wire. That setup has no visually noticeable dimness at the ends and is used for whole room ambient light.
 

ng.sa

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Apr 4, 2017
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After reading these replies and thank you for each reply I have realised that not being able to have 'long' runs is an opportunity !!!

I have now bought 5 x LED desk lamps that have cables < 1mtr that can be wall mounted if required with USB plugs, not 240V plugs.

I then built a set of small packs using Tesla 2170 with USB plug as output and if my calculations are correct, if I left the lamps running 24x7 I would not need to recharge the BATs. for a number of years. I have checked my figures many times and have decided to just give it a go and prove my theory.

Basically I'm now thinking I take the BATs. to the appl. not cable to the app.

Has anyone else used BAT. packs to power retail LED lights ( not LED strips ) ?
 

MBF Dan

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May 14, 2021
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After reading these replies and thank you for each reply I have realised that not being able to have 'long' runs is an opportunity !!!

I have now bought 5 x LED desk lamps that have cables < 1mtr that can be wall mounted if required with USB plugs, not 240V plugs.

I then built a set of small packs using Tesla 2170 with USB plug as output and if my calculations are correct, if I left the lamps running 24x7 I would not need to recharge the BATs. for a number of years. I have checked my figures many times and have decided to just give it a go and prove my theory.

Basically I'm now thinking I take the BATs. to the appl. not cable to the app.

Has anyone else used BAT. packs to power retail LED lights ( not LED strips ) ?
Something seems odd about your calculations but the best thing would be to try it out. I was just wondering how long a dewalt battery will run their led lights? I have a led lantern which isn't anything near that type of runtime I would say if it was fully charged a single day would kill it but I have no idea what they put in it for cells. It could be a single cell for all I know.
 

ng.sa

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These LED lights are 6 LED 1w 5v USB plug and dimmable, I have bought 50 from .cn and not one was DOA, so if I made a mistake it does not matter because if I had to charge even once a month I'm OK with that, because these are backup lighting ATM and just for 'testing'

But, I'm starting to think about using LED full time not just for backup, then I won't have to start the gen. and waste fossil fuels as I'm already running off BATs :)

I just would need a BAT oper. fridge to keep the beer cold !!!
 

JohnLee01

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Jul 1, 2021
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Hi guys,

Just wondering, why we are using high voltage lighting in our houses? In age of alternative energy, we have to increase energy efficiency, decreasing number of convertors etc. For example, we have low voltage solar panel, we charging low voltage battery. Then we have DC/AC (110/220) inverter. And finally, directly before light we also have convertor to decrease voltage for LED lights.

DC/AC inverter will discharge our battery in couple of hours, even we don't load it. today gold rate in hyderabad
 
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MBF Dan

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AC has less line losses than DC by a huge factor. Also the world is designed based on standard grid voltage. Simple mass production makes it cheaper to use the grid voltage and absorb the energy costs.
 

Korishan

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Jan 7, 2017
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Hi guys,

Just wondering, why we are using high voltage lighting in our houses? In age of alternative energy, we have to increase energy efficiency, decreasing number of convertors etc. For example, we have low voltage solar panel, we charging low voltage battery. Then we have DC/AC (110/220) inverter. And finally, directly before light we also have convertor to decrease voltage for LED lights.

DC/AC inverter will discharge our battery in couple of hours, even we don't load it.
Converting from DC->AC->DC is a waste, correct. However, there are some appliances that must run on AC power to function correctly. Your fridge for example requires AC. You can't power it with DC of any voltage. Same with airconditioner.
And it's not feasible to replace all the appliances with DC powered ones (the ones that are used in RVs for example) because they usually cost way more (just because it's a niche area, and not because the motor is more expensive). And as Dan mentions, AC is more robust on long runs for efficiency.
If you ran 120VDC through the walls, not only would the risk of death be increased (DC is far more potent than AC), but also an increase in wire size would be needed, and you would need to replace all your electrical outlets and switches to be able to handle DC voltages. Also, you would need to make sure that you either ran your power supply at a higher voltage and then use buck converters everywhere, or use devices that can operate at various different voltages.
The source voltage may be 120VDC, or what ever you use, but at the end of the wire where the device plugs in will not be. Just from 100Ft of wire, you can see a voltage drop 2% at 10A with 10awg wire. Most house wiring "14awg" which further increases voltage drop, which means you'd need to replace all your wiring.

Definitely not feasible at all.

If you really want to convert over to DC, then switch the things over that you use the most, the lights and fans. This will have the biggest impact on power losses through conversion, and these devices normally can run at various different voltages with very little or none at all noticeable differences

 

ng.sa

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Joined
Apr 4, 2017
Messages
88
G'Day John

Just wondering, why we are using high voltage lighting in our houses?

I have been thinking this for many years, that is why I'm now using LED that draw such a little amount that their batteries rarely need to be charged with a solar panel, sometimes just 1 x 1865 cell and the worlds shortest cable :)

In age of alternative energy, we have to increase energy efficiency, decreasing number of convertors etc.

+1

This is the conclusion I have come to as well, so just use less AC in only 'mission critical' situations and carry the power pack to the appliance after it is charged with solar.

In my part of the world were the sa.gov.au has sold our grid to .cn and guaranteed them a profit in a written contract, the grid provider is now talking about charging us to send solar power onto their grid.

For example, we have low voltage solar panel, we charging low voltage battery. Then we have DC/AC (110/220) inverter. And finally, directly before light we also have convertor to decrease voltage for LED lights.

DC/AC inverter will discharge our battery in couple of hours, even we don't load it.

This is not K I S S ( Keep It Simple Son ) is it mate ???

I now have 24v power packs running a fridge/freezer (F/F) in my house replacing our 2nd F/F that I can also use on 240v instead of the old 240v only fridge.

What is really interesting is that the pattern is that it is drawing only 0.2V / Hr which seem to be so wrong. I'm guessing the software in these fridges seems to cut the 24V feed after the pack drops below 22V, but I need to scientifically check this on many fridge as mine is a Aldi $600AUD cheap fridge ATM.

I will be testing 1 of our ACs for heating after the electrician installs a input cable and I'm going to introduce an inverter to the 24V power pack and test for heat and then in 3-4 months for cooling.

I'm so glad I never installed a power wall at this stage-:)
 

ng.sa

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Apr 4, 2017
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G'Day Dan


AC has less line losses than DC by a huge factor. Also the world is designed based on standard grid voltage. Simple mass production makes it cheaper to use the grid voltage and absorb the energy costs.

Not if the grid is very expensive and fails over and over and over
 

cak

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Mar 14, 2021
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I have also pondered this question and was thinking of designing my soon to be build new home to be all low volt DC. In the meantime I have been upgrading my current cabin/home with 24vdc as the main wiring with only a couple AC lines for high load devices like cooking. Through this process I have concluded that a low volt dc system makes a lot of sense in compact spaces like an RV, Tiny House, Boat where the wire lengths will be short and maximum efficiency is a high priority. For my small cabin I am pushing the longest wire lengths that I think make sense when I started looking at line losses. So now I am thinking with a standard sized home the advantage of being able to use standard appliances and such is worth a small energy loss penalty. If you are using a good inverter your loses are very low 5%ish so it doesn't take a very long wire run with low volt to reach a similar line loss.
 

MBF Dan

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G'Day Dan




Not if the grid is very expensive and fails over and over and over
I don't think you understood my point. I was saying mass production of things like 110vac lights and appliances makes it more cost effective to have an inverter in your off grid home that is running at grid voltage. It will be very expensive to get a DC dishwasher or refrigerator compared to the standard mass production unit. Let alone the cabling needed to power them on DC.
 

ng.sa

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Messages
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G'Day Dan

Thxs for the heads up & yes I was confused

"cheaper to use the grid voltage and absorb the energy costs."

This is what caught my eye when I scanned the post.

The cost of trons is a very touchy subject down under ATM, our politicians have sold the networks and given themselves a big pay rise. Lots of short term decisions, due to Rupert Murdock denning climate change.

This is why I looking for a way to disconnect from the grid for as many appliances as possible.

I have an electrician installing a DC AC tomorrow, so this will be very interesting for me :)

EDIT : AC = Air Con.
 
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MBF Dan

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Joined
May 14, 2021
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G'Day Dan

Thxs for the heads up & yes I was confused

"cheaper to use the grid voltage and absorb the energy costs."

This is what caught my eye when I scanned the post.

The cost of trons is a very touchy subject down under ATM, our politicians have sold the networks and given themselves a big pay rise. Lots of short term decisions, due to Rupert Murdock denning climate change.

This is why I looking for a way to disconnect from the grid for as many appliances as possible.

I have an electrician installing a DC AC tomorrow, so this will be very interesting for me :)

EDIT : AC = Air Con.
Unfortunately I can completely relate to your situation. I have an off grid system to install here this summer because if I stay on the gird I solar won't pay for itself in 20 years but if I leave the grid I can buy batteries and it will pay for itself in 9 years. More than half my electric bill is just connection fees that it literally wouldn't have it I lived one house south of me as the property line is the town line and they have a different power company. It is crazy.
But once I get a break in my farm work I will be installing my system and leaving the grid. I choose to keep everything standard AC and just buy two inverters that will handle the load.
 

Tyricores

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Aug 24, 2021
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G'Day Guys

We have to replace our roof as the tiles are well worn out now and while the roof is off I'm thinking of wiring in LEDs as 'backup' lighting.

We already have desk lights using USB plugs into 240V or power banks when the lighting goes off, which happens regularly even though we have the biggest battery installation in the southern hemisphere close by thanks to Elon !!!

I don't want to 'recycle' the old electrical system wiring etc. because in Oz I will lose my high feed-in tariff if I add any more panels to the current 6 panels, I am a victim of my foresight having install solar very early and locked in a very high return on the power we gen. from these panels.

I have got a couple of these "5-24V RF Wireless Remote Switch Controller Dimmer for Mini LED Strip Light" running a mock up prototype, but they are not really 12Amp, get very hot very quickly, so have a 6 x channel controller on the way 'slow boat from .cn' that I can wire up myself :)

The family really likes the remote controls and I expect to dev. an app to put on Droids ( I have 40 years exp. as Soft Eng ) in version 2px of the install.

Anyone got any suggestions about

- Wire gauge
- 24V LED lights for domestic
- Remote controllers for DC lighting
- Easy way to install cabling, I'm a OG -:)
- COTS for this type of sys.

TIA

NG
You can change the wiring in the house, make it more modern. I set up the main wiring with only a couple of AC lines for kitchen utensils. You can use a separate transformer if there is no specific DC or AC transformer. Much of your program depends on the purchased LEDs. It is necessary not to be mistaken with the selection of lighting parameters. There is always a lot of trouble. It is better to buy a camping lantern already. Lol. But in fact, you need to pay attention to all the characteristics of the diodes. The main thing is to avoid overheating the wires, install fuses. Otherwise, there may be a fire in the house.
 
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