Lighting & small water pump on same 12V circuit

[Will130]

Hi guys, quick question regarding the title. I am planning on putting 12V lighting around my garden and would like to include a small 12v pump for a small standalone water feature on the circuit. At a basic level this is pretty simple, but my question is around day vs night. Obviously, I want the water feature to be on during the day but not the lights, and I obviously want the lights on at night but not necessarily the water feature.

Do I just use a splitter before the first light with one line powering the lights and incorporating an inline daylight sensor to trigger the lights on/off and the other going straight to the pump?

I want the water feature quite far from where the transformer is so would I just need to ensure the transformer has plenty of additional wattage to ensure no significant voltage drop yes?

Second question: Is there any solution to being able to turn the pump off at night without turning the whole system off? I plan to use a smart plug to be able to turn the system on/off remotely but if there is a way to achieve separate pump control without using a separate transformer/circuit for the pump would be keen to hear it!

Thanks!

 

[Phaewryn]

Obviously, I want the water feature to be on during the day but not the lights, and I obviously want the lights on at night but not necessarily the water feature.

Second question: Is there any solution to being able to turn the pump off at night without turning the whole system off? I plan to use a smart plug to be able to turn the system on/off remotely but if there is a way to achieve separate pump control without using a separate transformer/circuit for the pump would be keen to hear it!

Thanks!

Split the power to each and place timers on both systems downline from the splitter (assuming such technology exists, I use 110V power to my pond).

 

[poconojoe]

Just wondering why you want to use all 12 volt equipment and why you want the transformer located away from the pond.

Be careful with how far the transformer is from the loads. (Lights and pump)
The further away the more voltage drop there will be, plus you may need to increase the size of the 12 volt wire as you get further away. It might get to the point where the size of the wire would be totally rediculous, it all depends on the distance, voltage and wattage of the loads.
You'll need to do your homework. There are charts for this. It's been a while since I have dealt with this and I no longer possess said charts. Perhaps you can look online.

Heres an example: if your pond was 50 feet away from the transformer and the load was 60 watts (5amps), at 12 volts, your wire will need to be 10 gauge. 80 feet away and you'll need 8 gauge wire. See how crazy it can get?

As you can see, it can get complicated, annoying and even quite expensive.

That being said, you're better off running 120 volt line voltage all the way to the pond and keep your low voltage transformer(s) near the pond. If they are not weatherproof, you can always house them in something that will protect them.

As far as switching, you can either switch the (120 volt) line side of the transformer(s) or the (12 volt) load side.

Personally, I would use two separate transformers. One for lights, one for pump. This way you can use modern wireless switch controls, as you suggested. I would worry that those devices may not operate with 12 volts. They probably need 120 volts to function. So you will have to switch the line side of the transformers. You might want to confirm that though.

Also, make sure everything is either 12 volt AC or 12 volt DC. It all needs to be the same. You cannot mix AC components with DC components. It's either one or the other.

Or, forget all of that and use a 120 volt pump as most of us do and get a set of 12 volt outdoor lights that come with their own weatherproof transformer. It's really the simplest way to do it if you ask me.

You could have two switches at the house. One controlling the outlet that the 120 volt pump is plugged into and the other controlling the outlet that the light set's transformer is plugged into.

Hope this helps and if you have more questions, maybe I can help.

 

[poconojoe]

Another thing to consider...
Generally, if you had two of the same exact pumps that ran on different voltages, you would want the higher voltage pump because that one would draw less current and the electricity costs would be less.

For example:
If you could choose between two air conditioners that were both 10,000 btu's, but one was 120 volt and the other 240 volt, you're better off with the 240 volt unit. Your electric bill would be lower.
Of course you'll need a 240 volt outlet, but you get the idea....

 

[GBBUDD]

Easiest way to do this is two transformers on different plugs that are plugged into there own remote switch. that way a standard 110 switch is readily available and cheaper

 

[poconojoe]

Easiest way to do this is two transformers on different plugs that are plugged into there own remote switch. that way a standard 110 switch is readily available and cheaper

Exactly

 

[combatwombat]

@poconojoe covered most of this.

Tell us more about the pump and lights. How many watts of lights. How many watts of pump? Since both systems will not be running at the same time, you only need to size your transformer for the largest load. Consumer landscape lights are almost exclusively VAC, so make sure your pump is VAC, too.

RE: Voltage drop. This is based on load and length of wire run. Your load and wire runs are fixed, so the variable is wire size. Take the largest load the circuit will handle and size the wire accordingly. Just google for any basic voltage drop calculator.

As for performing the switching. The easiest, most consumer friendly way to do it would be to get two transformers and two smart plugs with sunset/sunrise functionality. Then you can program each based on an offset time from sunset/sunrise. This isn't perfect because the offset will not be consistent throughout the year and weather conditions will affect it as well.

If you really want it based strictly on daylight, you can use a single transformer, split the wire run to the lights/pump and then use a normally open photocell relay after the split to control the lights and a normally closed photocell relay (not actually called that, name escapes me...) to control the pump. Also installed after the split.

 

[poconojoe]

Agree with @combatwombat.

I do want to stress one point.
If you plan on using one transformer for both, it's size and the size of the wire should be calculated at the full load of both the pump and the lights combined unless you can ultimately guarantee only one will operate at any given time. There are ways to achieve this with electrical components, but it will complicate things even further.
If there's any chance that both will run simultaneously and those components are not sized accordingly, you're going to have a problem. Something is going to burn up.
Just because it's only 12 volts doesn't mean it's not dangerous. A fire is a fire. Under sized 12 volt components can melt and burn up just as badly as 120 volt components.

Again, if you intend on locating the transformer a considerable distance away from the pond, this whole 12 volt idea can get complicated, confusing, expensive and maybe even dangerous.
It all hinges on how much load you have. How much does each component draw. If it's minimal, maybe it's not a big deal.

The transformers should be located close to the pond and switch the 120 volt line side of each.

The best thing to do would be Just buy an outdoor lighting kit that comes with it's own weatherproof transformer and plug it into a switch controlled 120 volt GFCI receptacle near the pond. Also, use a 120 volt pump instead of the 12 volt pump. Plug that into another switch controlled receptacle.

Instead of using GFCI receptacles, you can opt to feed the whole 120 volt circuit with a GFCI circuit breaker in your house panel.

 

[combatwombat]

If you plan on using one transformer for both, it's size and the size of the wire should be calculated at the full load of both the pump and the lights combined unless you can ultimately guarantee only one will operate at any given time.

Good point.

 

[Beercan31]

OR.... after doing your home work that @poconojoe stated above you can use a low voltage relay single throw/double pole. and control the relay with a timer. relay energized lights on, relay de-energized pump runs.

 

[poconojoe]

OR.... after doing your home work that @poconojoe stated above you can use a low voltage relay single throw/double pole. and control the relay with a timer. relay energized lights on, relay de-energized pump runs.

Or use a single pole double throw center off toggle switch.
Up will turn on one device, center is off and down turns on the other device.
Only one device can operate at a time.

You can get one that looks just like a regular wall switch and installs in a standard one gang box with a standard wall plate.

 

[Beercan31]

Or use a single pole double throw center off toggle switch.
Up will turn on one device, center is off and down turns on the other device.
Only one device can operate at a time.

You can get one that looks just like a regular wall switch and installs in a standard one gang box with a standard wall plate.

you are correct.
but I'm lazy and want everything as automated as possible,(hands off) figuring everyone else would like that way it also.

 

[combatwombat]

Or use a single pole double throw center off toggle switch.
Up will turn on one device, center is off and down turns on the other device.
Only one device can operate at a time.

You can get one that looks just like a regular wall switch and installs in a standard one gang box with a standard wall plate.

You would still need the relay to automate, otherwise you'd have to go flip the switch twice every day.

 

[poconojoe]

You would still need the relay to automate, otherwise you'd have to go flip the switch twice every day.

Yep. spdt switch would be totally manual.

 

[poconojoe]

If you want it automated, I guess two timers would do the trick.
If they are located outside, just get the weatherproof type.