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Run Pool pump on Off Peak - 3 Hour Timer

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b.james

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I have my pool pump on off peak. It only comes on during low demand times but left on it goes much more than I need .
Can the forum members suggest ways to build in a timer so that regardless when it turns on it only runs for 3 hours , once a day or at least once per switch on for 3 hours .

Naturally a normal power timer only runs when the power is on so they are unsuitable .
 

tcmtech

Banned
Most Helpful Member
Naturally a normal power timer only runs when the power is on so they are unsuitable .
Buy a digital one. They have battery backup for their memory so their settings are unaffected by the AC side power being turned off even for weeks at a time.
 

b.james

Member
EDIT -Got to appologise to tcmtech -In fact I dismissed this too quickly . a 7day timer with battery backup willl do the job in this case because power comes on fairly often and will be passed through by the timer if that timer is set to be switched on . The ON/OFF is all controlled by the timer so what happens with availability of power does not affect the on/off times if within 7 days and the batteries are recharged whenever power is available

Sounds good but from what I have seen the backup battery retains the settings ,it does not do the switching . Secondly you don't know when Off peak is going to be on . It varies with load at the suppliers whim . Set it for 3 am and it might be on one day and not another so the pool motor set for 3 am would often not get switched on.

This is one on ebay I found and they are reasonably cheap though.
http://www.ebay.com.au/itm/7-DAY-DI...63?pt=LH_DefaultDomain_15&hash=item4189517283

I need something that senses when off-peak is switched on and runs then for 3 hours and then does not turn on again until the next day
 
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b.james

Member
Don't seem to be available in 240 V but these might do it dependent on price of course and availability in Australia.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
Thinking out loud:

1) Can the utility provide a digital signal to indicate ON/OFF peak?
2) For wierdness, could you possibly determine this information from a webpage?
30 For additional wierdness, does the utility provide an webpage API?

I know about the whims, because we (US) have "peak energy savings days". So, even if you are not on peak metering, you can still save $ when they declare a day/time, usually in advance.
 

Reloadron

Well-Known Member
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There are plenty of timers out there that will work. The trick is knowing when to trigger them. I mean if "Off Peak" is the same hours every day then no problem but if the Off Peak floats around then you need a way of knowing when off peak actually is to trigger the timer.

Ron
 

kinarfi

Well-Known Member
B.james, Australia, cool, you have 240 volts, ok, does the utility turn your power off (doubtful) or just activate a relay (likely) that shuts down your pump during peak, if so you could power the relay with 24 volt and series the NC contact with the utilitie's contact so the pump shuts down 3 hours after the utility turns your pump back on, but if you have multiple peaks during the day, you would get multiple runs.
 

b.james

Member
As I understand it a signal is sent down one phase and this switches off-peak power on to a dedicated circuit that contains hot water heaters and the like .
I don't understand how that stops the metering of power use on the phase line all power is coming down but that must happen as off peak is separately metered at a lower rate.
It can come on at any time , once twice or even three times a day.
I'm starting to think an arduino setup to sense when on and maintain its own timer.
 

alec_t

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this switches off-peak power on to a dedicated circuit
So can you just connect a timer on to that circuit?
It can come on at any time , once twice or even three times a day.
When on, is it for at least 3 hours?
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
I found this http://www.airotronics.com/site/product-delaymake_TGCXB-E.php which could prove very useful, I think.

But you would need a something to reset it every 24 hours. You could probably use one of those programmable timers where you can set a daily times on for 15 minutes.

Your bigger problem is knowing when ON/OFF peak is. If it's strickly time based, then, again, a 7 day timer would work.

I took a brief peek at Australia's energy measuring stuff and dit appears it uses like a 15 or 20 minute interval where data is sent ot the utility from the "smart meter".

It would be cool if you knew when it occurs. I suspect, if I HAD to do the same and the peak times were fixed + and additional announced times,I might consider some sort of automation system where you could email/TXT the time/date of the energy savings period. There were some systems described in Circuit cellar that did just that. They retreived email messages and examined the headers and based HVAC control on that info. Some sytems that you can buy do the same with "password" authentication too. i.e. the password has to be sent in plain text in the message. Usually the purchased systems have a service/server that you subscribe to. I don't think they could get as fancy as you need.

Here (In the US and my state), if I allow the utility to shut off my AC at their whim, I get a reduced rate. If I had electric hot water, they could be allowed to control that too. They install a gizmo that uses the same network as the smart meter that interrupts the compressor signal to the compressor. If you have such devices in Austrailia, try to convince the Utility to provide that info as a dry contact. Maybe, it's even worth a suggestion.

These things are supposedly addressable, so therefore your unit might be able to be programmed to respond to Peak/Off peak rather than the more complex algorithm that they use. They don't have to turn everyone off.

In Canada, fossil fuel is expensive, but electric is cheap. Thus, dual fuel furnaces are useful when you have some sort of demand billing.

I'll think "out of the box" every time.
 

b.james

Member
So can you just connect a timer on to that circuit?
When on, is it for at least 3 hours?
Yes I want a timer to do exactly that , A pwoer point is switched on when off peak is available and the pump is plugged into that point. Usually the power is on for 4 to 6 hours but can be any period as it is controlled by the utility company.

Again something has to sense the power is available at the power point and switch on the pump - whatever time will do I think,say (x) -then at a max of 3 hours go off and not come on again for 21 hours or 24 -(x) hours . That be the problem
 

b.james

Member
Look carefully at what I suggested.
Looked carefully but I think your ego got in the way . Look carefully at what I posted . Sometimes thinking outside the box lands you face down in the dirt.

I appreciate your time and your contribution but that timer will not do the job unfortunately

I would have thought there would be a fairly standard product to fit this need but it seems not .

Perhaps this is an opportunity for someone to make a lot of money in Australia
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
Let's take this slow for a second. Looking at just the relay. Suppose it gets powered when on "off peak". It can accumulate to 3 hours and transfer the contact. OK, it; backwards, so a small relay can invert the off/peak signal. You now have a signal that can enable your contactor for three hours of elapsed time. Unfortunately, the output is also inverted. Again, a small relay could invert that.

Does this, at least, make sense?

You want this pump to run for 3 hours max/per day, on off-peak hours, right?
 

alec_t

Well-Known Member
Most Helpful Member
I'm a fan of doing things with discrete components, but I think this calls for a custom-programmed MCU instead. It will need a real-time clock to determine 24-hr intervals, plus a counter to accumulate 3 hrs of off-peak time within a 24-hr interval. If the MCU is powered via the off-peak power-point then it will need a battery back-up.
I'd be (pleasantly) surprised if there is an off-the-shelf time-switch available for the task.
 

b.james

Member
Let's take this slow for a second. Looking at just the relay. Suppose it gets powered when on "off peak". It can accumulate to 3 hours and transfer the contact. OK, it; backwards, so a small relay can invert the off/peak signal. You now have a signal that can enable your contactor for three hours of elapsed time. Unfortunately, the output is also inverted. Again, a small relay could invert that.

Does this, at least, make sense?--- I dont follow I am sorry

You want this pump to run for 3 hours max/per day, on off-peak hours, right?
Yes
 

b.james

Member
I'm a fan of doing things with discrete components, but I think this calls for a custom-programmed MCU instead. It will need a real-time clock to determine 24-hr intervals, plus a counter to accumulate 3 hrs of off-peak time within a 24-hr interval. If the MCU is powered via the off-peak power-point then it will need a battery back-up.
I'd be (pleasantly) surprised if there is an off-the-shelf time-switch available for the task.
Thats the line I will take if nothing else comes up. I have some Arduinos /ATMega328P and ATTiny85's so I'm starting to think about the code now .

Sense on or off main power/if flag not set / switch SSRelay 240V on/Start a timer first time /check if its been on before in 24 hrs and accumulate time run/ turn off ssRelay after elapsed time /Set a done flag for 24 hrs. Reset all after 24 hrs.

External power needed for MCU say 7- 12 V battery -charger on when off peak on- Probably a small LiPo 7.2 V would do with chip and SSrelay in a box. Normal plug outlet on top of box . Off peak in by plugged cord.
 

KeepItSimpleStupid

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Most Helpful Member
OK, I'll go back to my post a little later. I have a timer similar to this one: http://www.ebay.com/itm/AC-POWER-22...R-7-DAY-TIMER-TIME-RELAY-SWITCH-/330657453463 , but 120 V. I would have to find it and look at the instructions. Let's assume it can do a daily program of a 1 minute pulse.

I think it could be set for say a 1 minute pulse between 23:59 and 24:00 hours. Hence it generates the once per day reset pulse.

RESET is a contact closure, so, the output of the timer isn't suitable. A relay can generate the contact closure.

This is working backwards: A $20.00 timer resets a 3 hour accumulator.

I am also assuming two sources of power. On peak and Off peak.

==

I also agree, that if you can do the processor solution, go for it.

This http://www.gravitech.us/busio.html is an interesting platform that uses i2C for interfacing. e.g. AC presence detector

==

PS: I tend to throw out all idea, no matter how absurd initially. Something can generally be learned from that. This really is the best way and was suggested in a professional instrumentation publication. I also tend to look at "possible problems". Unfortunately, management needs training to accept the method.
 

b.james

Member
OK progressed a bit myself .
Wrote the code and got it working ,just got to lengthen the time periods .
I'll post it here in case anyone wants it and if anyone improves it perhaps they could post it back.
Powerlead in ,Power point out ,box ,Solid State Relay, Battery, another 240V relay maybe to sense on, Arduino
 

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