AC Monitoring

[Johny London]

Can anyone recommend a device for measuring ac power usage? Doesn't have to have resettable memories, special calculations et all - just a plug through or clamp on device that will tell me how many watts are being drawn at a given time. It would help me choose the right sized generator as well as help with day to day frugality

ta

[WotEver]

http://www.screwfix.com/p/energenie-ener007-energy-saving-power-meter-socket/3477h

tony

[Johny London]

Wow that was quick! Looks good. My other avenue is a sensor based one so it can go right at the outlet to everything - giving a grand total, maybe like this...

http://www.ebay.co.uk/itm/Npower-Home-Energy-Monitor-BNIB-/332178472535?hash=item4d57613e57:g:VsYAAOSwls5Y6itT

but what are people on their boats actually using?

[Alan de Enfield]

There is no need to monitor AC usage, but you do need to monitor DC usage (as the AC will come from the DC in many cases).

Smartguage is one commonly mentioned.

Personally I use a voltmeter, but rarely let the batteries drop below 12.5v anyway.

Experience tells one how long you 'can go' before needing to recharge. (I have a 1300Ah battery bank)

 

Ediut foe dyslexic fingers

Edited April 12, 2017 by Alan de Enfield

[Robbo]

23 minutes ago, Johny London said:

Can anyone recommend a device for measuring ac power usage? Doesn't have to have resettable memories, special calculations et all - just a plug through or clamp on device that will tell me how many watts are being drawn at a given time. It would help me choose the right sized generator as well as help with day to day frugality

ta

Clamp meter?   I would get a AC/DC one as it's ever useful on a boat.

[Johny London]

I've got a smart gauge, and a clamp meter. I wondered if there was a boaters favorite as far as ac monitoring is concerned. Looks like there are plenty of domestic ones about - just a question of finding one that is fairly simple and not too bothered with calculating costs on tariffs etc which would obviously be quite meaningless. Also something that shows quite clearly the lower end of the power consumption spectrum as I rarely expect to be pulling many kwh!

Now I've spotted this one...

http://www.ebay.co.uk/itm/NEW-MODEL-GEO-Minim-Energy-Smart-Electricity-Monitor-brand-new-and-boxed/122429465754?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40656%26meid%3D04106b29b5ca4d479dc7bd99f14ee5ee%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D282418744306

It looks like it can be set to display kw in current and historical, which would be more than adequate.

Alan, I DO want to know my ac consumption!

[philjw]

I have no experience of these bits of kit or how they work but I do know that ordinary voltmeters don't work well on the AC wave forms produced by inverters.  
I'm not sure where the OP is getting his AC from at the moment.  Will the domestic monitors produce an accurate result with an inverter? Does it make a difference if it is not pure sine wave?

Phil

[rusty69]

1 minute ago, philjw said:

 Will the domestic monitors produce an accurate result with an inverter? Does it make a difference if it is not pure sine wave?

I tried a domestic one on our modified sinewave inverter and concluded that it wasn't accurate. 

[nicknorman]

14 minutes ago, Johny London said:

I've got a smart gauge, and a clamp meter. I wondered if there was a boaters favorite as far as ac monitoring is concerned. Looks like there are plenty of domestic ones about - just a question of finding one that is fairly simple and not too bothered with calculating costs on tariffs etc which would obviously be quite meaningless. Also something that shows quite clearly the lower end of the power consumption spectrum as I rarely expect to be pulling many kwh!

Now I've spotted this one...

http://www.ebay.co.uk/itm/NEW-MODEL-GEO-Minim-Energy-Smart-Electricity-Monitor-brand-new-and-boxed/122429465754?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40656%26meid%3D04106b29b5ca4d479dc7bd99f14ee5ee%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D282418744306

It looks like it can be set to display kw in current and historical, which would be more than adequate.

Alan, I DO want to know my ac consumption!

Most clampmeters have an AC current range as well as a DC one, surely that allows you to work out the overall current demand and hence, multiplying by the voltage, the power. Just bear in mind that you have to put the clampmeter around just one conductor - if you put it around a 3 core flex you will get zilch.

We have a combi inverter that reports AC current output, either coming from the mains or from the inverter bit. It is quite useful to know how many combinations of toaster / coffee machine / electric kettle / washing machine / tumble drier / MIL's hair dryer/ TV / Sat box we can run without overloading the inverter (10A or so), or the shore bollard (16A).

[Johny London]

Well after a bit more searching I found something a bit more simple...

http://www.ebay.co.uk/itm/AC80-260V-20A-100A-LCD-Digital-Amp-Voltage-Current-Power-Meter-Ammeter-Voltmeter/152258591561?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D2220072%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40656%26meid%3D9ba908d237dd46c4bdb012d48761c395%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Dpp%26sd%3D172312284330

Pretty much has exactly what I wanted - though as with all these things it'll be consuming a little bit of power all the time the 240v is on.

I'll order one and report back but at a tenner it looks pretty useful.

[ditchcrawler]

Just now, Johny London said:

Well after a bit more searching I found something a bit more simple...

http://www.ebay.co.uk/itm/AC80-260V-20A-100A-LCD-Digital-Amp-Voltage-Current-Power-Meter-Ammeter-Voltmeter/152258591561?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D2220072%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40656%26meid%3D9ba908d237dd46c4bdb012d48761c395%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Dpp%26sd%3D172312284330

Pretty much has exactly what I wanted - though as with all these things it'll be consuming a little bit of power all the time the 240v is on.

I'll order one and report back but at a tenner it looks pretty useful.

Will you be using 20 Amps at 240 Volts, that more than most shore supplies will provide and also a decent size generator.

 

[nicknorman]

Just now, Johny London said:

Well after a bit more searching I found something a bit more simple...

http://www.ebay.co.uk/itm/AC80-260V-20A-100A-LCD-Digital-Amp-Voltage-Current-Power-Meter-Ammeter-Voltmeter/152258591561?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D2220072%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40656%26meid%3D9ba908d237dd46c4bdb012d48761c395%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Dpp%26sd%3D172312284330

Pretty much has exactly what I wanted - though as with all these things it'll be consuming a little bit of power all the time the 240v is on.

I'll order one and report back but at a tenner it looks pretty useful.

I would just think a little bit about exactly how you are going to connect it up and house it. Those screw terminals on the back will be permanently live so be careful! There is no means to connect the incoming and outgoing earths together so you will have to provide means of doing that. I can't help thinking it probably doesn't meet any safety standards so as I said, be careful!

[cereal tiller]

Just now, Johny London said:

Well after a bit more searching I found something a bit more simple...

http://www.ebay.co.uk/itm/AC80-260V-20A-100A-LCD-Digital-Amp-Voltage-Current-Power-Meter-Ammeter-Voltmeter/152258591561?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D2220072%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40656%26meid%3D9ba908d237dd46c4bdb012d48761c395%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Dpp%26sd%3D172312284330

Pretty much has exactly what I wanted - though as with all these things it'll be consuming a little bit of power all the time the 240v is on.

I'll order one and report back but at a tenner it looks pretty useful.

Have been using a similar one for a few Years,it displays AC volts and Amps,fitted it in a small grey 'Hobby Box' enclosure.

[ditchcrawler]

Just now, cereal tiller said:

Have been using a similar one for a few Years,it displays AC volts and Amps,fitted it in a small grey 'Hobby Box' enclosure.

Does it read accurately below 20 Amps, it says its 20 to I think 100 amps but I may have that upper figure wrong

[cereal tiller]

Just now, ditchcrawler said:

Does it read accurately below 20 Amps, it says its 20 to I think 100 amps but I may have that upper figure wrong

Yes,it seems accurate,a 13 AMP. plug feeds it and a 16AMP Female  leave the Enclosure to feed the Boat's RCD and main AC circuit

0.1 of an AMP. (23 Watts) is the smallest unit it will measure

Edited April 13, 2017 by cereal tiller

[WotEver]

Just now, ditchcrawler said:

Does it read accurately below 20 Amps, it says its 20 to I think 100 amps but I may have that upper figure wrong

???

the spec reads "Tesing current: 0 ~ 20A, display accuracy: 0.01A"

"Testing power: 0 ~ 4.5kW, display accuracy: 0.1W(<1kW) / 1W(>1kW)"

[WotEver]

For the larger unit...

Tesing current: 0 ~ 100A, display accuracy: 0.01A

Testing power: 0 ~ 22kW, display accuracy: 0.1W(<1kW) 

[ditchcrawler]

Just now, WotEver said:

For the larger unit...

Tesing current: 0 ~ 100A, display accuracy: 0.01A

Testing power: 0 ~ 22kW, display accuracy: 0.1W(<1kW) 

Ta, now I have a connection again I just checked the add and now see there are 2 units

[nbfiresprite]

accurac

6 hours ago, Johny London said:

Well after a bit more searching I found something a bit more simple...

http://www.ebay.co.uk/itm/AC80-260V-20A-100A-LCD-Digital-Amp-Voltage-Current-Power-Meter-Ammeter-Voltmeter/152258591561?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D2220072%26algo%3DSIC.MBE%26ao%3D2%26asc%3D40656%26meid%3D9ba908d237dd46c4bdb012d48761c395%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Dpp%26sd%3D172312284330

Pretty much has exactly what I wanted - though as with all these things it'll be consuming a little bit of power all the time the 240v is on.

I'll order one and report back but at a tenner it looks pretty useful.

I have these meters installed on both my boats and have proved to be accurate. No more shocks when the quartery bill arrives (moorers at Foxes have no access to the shoreline meter)As is the amps display, insuring you don't trip the shoreline breaker (6A) 

[Johny London]

Cereal Tiller - is it possible to disable the lcd backlight? Perhaps by unsoldering a connection?

I expect I'll rig it up near to my consumer unit.

I ordered one anyway.

[WotEver]

4 minutes ago, Johny London said:

Cereal Tiller - is it possible to disable the lcd backlight? Perhaps by unsoldering a connection?

I expect I'll rig it up near to my consumer unit.

I ordered one anyway.

If you switched off the LCD backlight you wouldn't be able to see the display. 

[cereal tiller]

36 minutes ago, Johny London said:

Cereal Tiller - is it possible to disable the lcd backlight? Perhaps by unsoldering a connection?

I expect I'll rig it up near to my consumer unit.

I ordered one anyway.

Amazingly low power for backlight,not really worth saving,me?,I prefer LED,Bright and Beautiful !

[nbfiresprite]

46 minutes ago, Johny London said:

Cereal Tiller - is it possible to disable the lcd backlight? Perhaps by unsoldering a connection?

I expect I'll rig it up near to my consumer unit.

I ordered one anyway.

No desoldering needed, small button to the right of the display, press once to turn backlight on or off. Hold down for 5 seconds to reset kwh reading

[Johny London]

Sounds perfect then, regarding the button for the backlight. You normally can see lcd displays pretty clearly without a backlight though.

Anyway - I saw this one - it might appeal to those who like led's and have a consumer unit...

http://www.ebay.co.uk/itm/311783732592?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

At the prices these things go for, it seems pointless not to have them.

[Johny London]

Just fitted my unit - wasn't sure if putting the inductor round the neutral wire would be ok but it was easier, readings look lower than I expected.