Plug in power monitor

[NeilP]

Anyone here use a plug in style power monitor that measures energy usage? The sort of thing you plug into your wall outlet, then plug appliance into and it gives you kWh used.

If you have one, does it work accurately on your SMPS bulk charger? I am trying to find one that will show me how much I use when I charge my bike

The one I have now, although it works, can't give a sensible reading on my BMS alloy shell charger

I plug it in to a 3kW kettle, and it reads correct, same goes for a 15W soldering iron. But my 2kW charger really screws with it

When running at 84 volts and 20 amps, it shows a mains draw of only 0.45 amps which is about 105 watts. Same issue with monitoring the Meanwell

I realise this is probably something to do with how the switch mode supply takes its power.
So any one know of a monitor that is accurate with this type of load?

 

[t3sla]

I use an el chepo watt meter to see how much my crummy 36V charger is drawing, it's really good as you can see when the current draw starts to decay as the battery fillies

What you require is a non invasive power monitoring, called a 'clamp meter' random ebay crap here

http://www.ebay.com.au/sch/i.html?_trkparms=65%253A12%257C66%253A4%257C39%253A1%257C72%253A5721&rt=nc&_nkw=clamp+power+meter&_dmpt=AU_B_I_Electrical_Test_Equipment&_sticky=1&_trksid=p3286.c0.m14&_sop=15&_sc=1

Works a treat as it just measures all the 'power' passing through the cable

 

[NeilP]

Yes, I know the sort of thing you mean, I have a clamp on AC meter around here somewhere too, but want a simple plug in type meter that you put the unit cost in and it tells you the actual cost on the display as well as current draw, Kw etc etc.

I have one but it does not accurately the power measured by the SMPS

I want something like this that will actually work ...unlike the one I have at present

http://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=energy+monitor&_sacat=See-All-Categories

 

[Jeremy Harris]

I've tried a couple of the cheap plug in mains power monitors, and generally they get a bit inaccurate at low power levels. They also don't have proper power factor correction, so don't give an accurate indication of power if the load is inductive or capacitive.

When I was doing some playing around with one of mine, I found that if I plugged a compact fluorescent lamp in to the thing, whilst it was already driving my freezer, the power indicated went down. I can only assume that the CFL had a power factor such that it messed up the reading from the freezer, or that the freezer had a power factor that was giving a wildly wrong answer and this was being corrected in part by the CFL.

They are OK for giving a relative indication of the power things use, but not great if you want to try and make some reasonably accurate measurements.

 

[Ykick]

Is that a Kill-A-Watt meter you're having issues with? I use a basic one with my MW's and seems to measure correctly. For example when my MW delivers 300Wh into the batteries my AC meter reads about 450-500Wh from my outlet. This is all just cheap consumer stuff but 'seems close enough for my purposes.

Funny you mention this because a friend of mine was recently looking at Kill-A-Watt meters and we were surprised by the large variety of models now available.

 

[NeilP]

Not a kill a watt, an un branded unit

This has a PF Display as well. But it shows 100 percent with both Meanwell and. Alloy shell unit

They are not just a little out, we are talking out by greater than a factor of 10. Expecting 1600 W or so, it reads 140 ???
Yet with loads such as kettle or soldering iron it gives spot on readings

 

[Ykick]

I'm no expert but likely a sample rate thing?

 

[NeilP]

Could well be, no way to check really..just looking for recommendations for one that will work