bought one of these to monitor the electric consumption of the electric car I recently purchased. The car isn't seeing much use so it only goes on charge about once week. I keep a note of the distance covered and record it against the kWhs used to recharge the batteries.
The strange thing is the meter records usage when the car isn't being charged.(i.e.) last week after recharging the meter read 73.65kWh. This morning when going to recharge the car again the meter read 74.16kWh so where did the 0.51kW go ? Gremlins Is my neighbour plugging in extension lead ?
Is it measuring its own consumption? A week to use 0.51kWh would suggest about 3W being used by its own circuitry. If it is measuring that, it could be the sort of figure you could expect from such a device.
Have you tried it on other sockets to see if it shows the same thing?
Was the car charger plugged into the meter? Does said charger have a physical on/off switch, that breaks the circut? Was that in the on or off position? Or does it have a "soft" power switch that just electronically switches the device "off". Or no power switch at all?
3W could easyly be the "standby" power consumption of the charger, in anything other than phyiscally switched off.
I've recently got one of those type of power meters. With it plugged in and powered up but nothing plugged into it it shows zero power. What does yours show? What does it show with the chrager in and "on"?
Have you tried fully charging it, leaving it standing for a week without use, and then charging again to see how much battery capacity has 'gone' without use ?.
I think he's talking about the meter for the house, rather than a "fuel gauge" meter in the car, showing how much energy the batteries have stored.
Fred, having recharged the car last week to "full", was it plugged into the meter for the week that it was not being used? Or does "when going to recharge the car again" imply that it nothing was plugged into the meter until you started to charge the car this morning?
Does the meter *only* measure electricity fed to the charger, or could it be including some other usage within the house? Is it a separate meter to the electricity company meter by which your bills are calculated? Could there be a small leakage current flowing even when the charger isn't supplying power to charge the car? Can you turn the charger off at its input when you know that you won't need to charge the car? 0.51 kWhr in several days is not much. To put it into perspective, my computer and monitor uses about 1.1 kWhr per day for the 12-14 hours that it is turned on (they are on standby overnight, and the monitor is on standby during the day when I'm not actually sat in front of it).
According to the blurb, it switches itself off at above 1650watts, so I would have thought it was totally unsuitable for measuring car charging consumption, anyway.
Hadn't spotted that little gem. Having an overload cutout above 1650W makes it about as much use as a chocolate teapot for many appliances - oh, and you wouldn't be able to use a kettle to heat the water in the chocolate teapot ;-)
You'd expect the cutout to be set at slightly more than 3 kW, to allow for the maximum 13A current draw (plus a bit of headroom) from one 3-pin socket.
The car charger is mounted on a wall of the garage and the supply is to a dedicated socket via the meter . I now understand the small stray usage I observe is down to the unit itself. Its obviously of no consequence. The unit maintains a running total which I find useful as it allows me to calculate the actual cost and stop SWMBO whinging about me getting free fuel for my small car while she has to buy diesel for hers. I've offered her the use of the i3 but she thinks it beneath her.
Just boiled a kettle full of cold water (8 "cups", nominal 3kW kettle) through my very similar looking power meter:
Took: 4'14"
0.196 kWHr
When heating:
2800 ish W (wandered about by 5 W or so)
1.00 PF
233 V (min, 236 max ish)
12.02 A (steady so presumably the wandering power reading is down to the wandering supply voltage the variations in current that causes being outside the resolution of the current measurement when at 12 A)
Sat on base, hot (it has a still hot LED indicator):
0.4 W
0.05 A
Removed from base:
0.0 W
0.0 A
Overall I'm quite impressed by this gadget considering it was only £12 or so. It seems accurate and capble of measuring very low loads.
Except you are paying for it. OK 1 W is only about £1/year but all those "little watts" soon add up. Just after I got a similar meter I counted how many devices where routinely plugged in and on, came to
48 (and I missed a few).
Just adding a remote switch to my office desk and switching off everything that doesn't need to be "on" (ie plugged in switched on, standby) over night has dropped the overnight base load by at least
I hope when you're charging the car, you're not filling the battery 100% full. When storing lithium devices (non-use situation), it's better to keep the battery fractionally full. Maybe 50% to 70% or so.
Only when you're taking a really long trip and plan to discharge the battery almost immediately, would you charge to 100%. Also, charging to precisely 100%, prevents regenerative braking from working for the first five to ten minutes. The car should switch modes on its own, because it knows the battery hasn't room to store regenerated charge at the moment.
Fractional filling will add some life to the battery pack.
It's the same with laptops. Laptops in the past charged to 100%, and some people left their laptop plugged in all the time. Even though the charger is smart, this tends to wear on the pack. More modern laptops have a "stage 1 only" charging option, which charges the pack to 80%, and then if you leave the adapter plugged in, the smart charger will never put more than 80% in. Which reduces the terminal voltage so it spends less time at 4.2V and more time at 3.7V (LiCo).
I'm sure this is explained in the documentation somewhere. Although manufacturers want you to think everything they make is an "appliance", BEV still isn't really at that point yet. We're still at the "pointy bits" stage and the "don't do that" stage. Some day the vehicles really will be don't care technology, and the biggest worry will be the manufacturer making shoddy body panels or the like. Or like the cars I drive, where everything is "blown alternators" :-) Before I take a car to the junkyard, the last thing to fail is the alternator. I saw a flicker the other day when I was out in the car... and I know what comes next. Some day electric cars will have a favored failure mode too. Maybe the bumper will fall off or something :-)
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