Earth Notes: Measuring Our Electrical Appliance Energy Consumption
Updated 2024-12-04.Read how once we have bought a gadget, we measure what it uses, and work out how to use it efficiently. No vampires here please!
There's an old adage in business: if you can't measure it, you can't manage it.
If you want to save cash (and carbon) on the energy that your appliances use then it helps to understand what they are up to! Here is what we did.
Home Electricity Usage
The data below is mains power consumption generally measured by plug-in power meter for select items.
If you get a smart meter with an "In Home Display" (IHD), or have a whole-home clip-on-meter then with a bit of clever detective work (and mainly turning everything else off that you're not measuring!) you can get some of this info too.
I like to know how much each gadget is using in normal use, and "off" or standby. Then we can turn off the power hogs quicker, and know what to look for in a replacement when we need one.
I also like to know when some of the appliances use energy during a cycle since their consumption is often very spiky. Did you know that your washing machine and dishwasher use most of their energy in one burst (or a small number of bursts) of a few minutes when heating water? Knowing that, I can better time my loads to be powered from the PV on my roof rather than paying for the energy to be imported from the grid! Generally our washing machine does any water heating right at the start of the cycle for example. Our dishwasher on ECO mode has a couple of bursts, one 20 minutes in at the start of the main wash cycle, and another a little later for the warm rinse. Each uses almost half the total energy of the cycle. Swishing stuff around is almost free for both machines.
See a record below of our main gadgets, and how much better some of the newer ones are than those that are no more.
Buying efficient replacements saves effort, energy and money!
Show Me The Money
A gadget or appliance using 1W all year costs about £2 per year at early 2022 prices! (It was more like £1 per year at 2017 prices.) So beware of devices such as microwave oven clocks and cable TV boxes and games consoles left on all the time. Even standby can be expensive!
| Item | Power W (peak) | Notes | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| *Heat pump (Daikin EDLA04E2V3 plus internal equipment) | ~11W idle, (~4kW) | Consumption is measured at the H4 boundary by the Eddi external current clamp 2 (CT2) as hph4 and includes the external unit, MMI, and OpenTRV unit. ~11W idle, ~60W just circulation pump running and MMI display lit (display ~2W, pump ~50W), nominally 4.35kW max, DNO seems to expect a maximum of ~9kW. As of 2024-11-30 ~3.6kW peak seen, more typical lower peaks of 2.6kW and 1kW (apparently cycle start transient), with normal running ~700W. MMI display draws ~2W. Installed in place of gas combi.  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Morgan's ASUS tower PC and monitor | 2W 'off', (120W) | The 'sleep' for the PC itself is ~1.8W, with the monitor bringing it to ~2W. In use the PC consumption peaks at just under 120W, more typically 60W to 100W. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| *Dishwasher (Electra C1845W) | 0.5W 'off' (~2kW) | See all measurements in the review. Typical ~0.73kWh for 'eco' (50°C, slow) cycle. Installed .  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| *Washing machine (Zanussi ZWF01483W) | 0.8W 'off' (2kW) | See all measurements in the review. Typical full cold cottons wash ~0.4kWh. Installed .  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| *Fridge/freezer (Siemens KG34NA10GB | 40W (360W) | Is A+ rated: should use ~0.75kWh/day; but used about 0.9kWh on its first full day, and a little over 1kWh/day thereafter. ~80W max running the compressor(s); higher peaks may be part of the auto-defrost mechanism or compressor start-up. See graph and .csv of 1 minute samples by an AlertMe energy monitoring system for : mean 42W (1.02kWh/d), max 356W, typically 0W or 75W.  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| *AEG NC4003020M multifunction electric built-under double oven (grill+fan) + IKEA Smaklig induction hob | ~8W (~4kW) | When on 'standby', with just the clock running, ~8W is drawn. On 2x32A circuits. Induction hob can draw 7.4kW max.  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| *Potterton Performa 24 central-heating and DHW gas-combi boiler | 2W (20-40W when CH is enabled) | When on 'standby', with just the timer running, ~1W is drawn. When producing hot water or central heating up to 140W is drawn, presumably at least in part for the combustion-assist fan. The central heating circulation pump alone seems to use 70W. The average power will depend on the duty cycle of the boiler, but maybe up to about 1kWh/day on a cold day; from 2008-09-22 16:30 for 24 hours (a mild day for February) ~0.5kWh was used. So, maybe 10kWh/y overhead for electronics and timer all year, rounding up to maybe 200kWh/y for DHW and space heat. For us in 2020 with ~3000kWh gas demand and a replacement heat-pump CoP of 3 plausible, we may already be using 20% of the 1000kWh/y electricity that we would need for a heat-pump. Also that implies the effective electrical CoP of our current gas boiler (ignoring the gas itself) is ~15. Replaced with a heat pump.  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| *Timeguard ZV700 smart light switch | ~0.5W | (Newer ZV700B 'phantom' load is 0.5-0.8W according the suppliers, typically 0.5W, and the ZV700 should be the same.)  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| *Cordless phone (Siemens Gigaset AL180 "ECO DECT") | ~1.5W | Must be left on to receive calls. Bought 2011-06 as replacement for broken Binatone on promise of low power consumption. Have enabled both ECO-MODE and ECO-MODE+ settings.  | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Toaster (Tefal Avanti Deluxe) 2+2 slot | 0W (1kW/| 0W not in use, 1030W for 2 slots, 2060W for 4 slots. Taking 2.5 mins to toast, that implies ~42Wh for two slices (N67HH meter still showed 0.0kWh). |  Slow-cooker (3.5l Argos Cookworks 420/7490 SC-35-R) | 138W (211W) | Has settings "low" (138W), "high" (211W) and "warm" (75W), all much higher than my previous ancient model. It is not clear if the cooker has a thermostat to reduce power consumption when the food is already hot (if the Suzhou Novus Appliances model, probably not). We anticipate using the "low" setting most of the time. Cooking times in the supplied recipe book (7h on low or 5h on high, typically) implies 1kWh consumption compared to a third of that for the older half-size cooker, so we may be able to do better. Our first meal for 4, with some left over to freeze, was ~8h on low and ~1.2kWh or 0.5kgCO2 (though most came direct from our solar PV on the roof). Was priced at £9.99 on (previously £19.99). |  Argos 425/0777 (MDT- | 183W | Seems able to get relative humidity down to ~50% even in the kitchen, though 2l/12h seems more realistic than claimed 10l/24h except at very high RH% (drying a plastered room 2015-12-09), at which extraction rates peaking at 2l/h may have been observed. One run removed ~1l (in ~6h) from kitchen using about 1kWh. |  Bedside lights | (11W) | One 7W CFL IKEA golfball and one 3.7W LED Istoria candle, but they're not used much anyway (was 2 CFLs totalling ~15W until about March 2012). | Xbox One S | 40W | Standby ~0.7W, idle after boot ~30W, playing a networked game and chatting ~40W; measured 2019-06-09. Apparently 90W is possible. |  TV (26"/66cm LED-backlit LCD LG 26LS3500) | 29W | Standby ~0.9W (higher than spec); energy consumption in Eco 'Auto' mode. Total consumption with PACE cable box on ~40W, with DVD on ~45W (other on standby each time). See review. This is one of the devices turned off entirely at night with our LIME plug. | (See the TV Corner energy use analysis also.)  Virgin Media Cable TV Box (TiVo / CT 8620) | ~21W (~19W) | Powering up ~13W. Hard disc (500GB) can be heard running even in standby. Power supply rated 12Vx3A ie 36W max. This is one of the devices turned off entirely at night with our LIME plug. | (See the TV Corner energy use analysis also.)  DVD Player | 6.5W (8W) | Standby about 1.2W. This is one of the devices turned off entirely at night with our LIME plug. | (See the TV Corner energy use analysis also.)  Toasted sandwich maker (SilverCrest) | 750W | 800W usage estimated from whole-house load , product marked 750W. |  Microwave oven Panasonic NN-K655 | 3W (1kW+) | ~3W standby with the clock/display active according to 2000MU-UK and N67HH. (Internal lamp failed ~.) |  Electric kettle | 0W (~3kW) | Can boil water for single cup (300ml). (~£32.) | Dishwasher (Zanussi ZDS2010) | 0W 'off', 2.4W 'delay' (2.2kW) | ~0.8kWh for 'ECO' (50°C, slow) cycle. Typically one load is run per day. ~0.02kWh to run a rinse, which with a little detergent I use as a surrogate pre-wash. ~100W most of the time that is it 'washing' without heating the water. 2.4W (as measured with N67HH) on 'delay' waiting to start a cycle, so adding ~8Wh to a delayed cycle. Expired 2020-11-26. |  Washing machine (Zanussi ZWD14581W front-loading 7kg washer-dryer) | 0W 'off' (2kW) | See all our measurements in the review. Basically it looks like we can save up to 90% of the energy per wash on average (taking ~0.1kWh to ~0.2kWh) with care and by using appropriate modern detergents, though in practice we are using a mixture of 40°C, 30°C and cold washes, apparently saving ~0.5kWh/d on average as of the end of 2009. Expired 2020-09-05. |  Electric kettle | 0W (~3kW) | Can boil water for single cup; could not find one with lower rating and adequate volume 2014. Failed/replaced 2020-05. |  Cable TV box (PACE) | 15-20W | Standby mode consumes maybe 1W less. (Higher reading from PM230, lower from 2000MU-UK.) See 2011-07 sample AlertMe graph of a few days' power consumption of TV+DVD+converter+cable (exec summary: whole CRT TV stand circa 2012 used ~73W when on, averaging ~0.5kWh/d consumption, mainly evening) with a 'standby' (and TV switched off) of about 16W, almost all from the PACE cable box. | 2 x Child's night-light (LED) | (0.5W each) | Device is rated 0.5W. All out of use by 2017. | *Bedside clock-radio(s) | 2-7W | (Higher reading from PM230, lower from 2000MU-UK. We have turned off one of the clock radios.) All out of use by 2015-03. | Electric kettle | 0W (~2kW) | ~35Wh (130kJ, or ~15g CO2 generating the UK grid electricity) to make a single cup of tea. Approx 0.5kWh/day usage when I am working at home! Replaced 2014. Successor 3kW 1-cup kettle replaced 2020-04. | Electric travel kettle | 0W (1kW) | May be slightly more efficient for a single cup of tea, but more importantly the lower-power element is within the planned power of our early-2008 grid-tie solar PV install, and thus we may import far less energy or even none at all to boil that cup of water when the sun is shining in return for waiting slightly longer. My measurements suggest that if I boil exactly the water I need, and manually stop the kettle just before it comes to the boil, then I use under 30Wh for one normal mug. Replaced 2014 |  FM radio (Alba CRM1009) | 1W (2W) | Uses ~1W in plugged in but turned off at the radio, ~2W with radio on. Replaced 2014. | *Gas cooker (electronic ignition and clock) | 1W | 1W standby with the clock active according to 2000MU-UK. Replaced 2013-05 with induction hob and electric (fan-assisted) oven. | TV (13" Sony Trinitron KV-1430UB CRT rated 70W, ~20 years old #519523, + converter) | 55-60W | Too old to have a remote or standby mode! (Higher reading from PM230, lower from 2000MU-UK.) This includes the power for a small separate SCART/UHF converter (3W) to allow use of a DVD player. Failing 2012-11-10 and replaced with 26" LED-backlit LCD using ~29W. |  *Cordless phone (Binatone Fusion 2200) | 3-7W | Must be left on to receive calls. Adapter plug physically broke 2011-06. (Higher reading from PM230, lower from 2000MU-UK.) | Baby monitor (child unit, parent unit) | ~5W total | ~2.5W total when both are on 'standby'. Baby monitor out of use ~2008-01, back in use 2008-11 for newborn! Out of use again ~2010-07. | Slow-cooker (1.5l) | 50W | Ancient "Tower" model from my student days (so a modern one could probably be much more efficient); 0.36kWh (~7h) cooked a curry for our family of four. Passed on through Freegle 2010-10. |  Dishwasher (Zanussi DW24) | 0W 'off' (3kW) | Undetectably low load when not running even with 'on' lamp lit. 1.27kWh for prewash+wash on warm day, 0.86kWh for 'quickwash' which is now our usual programme. Unmeasurably small (with current meters) amount of energy to run a rinse, which with a little detergent I use as a surrogate pre-wash. Expired 2009-12-12. |  Washing machine (Zanussi ZWD1260W front-loading 5kg washer-dryer) | 2-10W 'off' (2kW) | A few W (2000MU-UK reports 2W) even when apparently 'off' at the machine with the power light off, which is bad: definitely one to switch off at the wall. 0.74kWh for our typical full 40°C wash. 0.91kWh for a 60°C wash of towels with a 13°C mains inlet temperature (the manual specifies 1.10kWh, 63l and 145m for that wash, ie 0.22kWh and 12.6l per kg of washing; our replacement ZWD14581W is 0.17kWh and 8l per kg). 0.59kWh for a 30°C 'worn once' wash with a 10°C mains inlet temperature. 0.79kWh for a 40-minute tumble dry of a half-load. The water inlet valve takes about 10W when open, slowly turning the (front-loading) drum up to about 300W peak (<150W average) and up to ~600W peak while ramping up to high spin speed, and the heating element takes 1.7kW. Main bearings failed 2009-03-17! |  Flashing fancy inside/outside light string | 40W (100W) | Only on for a few hours per day and only for a few days per year. | Christmas tree lights (plain, incandescent) | 40W | Only on for a few hours per day and only for a few days per year. | Old stereo system | 20W | 20W standby: consumption not measured when in use. Little used and now unplugged when not in use. FreeCycled 2008-07! | Child's night-light (incandescent) | (5W) | 5W with light on; <1W in daylight should we forget to unplug it! Replaced with £2.49 LED night-light when bulb failed, and thus may just about pay for itself with saved electricity in a year or so. | *Fridge/freezer (Zanussi "ZFC 62/23 FF", circa 2000) | 80W (190W) | 0W minimum, +20W for internal light when door open. ~190W with compressor running. ~80W average measured over 1 day. This was our biggest single consumer of electricity in the house at ~2kWh/day. Replaced with A+ rated model 2008-03-03. | PC and monitor and printer | 210W (250W) | The monitor consumes 30W on standby and 80W in use. Working the PC harder increases its power draw from 130W to 170W. Switched to a power-efficient old/used laptop from 2007-11 as the PC started to fail. | |
Items marked * need to be (or are) left on 24x7.
Study and Other Electricity Usage
Mains power consumption measured by power meter for select items.
| Item | Power W (peak) | Notes |
|---|---|---|
| Wonderboom 3 portable Bluetooth speaker | ~2W (~4W) | Bought to let me get a bit more out of (bassy) music listening and generation vs laptop speakers and headphones. 5V USB power. Contains an internal ~14h battery. As measured with the Muker USB power meter on a test track played from the MacBook Air it draws ~.35A (~1.8W) minimum/silent, ~0.41A (~2.0W) on 'medium', and ~0.87A (~4.3W) maximum. Consumption can drop to zero while continuing to play, presumably because of the internal battery management system. A little under 1W inferred consumption from off-grid system, volume fairly low.  |
| Mac Book Air ("MacBookAir10,1", 16GB RAM, 1TB SSD, M1 ARM 4+4 cores, macOS 12.2.1, 13.3" LED-backlit LCD display 2560 × 1600, 2022, ~50Wh battery) | ~3.5W (~30W) | New unit bought because various bits of the old one were falling apart and/or had already been repaired, and the OS was not getting updated. Arrived 2022-05-18. Draw measured by Satechi USB-C power meter from Apple mains supply 0.29A@19.8V (5.7W) as I type this with Google Drive syncing, A little under 4W (0.30A@11.8V) while editing this in vi and GD done, ~1.8W (0.09A@19.9V) when sleeping. Briefly peaking at a little over 20W under reasonably heavy load. With battery full and not much going on, enabling "low power mode" (macOS Monterey 12.4 2022-06-27) reduced power draw ~15% from ~4.9W to ~4.2W. The mains power supply is rated to 30W max and can reach that when charging from the Apple mains adaptor (1.5A@19.7V). When forced to top-up battery charge from off-grid via a Veld VC48DG (nominal 30W from USB-C port PD) drew ~2.27A@9.97V (~23W).  |
| *Sunamp Thermino 150 ePV heat battery | 7W | More about the heat-battery project. 7W load for control system taken from manual, not measured. Thermal capacity ~7kWh, peak heating input ~2800W at 230V.  |
| *RPi to manage Sunamp Thermino | 2W | Estimated 2W (2014 B+ V1.2). May measure and tune in due course. |
| *Myenergi Eddi PV diverter + Hub | ~5W | Read more on this small vampire. Measured separately (3.3W+1.5W min) 2022-02-05 with Maplin N67HH.  |
| *Import and export meters (2x Itron Actaris ACE1000 SMO) | ~1.6W | Max 0.8W per meter from datasheet: not measured.  |
| *PV grid-tie generation equipment and meters (3 x Sunny Boy 1100, 1 x Sunny Boy 1200, Elster A100C, Iskra ME162 D3A52-L21-M3K0) | 3W | 2.7W consumption measured by Enphase Envoy-S Metered 'production' current clamp at night. Reported consumption wobbles up to ~20W at cusp of dawn/dusk.  |
| Acer laptop with LED-backlit screen (Aspire 5750, 8GB RAM, 500GB HDD, Windows 7, i5-2410M 2-core/4-thread 2.3GHz CPU, 15.6" LED-backlit LCD display, c2011) | ~12W (45W) | (0.6W 'off', 0.0W adapter only.) 3W difference between dimmest and brightest screen settings. Has to support some .Net development work, so a bit heavier-weight than the Tosh it replaced 2011-11. |
| Mac Book Air ("MacBookAir6,2", 8GB RAM, 512GB SSD, 1.7GHz Intel Core i7, OS X 10.8.4/10.9, 13" LED-backlit LCD display, c2013, ~50Wh battery) | ~6W (25W) | Adapter not plugged into MacBook draws <0.1W from mains (very good). ~6W once battery charged and working on a document with WiFi running (maybe idling nearer 5W with low display brightness with Mavericks), ~1--2W sleeping with the lid down. Can draw >40W when charging, lid closed. Running from ~12V off-grid via N59AC 70W laptop power adapter, editing text, network running, ~5W (measured via solar controller 2016-09-07); backing up to USB-powered HDD raises consumption to ~11W. lid down ~1.5W. Sample day's usage 2016-09-12 ~14h/~100Wh (without heavy computation). (Also see The Power Consumption Database.) Still in use 2023-09 as an alternate laptop, now on macOS 11.7.9 (Big Sur).  |
| *DrayTek Vigor 2862ac FTTC Internet router and dual-band WiFi | ~9W--11W | Unit states 27W max consumption on spec plate, 18W max online. (Setup.) 8.7W mains consumption (measured with N67HH) fresh out of box and before connecting to VDSL2 line 2019-05-02. 9.2W when up and running fully 2019-05-12T17:53Z, maximum 14.3W. Measured ~11W via 12V off-grid supply 2019-09-03T08:30Z.  |
| *Loop energy monitor | 2.5W | Not measured. Loop's FAQ says "How much power does my Loop Kit use?" ... "2.5W", though it's not clear if that is from mains via the supplied USB adapter, or direct from USB. (The USB adapter gets warm so direct may be significantly lower.) Running from off-grid seems to use ~3.5W. Loop system official switch-off date was 2020-11-13, though some features continued. Gas readings for 16WW stopped 2020-10-19, during minor works in the kitchen.  |
| Mac Book Air ("MacBookAir8,2", 16GB RAM, 512GB SSD, 1.6GHz Intel Core i5, macOS 10.15.3, 13" LED-backlit LCD display, 2019, ~50Wh battery) | ~6W (20W) | Refurb unit bought in error 2020-02 (1TB SSD was intended). Idle draw seems similar (<0.1W power supply plugged in but not connected to MBA, 1--2W with screen off, 4--9W screen on min to max with 6W at 'normal' brightness) but having difficulty getting this to draw more than ~20W from the mains even when busy, all measured with Maplin N67HH. |
| G-Technology 2TB G-DRIVE | 0W (~3W--5W) | Powered via USB; only used a few minutes per day for backups then disconnected to save power and for data safety. Consumption measured via Mac/mains/Envoy at ~3W idling 2018-09-02! Died prematurely before end of 2019.  |
| *Technicolor TG582n router + BT Openreach ECI Telecom ON316150 FTTC modem | ~12W | Now (partially) powered via 12V/mains converter, off-grid some of the time as PV dump-load, from ~2015-04. ECI box ~4.1W measured at the mains. TG582n died: replacing TG582n+ECI with Vigor2862ac 2019-05-02. Gone ~2019-05-12T16:00Z; new device being powered from mains for now. |
| Velleman K8200 3D printer | 1.5W (~80W) | While printing with PLA, which includes motors and heated platform and extruder. (Given away early 2016.)  |
| *Netgear DG834G v4 ADSL router and WiFi | ~8W | Up to ~10W with an extra LAN port in use. Down to ~7W with wireless disabled. Can be run from 12VDC (eg off-grid) or mains. (4W 'standby' consumed by mains adapter when unplugged from the modem until it failed.) Now powered via 12V/mains converter, off-grid some of the time from 2011, automated as PV dump-load ~2014-04. |
| *SheevaPlug server | ~4W (7W) | Low-power embedded "computing plug" for mail, Web and other servers. Mainly solar-PV powered (off-grid) thus reducing grid load still further. (3.5W minimum when quiet, max ~7W with mass storage active and CPU at 100%.) As of 2014-07 switched to Raspbery Pi B (then B+) solution entirely off-grid at ~2W or less.  |
| MacBook laptop with LED backlight ("MacBook6,1", 4GB RAM, 250GB HDD, 2.26GHz Intel Core 2 Duo, OS X 10.6.2, 13" LED-backlit LCD display, c2011) | ~12W (40W) | Adapter not plugged into MacBook draws <0.1W from mains (very good). Towards end of charging (~30m to go) with MacBook sleeping, draws ~20W, and with MacBook awake between ~30W and ~35W depending on screen brightness when otherwise quiet. ~12W once battery charged and working on a document WiFi running, ~1W sleeping with the lid down (after a burst to ~24W for ~20s while saving state to disc), deep sleep/hibernate mode knocks this down to essentially zero, ≤40W when busy (both CPU cores running flat out). |
| Toshiba laptop (L450D-13X, 2GB RAM, 250GB HDD, Windows 7) | ~20W (38W) | 0.8W 'off', 1.2W sleeping, 20W on but idle, 38W working hard. Default 'balanced' power settings a little reluctant to slow the CPU, etc, so switched to power-saving settings. Off most of the time. Second disc failure in a year killed it 2011-11. |
| Iomega 1TB USB 2.0 desktop external hard disc ("LDHD-UP", internally SAMSUNG HD103SI) | ~8W | Adapter not plugged into drive draws 0.9W from mains (not good). With drive on, ~8W idle or (gently) active. ~3W once 'ejected' ie put to sleep by the Mac. Power is switched off at the socket most of the time. Used with older MacBook so only very infrequently. |
| MacBook | ~19W (60W) | Not run absolutely flat out, nor on lowest-power settings. ~3W with lid closed. Screen from 'off' to max brightness ~5W difference. [Disc drive died, probably from static damage, 2010-02.]  |
| *Server | 20-27W (60W) | Low-power laptop/server for mail, Web and other servers. Partially solar-PV powered (off-grid) thus reducing grid load still further. (Higher reading from PM230, lower from 2000MU-UK when system/disc quiet but with all services running. Heavy disc activity adds ~3W according to the 2000MU-UK, and the is ~2W residual wastage in power supply when laptop 'off-grid', ie this mode cuts grid-power use by ~90%.) Replaced with ~4W SheevaPlug 2009-10. |
| ZyXEL P-660HW-T1 v2 ADSL router and WiFi | 8W | May be OK to power directly from 12VDC, ie battery (unofficially ZyXEL confirms this but it would void the warranty). 2W 'standby' consumed by mains adapter when unplugged from the modem. |
| *Cisco 828 DSL router | 9-14W | Safety rules and other reasons may require this to stay mains-powered. The higher reading is from the PM230 meter, the higher from the 2000MU-UK. Recycled and replaced with a combined ADSL/WiFi router ~2008-06.  |
| WRT54G Wireless LAN | 8-12W | Looks like it could run directly from 12V DC supply, or could be eliminated entirely if the server-replacement laptop can double as a WiFi access point. Trying to remember to unplug it when no one is using it, maybe 12h/day. (Higher reading from PM230, lower from 2000MU-UK.) Recycled ~2008-06.  |
| [*Servers] | [670W] | [Some very old equipment and an over-complex set-up. 220W for the Web server alone. Recycled having been replaced with <30W server/router 2007-07-22.]  |
Items marked * need to be (or are) left on 24x7.
Off-Grid Usage
Items for the 12V off-grid system.
| Item | Power W (peak) | Notes |
|---|---|---|
| Car fan with suction cup, 12V. | ~6W | Bought (Roadking) 2021-04-21, though item received was not that ordered (their supplier had mislabelled the stock) so only ended up paying ~£1.50 for it after a gently-negotiated partial refund! Thank you Roadking for continuing good customer service. Lighter-plug connection. When battery voltage is high (~14V+) during absorption, can overspeed! Sticks nicely to a corner of my desk for off-grid-powered cheap comfort cooling. |
| Veld VC48DG 2 Port Car Charger 48W | Bought (Amazon) 2022-04 for the new USB-C powered MacBook Air M1 to power it off-grid. Seems to contain a low-voltage cut-out with sensible hysteresis which means that my homebrew LVD may not be needed.  | |
| Skross Midget USB Car Charger 12V 2.1A (2.900608) | 0.5W idle | Bought (RS Components) 2018-07. Idle current including LED 0.5W. |
| All Ride USB 12V/24V 2xUSB 3.1A total (91492) and similar | 0.9W idle | Bought (Roadking) 2018-07. Idle current including LED 0.9W. |
| LinkOn Car Charger 63W USB C PD Power Delivery 3.0 and USB A Quick Charge 3.0 for MacBook MacPro... (45W max on USB C, 18W max on USB 'A') Amazon B077ZRBPNB | 0W idle | Idle current including indicator LED too low to observe in off-grid system, so likely <100mW. Supported ~20W load from MacBook Air without a blink ... but failed within minutes... |
| USB C Car Charger, Anker 49.5W PowerDrive Speed+ 2 Car Adapter with 1 30W PD Port for MacBook Pro/Air (19.5W max on USB 'A') Amazon B071WYF9HP | 0W idle | Idle current including indicator LED too low to reliably observe by off-grid system, so likely <100mW. Supported 6W--31W (~20W typical when busy) load from MacBook Air... Apparently failed 2020-06-13, replacement bought, which also failed, on first use.  |
Items marked * need to be (or are) left on 24x7.