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paulz
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# Posted: 30 Sep 2017 10:51am
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I have a couple of tablets and phones that stay plugged into their charges, which are plugged into my 12vdc battery. We stream videos on them too. Is it OK to leave them plugged in constantly or better to unplug when at 100%? My phone always says "unplug to save energy" when it hits 100.
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ICC
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# Posted: 30 Sep 2017 07:56pm
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Any modern device that uses a lithium based battery must have a charge circuit that terminates the charge when 100% charge is reached. It's the nature of lithium cells. If left on even a trickle they will deteriorate. Manufacturers don't want that. A reputable builder will use charge circuits that cut off. There may be a very small parasitic use of mains power with some devices. I have a rechargeable lithium light that when full, continues to draw 0.02 mA. That is insignificant even for those of us who are off grid.
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paulz
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# Posted: 30 Sep 2017 09:39pm - Edited by: paulz
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Thanks ICC. Why do you suppose they want you to unplug, for the .02mA? Or is it for the energy the charger is using?
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ICC
Member
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# Posted: 30 Sep 2017 11:41pm - Edited by: ICC
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Well, one way to look at it is that any unnecessary power use is 100% wasted.
Let's some math; if a device is just barely CEC certified (0.5W no-load dissipation) and left in the wall unused all month, you have 730 hours (in one month) * 0.5W * 0.001 W/kW = 0.365kWh [kilowatt hours] and electricity costs of, say, $0.20/kWh, and you have a cost of $0.07. Now, if you have 5 or 6 plugged 24/7 that would be $0.35 to $0.42 a month. It starts to add up. If everyone in town has 5 or 6 plugged in 24/7 that is noticeable. Count the entire country and you are talking real money being wasted. I read somewhere that there are probably over a billion of those wall warts in use in the US.
That's worst case scenario though as I know most of mine have extremely low idle loss.
I'm off grid with a robust enough system that I don't worry about it. I had a walk around and counted 15 chargers that are plugged in 24/7 and most are idle most days. Yikes! But the sun shines brightly, I don't worry.
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Steve_S
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# Posted: 1 Oct 2017 05:14am
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@Paulz, you have them plugged into your 12V battery ? I'm assuming you have some kind of inverter giving you 120V which the chargers are attached to, is that right ? If that's all attached to a power bar once charged, shutoff the power bar and save a bit. Like ICC says, the warts are just a small parasitic loss but can add up with the qty of gadgets... It's not the Big Sting that get's you, it's the thousand little ones that will...
@ICC, yeah I read that somewhere else too about over a Billion Wall Warts in the states alone... somehow I think that might be short.... think of the warts in garages, shops, sheds and those rarely used auto-charging lights and such... and the duplication where people have a wart at home for their phone but another at their workplace too... eeks... I wonder how many kilovolts, megavolts that adds up to every month... Ohh my... and you know how some of them are genuine power pigs too (thinking of the older types used for NiCad and the cheapo's of days past).
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paulz
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# Posted: 1 Oct 2017 07:35am
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Steve, I'm not using the AC wall chargers, just straight 12vdc USB charger. I only mentioned them as the possible source of the unplug to save energy message. I suppose my Anker charger uses some juice too.
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Steve_S
Member
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# Posted: 1 Oct 2017 07:45am
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Ahh, well that is likely more efficient than a collection of Wall Wart Power Vampires... Likely if you unplug devices that are charged, the draw would be quite minimal.
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Tree feller
Member
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# Posted: 5 Mar 2018 09:06pm
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A little off topic but i bought a couple mini usb solar panels and mounted one at my cabin. I also purchased 20000 mah battery that is always connected to the panel. It's a great way to break into the solar world without spending a ton of money. I'm really surprised at how well it works and the appliances that are available via mini usb.
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