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| Isle of Wight Music Festival |
Ever sat in a tent watching the battery on your phone or tablet die, with no mains power?
Such was my experience in Minehead last weekend. So I bought this:
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| RAVPower 26800mAh 3-Port 5.5A iSmart Output Portable Charger Compact Power Bank External Battery Pack |
It performed flawlessly, quickly recharging Clare's iPad, my Nexus 6 phone and my Nexus 10 tablet.
It then took around 14 hours overnight to recharge the Power Bank from empty, using the iPad's 5V 2.1A USB mains-charger.
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Tablets charge at 5V 2.1A from a USB mains-charger while for phones it's 5V 1A.
You can charge a tablet from a 1A phone charger - but it takes twice as long; you can charge a phone from a 2.1A tablet charger - the extra current capacity makes no difference and can't be used by the phone - but it's perfectly safe.
My Nexus 6 phone has a 3220 mAh battery, my Nexus 10 tablet has a 9000 mAh battery while Clare's iPad 2 has a 6,944mAh battery.
At 1 amp you would predict that the phone would take just over three hours to charge, the iPad would take seven hours and the tablet 9 hours.
This is why it makes sense, tablet-wise, to invest in a 2.1 amp charger like this, rather than just reusing old phone chargers, so as to halve these times..
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AmazonBasics Wall Charger with USB Outlet (2.1 Amp Output) |
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Due to various inefficiencies, you should multiply the device charging times above by up to an additional 50% (assuming you were charging from empty - but recall you are advised not to let the charge drop below 30% for long-term battery-health reasons).
