http:\/\/www.alchester.com.au\/powerful-laptop-with-virtualisation\/<\/a><\/p>\n
\nBattery Myths<\/b><\/u><\/p>\n
Whilst the label says:\u00a0 16,800mAh\u00a0 – but what can it do?\u00a0\u00a0 What voltage is it rated at?
\nJust what can you you do with this alleged 16800mAh of capacity?
\n
\n<\/u>Proposition:<\/b><\/u>
\n<\/b><\/u>the number more likely represents\u00a0 3.7v\u00a0 *\u00a0 16800mA\u00a0 being\u00a0 62.16Wh\u00a0 (but only as a PEAK!)<\/p>\n
\n<\/b><\/u>Stated Purpose<\/b><\/u>
\nLet’s consider these small external JUMP-START batteries offering 250-300CCA (500-600 peak CCA) for starting a car’s flat battery.
\nTheir design is based on short (3 second peak, and no more that 30 seconds)\u00a0 connection for a short COLD START of a medium sized engine.<\/p>\n
They do NOT offer holding power for sustained output.<\/p>\n
Don’t fall for the 16800mAh versus\u00a0 your internal battery of\u00a0 4025mAh and dream that it will run for 4 times the normal use of your laptop.<\/p>\n
The discharging process bears no relationship to such poor mathematical expectations
\n<\/span><\/p>\n10 observations<\/b><\/u>
\n<\/b><\/u>
\n1.\u00a0\u00a0 It is a Lithium Battery – but is it ION or Polymer
\nOf concern, was that the INPUT CHARGER was a light-weight humble\u00a0 240v – 12v adapter only providing 1A output!
\nThat’s an mere 12W charger trying fill up an alleged 16800mAh device!!\u00a0\u00a0 That will take 17 hours assuming no loss of current!<\/p>\n
2.\u00a0\u00a0 Batteries cannot transfer power to another battery at a consistent energy RATE.
\nIf they contain a 3.7 Polymer battery,
\nand if they have transformers that permit 5v\u00a0\u00a0 12v\u00a0\u00a0 16v\u00a0\u00a0 19v\u00a0 output,\u00a0 it is likely to be a a different Amperage output rate.
\nie:\u00a0 the test unit states:\u00a0\u00a0 OUTPUT of:\u00a0\u00a0 19v at 3.5A<\/p>\n
3.\u00a0\u00a0 But manufacturers of course,\u00a0 never state for HOW LONG that output can be sustained.\u00a0\u00a0 The reality is,\u00a0 it is NEVER sustained.
\nThe UNWRITTEN REALITY is that it is a maximum capability statement,\u00a0 for initial output only<\/u><\/span><\/p>\n4.\u00a0\u00a0 External Battery Output\u00a0 is 19v at 3.5A\u00a0 suggests output of\u00a0 (w = v * a)\u00a0\u00a0 of\u00a0\u00a0\u00a0 66.5W (watts)\u00a0<\/b><\/span>\u00a0\u00a0\u00a0 – a statement of maximum output capability….<\/p>\n5.\u00a0\u00a0 The laptop appliance will PULL (draw) the power that it requires (as a demand system),\u00a0 based on the laptop VOLTAGE and Amperage needed<\/p>\n
6.\u00a0\u00a0 EXAMPLE:\u00a0\u00a0 Gary’s Venom 13″ laptop with Debian Jessie – i7 CPU, 16GB ram 2x mSATA 512GB running raid-1 PLUS another 1TB SSD drive
\n1080 Hi-Res screen, backlit keyboard,\u00a0 Intel GPU (and an Nvidia GPU, disabled)
\nhas an INTERNAL\u00a0<\/b> 19.v\u00a0\u00a0 5600mAh battery.\u00a0\u00a0\u00a0 This is 2 years old, and degraded to 72%\u00a0 at 4054mAh\u00a0 according to #upower -d\u00a0\u00a0\u00a0\u00a0 and
\nroot@absvenom:\/home\/gaz# acpi -bV<\/b>
\nbattery 0: design capacity 5600 mAh, last full capacity 4054 mAh = 72%
\nSo, that power consumed for a realistic 83% usage of that degraded available energy is say:
\n83% of 4050mA \u00a0 in 70 mins\u00a0 =\u00a0\u00a0\u00a0\u00a0\u00a0 2881mA pe<\/u><\/b>r<\/u> <\/b>hour\u00a0 but only for\u00a0 70 mins\u00a0 until DEAD.<\/p>\n
7.\u00a0 So, the LAPTOP is drawing power for USAGE, during that one hour of operation is\u00a0 2.881A at 19.5v\u00a0 =\u00a0\u00a0\u00a0 56.18W\u00a0 constant demand<\/span><\/b><\/p>\n8.\u00a0 When connecting the external battery to the LAPTOP (fully charged to start with),\u00a0 what transpires is:
\na)\u00a0\u00a0 The Laptop declares it is being CHARGED from AC (but really from the external battery source)
\nb)\u00a0\u00a0 The internal battery level indicator declares it is 100% full until the external battery becomes depleted and stops
\nc)\u00a0\u00a0 The external battery lasted ONLY\u00a0 35 minutes
\nd)\u00a0\u00a0 Then the internal battery starts to discharge,\u00a0\u00a0 and in the test case,\u00a0\u00a0 reduced to 62% (down 38%)\u00a0 in a mere 20 minutes!
\n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 (of interest to notes, was a 12% loss in a 70 second interval!)….\u00a0 <\/i>
\nPrevious tests have show a\u00a0 1.18% loss of power every minute,\u00a0\u00a0 which is the typical expected.
\ne)\u00a0\u00a0 It was decided to abandon the testing,m and recharge the internal battery from 240v \/ 19.5v 6.15A (120W) external ADAPTER.
\nThis took from 15:21PM (at 62%)\u00a0 to\u00a0\u00a0\u00a0 16:50PM (100%)\u00a0\u00a0\u00a0\u00a0 ie:\u00a0 a little more than an\u00a0 90 minutes to top up 38%….\u00a0\u00a0 (using a 120W supply!)<\/i><\/p>\n
9.\u00a0 Meantime the external unit is now awaiting a long\u00a0 night to recover from its 35 minutes of enjoyment!<\/p>\n
10.\u00a0 Do they work?\u00a0\u00a0 For a quick boost for 35 minutes – yes, \u00a0 but for sustained usage: \u00a0 **NO**<\/p>\n
<\/p>\n
The good news<\/strong><\/span><\/p>\nThe conference where power for laptops was needed, saw it prudent to supply 4-way power boards under each table throughout the venue. \u00a0Nothing like 240v to run a laptop all day!<\/p>\n
<\/p>\n
If you want a jump start for your car, \u00a0here’s an example of what was tested<\/p>\n
http:\/\/www.ebay.com.au\/itm\/16800mAh-Car-Jump-Starter-Emergency-Charger-Booster-Power-Bank-Battery-SOS-Light\/262184551886?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140106155344%26meid%3D20a49226c27f472d80bc629cd86b9f53%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D252080316373<\/a><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
When recently confronted with a potential need to run a LAPTOP at a conference for 8-10 hours, \u00a0then an exercise was undertaken to explore external batteries on the market allegedly providing considerable extra power….. \u00a0but not so. \u00a0Read the fine print on the calculations! \u00a0 Some of these ‘boost’ batteries are in fact capable of […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-803","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=\/wp\/v2\/posts\/803","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=803"}],"version-history":[{"count":11,"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=\/wp\/v2\/posts\/803\/revisions"}],"predecessor-version":[{"id":815,"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=\/wp\/v2\/posts\/803\/revisions\/815"}],"wp:attachment":[{"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=803"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=803"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/abswww.alchester.com.au\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}