Received: from PCH.mit.edu (18.7.21.50) by mail.efplus.com (192.168.0.8) with Microsoft SMTP Server (TLS) id 8.3.485.1; Sun, 16 Feb 2020 18:45:18 -0800 Received: from PCH.MIT.EDU (localhost.localdomain [127.0.0.1]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 01H2VkkZ004506; Sun, 16 Feb 2020 21:36:49 -0500 Received: from outgoing-exchange-7.mit.edu (OUTGOING-EXCHANGE-7.MIT.EDU [18.9.28.58]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 01H2VjhS004494 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Sun, 16 Feb 2020 21:31:45 -0500 Received: from W92EXEDGE5.EXCHANGE.MIT.EDU (W92EXEDGE5.EXCHANGE.MIT.EDU [18.7.73.22]) by outgoing-exchange-7.mit.edu (8.14.7/8.12.4) with ESMTP id 01H2VWGQ019226 for ; Sun, 16 Feb 2020 21:31:33 -0500 Received: from oc11exhyb8.exchange.mit.edu (18.9.1.113) by W92EXEDGE5.EXCHANGE.MIT.EDU (18.7.73.22) with Microsoft SMTP Server (TLS) id 14.3.439.0; Sun, 16 Feb 2020 21:31:36 -0500 Received: from oc11exhyb4.exchange.mit.edu (18.9.1.100) by oc11exhyb8.exchange.mit.edu (18.9.1.113) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Sun, 16 Feb 2020 21:31:43 -0500 Received: from NAM04-BN3-obe.outbound.protection.outlook.com (104.47.46.50) by oc11exhyb4.exchange.mit.edu (18.9.1.100) with Microsoft SMTP Server (TLS) id 15.0.1395.4 via Frontend Transport; Sun, 16 Feb 2020 21:31:43 -0500 Received: from BL0PR0102CA0035.prod.exchangelabs.com (2603:10b6:207:18::48) by BL0PR0102MB3601.prod.exchangelabs.com (2603:10b6:207:35::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2729.29; Mon, 17 Feb 2020 02:31:43 +0000 Received: from CO1NAM03FT028.eop-NAM03.prod.protection.outlook.com (2a01:111:f400:7e48::203) by BL0PR0102CA0035.outlook.office365.com (2603:10b6:207:18::48) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2729.24 via Frontend Transport; Mon, 17 Feb 2020 02:31:42 +0000 Received: from p-impout001.msg.pkvw.co.charter.net (47.43.26.137) by CO1NAM03FT028.mail.protection.outlook.com (10.152.80.189) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2729.22 via Frontend Transport; Mon, 17 Feb 2020 02:31:42 +0000 Received: from [192.168.1.108] ([75.183.89.221]) by cmsmtp with ESMTPA id 3WCDj434P4hsv3WCDjvnF6; Mon, 17 Feb 2020 02:31:41 +0000 From: John Ferrell To: "piclist@mit.edu" Sender: "piclist-bounces@mit.edu" Date: Sun, 16 Feb 2020 18:31:40 -0800 Subject: Re: [EE] large USB power banks Thread-Topic: [EE] large USB power banks Thread-Index: AdXlPErvG18S7WgzTm6aQ2vJEhJ0mg== Message-ID: References: <15c8c6b973b5343c2becb83c6d63a638@mtlp000086> <20200216234805.GC16626@laptop.org> List-Help: List-Subscribe: , List-Unsubscribe: , In-Reply-To: <20200216234805.GC16626@laptop.org> Reply-To: Microcontroller discussion list - Public. Accept-Language: en-US Content-Language: en-US X-MS-Exchange-Organization-AuthAs: Anonymous X-MS-Exchange-Organization-AuthSource: TS500.efplus4.local X-MS-Has-Attach: X-Auto-Response-Suppress: All X-MS-Exchange-Organization-SenderIdResult: Pass X-MS-Exchange-Organization-PRD: mit.edu X-MS-TNEF-Correlator: received-spf: Pass (protection.outlook.com: domain of triad.rr.com designates 47.43.26.137 as permitted sender) receiver=protection.outlook.com; client-ip=47.43.26.137; helo=p-impout001.msg.pkvw.co.charter.net; dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mitprod.onmicrosoft.com; s=selector2-mitprod-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=e2i+rcZkyIf3i09vBdxjbJf73LSQhuLv4dUyX9rx8DA=; b=A5VT05AXm9Xd4Tj258hFyCPayO2XatnfElfXD297a85D/9jCrS4tmdfOnjsJfkZlY0GbtshV4Na2J4uo9N2KdcywKCNyJeGNBL23K+Mhn7VFTGaEve/aTDc86JZeXykWAkrB56fRRy9z1SAp3Ln4YHyE/JW02srO4qF67tQDorQ= authentication-results: spf=pass (sender IP is 47.43.26.137) smtp.mailfrom=triad.rr.com; mit.edu; dkim=none (message not signed) header.d=none;mit.edu; dmarc=bestguesspass action=none header.from=triad.rr.com;compauth=pass reason=109 user-agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 errors-to: piclist-bounces@mit.edu list-id: "Microcontroller discussion list - Public." list-post: x-beenthere: piclist@mit.edu x-mailman-version: 2.1.6 x-authority-analysis: v=2.3 cv=F9QpiZpN c=1 sm=1 tr=0 a=6CcecJFRP+ciuYZxb5RAIA==:117 a=6CcecJFRP+ciuYZxb5RAIA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=IkcTkHD0fZMA:10 a=x_9DLUGQ1kwbXRlYgOEA:9 a=QEXdDO2ut3YA:10 x-topics: [EE] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 I have a repurposed PC power supply on my bench That I have been tempted=20 to use power/charge multiple devices. What risks might I be taking? On 2/16/2020 6:48 PM, James Cameron wrote: > I've also used single cell USB power banks in some quick hacks. > > Where I've wanted less than 5V, I've taken power directly from the > cell terminals on the PCB. > > This defeats the discharge protection, so you have to add your own, or > procedures. > > It can also confuse any coulomb counter in the pack. --=20 John Ferrell de W8CCW "We must never become too busy sawing to take time to sharpen the saw." Source: Ergonomic Trends --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .