- Yamaha CDC-E250 problem. - 2 Updates
- does overcharging _lithium_ batteries release _hydrogen_? - 4 Updates
- 7805 regulator source? - 3 Updates
| Chuck <chuck30@deja.net>: Jan 10 08:31AM -0600 I cleaned and lubed a functional cd changer. After I was done, the number 2 disc tray won't retract. I stopped being an authorized. Yamaha tech 2 years before this model was sold and I'm having difficulty understanding how the changer mechanism functions. Any tips would be greatly appreciated. Thanks. Chuck -- |
| "Peter W." <peterwieck33@gmail.com>: Jan 10 07:34AM -0800 Service Manual here: https://www.hifiengine.com/manual_library/yamaha/cdc-e250.shtml Peter Wieck Melrose Park, PA |
| Jeff Liebermann <jeffl@cruzio.com>: Jan 09 05:44PM -0800 On Sun, 9 Jan 2022 13:40:39 +0000, danny burstein <dannyb@panix.com> wrote: >rest: >https://nypost.com/2022/01/08/number-of-fire-fatalities-in-nyc-jumped-16-percent-in-2021/ >Thanks... "Explosion Hazards from Lithium-Ion Battery Vent Gas" <https://www.osti.gov/servlets/purl/1574807> These gases build within the cell and can ultimately lead to rupture of the cell and release of the gases. The gas mixture generated and released is flammable, consisting of various mixtures of hydrogen, carbon-monoxide, carbon-dioxide and various hydrocarbons including methane and propane. Ignition of these gases result in fire and explosion scenarios that pose a significant risk to surrounding life and property. The article goes on to detail which gasses are produced, under what conditions, and in what proportions, which changes depending on SOC (state of charge). -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558 |
| Phil Allison <pallison49@gmail.com>: Jan 09 06:37PM -0800 danny burstein wrote: ================= > .... > Fire officials warn that when the batteries are damaged or overcharged, they > release hydrogen gas and can explode. ** Think that is not the most likely scenario. If ( whatever) gas leaks out under pressure, the cell is the unlikely to explode. That's why many rechargeable cells have vents built in - NiCd, NiMh and alkalines too. SLAs often have no vents and will explode( spraying acid) if over charged at a high enough rates. Strangely, NiCds will too, if charged under freezing conditions. The most likely *fire hazard* is damage - when there is a short in the wiring or from one cell body to another. The huge current that flows in the next few minutes will cause massive heating and set any flammable plastic involved alight. Then nearby carpets, and furnishings clothing etc. Lithium Ion ( LiPo ) cells are worse hazards that older types cos of the much greater energy storage per cell. The advice to have your eBike sited outdoors when charging is very wise. ..... Phil |
| danny burstein <dannyb@panix.com>: Jan 10 05:27AM In <q23ntg5lrilplci9dfa0tk0qabhpjjbp21@4ax.com> Jeff Liebermann <jeffl@cruzio.com> writes: [lots snipped] >The article goes on to detail which gasses are produced, under what >conditions, and in what proportions, which changes depending on SOC >(state of charge). Thanks. That article (which, despite coming through Elseveir, is a freebie) is *exactly* the background info I was looking for. So they seem to agree with me. In a residential setting with a couple of e-bike batteries, the fire risk is almost entirely from "thermal runaway" and not gas production/escape. Thanks again. -- _____________________________________________________ Knowledge may be power, but communications is the key dannyb@panix.com [to foil spammers, my address has been double rot-13 encoded] |
| Jeff Liebermann <jeffl@cruzio.com>: Jan 09 11:25PM -0800 On Mon, 10 Jan 2022 05:27:26 -0000 (UTC), danny burstein >>(state of charge). >Thanks. That article (which, despite coming through Elseveir, >is a freebie) is *exactly* the background info I was looking for. OSTI (US governmint office of scientific and techy info) apparently contracted with Elseveir to handle their distribution. I forgot to mumble something about the article search: <https://www.osti.gov> They have 23,135 articles listed under "lithium ion battery safety" keyword search: <https://www.osti.gov/search/semantic:lithium%20ion%20battery%20safety> or 147 under the exact phrase: <https://www.osti.gov/search/semantic:%22lithium%20ion%20battery%20safety%22> The first article found is rather interesting: "Materials for lithium-ion battery safety" <https://www.osti.gov/servlets/purl/1475493> This Review aims to summarize the fundamentals of the origins of LIB safety issues and highlight recent key progress in materials design to improve LIB safety. >So they seem to agree with me. In a residential setting with >a couple of e-bike batteries, the fire risk is almost entirely >from "thermal runaway" and not gas production/escape. In my never humble opinion, the more likely eBike scenario is mechanical damage, either from modifying or soldering the battery pack cells, or having the eBike crash into something. Also included are high resistance contacts causing the safety fuse to fail to trip, BMS (battery management system) misprogramming or miswiring, and various attempts to convince the eBike to deliver more power. Locally, I've only seen 3 eBike fires and have been told about 3 others. All were the result of owner tampering, shoddy repair, cell replacement, or combinations of these. A commercial eBike system is probably fairly safe. A do-it-thyself mess of mods and repairs is probably not so safe. Hint: Store your batteries in a fireproof box, preferably with a working smoke alarm nearby: "Underrated E-Bike Battery Fire Hazards Call for Attention on Safe Storage" <https://www.bike-eu.com/home/nieuws/2018/02/underrated-e-bike-battery-fire-hazards-call-for-attention-on-safe-storage-10132804> Methinks things will be better when the cobalt cathode are replace with LiFePO4 cells. -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558 |
| dplatt@coop.radagast.org (Dave Platt): Jan 09 02:49PM -0800 In article <qPqdneWhC6VHE0f8nZ2dnUU7-XudnZ2d@giganews.com>, >You could dig out an old Digi-Key catalogue and use the order page from >that - I assume - to get your free shipping. Photocopies would probably >be fine. Sure. Or, web-search the phase "digi-key order form" and you'll quickly find the PDF version. |
| Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Jan 09 08:47PM -0500 John Robertson wrote: >> Cheers >> Phil Hobbs > I take it you grew up in Vancouver, BC. Yup. Born at VGH, UBC undergrad, then went to grad school in California and moved to NY to work at IBM Research. > nice monstrous TEK surplus oscilloscopes that I couldn't afford back > in the late 70s and early 80s...And of course Main Electronics around > Main and 29th - but they are all gone now. Never went to either of those ones. I lived just up the hill from Hedley's place. > kinda dried up. And the High schools in Vancouver no longer have > electronics as a course - although they do have robotics and other > tech classes. Interesting, thanks! Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com |
| Jeff Liebermann <jeffl@cruzio.com>: Jan 09 05:49PM -0800 On Sun, 9 Jan 2022 14:49:23 -0800, dplatt@coop.radagast.org (Dave Platt) wrote: >>be fine. >Sure. Or, web-search the phase "digi-key order form" and you'll quickly >find the PDF version. That was too easy: <https://www.digikey.com/-/media/PDF/Help/Order%20Form/order-form_en-US.pdf?la=en> On the form is printed: SHIPPING INFORMATION We pay all shipping (our choice of method) and insurance to addresses in the USA and Canada when check or money order accompanies order. See "Shipping Charges" in the Digi-Key Terms and Conditions for details on heavy/oversize items. Thanks. -- Jeff Liebermann jeffl@cruzio.com PO Box 272 http://www.LearnByDestroying.com Ben Lomond CA 95005-0272 Skype: JeffLiebermann AE6KS 831-336-2558 |
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