Conflict of Interest Notice - my employer makes multi-chemistry battery chargers that are both stand-alone and integrated into other end-use products - so this is serious stuff for me, and not worthy of a 'casual' reply.
There should always be a 'concern' where batteries and chargers meet - regardless of the power level. 1. Battery safety from charger safety are not seperate issues - a properly designed charger can mitigate many battery failures. 2. UL issued a Certification Requirement Decision for UL1310 that applies to units powered from ITE ports (USB, POE, etc). 3. I am not certain of the meaning of "power energy", but will guess that, below a certain VA and A, it is not considered a hazard. This level is defined in various product safety standards and also in various electric codes. A class 2 power source, even if rated as inherently limited, can still become a hazard with an improperly designed charger and/or battery. 4. Integrated chargers for a radio device, where conformity is based on the RTTE directive, do not have a lower voltage limit. 5. Although a test report, that would indicate conformity to a safety standard harmonized in the LVD, is not required as a basis of the presumption of conformity for a CE mark on an ITE port powered charger, I do investigate our chargers to IEC60950-1 and/or IEC60335-2-29. 6. Battery explosions due to incorrect charger operation, mechanical abuse, and/or a battery manufacturing defect are, in fact, mitigated by tests and construction requirements indicated in UL1310, UL1642, and UL2054. 7. According to the USB 2.0 standard, power is supposed to be current-limited to 0.1A per unit, with max draw of 5 units for any single device, and the series 'B' connectors are further limited. EIA 364 is normative for USB power conductors and connectors - so there is series R from the max size of 20 awg wire in the conductor and inherent contact R. "High Power" usb devices are restricted to 5 units of power - approx 500mA. Some externally powered hubs can provide several amps - so you cannot assume the end-user will always be limited to 500mA. Brian > -----Original Message----- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf > Of Scott Xe > Sent: Thursday, July 09, 2009 7:38 AM > To: EMC-PSTC@LISTSERV.IEEE.ORG > Subject: How to determine if battery-operated product is safe or not > > We have an USB rechargeable battery-operated video clip/MP3 > player. As > battery-operated products do not fall into LVD directive, > what can we apply > the basis to determine the product safe or not? Looking at > historical > safety hazard reports on the market, there was not much any > recall on this > type of products except the explosion of rechargeable battery pack. > However, the possible explosion of rechargeable battery pack > cannot be > picked up by LVD directive or dedicated UL1642/2054 battery cell/pack > standards. Otherwise, Sony did not need to recall millions > of battery packs > and the said standards are not required the review. What is > potential > hazard do we need to look at this type of products? As the > safety hazard is > tied with power energy, is there any reference that there is > no safety > concern if the power energy is below certain level? > > Thanks, > Scott - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
