RE: Rechargeable and Non-Rechargeable batteries
Chris - You might be able to find a barrel connector with a switch mechanism built in that will remove the batteries from the circuit automatically, as the plug is inserted. This won't allow for charging NimH or other secondary cells, but it's safer for primary cells. Long ago, I owned a few pieces of consumer audio equipment that allowed operation by batteries and by either a direct plug-in or line voltage. In these pieces, there were power connectors that had switches built into them, so that the batteries were removed from their circuits to prevent charging currents from flowing. In those days, consumer NiCd batteries were all that was available and more rare, thus more costly, than today; most batteries were nonrechargeable laclanche cells that got messy when placed under 'significant' reverse charging conditions. Regards, Peter L. Tarver, PE ptar...@ieee.org From: Chris Maxwell Sent: Wednesday, April 14, 2004 10:44 AM Where I'm really lacking in knowledge (among many areas) is when it comes to handling standard sized, yet rechargeable batteries. For instance consider the following example: 1. A case designed with a wall wart power input and a spot for AA sized batteries. 2. The product would be designed to recharge AA sized NiMh batteries, if installed. 3. Alternatively, the user could install AA sized alkaline batteries; but they would have to set a switch in the battery compartment to disable the charge circuitry. This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Rechargeable and Non-Rechargeable batteries
Totally anecdotal reply. I have a Fluke 97 Scopemeter I purchased perhaps ten years ago. It has a wall-wart supply that recharges internal C-cell batteries, but it can also run on alkaline or other non-rechargeable C-cells. To the best of my knowledge, it is up to me to remember what batteries I have in there, there is no switch at all. If I want to run off mains power, I have to either have rechargeable batteries, or remove the non-rechargeables. I don't know much about this, but I seem to recall that it took a long time to recharge the Ni-Cds. Maybe they got around the hazard by having a low enough charging current it wasn't a hazard? From: "Chris Maxwell" Reply-To: "Chris Maxwell" List-Post: emc-pstc@listserv.ieee.org Date: Wed, 14 Apr 2004 13:44:29 -0400 To: "EMC-PSTC Internet Forum" Subject: Rechargeable and Non-Rechargeable batteries Hello good people of the group. We generally test our equipment to EN 61010-1. We usually have rechargeable batteries in our product; and they¹ve never really been a safety problem, other than adding diodes and ³approved² charging methods. Usually the batteries that we use are so oddly shaped, that there is a very small risk of a customer putting in the wrong type of battery. Where I¹m really lacking in knowledge (among many areas) is when it comes to handling standard sized, yet rechargeable batteries. For instance consider the following example: 1. A case designed with a wall wart power input and a spot for AA sized batteries. 2. The product would be designed to recharge AA sized NiMh batteries, if installed. 3. Alternatively, the user could install AA sized alkaline batteries; but they would have to set a switch in the battery compartment to disable the charge circuitry. Assuming all warning labels and documentation were in place? Is this a generally accepted practice; or is it too unsafe to require the customer to throw a switch. That¹s my specific question. Now a more general issue. Up until now, I¹ve learned about battery safety indirectly. As in, I submit a product to the lab, make any required changes (diodesŠ) and ship product. I haven¹t yet found a reference that outlines the safety requirements for batteries in EN 61010-1 or EN 60950 equipment. Is there something that I¹m missing in the standard? Or, is this one of those issues that is handled by experience, agreements and memoranda among the various safety certification agencies? Alternatively, is there a stand-alone IEC specification regarding battery safety? As always, the collective time and energy of the group is appreciated. adTHANKSvance Chris Maxwell Design Engineer Nettest
Re: Rechargeable and Non-Rechargeable batteries
I read in !emc-pstc that Chris Maxwell wrote (in <39f7060a00b5e946b516261c077441c002a...@utexch1w.gnnettest.com>) about 'Rechargeable and Non-Rechargeable batteries' on Wed, 14 Apr 2004: >We generally test our equipment to EN 61010-1. We usually have >rechargeable batteries in our product; and they've never really been a >safety problem, other than adding diodes and "approved" charging >methods. Usually the batteries that we use are so oddly shaped, that >there is a very small risk of a customer putting in the wrong type of >battery. > > > >Where I'm really lacking in knowledge (among many areas) is when it >comes to handling standard sized, yet rechargeable batteries. > > > >For instance consider the following example: > > > >1. A case designed with a wall wart power input and a spot for AA sized >batteries. > >2. The product would be designed to recharge AA sized NiMh batteries, >if installed. > >3. Alternatively, the user could install AA sized alkaline batteries; >but they would have to set a switch in the battery compartment to >disable the charge circuitry. > > > >Assuming all warning labels and documentation were in place? Is this a >generally accepted practice; or is it too unsafe to require the customer >to throw a switch. It specifically isn't allowed in IEC 60065, which is aimed at consumer products, used by the general public. But for IEC 61010 equipment, it MIGHT be considered acceptable to have a switch. However, for Europe (if relevant) labelling is not an acceptable solution in many cases, because it should be multilingual and that is impracticable. > > > > > > > >That's my specific question. Now a more general issue. Up until now, >I've learned about battery safety indirectly. As in, I submit a product >to the lab, make any required changes (diodes...) and ship product. I >haven't yet found a reference that outlines the safety requirements for >batteries in EN 61010-1 or EN 60950 equipment. Is there something that >I'm missing in the standard? Not that I know of. But the Hazard-Based Standard, in development to replace IEC 60065 and IEC 60950, will have published justifications for all its requirements. However, it's a big task and the results won't be published for a while yet. I'll look to see if there is anything about batteries already written, but it won't be in the public domain. >Or, is this one of those issues that is >handled by experience, agreements and memoranda among the various safety >certification agencies? Well, that's one important activity, but it's not the main way in which IEC safety standards are prepared. Standards committees are composed of **industry experts** and representatives of test houses and certification bodies, with a few academics. The presence and active, indeed often vociferous, participation by industry experts should dispel any impression that the safety requirements are imposed from 'above' or 'elsewhere'. But it's still a widely-held impression. > > > >Alternatively, is there a stand-alone IEC specification regarding >battery safety? You could try searching at http://www.iec.ch A vast amount of information there is publicly available; it's not all behind passwords. -- Regards, John Woodgate, OOO - Own Opinions Only. The good news is that nothing is compulsory. The bad news is that everything is prohibited. http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Rechargeable and Non-Rechargeable batteries
Hi Chris: > 1. A case designed with a wall wart power input and a spot for AA sized > batteries. > > 2. The product would be designed to recharge AA sized NiMh batteries, > if installed. > > 3. Alternatively, the user could install AA sized alkaline batteries; > but they would have to set a switch in the battery compartment to > disable the charge circuitry. > > Assuming all warning labels and documentation were in place? Is this a > generally accepted practice; or is it too unsafe to require the customer > to throw a switch. For the purposes of safety, the switch is useless because the charger would be tested with all AA- sized batteries with the switch in both positions. Today, low-cost battery-chargers include circuits that can detect the type of battery and charge or not charge accordingly. I believe commercial battery-charger ICs are available which will both detect the type of battery and charge (or not charge) accordingly. Best regards, Rich This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
