In the standard:
M.3 covers protection circuits of the batteries with a requirement that the battery temperature does not exceed the specified limits. This includes single fault and abnormal operating conditions. Temperature monitoring might not be required provided that, during single fault testing, the cell temperature does not exceed the limits before the protection circuit kicks in. M.4.2 covers charging of secondary lithium batteries with a requirement to not let the cells be charged at under or over temperature. Cell temperatures need to be monitored. I feel like your proposal could adequately cover M.4.2. To ensure that M.3 is met that will require some testing / further evaluation. All the best James James Pawson Managing Director & EMC Problem Solver Unit 3 Compliance Ltd EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy <http://www.unit3compliance.co.uk/> www.unit3compliance.co.uk | <mailto:ja...@unit3compliance.co.uk> ja...@unit3compliance.co.uk +44(0)1274 911747 | +44(0)7811 139957 2 Wellington Business Park, New Lane, Bradford, BD4 8AL Registered in England and Wales # 10574298 Office hours: Every morning my full attention is on consultancy, testing, and troubleshooting activities for our customers’ projects. I’m contactable between 1300h to 1730h from Monday to Friday. For inquiries, bookings, and testing updates please send us an email on <mailto:he...@unit3compliance.co.uk> he...@unit3compliance.co.uk or call 01274 911747. Our lead times for testing and consultancy are typically 4-5 weeks. From: sgbrody <sgbr...@comcast.net> Sent: Monday, April 24, 2023 7:55 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] 62368 Battery question James, Do you believe that compliance can be achieved if the batteries are NTC monitored only when the batteries are bring charged? The microcontroller that would monitored the NTCs will only be powered when recharging, otherwise it will not be powered. So I am told. Thanks, Sent from my T-Mobile 5G Device -------- Original message -------- From: "James Pawson (U3C)" <ja...@unit3compliance.co.uk <mailto:ja...@unit3compliance.co.uk> > Date: 4/24/23 3:10 AM (GMT-05:00) To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] 62368 Battery question The standard requires that the battery charging circuit must terminate the charge if the temperature of the cell (measured as per the cell manufacturer’s instructions, usually a thermocouple on the negative terminal IIRC) exceeds the manufacturers specifications. If the cells are in a thermally homogeneous part of the equipment then perhaps sensing just one cell could be considered adequate. Temperature testing would give you this answer. What happens if the internal resistance of the cell goes up, or the design is non thermally homogenous? In this case two thermistors might be sensible. If your charging circuit only has one thermistor trip input then perhaps you could use a comparator of some kind to monitor temperature of the second cell. All the best James James Pawson Managing Director & EMC Problem Solver Unit 3 Compliance Ltd EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy <http://www.unit3compliance.co.uk/> www.unit3compliance.co.uk | <mailto:ja...@unit3compliance.co.uk> ja...@unit3compliance.co.uk +44(0)1274 911747 | +44(0)7811 139957 2 Wellington Business Park, New Lane, Bradford, BD4 8AL Registered in England and Wales # 10574298 Office hours: Every morning my full attention is on consultancy, testing, and troubleshooting activities for our customers’ projects. I’m contactable between 1300h to 1730h from Monday to Friday. For inquiries, bookings, and testing updates please send us an email on <mailto:he...@unit3compliance.co.uk> he...@unit3compliance.co.uk or call 01274 911747. Our lead times for testing and consultancy are typically 4-5 weeks. From: sgbrody < <mailto:sgbr...@comcast.net> sgbr...@comcast.net> Sent: Friday, April 14, 2023 10:48 PM To: <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] 62368 Battery question I have a product that uses 2 rechargeable C cell LiPo batteries that are not in a single package. Does or should each have a monitored NTC? I believe yes bit seeking other thoughts. Thanks, Sent from my T-Mobile 5G Device - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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