Charger Teardown: is that safe? - Page 1
Forum section: electronics / general

author: zerobrain
author_rank: Contributor
timestamp: May 16, 2015, 10:47:54 am
content: Hi,i am doing a review of a foxnovo F2 charger, which looks quite well, but after doing a teardown I´m having second thoughts.(See attaachments). The spring contacts for charging are equipped with an additional wire, reducing the resistance. Which is great and works well, but if the wire would become loose (this is the kind of typical travel charger... what could EVER come loose there), they could fool around and make contact to the mains area of the PCB.I would consider this "not safe".best regardsDominik

author: rsjsouza
author_rank: Super Contributor
timestamp: May 16, 2015, 11:30:08 am
content: My Nitecore Intellicharger i2 is very similar to your charger, and it does not have the wires. However, I have it for several years and its spring contacts really work fine - no complains.

author: wraper
author_rank: Unknown
timestamp: May 16, 2015, 11:37:03 am
content: Creepage distance between mains and secondary is low for double insulated (not grounded) device. It' shouldn't kill you but is not good either.

author: zerobrain
author_rank: Contributor
timestamp: May 16, 2015, 11:40:23 am
content: @rsjsouza: thanks for the image. It really looks very similiar (see attachment).@wrapper: I´m not talking about the creepage distance, but about what happens if the wires would get loose...

author: amyk
author_rank: Super Contributor
timestamp: May 16, 2015, 03:11:37 pm
content: It's a battery charger. You're not supposed to be holding it in your hand all the time nor be touching the terminals while it's on. If it worries you any bit, unplug it before adding/removing batteries.

author: wraper
author_rank: Unknown
timestamp: May 16, 2015, 04:17:38 pm
content: Quote from: zerobrain on May 16, 2015, 11:40:23 amThen your concern is in wrong order of priority. And it seems that wire should break off at the both ends to be able to reach the mains part.

author: zerobrain
author_rank: Contributor
timestamp: May 16, 2015, 05:28:48 pm
content: Thanks for all the very good feedback!But you may have gotten me wrong. I am not frightened that this thing may kill me - this is extremely unlikely, but i was wondering if this is compliant to insulation class II (as it states).Addition: i tried it: it is sufficient for the wire to break at one point to reach main potential easily (unlikely - i know, but that´s not the point of electrical safety)...

author: Rick Law
author_rank: Super Contributor
timestamp: May 16, 2015, 11:03:08 pm
content: Since you said you are basically happy with the performance and your only concern is mechanical breakage:- Use some tapes to tape it down?- Hot-glue the wire to make sure if it breaks, it has little room to move?

author: zerobrain
author_rank: Contributor
timestamp: May 17, 2015, 05:09:23 am
content: Thanks for the reply.I must point out that i am not really anxious about my safety in this special case (as i pointed out), i just wondered if that is according to norms "correct". If anybody is interested (an can read german or is brave enough to use the integrated google translate function), my review of the unit looks as folloes:http://www.zerobrain.info/fotokatastrophen/2015/5/7/test-akkulader-nimh-li-ion-foxnovo-2-port