Help needed! - Page 1
Forum section: electronics / beginners

author: some1
author_rank: Newbie
timestamp: October 26, 2013, 02:47:15 pm
content: Hello EEV forum just registeredStraight into the problem: i have a li-ion battery (made for an ipod-touch 4) with out the outer shell..When i tried to solder it to the ipod's motherboard one the connections on the cable went useless...After , i tried to solder another cable from a similar (same) battery on the cell. The cable is connected to a small PCB line witch has from (right to left) 3 real tinny resistors on each road , a puffy resistor , (connection to cell) , a tiny one again along with a "chip" with 3 pins on each side , the second connection , and finally a chip locking like thing with 2 pins on each side.. Now the actuall problem is that last chip witch was burned during soldering and when i cuted it off the pcb everything looked fine on the volt meter. And my question is:Am i able to use the battery on the phone without it , will it have any effects?thanks in advance

author: rexxar
author_rank: Frequent Contributor
timestamp: October 26, 2013, 02:52:16 pm
content: That chip is part of the protection circuitry. That is, the circuity that prevents your Li-ion from catching fire and killing you. You should get a new battery, it's not like they're very expensive.

author: some1
author_rank: Newbie
timestamp: October 26, 2013, 03:10:02 pm
content: isn't the phone's motherboard witch knows when to stop the charge of the battery..?

author: Nerull
author_rank: Frequent Contributor
timestamp: October 26, 2013, 05:10:30 pm
content: If the phone had all the required protection circuitry, they wouldn't have put it on the battery now would they? That circitry is there to keep the battery from being overdischarged - killing it - or overcharged - setting it on fire. You want it.

author: c4757p
author_rank: Super Contributor
timestamp: October 26, 2013, 05:35:55 pm
content: Li-ion battery{dangerous things}Your li-ion battery{broken things}({dangerous things}{broken things}){trash}Your li-ion battery{trash}Q-E-motherf-ing-D. Now throw that shit away before it burns your house down.

author: SeanB
author_rank: Super Contributor
timestamp: October 26, 2013, 05:43:18 pm
content: New battery time, and now be more careful when soldering it in now. The old one can be made to fail very easily now just by overcharging it, which will make it go from flat to a pillow and then burst. Recommend if you want to try do it outdoors well away from flammable things like wooden houses.

author: Neilm
author_rank: Super Contributor
timestamp: October 26, 2013, 09:04:27 pm
content: There are a couple of ways charging can be done in Li-Ion batteries.1) There is a charger in the unit that does everything and the circuit in the battery is purely that required to protect the battery from overcharge etc.2) There is a charger in the unit that does what it is told, and the circuits in the battery monitor the cells and communicate with the charger in the unit to tell it what to do.The second one is liable to have handshaking and possibly some form of authentication. From your description is most likely the first option, but I can'tIf the protection circuit is damaged then get rid of the battery. Li-Ions can explode if improperly charged and many manufacturers rely on that circuit in the event of a charger fault. Not having it WILL lead to a fire.

author: ivan747
author_rank: Super Contributor
timestamp: October 27, 2013, 05:01:12 pm
content: And that's a very nasty fire: