Editing Battery Refurbishment (section)

== Step 5: Map the pack before you cut anything ==

[[File:Battery guide - AST laptop NiMH pack.jpg|thumb|300px|A sealed NiMH laptop pack. Nothing about the outside tells you how the cells are wired inside — which is why the pack gets mapped before anything is disconnected.]]

Draw a diagram. Record:

* '''Cell count, orientation and physical arrangement''' — which way each cell faces, and which cells are in each parallel group.
* '''The series/parallel wiring''' — trace each nickel strip and mark on your diagram what it joins.
* '''The thermistor''' — a two-wire component pressed against a cell. Note '''which''' cell and '''where''' on that cell. The most common type is a 10 kΩ NTC, reading 10 kΩ at 20 °C, with resistance falling as it warms. You can identify it with an ohmmeter: warming the pack with your hand is enough to see the value change.<ref name="bu-911" />
* '''Balance / sense leads''' — some fuel-gauge chips run a separate wire to each series node. '''These must be reconnected in the correct order''', starting from cell one and working up.<ref name="bu-911" />
* '''Fuses, PTC devices and thermal cut-outs''' in the strip work — these are easy to mistake for plain strip.
* '''The pack connector pinout.''' A typical smart pack has five or more contacts: positive and negative at the outer edges, with thermistor, clock and data on the inner contacts. There is '''no standard for the arrangement of the inner contacts''', so find positive and negative with a voltmeter and work outwards from there.<ref name="bu-911" />