# 4.2.3 Encoder backup battery replacement

A dedicated battery attached to the serial encoder retains the position data of each axis regardless of whether power is supplied to the controller. The battery should be replaced at two-year intervals.

The method for replacing the encoder backup battery of each axis is as follows:

1\. While the controller power is on, press the emergency stop switch.

{% hint style="warning" %}
**\[Caution]**: Before correcting the encoder offset, set the operation preparation at ON, and ensure that the power is connected by pressing the enabling switch of the teach pendant for two to three seconds.
{% endhint %}

2\. Identify the position of the battery of each axis, and remove the frame cover of the battery by removing bolts with a torque wrench.

![](/files/-MjXeomOfrLuT7kie6M5)

<table data-header-hidden><thead><tr><th width="150" align="center">No</th><th width="150" align="center">Axis</th><th align="center">Cover</th><th align="center">Bolts</th></tr></thead><tbody><tr><td align="center"><strong>No</strong></td><td align="center"><strong>Axis</strong></td><td align="center"><strong>Cover</strong></td><td align="center"><strong>Bolts</strong></td></tr><tr><td align="center"> <img src="/files/-MjRus7XMyFc_7foIrTV" alt="" data-size="line"> </td><td align="center">S</td><td align="center">LOWER FRAME COVER</td><td align="center">Hex socket bolts (M3X6, five pieces)</td></tr><tr><td align="center"> <img src="/files/-MjRus7_l8QYQqtaolB0" alt="" data-size="line"> </td><td align="center">H</td><td align="center">UPPER FRAME LOWER COVER</td><td align="center">Hex socket bolts (M3X6, five pieces)</td></tr><tr><td align="center"> <img src="/files/-MjRus7aY2qzsW2-lZV5" alt="" data-size="line"> </td><td align="center">V</td><td align="center">UPPER FRAME UPPER COVER</td><td align="center">Hex socket bolts (M3X6, six pieces)</td></tr><tr><td align="center"> <img src="/files/-MjRus7bsBN0VsCTvS1v" alt="" data-size="line"> </td><td align="center">R2</td><td align="center">ARM FRAME COVER</td><td align="center">Hex socket bolts (M3X6, six pieces)</td></tr><tr><td align="center"> <img src="/files/-MjRus7cwv-RHIj9H_A6" alt="" data-size="line"> </td><td align="center">B</td><td align="center">ARM PIPE COVER</td><td align="center">Hex socket bolts (M3X6, six pieces)</td></tr><tr><td align="center"> <img src="/files/-MjRus7dwuAFL4-yBNhi" alt="" data-size="line"> </td><td align="center">R1</td><td align="center">HAND GRIP</td><td align="center">M3 small-diameter bolts (four pieces)</td></tr></tbody></table>

3\. Identify the orientation of the battery terminals, and replace the old battery with a new one.

{% hint style="warning" %}
**\[Caution]**

* Only use the battery of the designated specifications (ER6C (AA 3.6 V) / manufacturer: Maxcell).
* Identify the orientation of the battery terminals, and insert the battery correctly.
* Do not recycle or arbitrarily dispose of the battery. The battery should be disposed of as an industrial waste according to the applicable national or local laws and regulations.
  {% endhint %}

4\. Put the frame cover on the axis, and fixate it by fastening bolts with a torque wrench.


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