How to fix SRAM Battery

It is well know that SRAM Red eTap Battery has an easily broken lip. I figured out the way to fix the issue.

The SRAM engineers didn't do a good job designing the battery and holder. The battery is subjected to serious hammering loads which results in the tab breaking off the battery body. Ideally this tab must be much thicker and battery should have more support.

You can always buy a battery replacement which will last you a few months. Then it will break the same way. You can get away with cheaper Chinese clones. They do work and twice less expensive yet not hold the charge as well as OEM.

Step by Step Guide

  1. Find a good piece of metal that is 1mm thick, hard to bend but not brittle. I used copper stripe.
  2. Carefully file or mill channel in the bottom of the battery that had the broken tab. The channel width supposed to be the same width as the tab - 7mm.
  3. Cut a 25 mm long piece of metal stripe with 7mm width.
  4. Bend the 2-3 mm long tab on the stripe. You will get L-shaped structure.
  5. Fit the stripe into channel. Put the assembly into battery carriage and do final alignments. Add markings to align the stripe during glueing step.
  6. Use epoxy to glue the stripe in the channel.
  7. Upon the expoxy curing do final test, bend the new tab a little bit. Use file to remove extra epoxy or file the tab roughness.

Result

I posted results on my instagram, here is an embedding of this post:

The lifetime of fix is limited by the battery internals. I have modified 2 SRAM batteries and 1 Chinese clone. First SRAM battery body eventually spliced apart in the middle. Second I broke myself by misplacing a bike while storing. Chinese clone failed electronically. This all happened over 3 years of the bike ownership and 20000+km on odometer. I am looking into 4th modification.

I hope this page will help you to save time, money and frustration.

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