Replacing The Coin Battery In the Specialized SL TCU Gen 1

[Stefan Mikes]

Whenever you get this error message on your SL TCU Gen 1:

(The blue and red bars far apart, the red LED flashing) then you need to replace the CR1620 coin battery. Which is not the easiest task.

Prepare:

• A fresh CR1620 battery
• The T10 Torx key
• Tweezers
• A thin, long and sharp object such as small scissors.

Replacing the battery in the TCU is as troublesome as it is with some wrist-watches: limited space makes the removal of the original coin battery difficult.

Remove the screw from the TCU and pull the unit outside. If you want to remove the unit completely, you need to pull it forward (in the direction of the handlebars).

The internals of the TCU are protected against the moisture and dust with a rubber flap marked with the USB icon, open the flap. You will see the service micro-USB socket and the battery in a very narrow slot.

There's a tiny shiny piece of elastic metal to keep the battery in place. Using tweezers and your non-dominant hand, keep the piece of metal depressed. Use your dominant hand and the long sharp thin object to drag the old battery out (it is the infuriating part of the task there!). Replace the new battery as shown. Close the flap. Secure the unit in the frame with the screw.

The procedure can be pretty irritating. Thank you @kahn for heads-up of several months ago! Thank you @Allan47.7339 for explaining the error codes to me!

P.S. The original battery was good for 359 rides in 21 months. I found the rubber flap opened and expect there could be some water ingress into the unit to produce the error code. I dried the inside of the unit with compressed air before inserting the fresh battery.

 

[Marcela]

Wow. That's kind of like playing Twister

 

[kahn]

Wow. That's kind of like playing Twister

It is worst than that. It is nearly impossible although it appears Stefan did it. And great close up photos by the way.

 

[Stefan Mikes]

It is worst than that. It is nearly impossible although it appears Stefan did it. And great close up photos by the way.

As long as the tiny metal lock is out of the battery way, and you can insert a thin, hard and rough object between the battery top and the wall, and you patiently rub the battery, it will eventually give up

 

[eddief]

I need to do this as my bike is one of the older ones. Wondering if you think it's possible to get needle nose pliers gripped around the sides of the battery and be able to sort of yank it out...even without depressing the spring piece on the top?

 

[kahn]

I need to do this as my bike is one of the older ones. Wondering if you think it's possible to get needle nose pliers gripped around the sides of the battery and be able to sort of yank it out...even without depressing the spring piece on the top?

There is almost no room inside of that battery compartment. I tried using very fine tweezers and still could not get a grip on the darn thing. Let's see what Stefan has to say.

 

[Stefan Mikes]

I need to do this as my bike is one of the older ones. Wondering if you think it's possible to get needle nose pliers gripped around the sides of the battery and be able to sort of yank it out...even without depressing the spring piece on the top?

As @kahn said. You should keep the tiny shiny springy thing depressed all the time (to make way for the battery) then insert, say, a needle into the narrow space between the wall and the battery top (or, the side of the battery) and try "rubbing" the battery out. The latter will eventually yield.

 

[eddief]

are you depressing the spring thing or lifting it up off the top of the battery?

 

[Stefan Mikes]

Lifting it up.

 

[eddief]

I tried today and could not get it out. Got the metal tab out of the way with a tiny tweezers that stayed in place by itself but could not get anything in there to get a fix on the battery. What would be that thin and with a surface rough enough to pull out on the battery?

 

[gpburdell]

Maybe mini needle nose pliers?

 

[eddief]

just found this: https://support.specialized.com/turbo/en/turbo-bike-faqs/q-how-do-i-replace-the-battery-in-the-tcu

 

[Marcela]

just found this: https://support.specialized.com/turbo/en/turbo-bike-faqs/q-how-do-i-replace-the-battery-in-the-tcu

That's one of those read the instructions afterwards, afterwards you've fried the unit.

 

[eddief]

Think I will take the TCU out of the bike, bring it to the bike shop, and ask them to do the replacement...and show me how and with what tool they do it.

 

[eddief]

Took the TCU and a new packaged battery to the local Specialized-owned bike shop today. I assumed they'd have the right tools and be able to install new battery in a couple of minutes. Mechanic says has done 6 of them and only once was he able to get it out as has been described here. Instead he pried open the case and was able to carefully scooch out the old, install the new and snap the case back together. Prying open the case was tricky...even for him.

 

[BioWheel]

Took the TCU and a new packaged battery to the local Specialized-owned bike shop today. I assumed they'd have the right tools and be able to install new battery in a couple of minutes. Mechanic says has done 6 of them and only once was he able to get it out as has been described here. Instead he pried open the case and was able to carefully scooch out the old, install the new and snap the case back together. Prying open the case was tricky...even for him.

I've ordered my plastic tweezers. Your post makes me a bit nervous but going for it.

 

[eddief]

maybe these will help even though not plastic: The edge of those batteries do have a tiny lip between the top and bottom and maybe you can hook the lip with one of these?

https://www.harborfreight.com/6-pie...x4xmHRK6JmK5GXtNZZGVD6opL782LT9BoC4PIQAvD_BwE

 

[kahn]

maybe these will help even though not plastic: The edge of those batteries do have a tiny lip between the top and bottom and maybe you can hook the lip with one of these?

https://www.harborfreight.com/6-pie...x4xmHRK6JmK5GXtNZZGVD6opL782LT9BoC4PIQAvD_BwE

And if not, you can take up dentistry!

just found this: https://support.specialized.com/turbo/en/turbo-bike-faqs/q-how-do-i-replace-the-battery-in-the-tcu

Useless instruction! Been there, done that. Bike shop did it for me or maybe not.

 

[Stefan Mikes]

Nobody owns a needle here?

 

[kahn]

I've ordered my plastic tweezers. Your post makes me a bit nervous but going for it.

Where'd you find plastic tweezers? I see reviews on some Amazon items are pretty poor!