Replacing an SRM battery... at home :o)

Discuss light weight issues concerning road bikes & parts.
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pritchet74
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Location: NorCal

by pritchet74

Crap. So they are making them now to prevent us from changing our own batteries?
Have you ever wondered if there was more to life, other than being really, really, ridiculously good looking?

by Weenie


Chiva
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Joined: Sat Apr 03, 2010 11:05 pm

by Chiva

pritchet74 wrote:Does anyone have pics of a D/A 7950 SRM with the cap off? I can't sort out how to get mine off.


I used a #15 blade surgical scalpel. If you don't have one you could use an exacto knife.

hyunsoo
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Joined: Thu May 19, 2016 2:35 pm

by hyunsoo

Call SRM and check with them first. If they had a known batch of bad batteries they will replace it for free.

415brian
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Joined: Fri Sep 30, 2011 4:48 pm

by 415brian

I'm trying to remove the lid on my SRM Specialized PC6 to replace the battery, but I'm not having any luck. Can anyone offer some guidance?

In my photo below, will the lid separate along the seam with the red arrow?

Image

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ms6073
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Location: Houston, Texas

by ms6073

Prior to mid 2014, the cover was on the torque ring side (faces in towards the frame), but I think for the current generation of SRM Powermeter, the cover is on the side with the logo (faces out away from frame)
Michael - The Anaerobic Threshold is neither...

415brian
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Joined: Fri Sep 30, 2011 4:48 pm

by 415brian

Interesting. Here's the other side; the side facing outboard. I removed the SRM decal. Do you think I should try to pop/pry this side along the seam where I added the yellow arrow in the photo below?

Image

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ms6073
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by ms6073

I would think so but seems curious to ask, is that an o-ring just below the poitn where your arrow is pointing. I suggest using a magnifying glass to examine the edge to make sure there is a seam separating the two halves. I will say this as well, once you get the cover open, be very careful with the battery wiring as my 2015 SRM DA 9000 has a different battery cell than my 2014 Hollowgram SRM. Iwill also mention that the harness from the battery is comprised of two very short, 32-gauge wire leads terminating in a fragile micro connector that is pluged into the PCB.
Michael - The Anaerobic Threshold is neither...

415brian
Posts: 52
Joined: Fri Sep 30, 2011 4:48 pm

by 415brian

Success. It was the seam marked by the yellow arrow in the photo above; the outboard side; away from the frame.

I had to use a blade along the outer and inner edges of the cover to overcome some silicone sealant. The o-rings look okay, but I'd prefer to replace them. Anyone know a good source for large o-rings? A quick google search didn't find obvious candidates.

Lastly, I discovered a good bit of moisture under the cover. I'm hopeful that it's intentional (e.g. silicon grease) and not a symptom of a larger problem. I'd welcome any opinions.

Image

Image

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ms6073
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by ms6073

Thats great news. From that image, I think the wet stuff is di-electric grease or silicon sealant, but a quick test would be to run a blow dryer across the PCB to see if it persists or evaporates. On the plus side, you have the older style with slightly larger gauge wire leads soldered to the PCB which is much easier to deal with than my DA 9000 SRM.
Michael - The Anaerobic Threshold is neither...

Hoffy
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Joined: Thu Mar 26, 2015 11:27 am
Location: South Australia

by Hoffy

I have a question, i recently replaced the battery in my PCV and all was well and good, transmitting power/cadence/speed from the sensors and cranks. Have been charging it regulary, and all of a sudden the screen goes blank. Unit will not wake up even when repeated plugging into charger and pressing mode. Opened it up and battery was dead flat, tried charging the directly through one of my chargers, unit comes alive but as soon as the charger is taken of it quickly turns off within 20 seconds. Multimeter shows battery is rapidly discharging. Also tested the charger and it is all good and working. Could this just be a dodgy battery? Thanks

sungod
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by sungod

Hoffy wrote:I have a question, i recently replaced the battery in my PCV and all was well and good, transmitting power/cadence/speed from the sensors and cranks. Have been charging it regulary, and all of a sudden the screen goes blank. Unit will not wake up even when repeated plugging into charger and pressing mode. Opened it up and battery was dead flat, tried charging the directly through one of my chargers, unit comes alive but as soon as the charger is taken of it quickly turns off within 20 seconds. Multimeter shows battery is rapidly discharging. Also tested the charger and it is all good and working. Could this just be a dodgy battery? Thanks


you can get an idea if it's the battery by putting the meter in-line with it and seeing what current is being drawn during discharge

if the current is really low, suspect the battery

if it's high, maybe there's a tiny sliver of loose solder or wire that's causing a short somewhere

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Vallinotti
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by Vallinotti

Could someone advice which battery to buy to replace the battery of a SRM DA 9000?

goodboyr
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Location: Canada

by goodboyr

ms6073 wrote:Thats great news. From that image, I think the wet stuff is di-electric grease or silicon sealant, but a quick test would be to run a blow dryer across the PCB to see if it persists or evaporates. On the plus side, you have the older style with slightly larger gauge wire leads soldered to the PCB which is much easier to deal with than my DA 9000 SRM.


I just finished replacing the batteries on an SRM DA 7800. Second time I've done this. In Canada these batteries are 25$ each. As stated and shown, the connecting wires are thin gauge, soldered directly to the board. You need to be very carefull when stripping the insulation or you will pull the wires from the board. Which is what happened to me (probably because this is the second set I've changed in this srm). So I had to resolder them to the board. Amazing that after all these years, SRM doesn't use zero insertion force plugs to connect to the battery. And why do you think SRM needs such high amperage batteries in the first place? With two in this model, that's 1.5 amps! My guess is that they are lazy with the wireless design, so compensated by using lots of battery power. Downside of course is that when replacing these, be real careful with any bare wires. A short can release a lot of energy. I use small pieces of self vulcanizing rubber tape to insulate.

Makes me appreciate my quarqs even more.....

Rant over......

Image

goodboyr
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Location: Canada

by goodboyr

pritchet74 wrote:This is mine. No screws and no spot to easily put the screwdriver in there. Any ideas?

Image

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That's the 7800. The lid is the front side . A thin bladed screwdriver will pop that off.

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by Weenie


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ms6073
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by ms6073

Vallinotti wrote:Could someone advice which battery to buy to replace the battery of a SRM DA 9000?

Remove the SRM from the bike and unbolt the torx head screws that secure the crank arm to the spider and you will then be able to remove the front cover with a precission screw driver. I cannot recall what the battery model was but unlike our Hollowgram SRM's, I was not able to source a direct replacement in the US, and you will need batteries with pre-soldered pigtails. As I cautioned above, the DA 9000 SRM uses a micro connector with 32-gauge wires, so unless you are a master with a soldering iron and micro electronic PCBs, I am going to dsuggest you send it to an SRM Sewrvice center. I managed to mangle the micro connector on mine, thus I had to send it to SRM anyway, but on the plus side, SRM updated the firmware so that now my Garmin displays the battery status under sensor details.
Michael - The Anaerobic Threshold is neither...

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