Thread: Assembly of Di2
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Old January 29th 20, 01:36 AM posted to rec.bicycles.tech
JBeattie
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Default Assembly of Di2

On Tuesday, January 28, 2020 at 4:59:05 PM UTC-8, Tom Kunich wrote:
On Tuesday, January 28, 2020 at 1:40:42 AM UTC-8, wrote:
On Monday, January 27, 2020 at 1:59:08 AM UTC+1, Tom Kunich wrote:
On Thursday, January 9, 2020 at 9:43:42 AM UTC-8, Tom Kunich wrote:
It occurs to me that I should install the hydraulic brakes before I attach the electronic wiring. What do you think?

Well, I have put the Di2 together. And nothing works. The possible sources of error a

1. The wiring is incorrect. I assumed that the left and right shifters would go into the left and right connector of to two holes of the 5 hole Stem unit. The manual is not clear about this so it was ad lib.

2. The new battery could be flat. I have no way of measuring the voltage under load but the unloaded voltage is 8 volts and Shimano says that 7 something volts is a full charge. I bought a new charger but I don't think it was new since it didn't come in a box or sealed plastic bag and when I questioned the seller he promptly returned my money and said that I could keep the charger. Looking at the output voltage it measures zero but I don't know what the charging circuitry is. It could turn off with no detectable load. Hmmm. So I bought another "new" charger and hopefully this one will work.

So the question is this: Could the battery be so flat that the unit wouldn't turn on?


Possible, but I never came across a new battery out of the box that was so dead that it wasn't able to power a led.

Lou


I find it curious as well. Nut Lithium Ion batteries are odd works. Perhaps plugging it into the battery charger whish isn't working drained the battery. And the high voltage measurement I got was because there was no load on it.

In any case the new charger should arrive Friday and I'll test the charge again.

Otherwise I'll have to replace the stem unit. I have no idea why his stem junction box is a five port unless he was running TT bars with end shifters.


Is this a trick question? If your battery is showing 8v, it's not dead. No? Why would load matter -- except for measuring capacity. I understand the battery may have a protection circuit, but wouldn't that decrease the measured voltage?

I don't have an EE degree, but I measure batteries with a multimeter all the time to see if they are alive or dead, and if one showed 8v it would not be dead. I think you messed something up. Just check the quality of your connections. Do you have the little tool? https://www.youtube.com/watch?v=OkdY9q-u5Dk If you're not fishing wires, it's really pretty fast and easy. Its the fishing that takes time.

-- Jay Beattie.






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