On Thursday, January 30, 2020 at 12:36:59 AM UTC+1, Tom Kunich wrote:
On Wednesday, January 29, 2020 at 1:07:02 PM UTC-8, jbeattie wrote:
On Wednesday, January 29, 2020 at 12:26:32 PM UTC-8, Tom Kunich wrote:
On Wednesday, January 29, 2020 at 12:00:57 PM UTC-8, jbeattie wrote:
On Wednesday, January 29, 2020 at 11:17:16 AM UTC-8, Tom Kunich wrote:
On Tuesday, January 28, 2020 at 5:36:21 PM UTC-8, jbeattie wrote:
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.

Jay, stop showing that you don't know anything about engineering. A battery is similar to a capacitor to the extend that load matters to output voltage. Even a small charge on a battery can show "normal" voltage if you are measuring it unloaded.

So what is the likelihood that a battery showing 8v will not produce enough current to run a tiny LED? I mean your not cranking a starter motor. I represent these guys and will see what they have to say. https://mobilepowersolutions.com/ Every time you have some problem, it turns out to be some bizarre mistake, as with your bottom bracket measurement, seat tube clamp diameter, etc., etc. This is not rocket science. Di2 is an easy install.

-- Jay Beattie.

Tell us how many Di2 you personally installed? What is bizarre is that you represent some people and hence know electronics engineering. Or that you believe that the only thing inside that stem junction box is an LED.

Exactly one. And I confess to breaking the wire to my RD while washing the bike a little too vigorously on my wash stand (dragged the wire into the cassette with a brush). I soldered it back together and used some shrink tube to seal it up. I may put in a replacement wire one day. That shorted the battery, BTW, which has had no problems since. I also confess to needing to read up on programming because I want to change some presets.

You don't need an EE to build a Di2 bike. All you need is YouTube. And I'm sure there is more than an LED in the junction box, but it it is getting power, the LED will blink red at basically any voltage output until it is absolutely dead. I would figure that you would get the blinking red with even a bad battery with some voltage output if it were properly wired. Check all your connections again. Use the tool.

-- Jay Beattie.

Jay, an LED requires 1.5 volts bias or so to turn on. This is why I was saying to you to not try to be an EE. You can easily discharge the battery to below the bias simply by leaving everything on. At $100 for a battery I sure hope this bad battery charger didn't ruin the battery.

Tom what I would do to check the battery is take a LED with a 400 ohm resistor in serie and try to drive 20 mA through that LED at 8 Volts. If LED doesn't light battery is dead.

Lou