New to DI2

[KnackeredBike]

But charging a battery after 25% use just seems pointless to me & not what that battery was designed for?

Nickel batteries have totally different chemistry so best to forget about those.

The battery voltage in all batteries including Li-ion changes depending on the charge of the battery - in Li-ion from about 4.2V at 100% to 3.5V when dead. The battery is "happiest" somewhere in the middle, and below 4.05V for all sorts of reasons, mostly internal corrosion and parasitic reactions within the battery.

Now in your smart phone it is more valuable to have as much charge as possible from day one, because the battery and indeed phone are cheap, and indeed battery life is more difficult to quantity because you use it different amounts each day.

Electric cars are much more strict, normally limiting charge to within 80% and 20% to keep voltage in a less "stressful" place for the battery - not least because if you can commute to work, then a year later you no longer have enough charge to, it is more noticeable and much more expensive to fix. I don't know whether eventually there will be an "emergency" 20% to use if you get stuck, or if it would just be abused by people using it every day.

 

[fatjel]

@Gary E I understand the battery last 24hrs ..
LEL etc takes longer than that ,
Hence I've been wondering if they can be charged from a dynamo or power pack

 

[Dirk]

@Gary E I understand the battery last 24hrs ..
LEL etc takes longer than that ,
Hence I've been wondering if they can be charged from a dynamo or power pack

The battery life is not time related when riding; it's load related.
The available charge reduces as a factor of the number of gear changes made, along with the very small current used to run the electronics. The biggest current drain is from the driving the servos that operate the front and rear mechs.
The battery generally lasts a bit more than 600 miles on my Di2 - lots of hills and gear changes around here. It would last a lot longer if it was flat.
Can't think of many people who would get anywhere near running a battery flat in less than 600 miles, unless it was faulty.

 

[PlanB]

Nickel batteries have totally different chemistry so best to forget about those.

The battery voltage in all batteries including Li-ion changes depending on the charge of the battery - in Li-ion from about 4.2V at 100% to 3.5V when dead. The battery is "happiest" somewhere in the middle, and below 4.05V for all sorts of reasons, mostly internal corrosion and parasitic reactions within the battery.

Now in your smart phone it is more valuable to have as much charge as possible from day one, because the battery and indeed phone are cheap, and indeed battery life is more difficult to quantity because you use it different amounts each day.

Electric cars are much more strict, normally limiting charge to within 80% and 20% to keep voltage in a less "stressful" place for the battery - not least because if you can commute to work, then a year later you no longer have enough charge to, it is more noticeable and much more expensive to fix. I don't know whether eventually there will be an "emergency" 20% to use if you get stuck, or if it would just be abused by people using it every day.

So if the 20-80% capacity rule is the way to keep a battery healthy, would topping it up to full from 75% not be a good thing?
I try not to store power tool batteries fully charged as I believe it not good for them.

A charging system could easily be installed into the front hub, but I genuinely believe this would shorten the life of the battery, just the same as a laptop running constantly off the mains.

Car batteries are designed to run at full charge, whereas a leisure type battery for use with say a golf cart or caravan needs a deep cycle of discharge to stay healthy.

To be honest, I can't get my head around spending north of 3 grand on a push bike & then worrying about preserving the life of a 50 - 100 quid battery.
A bit different with a mobile where the battery is incorporated into the phone.

 

[Gary E]

OK, my bike just turned up
There's no operators manual an dthe only ones I can find online seem to be very in depth but don't give simple operating instructions.
For example...
Is the system just left on the whole time? (no on/off).
What is the button on the junction box for and what button pushes cause/call up what lights?
What other lights/diagnostics/adjustments can be done from the shifters themselves (read something about pressing and holding the shifter to place the system in a certain mode??)
Thanks in advance. I'm sure I'll think these are daft questions myself once I'm up and running but at the moment I'm clueless

 

[User269]

OK, my bike just turned up
There's no operators manual an dthe only ones I can find online seem to be very in depth but don't give simple operating instructions.
For example...
Is the system just left on the whole time? (no on/off).
What is the button on the junction box for and what button pushes cause/call up what lights?
What other lights/diagnostics/adjustments can be done from the shifters themselves (read something about pressing and holding the shifter to place the system in a certain mode??)
Thanks in advance. I'm sure I'll think these are daft questions myself once I'm up and running but at the moment I'm clueless

How to check the battery

How to charge the battery

How to adjust the gears