2019 Supercharger battery issue

[shadowfax]

When recharging my 2 batteries the parallel system doesn't always work correctly. When working they alternate charging 4% in one battery and then an increase of 4% in the other. (They also discharge this way when in use). Lately, ONE OF THE BATTERIES TAKES THE CHARGE EXCLUSIVELY and will charge to 100%--while the other battery won't charge until the charging battery tops out at 100%. I have tried switching the battery positions; resetting the higher charged battery; resetting BOTH of the batteries; and pulling the plug and starting over.

I have not found any trick or experiment to help me resolve this further... Is anyone else having this problem and/or have a solution.

Thanx in Advance--shadowfax

 

[Chris Nolte]

This is the way the Bosch system works or at least the way the latest software works. Discharging happens 5% per battery and switches back and forth to attempt to keep them even, whereas charging is completed one battery at a time. I was also confused by this, but this is the way it’s designed.

In theory if you were just interested in getting a quick charge on both batteries it would be better to charge each to ~70% as the last ~30% of the charge takes a lot longer. Maybe in the scenario you can remove the batteries and charge them individually.

I hope this helps.

 

[shadowfax]

just to confirm, when I first got my bike (August) it CHARGED back and forth BETWEEN the two batteries. Being a curious newby (and wanting to protect against overcharging), I monitored their progress numerous times. Only rarely would they be out of synch and one would charge to the max individually. More recently (perhaps with upgraded Kiox programing), does it charge individually. Occasionally, it still charges (NICELY) in parallel.

As I recall, charging in Parallel was important to battery life both in terms of an overall slower charging process, and more importantly, in being able to control holding the battery charge below 80% in both batteries conveniently. Seems like these are important considerations for how Bosch would approach writing their software.

care to comment?

 

[Alaskan]

I have a Delight Mountain and an Homage Rohloff HS both came with the optional dual batteries with wiring and mounts installed. In both cases they drain the batteries more or less evenly (5% back and forth so I'm told) but have always charged them in sequence, first one fully charged and then the other. I have never heard of them charging back in forth in small increments. If anyone should know the right answer, that you can rely on it is @Chris Nolte .

 

[Ravi Kempaiah]

When recharging my 2 batteries the parallel system doesn't always work correctly. When working they alternate charging 4% in one battery and then an increase of 4% in the other. (They also discharge this way when in use). Lately, ONE OF THE BATTERIES TAKES THE CHARGE EXCLUSIVELY and will charge to 100%--while the other battery won't charge until the charging battery tops out at 100%. I have tried switching the battery positions; resetting the higher charged battery; resetting BOTH of the batteries; and pulling the plug and starting over.

I have not found any trick or experiment to help me resolve this further... Is anyone else having this problem and/or have a solution.

Thanx in Advance--shadowfax

Interesting that you have also observed this. I thought I was the only one and perhaps I might be little cuckoo...
Back in June, the batteries on my delite would charge in sync (5% on one and back n forth) and sometime in October, when I noticed, it was one battery to 100% and then the next one.
I tried experimenting with different SOC (if both batteries were at 40% VS one at 60% and another at 40% etc.). I could not figure it out and it was embarrassing.

regarding slow charging:

Whether you charge it 2A or 4A, the benefits are quite small. Because both are still under 0.5C charge rate.

I would not worry too much about that.
As long as you don't leave them at 100% for days on end and charge them when they are cold... you are fine.

 

[shadowfax]

thanx for sharing..... Guess we're In the same boat. I kinda figured out my new routine today: plugged in after a ride and software took Battery #1 to 75% (lower battery charges first). The top battery (35%) was then super easy to take out and just plug it in independently counting bars for where I want to leave it. In this case fourth bar had just stopped flashing and thus I'm probably 80%ish for the 2 days until I ride again.. Not quite as cool as having Kios do the work for me and give me a more accurate readout.

finally, could you say more about your final line "charging them cold". Somehow I missed this was an important variable to consider...

thanx in advance..

 

[Ravi Kempaiah]

finally, could you say more about your final line "charging them cold". Somehow I missed this was an important variable to consider...

This may seem very anal for E-bike battery management but if you own an electric car, it will be self-evident.
Lots of Tesla owners know this because Tesla prevents charging at high current when the battery is cold. Let's say your was sitting in 25F overnight, you can't simply charge it at the highest current.

Similarly, when you want to use the "ludicrous" mode ( there are tons of videos on YouTube where they launch the car in this mode and capture the passenger's reaction).... you will have to warm up the battery.
You can't use it just like that .

Similarly, Nissan Leaf prevents you to fast charge if the battery is too cold or too warm.. When you charge the battery at low temperatures, it can lead to parasitic reactions that degrade the electrolyte chemistry. Cars come with 8yr warranty, not the 2yr or 500cycle warranty that we see on E-bikes. If a car company offered 2yr warranty, they would not even exist ..... 8yrs is a minimum to exist in the EV industry.

As is said, if you were an EV owner, it would be much easier to connect the dots. I can send scientific articles and videos if you are interested in learning more.

 

[webcurl]

My 2018 SC has always charged 1 to about 80%, then charge the other to about 80% then both simultaneously to 100%.
Same for both the 2A & the 4A charger.