at what battery level your motor turns off ?

rzr

Active member
Sep 26, 2022
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bcn
I was riding on eco slowly to home, with about 7%,
when suddenly Bosch 4gen (Rail), turne off, and display (nyon) was only showing an exclamation mark on battery.
At home, when i started charging the battery, it started already from 5-6%.
Is it normal?
I guess I have to take it into account always?
 

Voluptua

Active member
Oct 4, 2020
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United Kingdom
The light question is relevant because the Bosch system cuts out the motor with some battery left, so you can pedal yourself home with the lights on. It's a shame this is not a feature that can be disabled, as Bosch don't know how close you are to home when the cut out happens (you might have just enough battery to get there if it would let you), nor if you have a spare battery to hand (so you might as well drain your first one completely). Nor if it's full daylight, so you don't need the lights.
 

rzr

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Sep 26, 2022
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So without light it allows to work a bit more (drain more battery) ?
When you connect a light, you have to activate it in a software as well? (By service I guess?)
so if I disconnect the light - i have to visit a service to change it in a softwre ? (or use quick connector in a future, but then, it'll reserver 5-6% always anyway)
 
Last edited:

Tonybro

🦾 The Bionic Man 🦿
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Shimano have a similar function and it cannot be disabled even if you have no light, FFS! I don't have a light on either of my Shimano bikes but it reserves 5% power for the light! I cannot disable it. I can see why it is there, for safety, when you do have a light connected but surely it should be able to recognise whether a light is connected or not and disable accordingly...
 

raymal

Member
Dec 18, 2020
39
17
Southampton
Shimano have a similar function and it cannot be disabled even if you have no light, FFS! I don't have a light on either of my Shimano bikes but it reserves 5% power for the light! I cannot disable it. I can see why it is there, for safety, when you do have a light connected but surely it should be able to recognise whether a light is connected or not and disable accordingly...
Ummm - think you can, I've had it switched off on my Pivot but it could only be done by a Madison tech via my lbs. If you take your bike to a Shimano dealer they might shrug their shoulders at the request but if that's the case, ask them to contact Madison directly (assuming UK) for their intervention and they should be able to switch it off via remote access
 

Zimmerframe

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Jun 12, 2019
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There's some similar info/more info in these two threads :


 

Voluptua

Active member
Oct 4, 2020
103
65
United Kingdom
So without light it allows to work a bit more (drain more battery) ?
When you connect a light, you have to activate it in a software as well? (By service I guess?)
so if I disconnect the light - i have to visit a service to change it in a softwre ? (or use quick connector in a future, but then, it'll reserver 5-6% always anyway)
Yes - if you didn't have the light fitted, you'd be able to use more of the battery. And yes, this feature is software controlled, so you'd have to visit a dealer to change it.

In some other posts - see Zimmerframe's links - there have been suggestions that the percentage of battery retained might be tweaked by adjusting the power that the motor believes the lights are set at. And - again see links - you might be able to run the lights from another port. I've not tried these ideas - I've just put up with the reduction in capacity.
 

rzr

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Sep 26, 2022
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bcn
I have 1000lm 2 LED Lenzyne, described as 6W, so not very power hungry
 

rzr

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Sep 26, 2022
344
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bcn
Can you put up a link or pic to which light you have? I will check if it can run off the aux power, 1 amp.
what's the voltage on aux power output ?

compatible with 12V 1A (or 6V 2A) outputs (as i mentioned, it's 6-7.5W so it matches 1000lm).


 

Hardtail

Active member
Mar 8, 2021
211
129
Uk
what's the voltage on aux power output ?

compatible with 12V 1A (or 6V 2A) outputs (as i mentioned, it's 6-7.5W so it matches 1000lm).


Yeah so your light outputs 1.5 amp at 12v, which means it won’t run off the Aux Power Port, which can only take 1 amp.
Apart from adding a buck converter, 36v to 12v, to the loom you are stuck with the Bosch lighting system which will save a bit in the battery reserve whether you are using the light or not.
You mentioned 7% which I think is reasonable as without out lights on a Gen 4 Purion display my bike would slowly throttle power from 4% or similar.
 

rzr

Active member
Sep 26, 2022
344
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bcn
Yeah so your light outputs 1.5 amp at 12v, which means it won’t run off the Aux Power Port, which can only take 1 amp.
Apart from adding a buck converter, 36v to 12v, to the loom you are stuck with the Bosch lighting system which will save a bit in the battery reserve whether you are using the light or not.
You mentioned 7% which I think is reasonable as without out lights on a Gen 4 Purion display my bike would slowly throttle power from 4% or similar.
I don't undestand. Do you mean Aux can give 12V 1A ? = 12W, looks like enough - the light is rated at 7.5W
 

Hardtail

Active member
Mar 8, 2021
211
129
Uk
I don't undestand. Do you mean Aux can give 12V 1A ? = 12W, looks like enough - the light is rated at 7.5W
Sorry I misread the chart you posted, it states 1.5amp @ 12v for the Bosch gen 4, that is obviously what the bosch can output not the light... So yes, your light draws .65amp which means you can run your light from the Aux Power Port, which can output 1 amp.
See this thread for the cable etc, I used: Running lights from Bosch gen 4 power port...
As long as the light has it's own power button it will work.
You need to get a service centre to turn off the lighting circuit and enable the power port. In my experience, this can be difficult having to explain why you would want to do this as the 'expert' had very little knowledge of the Bosch system.
 

Hardtail

Active member
Mar 8, 2021
211
129
Uk
I try to never go under 10% as it's not good for the battery. never had it turn off.
Bosch knows this also, there is some literature that mentions the battery percentage has been adjusted to account for this so that their batteries last longer, also hence why the earlier incarnations, purion for example, will cut off at X% but the smart systems will run down to 0%, even with the light circuit activated.
 

rzr

Active member
Sep 26, 2022
344
215
bcn
Sorry I misread the chart you posted, it states 1.5amp @ 12v for the Bosch gen 4, that is obviously what the bosch can output not the light... So yes, your light draws .65amp which means you can run your light from the Aux Power Port, which can output 1 amp.
See this thread for the cable etc, I used: Running lights from Bosch gen 4 power port...
As long as the light has it's own power button it will work.
You need to get a service centre to turn off the lighting circuit and enable the power port. In my experience, this can be difficult having to explain why you would want to do this as the 'expert' had very little knowledge of the Bosch system.
ah damn.... so service centre has to deactivate one, and ACTIVATE aux port ?
I can already imagine that conversation.... and their stating that it's not possible, or i want to do smth wrong
and that they can't do that ( they don't know how / they don't understand / they don't want to take responsibility....)
 

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