Running lights from Bosch gen 4 power port...

[Hardtail]

Im interested in wiring a light to. When I do my rides I allways have 1250 wh battery with me. If the motor cuts out at 10 % of each battery that mean I lose 125 wh??

Mathematically speaking yes, but how often would you burn the candle all the way down on both batteries. It seems crazy right!

 

[Sander23]

I have 2 625 batterys.
Bike is derestricted , and I like to do big rides, and on my way back to home I like to use emtb mode or turbo

 

[Sander23]

So had anyone with a bosch gen 4 (not smart system) turn off the motor at 10 %? I've read somewhere that the reserve is set at the maximum wattage of the light and that for 2 hour long

 

[Hardtail]

So had anyone with a bosch gen 4 (not smart system) turn off the motor at 10 %? I've read somewhere that the reserve is set at the maximum wattage of the light and that for 2 hour long

Yeah, I’ve had it happen a bunch of times, always around 10%, hence this thread.
So you read that the battery reserve for the light is determined by the maximum wattage of the light. Interesting.
I still have the light circuit enabled, despite still running the lights from the AUX power port. So as I have nothing plugged in to the front or rear light ports I will test the theory.

 

[Hardtail]

I still have the light circuit enabled, despite still running the lights from the AUX power port. So as I have nothing plugged in to the front or rear light ports I will test the theory.

Its still shut off at 10%… well 9%. That is with light feature enabled, but not turned on via the Purion, nothing plugged into the light ports.
Interestingly it also shut down the Aux Power power.
So all you have is an ebike that can run a light for a few hours.

 

[-Matt]

Hmm im currently waiting for the delivery (hopefully Monday) of a new Cube Stereo with the 750 battery (smart system), which i asked the supplying dealer to enable the front and rear headlight socket.

They did warn me that its not good to have them enabled without anything plugged into them incase of water ingress.

But did not mention the possibility of the motor shutting down at 10%!!

I guess there is one way to find out.... If it is the case, i think i will get them turned back off, and use battery lights during the winter.

 

[Sander23]

If only there was a way to enable and disable it myself I wouldn't mind the shut down at 10 %.
Im not doing those big rides in the winter anyway. I would turn it off in the summer.

 

[Sander23]

This(page2) explains it well and that by a bosch expert

Low Battery Cutout for Bosch Gen4?

Hi All, Unfortunately, I doubt that Bosch will make the battery reserve configurable, and I personally hope that we do not. I realize that my opinion on this won't be popular, but keep in mind that Bosch designed it the way they did for a reason, and it is in Bosch's best interest to offer as...

electricbikereview.com

This explains it kinda

I just got off the phone verifying this. The battery percentage displayed is the total available capacity. In your example above, 64% is what you have left for assistance, and does not account for any 2-hour light reserve or eShift reserve. Thinking some more on it, it would be really confusing if Bosch displayed total battery capacity, and left us to guess where the reserves and low-voltage cut-out played in. The display shows what you have left to use.*


For example, if we look at (2) identical eBikes, one with lights and one without:

eBike 1: 500 Wh battery, Active Line DU, no lights: 100% battery charge

eBike 2: 500 Wh battery, Active Line DU, lights (10w * 2 hour reserve): 100% battery charge

For #1, that 100% battery charge equals [ X Wh] available
For #2, that 100% battery charge equals [ X - 20 Wh] available


Hopefully this helps?




*In a perfect world, you'd stop seeing assistance right around 0%, but this is not always the case. According to my phone call, we've seen multiple times where eBikes with eShift, high assist levels, etc., get to around 10% and stop assisting. This is because the 10% remaining is not really enough for any assist, given the immense power draw of the system and it's extras (lights, eShift, etc.) Especially true in hilly areas where heavier bikes consume much more energy

 

[Akiwi]

Read that thread, Low Battery Cutout for Bosch Gen4?
It explains a lot.
What I got from it. (This is my interpretation so might be wrong)
The displayed Percentage is what is available for assist, and takes into consideration the reserve for lights.
If your motor cuts of before 0%, this is probably due to the High load from the system, and the battery not being able to give enough power.
(In my case I was on a 16% climb when it cut off at 8% battery capacity. I think I had the light on as it was evening and I was on a road).
When your dealer activates your light socket, he can set a value between 3w and 18w. This determines where the cut off point is for your battery, as by law it should have enough power for 2 hours of light.

Soooooo. In conclusion.
If you want to keep your lights and maximize your battery, then get this value set to 3 w. This will minimize the amount reserved in your battera. Also from what I gathered the system will send only 3w to your light only when you have exhausted your battery, so for the last 2 hours. When in normal riding mode, your light will operate at normal brightness. In limp mode the light will be on, but only get 3 watts of power.

If this is true I will check with a local emtb shop, and get my system set to the 3w value. I don't need full brightness from my light if I am limping / pushing my way home, just enough light to be seen by cars if I am on the road.

 

[Sander23]

Installed a supernova m99 mini pro 1 week ago on a bosch gen 4( not smart system). Activated the lights and let it set at 16 watt. Only did 1 ride yet but motor cut off at 10 %

Read that thread, Low Battery Cutout for Bosch Gen4?


Soooooo. In conclusion.
If you want to keep your lights and maximize your battery, then get this value set to 3 w. This will minimize the amount reserved in your battera. Also from what I gathered the system will send only 3w to your light only when you have exhausted your battery, so for the last 2 hours. When in normal riding mode, your light will operate at normal brightness. In limp mode the light will be on, but only get 3 watts of power.

If this is true I will check with a local emtb shop, and get my system set to the 3w value. I don't need full brightness from my light if I am limping / pushing my way home, just enough light to be seen by cars if I am on the road.

Have you checked yet? I'm interested in this to. If that's the case I will set it at 3 w if I can keep the full wattage of my light in normal mode

 

[Akiwi]

Installed a supernova m99 mini pro 1 week ago on a bosch gen 4( not smart system). Activated the lights and let it set at 16 watt. Only did 1 ride yet but motor cut off at 10 %

Have you checked yet? I'm interested in this to. If that's the case I will set it at 3 w if I can keep the full wattage of my light in normal mode

NO, sorry I haven't

 

[Kiwimike]

Great thread folks. I'm going to get an Exposure Flex light for MTB rides, and I always ride with a helmet light as well to see round corners and to fill in shadows on the trail. So: if I get down to 10% (non-Smart Gen4 CX) and it cuts out, if I turn the light off, do I get the 10% back to use, and get home using my helmet light?

I'm assuming if you power off the light all together, the motor doesn't 'see' it - and releases the 10%?

 

[All4Fun]

Great thread folks. I'm going to get an Exposure Flex light for MTB rides, and I always ride with a helmet light as well to see round corners and to fill in shadows on the trail. So: if I get down to 10% (non-Smart Gen4 CX) and it cuts out, if I turn the light off, do I get the 10% back to use, and get home using my helmet light?

I'm assuming if you power off the light all together, the motor doesn't 'see' it - and releases the 10%?

Smart thinking.... not working, the system is set for use with lights, not using them wouldn't help.

 

[Kiwimike]

Smart thinking.... not working, the system is set for use with lights, not using them wouldn't help.

But my motor lights ports are enabled. And I can use 100%. If the light is off, the motor can’t see it

 

[All4Fun]

When the use of lighting is activated, the computer reserves capacity for that, say 10%, the remaining 90% is the 100% on the display to be used for support.

 

[Sander23]

When the use of lighting is activated, the computer reserves capacity for that, say 10%, the remaining 90% is the 100% on the display to be used for support.

No, it literally shuts down the motor on 10 %

 

[Sander23]

Great thread folks. I'm going to get an Exposure Flex light for MTB rides, and I always ride with a helmet light as well to see round corners and to fill in shadows on the trail. So: if I get down to 10% (non-Smart Gen4 CX) and it cuts out, if I turn the light off, do I get the 10% back to use, and get home using my helmet light?

I'm assuming if you power off the light all together, the motor doesn't 'see' it - and releases the 10%?

Maybe your bike came with pre-installed lights buy is not yet activated?

 

[Akiwi]

To summarize what is said in the thread.

In order to use lights on the Bosch motor, you need to get the ports activated by your dealer.
When you activate the ports, you can set the power of the lights from 3W to ...?
The motor then automatically adjusts the cut off point for the battery to reserve enough battery power for 2 hours of light without the motor working (As the system says the battery is empty). Therefore, it is advised to set the wattage to as low as possible.... not tested this yet.
The 0% - 100% Battery indication is adjusted accordingly.
Turning the light off makes no difference as legally the system has to reserve enough power for 2 hours of light usage.
If your system turns off your motor before the battery is at 0%, apparently this is not related to the light, but to the fact that the battery occasionally cannot deliver enough power to the motor e.g. on a steep climb. So, you can lose power to your motor either at 0% or if the battery is not able to provide enough power when nearly empty.

 

[Sander23]

To summarize what is said in the thread.

In order to use lights on the Bosch motor, you need to get the ports activated by your dealer.
When you activate the ports, you can set the power of the lights from 3W to ...?
The motor then automatically adjusts the cut off point for the battery to reserve enough battery power for 2 hours of light without the motor working (As the system says the battery is empty). Therefore, it is advised to set the wattage to as low as possible.... not tested this yet.
The 0% - 100% Battery indication is adjusted accordingly.
Turning the light off makes no difference as legally the system has to reserve enough power for 2 hours of light usage.
If your system turns off your motor before the battery is at 0%, apparently this is not related to the light, but to the fact that the battery occasionally cannot deliver enough power to the motor e.g. on a steep climb. So, you can lose power to your motor either at 0% or if the battery is not able to provide enough power when nearly empty.

Exactly. You can set the wattage from 3 to 18W.
I emailed bosch directly about this, they haven't responded to me for 2 weeks.

I've put mine on 16 watts, but its not clear if i put it at 3w that my light oparates at full power in normal use. I haven't seen or hear anyone do it.

In reality That would mean it would reserve 32 wh. Now it shuts down at 10 % on a 625 battery(and i ride with 2 powertubes).
Or It reserves double of what it should ,
Or the last 10 % of the battery is not equal to the firts 10% of the battery


If even put it in eco so I would draw less power but it doesn't make a difference

 

[Sander23]

So I called bosch today, they claim if you put the light at 3w , it will constantly oparate at 3 w.
They also said that this is meant for speed pedelecs

 

[BeBiker]

Some updates on the so-called "smart" Gen4 Bes3 750Wh:
It cuts off at 0%, but that's a recalculated scale.
So also here we loose (6% ?) of the energy.

Have a look at the "Light reserve mode":

Well, it seem they're right.
When 12v lights enabled, the previous Gen4 versions cut off at 6% or 10% battery level. (some legal stvzo requirement)
The so called "smart" Gen4 (bes3) recalculates the scale, cuts off at 0%, but preserves power for the lights. (43.2Wh ?)

Off to the store, to disable this madness. I'll cut into the wiring to tap directly into the 36V.

View attachment 97975

 

[Hardtail]

So I called bosch today, they claim if you put the light at 3w , it will constantly oparate at 3 w.
They also said that this is meant for speed pedelecs

I thought this would be the case. It looks like @BeBiker Buck Converter is the best workaround to get the most battery life when running wired lights.

 

[rzr]

so my bosch gen4 625Wh disabled power at 6-7% recently, i was cruising back home on eco/tour mode.
so basically, it reserved 38-43Wh for a light for 2h ? therefore software assumed i have ˜20W light ?

 

[Hardtail]

so my bosch gen4 625Wh disabled power at 6-7% recently, i was cruising back home on eco/tour mode.
so basically, it reserved 38-43Wh for a light for 2h ? therefore software assumed i have ˜20W light ?

Correct, knowing that your light draws 7.5w you can have a dealer reduce the current down closer to that. I’m not sure of the increments available but something around 9w will do. Dependant on the LED driver if you drop below the required amount it won’t be dull it just won’t turn on.

 

[rzr]

i'd like to set it to minimum, like 3W. just to have more power available for me/motor.
I guess ,better to connect it to aux power port

 

[Hardtail]

i'd like to set it to minimum, like 3W. just to have more power available for me/motor.

It is worth a try, either your light won't turn on or it will be dim.

 

[Sander23]

i'd like to set it to minimum, like 3W. just to have more power available for me/motor.
I guess ,better to connect it to aux power port

Pls let us know if that works. My battery cuts out at 10%. I ride with 2 battery and lose 10% on both. My light is set at 16 watts.
I called bosch belgium out this, they claim that the light will operateur at 3 watts( although I have the feeling that the person who I spoken with doesn't know much about the matter.

They say it's designed for speed pedelecs

 

[mak]

It all sounds a bit trivial longing for the last 10% of battery, after experiencing the brutal reality of a 5 mile ride home up hill before knowing about the 10% cut off ( just had the light activated) it does sting a bit.

Its not so much the 10% figure that seems trivial its the reality of that amount removed from your ride . I could do a decent 18 mile ride with 30% left on my old gen 4 bosch 625 set up, it was only after the 10% shut off I had to recalculate what was acceptable with that amount of battery left.

 

[Hardtail]

So... I wired in a 36v to 12v buck converter over the weekend, through a switch, and it didn't work, as soon as the converter gets powered the lights flash on for a second then everything shuts down.
I bypassed the switch and the same happened when powering up the bike.
This is the converter I am using:
This converter is rated up to 40v, the Bosch Gen 4 is a 36v system. I tested the voltage out of the battery whilst in the bike and turned on and I get 41.5V so I am hoping that it is the converter that is shutting down the system as opposed to Bosch sensing the voltage drop and shutting down...

I wired the converter between the battery and the motor, The same as seen HERE, I have double-checked my wiring multiple times and am sure that everything is done correctly.

The bike works just fine with everything removed.

Any ideas?

My next move is to order a 48v converter and see if that remedies the situation.

 

[Kiwimike]

If it’s only a 36V converter it might be maxed out by the 41.5V actual voltage.