Trek Domane+ - non_OEM solutions for Kiox mount, and lighting suggestions.

[FInx]

Hi all,

This is a difficult question to ask, as the issue is somewhat complicated and difficult to describe.

I have a Trek Domane+ HP7 with the Bosch Performance Speed Motor, and an integrated proprietary mount (Blendr type thing) that is clamped to the handlebar between the stem bolts.

I love everything about the bike except.

1. The fact that the Kiox is bolted directly to the front light 'blendr' mount means it's not possible to adjust the viewing angle of the Kiox display independent of the light beam angle. I'm fairly sensitive about making sure I have my very bright front light angled in such a way as to not blind oncoming riders (on the trail) or drivers (on the road). Unfortunately, this puts the Kiox at an angle that makes it difficult to see in some lighting conditions.

(PS: Please ignore the annotation about the inaccessibility of the Walk Assist button. Although it is annoying, and obviously poorly designed, it is not a big issue for me as I rarely if ever have need for it - I also used this image to show some of these issues to the management staff at my bike shop while in home isolation).

2. The Kiox lighting control is limited to switching between 'high beam' and 'low beam' using the Kiox control pad. I need to have a flashing daylight 'see me light' mode and want the ability to turn the light off completely when it's not needed at all (riding on a rural bike path on a sunny day, working on the bike in the stand, etc...) . I'm not sure if this is something that could be changed in the software the dealer has (if it is, they aren't offering), but I don't see any options to change these settings in the Kiox menus or the phone app (connected via BlueTooth).

I've done a lot of digging around looking for alternative mounts that will separate the Kiox from the light so I can adjust them separately. So far the only solution I've found (that I can actually get in the US anyway) is the Blendr Kiox Mount from TrekBikes.com.

I have ordered one of these, but I don't actually have it yet. I will likely end up using this solution though.

There is one other option, and that is the standard 'Stem Cap' Kiox mount, which is used on many MTBs.

These are easy to come by, but I tried it, and it is not a viable solution for me as on the drop bar road bike (with a long 120mm stem) the display and it's controls are too high and too far back to see without taking my eyes off the road.

Unfortunately, using the Kiox Blendr Mount will mean that I have to use a different front light, as the Bontrager light's housing is integrated into the Blendr mount (hard to see in the picture).

I've been looking around at lights, but it's so very confusing. Bosch says any 12V light with max 1500milliamps output will work. I don't know if that is combined output, or applies to front and rear independently. I don't ride in pitch black conditions, so I don't need a mega bright light. Enough light to light the paved path in front of me at a safe distance is fine. I do want to replace both the front and the rear light , as the current rear light is mounted under my seat and is not visible with my commuter bags attached, so I need an alternative there as well.

My light requirements are.

• Powered by the Bosch motor/battery, preferably with minimal modifications (i.e no drilling, etc.. nothing to invalidate my warranty). Plug and play is ideal, but I'm not opposed to doing some soldering/splicing as long as I have very detailed instructions that can be implemented without invalidating the warranty.
• Must have Off/Bright (night)/Flash (day) modes at a minimum. Having multiple brightness settings (high/low beam) is fine, but these three are a must.
• Needs to have flexible mounting options. If I end up with the Kiox Blendr mount, I can't directly mount using a Blendr (middle of the stem) attachment, so either something that can attach to the lower stem bolts, or a low (narrow) profile handlebar mount (preferably with the light underneath).
• Ideally, it would need it's own control button (on/off mode change), as I don't see any options to change the functionality of the Kiox light contol butting (only changes between high/low beam).
• Must be friendly to oncoming traffic (riders, pedestrians or drivers). I commute mostly on an suburban bike path and don't want to blind oncoming cyclists. I'm not off road, so don't need a particularly wide beam pattern. Somewhat bright and focused down to the path in front is me.
• Not too fussed about price. I'm happy to pay a premium for a good quality light that suits my needs.

I'd prefer the two lights are from the same manufacturer. I've looked at Supernova, Lezyne, Light and Motion, but there is so little information about these on the manufacturers websites. i.e. how they integrate to the existing Kiox software and control button (vs. having their own independent on/off button). Anyway, I'm very confused about how to proceed here. I think I've solved the Kiox mount problem with the dedicated Blendr mount. Now I just need to find a lighting system that does what I need, is fairly easy to install, and won't invalidate my warranty if I install it myself (the shop that sold me the bike won't install anything they don't sell).

The Supernova lights are particularly appealing looking at their website, but the 'dealers' listed for my area don't seem to stock anything in the store, and the employees don't know anything about them. Being a German company (I'm in the US) has made it difficult to talk with them about the details I'm seeking.

I guess I'm hoping against hope that either someone from Bosch or another user here can point me in the direction of a lighting solution that meets my needs. I'm not having much success at the shop where I bought the bike, or communicating with Bosch or Trek directly via email. So far, everyone is pointing fingers at 'someone else'.

Thanks in advance

 

[William - Bosch Team]

Hello!

There is a lot of info here, but I'll try to shed some light on the Bosch/Trek/aftermarket compatibility, and clear up some of the details.

Your Performance Line Speed Bosch Drive Unit is designed to provide a maximum of 1500 mA at 12v, distributed among the (2) lights. Ideally, this split is 1100/400 mA, front/rear.

Trek uses a super cool, but proprietary light setup on many of their eBikes. This is likely contributing to some of the "pointing fingers at someone else" that you are unfortunately experiencing.

Bosch designed all of their Drive Units with (1) front light port, and (1) rear light port. Once compatible light(s) are installed, and the software properly configured, the rider can use the "light" button on the Kiox head unit to toggle the lights ON/OFF. This is the full extent of light control options with Bosch.

The custom Hi/Lo light switch that sits immediately to the left of your Kiox remote is actually a proprietary Trek part. This custom Trek switch generally works in tandem with a custom Trek light distribution "device" that sits inside the frame somewhere. This light distro device gets power from the light port(s) on the Bosch Drive Unit, but beyond that, only Trek can define how it behaves in terms of compatible lights.

In terms of mounting options, this is another place where parts from several different sources are somewhat mixed. The only Kiox mount that Bosch makes is the one in the picture you posted... mounts in place of stem top cap. The only remote mounting option that Bosch offers sits over on the left side of the bars, where a front shifter would normally be on a flat-bar bike. The thumbnail below shows Bosch's Kiox/remote mounting options.




Trek does a good job of integrating these Bosch parts onto a drop-bar eBike, but as in your case, sometimes a little customization is desired. I share this not as a cop-out, but to set a realistic expectation for some of the challenges associated with sourcing alternative mounting solutions.

The good news is that many 3rd-party manufacturers out there make some cool options for relocating the Kiox mount, as well as the remote (I think?) Hopefully my associate Stephen can chime in as he is our resident "aftermarket Kiox mounting expert." Or he at least knows more than I do on this.


Light & Motion has some great options (Seca 1800 will NOT work with your Drive Unit.) L&M publishes a really cool chart to help determine compatibility (again, Trek's specs may differ due to their custom light distro setup). While we can't really recommend or officially endorse a specific light for you, please feel free to post any options you find, and we can work on figuring out compatibility.

Edited to add this helpful link: https://mk0lightandmotidqi7v.kinsta...Bike-Lights-Power-Consumption-Reference-1.pdf



I'll text Stephen to wake-up and give us some options on mounting solutions.

 

[FInx]

THANK YOU SO MUCH @William - Bosch Team !! This kind of customer service is one of the reasons customers become loyal to brands!

Your explanation of the light modes is great, but there is one piece I dont fully understand. You said that the Kiox should be able to turn the lights off and on via the light switch on the Kiox itself. The light switch on mine does absolutely nothing (at least not that I can see).

Is this because.

1. I've failed to find the appropriate setting withing the Kiox or eBike Connect App?
2. This is a software setting that can only be changed by the dealer?
3. I have a defective unit? ( I doubt this is the case )

Re: Alternative Kiox Mounts. I've found some online. Most of them are only sold in Europe. I saw one I rather liked on Moustache Bikes website, but they don't sell them online and suggest to 'contact a dealer', of which there are none in my area.

Electrical Bikes powered by Bosch - Moustache Bikes

Moustache is the strong belief that the electric bicycle represents an incredible opportunity for the development of bicycle use! We believe it is the perfect tool to leave the car in the garage.

moustachebikes.com

I tried the stem cap mount found on many MTB's. On my setup, with a 120mm stem angled down, the Kiox just sits up too high off the top of the stem (sorry, I don't have a picture). I do need to cut a centimeter or so off my steerer, which would help some, but I'm not planning to do that in the short term, until I'm sure about my fit.

The one shown on Moustache Bikes website would work pretty well I think, as I could mount the Kiox alongside the stem as shown above, and use the Trek Dual Blendr mount to mount my main bike computer (Wahoo Roam) on the top half, and have the new front light, whatever that ends up being, hanging from the lower mount.



FWIW, here is a picture of the subject bike on it's shakedown ride. There are a few things changed or missing here. The stem is now angled down. The Elemnt Bolt is now a Roam, and not shown is the Tailfin Trunkbag, which sits on top of the two panniers attached to the seat tube, which carries a second battery nestled into some Kaizen Foam to keep it safe.


I get about 80-90 miles of range on this, which is not too shabby considering the hilly terrain I ride in the Seattle area, and the system weight, with the 60cm bike, two batteries and my fat butt is pretty significant.



Here is the stock photo of the Tailfin Trunk Bag, which I use with or without the shown panniers to carry the second battery.

 

[William - Bosch Team]

You are welcome! Glad I could help!

First of all, that's a good-lookin' eBike! I haven't seen that color in the wild yet. This is an awesome commuting setup, and that's impressive range. How far do you go daily? Is this on the Burke-Gilman Trail?



To answer your light question...

#2. 'A software setting that can only be changed by the dealer.' The dealer can select from (3) options for lighting operation (don't quote me on the wording below, but it's close enough):

1. Lights disabled
2. Lights switchable ON/OFF
3. Lights permanently ON

The OEM (Trek) decides which setting to select at time of eBike assembly. In the case of Trek's special lighting controls, it would probably make sense that they set this to 'permanently ON,' and then use their own switch to select the actual light function. Otherwise someone might accidentally hit the Kiox light button, and cause the other light switch not to work. In theory, this setting should still be selectable by the Dealer, but it is possible that Trek decided not to allow all (3) choices to avoid the scenario I mentioned above. Hard to say without seeing Diagnostic on this eBike.


That Moustache mount you posted is one of the ones I was thinking of. I feel like Stephen somehow ordered that one, or one like it for shipment to the US, but I'm not positive. I'll try to find some more info.

 

[FInx]

Thanks @William - Bosch Team ,

This is super helpful!

That color is actually a Trek Project 1 "Brushed Metal" finish. Probably not many of them floating around. I'm not too fussed about colors, but the three defaults were pretty terrible, so I went with the P1 option.

That picture was taken on the East Lake Sammamish Trail just south of Marymoor Park. I was just out on the first test ride seeing how things worked when I took the picture.

I live in the Bothell area and commute from there to Bellevue on the Sammamish River Trail. This is 30 miles round trip, so I only need one battery for this. The 2nd battery set up is for longer weekend rides up into the hills (Snoqualmie Valley, etc..).

I'll check with the Trek shop where I purchased the bike about changing the light setting. I'm curious to see how this goes.

Hopefully Stephen can help me find a place to actually buy that mount. That would give me a few more of options.

Thanks again,
Finx

 

[FInx]

It seems I've found a source for the mount shown on Moustache Bikes website at bike-discount.de. They call it the Acid Bosch Kiox Bracket.

Unfortunately, they don't even list the US as a delivery destination (American Samoa and Puerto Rico are listed along with most other countries - but I don't see a USA option).

Bosch KIOX Bracket

Features - Bosch KIOX bracket Handle bar mount for Bosch KIOX display Two mounting options Option 1: centered ahead stem Option 2: sideways along stem Angle adjustment Material plastic Color black...

www.bike-discount.de

Google searches Acid Bosch Kiox Bracket have been fruitless..

The search goes on....

 

[William - Bosch Team]

Ah, that makes sense! I forgot about Project 1 for eBikes. It's an exciting color, yet subtle enough for a commuter.

I believe the Acid mount is the one I was thinking of. I'll keep digging.

 

[Stephen - Bosch Team]

@FInx

Thanks for providing such great details on your previous comments--always helpful to digest with visuals, etc.

In terms of the aftermarket options (that i know of)---it may be tricky. Knowing the setup of the Domane + and now as of Friday getting to see one for the first time, I am unsure of what third-party options will suit your desires. Overall, if you keep the lighting setup as is, but look to mount the Kiox in a different manner, I believe there are options. If you look to replace both the light setup and Kiox setup, there will be more hurdles.

I have the Acid one you linked above---really good mount. You would need to keep the high/low beam light switch because built into that switch is placement for the Kiox remote. If you removed that high/low beam switch, there is no spot to mount the remote.

The Moustache one pictured above will not work if the high/low switch is removed. That picture is for a mountain bike setup they have so there is a 22.2 mm section of handlebar for the remote to be attached. I have attached a photo below, this is of the Moustache Dimanche 28.5---that would be a solution as they have incorporated a section for the remote. Note, that was the best picture I found of their setup

Another doable setup, however I do not know of any aftermarket availability is the next picture I've attached. This is of the new Cannondale Topstone Neo--which uses a Kiox and brackets provided by Cannondale.

Let me know what you've been thinking over the weekend.

Cheers

 

[FInx]

Thanks @Stephen - Bosch Team , I really appreciate you guys chiming in here.

I've still not been able to find of the Acid Kiox Mount Brackets anywhere. I've found a few sources, but they are all in Europe, and those that aren't out of stock, don't ship to the US. I'll keep an eye on Ebay in the mean time. Hopefully I'll find one.

For now, I think this is going to be my approach (check my work - especially as it pertains to the lighting, as I'm not sure how the proprietary Trek switch system will work with my proposed idea.

My plan would require replacing the Bontrager lights (at least the front one) with the Light and Motion Nip 800 (and possibly Tuck in the rear).

I would start by removing the proprietary Bontrager light/Kiox mount from the center of the stem, and replacing it with a Blendr Dual mount like the one pictured.

I would put the Trek Blendr Kiox Mount on the top mount point, and hang the L&M NIP800 from the bottom. Then put my Wahoo Roam on it's own mount off to the side.

I don't consider this ideal, as my Roam is my primary display. I really only need the Kiox there to turn the system off and on, and know what mode I'm in.

Ideally, I would like to move the Kiox behind the bar using the Acid Mount and put my Roam on the top mount point of the Blendr Dual. If I lose the functionality of the proprietary light button the Kiox switch, and or the light on/off on the Kiox itself, I'm ok with that, as long as I can turn the lights off and on, and change modes using the button on top of the NIP800.

Of course all of this depends on the compatibility of the NIP/TUCK light system (or another if necessary) with the Bosch/Trek motor (and the funky custom Trek switch on the Kiox switch).

Does my plan seem viable?

Any idea where I might find one of those Acid Kiox Mount Brackets?

Thanks

Jim

 

[Ebiker01]

THANK YOU SO MUCH @William - Bosch Team !! This kind of customer service is one of the reasons customers become loyal to brands!

Your explanation of the light modes is great, but there is one piece I dont fully understand. You said that the Kiox should be able to turn the lights off and on via the light switch on the Kiox itself. The light switch on mine does absolutely nothing (at least not that I can see).

Is this because.

1. I've failed to find the appropriate setting withing the Kiox or eBike Connect App?
2. This is a software setting that can only be changed by the dealer?
3. I have a defective unit? ( I doubt this is the case )

Re: Alternative Kiox Mounts. I've found some online. Most of them are only sold in Europe. I saw one I rather liked on Moustache Bikes website, but they don't sell them online and suggest to 'contact a dealer', of which there are none in my area.

Electrical Bikes powered by Bosch - Moustache Bikes

Moustache is the strong belief that the electric bicycle represents an incredible opportunity for the development of bicycle use! We believe it is the perfect tool to leave the car in the garage.

moustachebikes.com

View attachment 54404

I tried the stem cap mount found on many MTB's. On my setup, with a 120mm stem angled down, the Kiox just sits up too high off the top of the stem (sorry, I don't have a picture). I do need to cut a centimeter or so off my steerer, which would help some, but I'm not planning to do that in the short term, until I'm sure about my fit.

The one shown on Moustache Bikes website would work pretty well I think, as I could mount the Kiox alongside the stem as shown above, and use the Trek Dual Blendr mount to mount my main bike computer (Wahoo Roam) on the top half, and have the new front light, whatever that ends up being, hanging from the lower mount.

View attachment 54410

FWIW, here is a picture of the subject bike on it's shakedown ride. There are a few things changed or missing here. The stem is now angled down. The Elemnt Bolt is now a Roam, and not shown is the Tailfin Trunkbag, which sits on top of the two panniers attached to the seat tube, which carries a second battery nestled into some Kaizen Foam to keep it safe.


I get about 80-90 miles of range on this, which is not too shabby considering the hilly terrain I ride in the Seattle area, and the system weight, with the 60cm bike, two batteries and my fat butt is pretty significant.

View attachment 54405

Here is the stock photo of the Tailfin Trunk Bag, which I use with or without the shown panniers to carry the second battery.

View attachment 54406

Congrats on an awesome ebike and paint choice !

This one is my fav. road ebikes. Can't understand why so many went with the S. Creo over what Domane +HP offers (1125WH total battery capacity ) , real 28mph speed, a more powerful motor, fenders, rack.

Q- Why do you have to carry the spare in the rear ? I'm assuming this is the 2019 +HP , on which you can add a 625wh pack directly on top of the current 500wh battery.

How is your experience owing it aside from what you already have been writing the thread ? Have you looked into switching the chainring for a 50t/52t one ?

 

[Ebiker01]

As far as lights , the easiest set up would be with a L&M Seca 1800/2200/2500 , you would keep the 3 or the 6cell battery in the case on the top tube.
In my case i've chosen the Seca 2500 over Supernova b/c this way it won't use up my battery. Mine has a 6cell and i need to run it at high beam nigh time.

 

[FInx]

Hey @Ebiker01 ,

According to the Bosch folks in this thread, the Seca wouldn't work, which is why I went with the NIP800 (yet to attempt to install it).

As far as carrying the second battery (i.e having additional range option beyond the single battery), it's just something i wanted to have for longer weekend rides. We have a lot of amazing gravel roads in our area. It's not uncommon for me to ride 100+ miles on any given Saturday or Sunday in the summer.

For my commuting to work, and just riding around town running errands, I leave the second battery at home. However, If I'm going to take the Trek out on a long gravel ride, I didn't want to take a chance on running out of battery at the bottom of the very long steep hill that leads to my house.

I pondered the extended range battery option, but that harness has to be permanently wired to the motor by the shop techs, and it takes up one of my water bottle slots, which I wasn't willing to do.

The second battery was a better option for me, and when it's tucked away in it's little foam cradle inside my Tailfin saddle bag, I don't even notice it's there.

As far as the bike, I love it. I have been on rides as long as 70 miles up to this point, and it's surprisingly comfortable. I was a little worried about the fit, as Trek's have a shorter top tube (Frame Reach) than I'm used to on my road bikes, and I wasn't sure I was going to be able to set it up to my liking, but I was able to get a good fit with slightly longer stem set negative 6 degrees.

I've had zero issues with it so far (Kiox mounting issues aside). In fact, I've not even had it back at the shop since I bought it. I really need to get it in there so I can get the steerer tube cut.

As far as the Creo, the non-removable battery was a deal breaker for me. I commute to work and am not allowed to bring the bike inside. I wanted the ability to remove the battery to charge it, or if I need to put it in the stand to work on it. It also makes the bike a lot lighter when it's being transported or on the bike rack.

 

[William - Bosch Team]

... I really only need the Kiox there to turn the system off and on, and know what mode I'm in.

Hi Jim,

If you aren't really using the Kiox for all of it's wonderful features, there is another potential possibility. It involves quite a few "ifs," and would require some Trek research, but you seem up for the challenge of figuring out custom solutions.

I'm not 100% familiar with all of the features of your Domane+ HP7, but you may be able to switch the Bosch Purion display. The advantage being that it combines display and remote into a single, smaller unit. The disadvantage is that you lose the nice color display, and all of the extra features of the Kiox. There is even a custom Trek Hi/Lo light switch to work with it (see Trek Crossrip+.) I'm not sure if Trek's proprietary light controller is the same internal part for both bikes, or if it is different. The switch definitely looks different.



Again, I'm not yet sure if this would be feasible, or even a good idea, but I wanted to put the idea out there for you to look at. Maybe gives you more flexibility?


I can dig into the Bosch compatibility aspect a little more later on today.

 

[FInx]

Thanks @William - Bosch Team . I don't think it's worth the downgrade to the older display unit. I actually like the Kiox display. I just want slightly different light functionality than the stock Trek setup allows, and to hopefully disengage the fixed Light/Kiox mount system.

 

[William - Bosch Team]

I'm happy to hear you say that! I much prefer the Kiox over the Purion, but wanted to share all options I knew of.

I'm excited to see what you get worked out!

 

[FInx]

I'm happy to hear you say that! I much prefer the Kiox over the Purion, but wanted to share all options I knew of.

I'm excited to see what you get worked out!

Unfortunately, It's going to be a bit before I can attend to the Trek. I had to leave town to deal with a family situation, and not sure when I'll be home and able to ride.

I'm still scouring the interwebs looking for a source for that Acid mount (I think they are used on some Cube bikes as well, based on pictures I've seen).

jim

 

[Ebiker01]

As far as the Creo, the non-removable battery was a deal breaker for me.

That and it's small 320wh size were factors that also made me gravitate towards the Domane +HP. I don't own on, but is highly on my radar. Now you are giving my intentions a big boost, we have 2 Trek stores in Ny , i will inquire with them.

Also another advantage - the motor on The Domane is more powerful .

Regarding the Seca, only the Seca 1800 can be wired directly to the battery , anywhere from 6v-24v. I have to reread why it is not doable on your bike , but it should work.

The Seca 2200/2500 have their own 3cell and 6cell battery.
I already had spliced the wires to an Busch & Muller Lumotec IQ-X-E headlight(for daytime, i can turn it on/off) , and was too lazy to add an additional light to be wired directly.

If you want extended range and fast charging, you can also get a GrinTech Satiator charger . You won't even need to carry the spare. Can charge it @6amps, the battery is between 11.6-12.6ah , very okay to charge @6ah, even 6.5.

I do fast rides with my ebike and sometimes i take the Satiator and in a 60-70mile ride i stop 2x30min. for charging the battery. I have a handlebar bag and it fits fully inside of it.


Why do you think many people went with the Creo instead of the +HP ? There are 10+threads and hundreds of posts about the Creo...

Trek did reveal it about 9months later then when Creo came out , but still, this is probably the only thread about it, besides another one that i made about comparing this 2 top e road bikes.

 

[Ebiker01]

According to the Bosch folks in this thread, the Seca wouldn't work,

It could def. work on 3modes out of the 4. Maybe on Hi mode as well.

1st ) From William @ Bosch earlier message : "Your Performance Line Speed Bosch Drive Unit is designed to provide a maximum of 1500 mA at 12v, distributed among the (2) lights. Ideally, this split is 1100/400 mA, front/rear."

2)Seca 1800 manual:

• Designed to seamlessly integrate into an e-Bike’s 6V to 24V on-board battery on select systems
• 1.9A peak current draw on high power with 12V system

So, we have 1.5A available vs 1.9A required @PEAK @ HI power

How do we get the 1.5A available ?

Like this:

You could disable/disconnect the rear light , also disable the Bontrager light. 1100+400=1.5A

For rear , you could use a Cygolite Hypershot(350lumens) , then you would have 1.5A available solely for the front.

Now the Seca 1800 peak is 1.9a on HI, can just use the regular beam . Maybe it can work on HI as well, i would give it a try.
But better to also call the folks @Light&Motion and give them the details.

The easiest option would be to just get a Seca 2200 with the 3cells, and then there is no need for wiring. The power button is very easy to use and very responsive. You need a
nice and bright light for this Ebike !

 

[FInx]

Thanks @Ebiker01 , I appreciate the info, but I really want to stick with integrated lights (not have to deal with separate cells to charge/replace), and just keep the system as simple and clean as possible. I'm either going to go with either the L&M NIP/Tuck system, which will more than serve my needs, or just stick with the Bontrager lights.

Still on the hunt for the Acid Kiox Mount Bracket if anyone has a line on one...

 

[William - Bosch Team]

Hi @Ebiker01,

There is a lot of confusing info out there on eBike lights, and compatibility. I'll attempt to shed some light on the situation (have I already used that joke? )

There is no light configuration that integrates directly to a Bosch eBike Systems battery (unless someone rigs something up, which is very highly discouraged). All lighting power on the Bosch System comes solely from the (2) light output ports located on the Drive Unit.

According to L&M's super handy chart, the Seca 1800 is ONLY compatible with a Gen 2 Bosch Drive Unit, with the light output set to 6v in the Bosch DiagnosticTool. It is not compatible with any other Bosch Drive Unit generation. Even so, if you look at the wattage of the Seca 1800 @ 6v (see chart below, sourced from L&M website), it's actually lower wattage than the Nip 500 @ 12v. Watts don't necessarily equal lumens or "brightness," as there are many other factors involved (quality/config of LED(s), reflector quality, reflector pattern, etc.), but you get the idea.

You could possibly get away with using a lower power setting on the Seca 1800, but we don't recommend this as I'd imagine it is quite easy to accidently select a higher mode. Attempting to connect a Seca 1800 (on full power) to any other Bosch Drive Unit configuration outside of what I listed above will trigger an error code, and likely render the Drive Unit non-operational until the issue is corrected. Correcting the issue may or may not require error code clearing by dealer. Not a good situation. As with the 6v scenario a few paragraphs up, running the Seca 1800 at a lower setting might not gain much, if anything, over a different and more reliable light option.

As far as getting the 1.5A, it is "there for the taking" so to speak, assuming that the light ports have been activated in the DiagnosticTool (or from the assembler), and assuming compatible lights are connected. 1.5A is the maximum current draw the Drive Unit will allow for any connected lights, and will trigger an error code past that.

I've asked before about "deleting" the rear light, and trying to get all 1.5A from the front port, but I'm not 100% clear on the responses I received from our engineers (likely due to my own communication issues .) Best practices would dictate trying to stick to the 1100/400mA split.

Like you suggest, using a dedicated light battery is the best option for going brighter than the Bosch System allows for. I find my integrated eBike lights generally work great for my purposes, but when I want more, I use a Serfas TSL-T1000 that I have for MTB night riding/racing.