My experience with using a bike computer to automatically control an ANT+ light network is spotty at best. The whole concept as now implemented is just not all that robust.

It would be nice if they allowed you to turn each feature on independently, but unfortunately that’s not the case.

Another one of my friends recently purchased a Varia radar. However, he bought the new RTL515 which has Bluetooth and another light mode. He uses RideWithGPS when using routes and navigation and since the new 515 is compatible with RWGPS it was a no brainer. He sent me the following photos of how it appears on RWGPS and I thought that some of you might be interested in case you want to purchase a Varia but didn't want the added expense of having to purchase a GPS computer as well. He walked to the corner of his street to test it, thus the slow speed.

No car detected



Car detected

After playing with this and a chance conversation with my firmware architect at work I actually have the Garmin 130, Garmin RTL510, and Bontrager Ion 200RT working reliably. Both the RTL510 and the Ion 200RT turn on when the 130 powers on, they turn off when the 130 powers off, they change modes reliable, and I can control each one independently if I want. I've found that if I keep the Light network Configuration to "Auto" the 130 adjusts the light modes of both the Ion 200 RT and the RTL510 depending on the ambient conditions. If I switch the Configuration to "Independent" both switch to the last state the lights were in when they were last in the "Independent" mode. I have both set to "Off" so I can quickly shutoff the lights when I need to.

The key to getting this to work is to have the head unit add the lights when everything is in position on the bike. My firmware architect worked on a project a few years back that investigated the use of ANT+ in an industrial setting. He remembered that ANT+ would attempt to determine the "quality" of the connection and would adjust during operation to optimize it. He remembered the initial pairing established a base setting and if this was too far off the system couldn't adjust sufficiently, with inconsistent communication as the result. So I tried what he suggested and it seems to have made a difference.

As far as finding the lights on at random times, I figured out that when I unmounted the 130 from my computer after syncing it would create a network with the lights, turning them on based on the time of day. But my bike lives in the basement when not in use, and the computer I use to sync it is upstairs. The 130 couldn't (still can't) reliably create a light network that far apart, thus the lights would sometime be on, or off, or at seemingly random states. Now I take the 130 off the computer and place it on the bike after syncing and everything is good. I haven't had any random operation of the lights since starting to do this.

Overall I'm really liking having the radar.

That sort of is what my experience with ANT+ light networks was. It’s kind of a “Simon says” kind of thing. It’s not in the “just works” category of tech products I own. Now that daytime running lights have become a thing, hopefully we see the wrinkles in this ironed out. In my opinion, once you pair the lights and the computer, it ought to just work after that.

I guess it works with RWGPS because of the BLE connectivity. This isn't available on the Varia 510. Cool!

Does the RWGPS app work with the previous generation Varia on phones that have an ANT+ antenna?

I'm not sure! My only suggestion is to download the app and try it. You may have to update the Varia's firmware to the latest version for it to work but I'm also not sure of that. I have the RTL510 so I can't connect it to my phone. The radar connection/configuration page in the app, with a free account, isn't disabled. I'm guessing this feature is available for free accounts, On an Android, I don't know if you can connect via Ant+ or no; even if the phone supports it.My friend has his connected to an Android phone (not sure what make/model) via BTLE.

I have the RTL 510. I absolutely love it. I was hesitant riding on the road but this device increases your confidence. I ride later in the evening on quieter roads. With the RTL I take the whole lane. The RTL gives me lots of warning about approaching cars, long before I hear them. Once the alarm goes off I pull over to the far right to give the car lots of passing room.

The one issue I have noticed with the RTL 510 is that it drains the battery on my Garmin 1030, much, much quicker. Quite a noticeable increase in battery drain.

Brilliant! My concerns exactly!

I see you even have your name on the device. I wonder if the tie strap reduces the radar range?

Alan, thank you for your comments. I have purchased the Varia RTL510 and I find it to be a very useful device in my road-safety arsenal. I cannot imagine riding without it.

BTW, I also added a small camera lens cap strap to the Varia, just it case it should ever fall off its mount.

Ride safely.

Has anyone noticed that the Varia significantly decreases the battery life of the Garmin head unit?

Yup. Most definitely with the 520. I think I calculated it out to 1% battery life for every 2km.

Thanks. I have a 1030 which has a large battery and when running the Varia, the battery drains fast. I disconnect the Varia when I hit the offroad sections of my gravel ride.

Doesn't seem to affect the battery life on my Edge 130 at all.

What is you're comparative measure?

Yeah.. for me it's about the same at 1%/mile.
Though, that's not additional/incremental. A 50 mile ride would would probably use maybe 30% without the Varia.. so maybe overall incremental of +50% battery usage.

Not using the Varia.

I meant some reference to how much charge reduction, etc. which I noticed in a subsequent post. It's not surprising I don't think. Lots of communication between the units and updating the display in traffic.

Battery drain is evidently an issue with some head units as it'll kick on the backlight when an approaching vehicle is detected. A guy in my club connected to my Varia during a century and he had to disconnect after a few hours because he didn't think that his 520 would make it the whole way. I believe that some here have experimented with backlight settings and have deceased the drain rate significantly.

I recently picked up a 530 (after using a Wahoo Bolt for the last two years) and was happy to see more than acceptable battery life when using the Varia; I think that it would easily cover back-to-back centuries.

WhyFi I think the 530 allows you to turn the backlighting off completely. The 520 does not. I've reduced the backlighting to 30% and it did help prolong battery life. I think I'd be ok with the 520 for a century. Mind you if there were a LOT of cars zooming past me, it might be close.

Oof - that blows (relatively), but it's good that you've at least mitigated it. FWIW, my first ride with a 530 was a century and, because I hadn't RTFM, I had put it in Battery Saver mode, which turns off the screen completely until Navigation or an approaching car, etc wakes it up. I didn't realize that it was the Battery Saver mode that was responsible for the mildly-annoying blankness, but at the end of the ride (106 miles, TBT navigation, radar) the battery was at 77%.