Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Will leaving the helmet on brake light only mode run the batteries down, when not in use ?
Document: I recently purchased a Gmax GM54 Helmet so this wireless brake light kit was very appealing. Despite other reviews, I found the install very easy. I did get a copy of the wiring diagram for my bike (2006 Yamaha Vstar XVS1100 Classic) so I could verify which wires on the rear wiring harness I needed to use during install. I chose to remove the blades from the harness and direct solder the sending unit for the cleanest install (and easy removal if I chose so later).
This item (G-Max LED Brake Light Kit) arrived in a very timely manner (Yay!)... before I received the helmet, in fact. I was going to wait for the helmet to arrive, before I did anything with it, but, on a whim, decided I could/should check it out by installing batteries and plugging the light into the battery pack. Only one (of two) LEDs worked.
This installation and use is very simple and the helmets work great. (I have only tested using a power supply and not on the actual bike brake yet - way too cold outside )  I read some where that if you have two helmet-lights they will both work from one transmitter. Both my helmets work great individually but not both from one transmitter and if I use both transmitters neither will work, how weird is that?
This unit was easy to install, understand and use WITHOUT THE BRAKE SWITCH FUNCTION. It works with or without. Just push the button to enter 1of 3 modes; solid, slow flash or fast. Another press and it fades to shutdown. I can't use the switch on my bike. I just wanted to install the light for more conspicuity.
Replace the battery cover and single screw and you're done!Great product, extra lighting really stands out, several people stop and comment any time I ride at night.Also, I have my unit connected to my Kuryakyn run-turn-stop controller with flasher, so the helmet LED light also flashes three times along with the rear lights when I stop - gets even more attention.
This brake light in the helmet blows people away. It is always noticed and makes your personal safety enhanced. All riders should have this.
Light was real easy to install in helmet. The transmiiter for my application (two riders) was a little different. I have two Gmax 67S helmets with the Led brake lights installed. The only problem I encountered was I could not get them to pair off a single transmitter as indicated on the Gmax video.
When she does not ride I switch the switch to the other on position and my helmet brake light functions. I personally could not make two transmitters wired together work as it would cancel out both lights on the helmets. I would reccommend this product to anyone who wants a safer ride and has a little electrical wiring ability.
So this kit installs easily into the GMax helmet. The wireless sending unit is also easy to install. (Assuming you can read/comprehend + and -. I'd like to call it fool proof, but I watched a youtube video of some yahoos installing this and getting it wrong. But really... there is an LED on the sending unit. If you got it connected properly, the LED lights with the brake light and goes off with the break light.)
Why it needs to work that far away I can't tell you. There is a very slight lag between the time you squeeze the brake lever and the brake light coming on the bike an the brake light coming on the helmet. That's ok though because I think it garnishes more attention that way. It is very visible. EXCELLENT purchase. Install was pretty simple. on the VN750 Vulcan the Black/yello wire was ground and the blue wire is the brake light.
Answer: It seems that after a certain time without activity the receiver shuts off. Like if I ride to work when I get ready to go home I have to press the button and cycle through the settings to get to brake mode again. So no it won't run down the battery.