Night Riding

So summer, although not technically official until tomorrow, is here in the southeast U.S. Temperatures are already hovering around 98F/36C with 100% humidity to boot. This has resulted in my need to ride at dusk and into the nighttime hours to stay active. I've never ran a headlight up until now but have really come to enjoy all the benefits of evening rides now that the technology has evolved to where it is today.

I purchased a Serfas TSL 1800 a few weeks ago and have been really happy with it's functionality, quality and beam intensity. My only hang up was having to velcro the battery pack to the frame as it becomes loose and is exposed to debris and occasionally water.

I know the power supply generates a lot of heat and needs adequate airflow to keep the circuitry cool and functioning correctly but I do not typically require the light throughout my normal trail. Without cloud cover I only run it inside the heavily wooded section and throughout the downhill sections.

I had seen some of the water bottle batteries that NiteRider manufactures but could not locate anything that I felt was compatible with my Serfas so with a cheap bottle, an Exacto knife, some electrical tape and closed cell foam I made my own. I've taken it on five rides so far without issue.

The cleaner cable routing and additional battery protection provide peace of mind and a more streamline configuration. Just thought I'd share with the forum with summer approaching.
#rideon

Re:

Batteries are heavy lumps, is your carbon bottle cage up to it? I would prefer something more resilient and not as good looking to ensure your bottle / battery stay put. Having done alot of night riding I know that trying to fix, or even find, broken kit in the dark is not fun.

Great point. The 4 cell lithium ion battery is pretty small and I expect it to weigh about the same or even less than the bottle full of water. So far I haven't had an issue but will take your advice and install one of my cateyes or king cages. These both have proven ejection proof for me in the past.

Re:

I did something similar with my battery pack, but didn't make quite such a tidy job of it.

My battery pack looks like this, and it looks to be well sealed with plastic ends and rubber gaskets either end of an extruded aluminium tube:



I didn't like strapping it to the frame, so I just wrapped in bubble wrap and stuffed it into an old water bottle with the top cut off:



Not neat, but what the heck, I only use it in the dark.

That will work!

Re:

Night riding? It's hardly ever dark here at the moment! :shock:

Good idea. Although, it would need to be fully watertight to withstand the summer we're having right now...:roll:

The "power supply", or at least the bit that generates the heat is in the lamp unit, the battery should barely even get above ambient temperatures. My battery actually has double insulation (~12mm neoprene) to keep it warm inside the insulated bottle during the winter (lithium chemistry batteries lose approx 50% capacity against tested levels at zero centigrade) no issues running it outside at 30 degree ambient. (Was a factory upgrade)

The current drain on a bike light battery, even the insane ones, isn't enough to significantly heat the battery, unless you get down to ~20 minute run times....... Even then it'll only be warm to the touch. More than this, you might have a faulty battery!

And the battery will be lighter than a full bottle, mine (larger capacity than all but the biggest serfas pack) is about 400 and something grams all up. Compared to the 700 ish of a large water bottle.

Thanks Matt

The manual advised the light definitely needed airflow for cooling so I thought the power supply may as well but good to know. This will actually help to further waterproof the cell with a thin sheet of poly.

The power supply is in the light, it does need cooling. It's the bit that converts the gentle trickle from the battery to what the lamp needs. The battery is not the power supply.

Most of the lights I have start shutting down and derating once I stop moving, as the power supply/lamp is overheating due to a lack of air flow.

Some lamps even have extensions to allow you to helmet mount the light, and put the battery in a pack or pocket. No battery cooling issues there!