Well, the batteries are beefier than what would normally be needed for lighting, there's a 100W shortwave radio station transmitter on there too. That set chews 10W just idling. I run a 12V 10Ah LiFePO₄ battery pack which I charge each night from mains. I can also charge it from solar.

The set-up is custom, as described above. It's not portable between bikes, but isn't difficult to fit or detach from a bike.

I think this is a key consideration. The device you wear has an advantage in that you can use it on any bike, including the one you borrow, however:

- It's an extra piece of equipment to worry about.
- It's going to be problematic with backpacks and unworkable for recumbent cyclists.

Having the device accommodate the permanent-mount and temporary installation would be best.

This is probably going to be the hardest bit. For battery capacity, I wouldn't consider anything much less than 40Wh capacity.

Morning!
To answer questions regarding battery life:
The prototype has a single cell Lithium 1000mAh battery in each Lightpod and also in the controller (about half the size of the battery in a smartphone), which gives a battery life of over 5 hours on full bright white and much longer if brightness is dimmed. If set to the other modes at full brightness: flashing white approx 10 hours, solid red approx 10 hours, flashing red approx 20 hours.
The Lightpods and controller are all rechargeable via mini-USB and take about 2 hours to fully charge.

[MENTION=400786]Redhatter[/MENTION] - for a 40Wh battery (3.6v * 11,000mAh) you would be looking at about a 250g battery pack which would equate to 1Kg of battery packs which unfortunately would not be very wearable.

Regarding the system being permanently affixed to your bike, I would be interested in hearing about your experiences in other cities regarding theft, but in Melbourne you basically need to take everything off your bike if you don't want it to be stolen (sometimes they even take seats and wheels!!), so that is why I have gone for a wearable/easily removable design.

Yeah, you want a LED module that's no less than 1W. With two lights on the front, and two on the rear and a 50% duty cycle, that's 2Wh consumption. That's assuming 100% efficiency in the LED driver. While you're not going to ride with them on permanently, it'd be wise to plan for worst case, maybe a 2 hour commute with hazards on… which would suggest a 4Wh battery for a portable unit.

Better though, is if it can be charged up and last the week, in which case, a bigger pack is worthwhile.

Hrmm, remind me never to go through Melbourne with my bike. I've never had problems in Brisbane.

The top box is locked into place, and secured with a bolt through the bottom (tightened with a wingnut on the inside). I normally stow the battery in there as well as my tools and a radio transceiver, so there's about 16kg on the back. All up, the bike weighs about 40kg, you will not move it in a hurry.

Garmin's new "smart lights" work as as blinkers (automatically?) when you pair them with an Edge.

Garmin | Edge