Most of our Curve crew use the kLite Bikepacker ULTRA kit for their bikes, but we often get the question of which bar switch harness to pick and how to plug it all in to allow for the best efficiency for lights and charging of devices.
Read on for technical lead Jimmy Röstlund's answers to all your questions.
A full kLite setup consists of the light, USB charger, and a wire harness with a bar switch plus an optional rear flashing light. The bar switch comes in two variants - dual and single-use. The difference between the two is that the dual-use switch always sends power to the charger to power the rear flashing light, whereas the single-use variant switches between light or charging. So, which of the two switches should you choose?
That comes down to a few factors. For example, if you plan on purchasing the rear flashing light, the choice is simple - for this, you MUST get the dual-use switch; otherwise, the rear light will only be on when you've set the switch to charge. If you don't want the rear light, though, that's when you have to put some thought into how you want to use your lights and charger while riding.
The dual-use switch is suitable for charging a device or cache battery while powering the front light. The downside is that the front light will almost always dim slightly due to the connected device’s charge. To work around this and restore full power to the front light, you'll have to disconnect the charging USB device yourself.
The single-use switch, which is my preferred option, is suitable for when you prefer full power to the light at night and can simply charge your devices during the day. There is also a safety aspect to this if you are riding in very dark areas with technical terrain. Limiting the strength of your light can be risky. Another factor is climbing; we need pedal power to make the dynamo charge the kLite set up. If you are climbing for long periods, charging your light and device is going to be tough.
Simply put, LIGHTS ON = CHARGING OFF, and vice versa. This works great for long rides where you can let the dynamo trickle charge a cache battery during the day when the light is not needed. Then when it gets dark, you can use the cache battery to top up your phone or other devices as needed. Any of the Curve crew will highly recommend carrying a cache battery on any bikepacking trip; it’s always good to have a backup power source if you can’t access a wall socket regularly.
What is the most efficient way to charge your devices? We recommend you never charge your phone straight from the kLite USB charger. Instead, carry a cache battery and let the dynamo top this up while riding, then charge your phone/other devices from the battery. The big benefit of this is that the cache battery acts as a "buffer" and gives the phone a more constant voltage which is better for the phone battery.
Jimmy’s setup as follows: SP-Dynamo hub connected to the switch harness. Switch harness connected to the light and USB charger 5000mAh cache battery plugged into the USB charger Phone or other USB powered device plugged into cache battery when needed
Finally, my light is attached to a stem-mounted computer mount with a GoPro attachment underneath. I have also strapped my switch to this mount which keeps it all nice and tidy. My Terra Rosa Gear frame bag has a cable entry flap, so I'm able to keep the kLite USB charger, and my cache battery nicely tucked away inside.