As one of my customers recently stated, "What good is a light without a battery!"

OK, so it looks like it's past time to start answering the battery question and take a look at how to make sense of the many options that are available to you as a DesignShine owner.

The good news is that the lights are performing VERY well over time. The bad news is that the TIME for some of you has grown long enough that the original 11.1V battery is probably nearing the end of its useful life. I've had several customers now in the 1.5 to 2.5 years use range with batteries that have died. Of course there are still a LOT of folks in the 2+ year category that are still running, so obviously there are a LOT of variables at play here with regard to average battery life.

Q: How do I know if the battery is nearing the end of it's life?

A: There are a number of clues for answering this question. Primarily, you'll see the run times start to become shorter and shorter. Also (and more insidious) the battery life AFTER the low capacity warning has come on may start to become exponentially shorter. In a worst case scenario, you might just see the beginning of the low warning indication, and shortly thereafter the light will shut off. Normally, you would be able to continue to turn the light on (at low power) and, at a minimum, continue to get one-minute bursts of light until you have finally hit the self-protection cut-off in the battery itself. However, as the battery ages and loses capacity, the voltage discharge curve starts falling off sooner and at a more rapid rate. This means that it's easier to go TOO far into the discharge curve before the light's one-minute shutdown routine can kick in and turn off the light. At this point, if you're caught out on the road or trail without an extra battery or light, you're just toast.

In some cases you may have put the pack "up for the winter" only to come back in the spring to find out that it's no longer taking a charge. This shouldn't be typical, but if a pack has been stored for several months at a full charge without being used, this can seriously shorten it's life. Even if you've taken really good care of the pack and stored it at half-charge, it's still possible for some of the early packs to go South due to cell imbalance (I didn't start incorporation of the balancing circuit until build #2). Of course this would apply to any 3rd party vendor's batteries as well without a balancing circuit.

Q: So what are my options for getting back up and running with the long burn times that I used to enjoy?

A: One of the nice things about these lights is that the power supply circuit has a very wide input range: 6 to 12.6V for the taillight, and 6 to 16.8V for the headlight. There is nothing proprietary about the original batteries. My desire was to have these lights be as user-friendly and DIY accessible as possible. ANY 11.1V OR 7.4V li-ion battery pack will work with these lights! Jump to PART 2 in the next post I'll look at vendor specific information.