Friday, June 3, 2011

I swapped out some components on my Cygolite bike headlamp

I bought a nice front facing bike light a few years ago from a local bike shop, it was the Cygolite Rover LED II.  It was super bright had 3 brightness settings and a flash option.  Living in Alaska I used it all the time in the fall and spring when the days are short, but rarely in the summer since it stays light out for so long.  So this spring when I went to use the light I got about 10 minutes into my ride when the LED switch on top of it started flashing and it shut off.  Since I still hadn't gotten out of the downtown area I was easily able to ride back to my apartment since there were street lights everywhere.

When I got back home I grabbed the battery pack that is shaped like a water bottle that fits in my bikes holder.  Doing a quick search online I found the replacement was going to cost $40 plus about $12 in shipping to Alaska.  There were a few things I didn't like about this battery pack though.  First of all the charger for it had no auto shut off so the manual tells you to remember to unplug it after charging it for 4 hours so you don't overload the batteries.  This was always a big pain in my arse as I used it in the evenings for rides so if I plugged it in after the ride I'd be expected to unplug the charger sometime in the middle of the night.  The other issue was not using it in the dead of winter or most all summer I would forget to plug it in every few weeks to charge it which probably led the batteries to an early death since recharables don't like being drawn down to 0 power and staying that way for months as it prevents them from being able to fully charge.  Plus once the batteries died while I was on a ride I was SOL unless I wanted to pick up a second one.

My solution was to crack the thing open and see if I could replace the batteries in it with a 4 AA battery cage.  The batteries they were currently using were NiMH 1.2volt (2500mA) wired in series to get the 4.8 volts.  They were the same circumference as a standard AA battery but were about a half inch longer.  I have packs of Sanyo Eneloop (NiMH 1.2V 2000mA) rechargeable I use for almost everything (another post where I can gush about how much I love eneloop batteries sometime).   They had a little less capacity then the ones that came with it, but if the light died while I was on a trail I could easily swap out the batteries with some others.  When I go for bike rides I usually have a back pack I take with that has my Cannon camera that uses 4xAA batteries.  I also usually carry 4 extra batteries on top of that.  So extra batteries to swap out isn't that big of a deal.  After hooking up my new battery cage and testing it last night I found on the brightest setting I could get exactly 2 hours of light from my eneloop batteries which is long enough for most of my late night bike rides especially since when I'm riding through populated areas with street lamps I usually turn the brightness down to the lowest setting as I only need the light to help cars see me when riding in and out of the city so one set of batteries should last 2 - 3 hours depending on brightness settings.

Total cost to fix my battery pack was about $2 for the battery cage (plus the rechargeable batteries that I already had plenty of).  Now it's far more versatile for me since I can swap out rechargeables in it when I need.  I took pictures and documented the process since it was a really simple fix.  I might post it up on as my first post.  Seems like the same could be done for a lot of remote control toys or possibly even power tools that use 4.8 or 9.6 volt battery packs as well.

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