Friday, April 17, 2015

Equipment Check - Siva Cycle Atom

I purchased a Siva Atom via their Kickstarter campaign.  My main goal was to use it on long rides where I want to run a GPS app on my phone within sucking the battery dry.  I don't intend to use it to power lights.  It took them longer to get to production than they originally anticipated.  I took delivery on my Siva in late November 2014, just as winter got started.  Consequently, it sat on my workbench until a couple weeks ago.

I mounted it on one of my bikes (a Giant FCR3).  It took all of about five minutes to mount.  Like most modern bikes, the Giant has vertical dropouts, so all I needed to do was remove the rear skewer, wiggle the rear wheel out far enough to slip the dyno over the left side of the axle, wiggle it back, then replace the skewer.

In the time since I first installed it, I probably rode that bike to work (1+ hour one way) five or six times.  Assuming the dyno was putting out juice, the little battery pack in the Siva should be very well charged.  Other than a little bit of "notchiness" felt and sound heard when walking the bike, I couldn't tell the Siva was doing anything.  Once riding at a very low speed (couple mph?), I can't tell that it's there.  Of course, I'm getting to be an old fart, so my hearing isn't what it used to be.

A few days ago, I swiped a horrible mounting bracket from my wife's bike (well, "swiped" is kind of a strong word - she didn't like it one little bit and told me I could take it), slapped it on my Giant, then zip-tied a USB cord to my top tube and plugged in the phone.  Nothing.  "Damn," I thought.  "Oh well, nice experiment."  I turned on My Tracks to guarantee the phone was doing something marginally useful (though I do know how to get to work) and battery consuming as I rode.  Once I got the bike rolling, the phone started charging, as evidenced by the lightning bolt battery icon.  Whew!  Apparently, the little battery pack on the Siva won't discharge through the USB connector, only through its own USB port.  I will have to confirm that with the Siva folks.

Midway through the ride, I checked and the little lightning bolt icon had disappeared from my phone's display.  "Damn," I thought.  "Oh well, nice experiment," and continued on to work.  When I got near work I stopped just short of the office so My Tracks wouldn't spazz out when the GPS satellites disappeared behind the tall buildings.  I noticed the screen said, "fully charged," and when I unplugged the USB cable from the phone, the little green light behind the speaker turned off.  So, all was well on that front too.  Looks like the phone's charging circuitry disconnected itself from the 5v power once the battery was fully charged.  To be fair, the phone had been connected to a power source overnight, so it was already at 98% when I started out.

The phone was in a somewhat lower state of charge when I rode home.  On the ride home, the phone started out at 81%, ended at 92%.  Again, this was with My Tracks running.

After another day, I purposely left my phone disconnected from the charger last night.  When I took off this morning the battery charge was at 7%.  I didn't run My Tracks on the ride in this morning.  When I got to work, it was at 19%.  Fairly reasonable, though I was hoping for a bit more out of a one-hour ride.

So far, I'm happy with the Siva.  I haven't used it enough to really test its robustness, and haven't really tried it in wet weather.  If you're a dedicated dynohub person, I'm sure it won't be for you.  For someone like me who uses (recharegable or USB) battery lights, the Siva looks like a decent option.