Others have posted that they've used chargers from their iPhones and different Android phones with no problems. I haven't, nor will I try it. Different chargers charge at different rates. I'm concerned with charging my watch at a higher rate and possibly overheating the battery and damaging my watch.
Different chargers charge at different rates. I'm concerned with charging my watch at a higher rate and possibly overheating the battery and damaging my watch.
There's a lot of confusion out there regarding chargers. USB chargers are 5 volts DC. All should be able to supply 500 milliamps of current, some can supply more if the device being charged wants more current such as an ipad or a tablet may. Operative word is supply, as in it's there if the device being charged wants it.
The amount of charging current is controlled by the device being charged. It won't charge faster than its charging circuit allows.
Of course the above assumes you didn't buy some piece of crap charger off of ebay or out of a $1 bin at the Quik-E-Mart. That POS might not regulate the voltage well and present something other than 5VDC, or it may pass off raw rectified AC as DC. This sort of dirty power can mess up some devices. In extreme cases they can cause the battery to overheat and catch fire, or just catch fire themselves.
Easy fix though is stick to known, good brands of chargers from reputable sources.
As an engineer myself, I can assure you there is nothing to be safe rather than sorry about.
If you have a good quality USB power supply such as a Samsung or Apple charger for your phone, then that is 100% perfectly fine to use to charge the 235.
As stated before, the charging circuit in the watch controls the charging current and ensures battery is charged to the correct voltage. It's irrelevant if the power supply is rated for 1A, 2A or 100A. FYI the charging current for a battery of the size that would be in the FR235 would only be about 30-40mA.
The only concern is if you have a crappy $2 El cheapo power supply from China that will have bad voltage regulation. Anything that is USB and actually meeting compliance (I. E. All those msrking on the side of the charger) will be fine.
Another thing with the 230/235/630 is that it can be charged while you're using it (on a very long run/walk, etc, or when you're away from a place where you can "plug in").
For that I use a battery USB charger for cell phones. You connect it, and whatever you're running stays running (there's no charging screen), but if you have something that shows battery level on the screen, you should see that increasing (there a a couple of connect IQ data fields that do that during a native activity, like "run")
