answered
2015-03-31 17:52:57 +0200
Allow me to correct a common misunderstanding.
1A or 2.1A is the charger's maximum current rating, not voltage. You will find that both chargers give exactly the same voltage, namely 5V.
How fast the battery will charge depends on three factors. Four if you also count the battery depletion level as a factor. These are:
The battery. There is a certain maximum current a given battery can accept before bad things start happening (battery wearing out, overheating or even exploding).
The charging circuitry inside the device.
The maximum current rating of your charger.
As you can see, the charger is only one factor, and I deliberately placed it last because the first two are much more crucial. If your battery and/or charging circuitry in the phone can only accept 1A, then it makes no difference if you use a 1A charger or a 5A one, the phone will only take as much as it can.
The only case when the charger rating makes a difference is when you use a charger with a rating lower than nominal, in which case the battery will charge slower. You cannot make it charge faster.
You can try in an external charger thus changing the factor #2 on my list but I would not recommend it lest you exceed the limits given by factor #1 and damage your battery.
Perhaps Jolla can ntell us what the battery's parameters are; I have not been able to find anything.