Not All 12V USB Chargers Are Created Equal
With the influx of cheaply made Chinese point of sale USB chargers, I call them check out line chargers, these devices have become one of the most failure prone items I see used aboard boats.
The cheaply made check out line USB chargers tend to heat up and have an extremely high failure rate. Most of these USB chargers were designed for smaller smart phones not for charging iPads or tablets. On top of that Android and Apple have different USB charging protocols and Apple does not use the USB 2.0 standard. When purchasing a USB charger be sure it’s capable of at least 2.1A, or preferably, 2.4A per USB port and designed for use with your product. Anything less is simply inadequate for charging tablets.
The current iPads require 2.4A to charge, as Apple intended them to. Don’t be fooled by products like the Blue Sea permanent mount dual USB socket charging ports. The current models only provide a total output, shared across both USB outlets, of 2.1A. Plug in two iPads and they begin to get very warm and the iPads will charge very, very slowly. Eventually they overheat and die. Blue Sea has a new 2.4A per port model coming out in the Spring of 2016.
Personally I prefer to avoid a permanent mount style as it limits you to USB charging only. If or when they fail, and they likely will, you are paying more, will need to physically re-wire the socket, and you lose the ability to use that socket for anything but USB charging.
Contrast the Blue Sea permanent mount type to the SCOSCHE USB inserts I have pictured here. The top model can charge at the full 2.4A PER USB PORT. The cost at Amazon (Jan 2016) is $11.16 with free Prime shipping vs. $20.00 plus for the Blue Sea permanent mount USB charger.
Installation of the SCOSCHE is simple, just slide-it-in to any 12V charging socket.
By using a standard 12V socket you retain the dual use of it and when, not IF, a cheap USB insert fails you simply unplug it and slide a new one in. While I generally love Blue Sea products I am not a fan of the Blue Sea fixed mount USB outlets.