USB Power for Fishfinder?

I'm looking for power solutions for a FF that will arrive in a few days. I'm wondering if anyone has used power over a USB cable. Here's the type of battery that looks interesting--small, light, cheap, and indicates that it can output 12V at 1.25amps, 10 amp hour rating.

http://www.amazon.com/Aukey-10000mAh-Portable-External-Supported/dp/B011U0AY22/ref=sr_1_1?s=wireless&ie=UTF8&qid=1451427425&sr=1-1&keywords=external+battery+charger+usb+3.0

USB line out voltage is always 5v.  It's the USB standard.

It seems that the USB standard continues to develop. I also thought that 5V is the USB max, and was surprised to see USB batteries that offer 9 and 12V output. I don't know if the operating device controls that voltage. Thus my confusion.

Powered USB is also on its way:

The implementation allows a choice of three different voltages, providing power at 5 V (30 W), 12 V (72 W), 24 V (144 W) as well as a custom voltage. Some implementations provide 19 V or 25 V. The connectors are able to operate at up to 6 A (3 A per pin) peak, but according to the specification, hosts are required to provide a minimum sustainable rms current of 1.5 A at 5 V (7.5 W) or 12 V (18 W), or 2.3 A at 24 V (55.2 W), only. For comparison, a standard USB 1.x and 2.0 hosts supplies 5 V at up to 0.5 A (2.5 W).[6] USB 3.0 supplies 5 V at up to 0.9 A (4.5 W)[7] whereas hosts conformant to the USB Battery Charging Specification can deliver up to 1.5 A (7.5 W).

not sure if that device will work, but there are plenty of cheap USB-to-alligator clip cables on the market.

The standard port for a USB cannot provide any more than 5 volts.  Powered USB has been around for over a decade and requires some pretty weird looking connectors.  Any battery that has USB output ports and claims to also support 9 volt or 12 volt must also have another output port through which to provide that 9 or 12 volt option, which is the port you would ultimately use to power a sonar.

I would guess that the 12V output goes through the DC input port on the side, not one of the USB ports.

That is how I see it also.  Both USB ports look to be typical with one providing the higher amperage output.   The items description really is confusing.  If the side connection is also an output,  you think they would mention how it's output can be switched between 9 and 12 volts.  I't only mentioned button states to be to turn it on / off and turn on the flashlight 


Lithium type batteries are based on individual cells that provide typically 3.6 to 4.2 volts when fully charged.  A 12 volt lithium battery provides that 12 volts by utilizing 3 to 4 of those cells connected in series.   So you can see how a battery that can provide 12 volts can be charged with a 5 volt input as it is charging each cell individually.  Basically the cells are charged in parallel but combined or in series to provide the batteries overall output voltage

You're misunderstanding the USB standard.  All USB ports, USB1, USB2, USB2.2, USB3 and USB3.1 are 5v ports and cannot be switched to higher voltage.

If someone could press a magic button and change the USB line out voltage from 5 to 12 volts it would fry every USB device plugged into it and there'd be flaming iPhones all over the streets.

If you look at the 18000mAh Aukey model  https://www.amazon.com/dp/B00NBI1GQK/ref=cm_sw_r_cp_awd_inxFwbNNSPJYT
or any of the other external/backup batteries folks have mentioned using, you can see that they include a round, dedicated DC line out plug that is not a USB port.  Those are the plugs that you need.

I cannot imagine why anyone would try to manufacture a combination DC line-in and line-out plug.  It would be far more expensive to wire the circuitry to do that then it is to add a second circuit and separate plug.  And if a punkinhead like me plugged the charger into the port while it is in the output mode...

Thanks for all the replies! Yes, I didn't understand how 12V would be delivered through a standard USB port--too many risks to devices assuming max 5V output.

There's a lot battery discussions at ncka.org.  A few of us are using 7 inch Chirp units and use LiPo batteries.  I personally Dragonfly 7 since Oct 2014 and love it.  I did away with AGM / SLA batteries and have been using LiPo. 

http://www.norcalkayakanglers.com/index.php?topic=69206.0