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Operating a Bluetooth GPS receiver without a battery
Roy33
Is it possible to operate a Bluetooth GPS Receiver (e.g. BT-Q818) using a USB/Power cable without the use of an internal battery. Currently if the battery is removed the unit will not power up even if connected to the mains.

Would like to have the unit operate (on/off) only when an external power-source is available e.g. when hooked up to the car this will allow me to start/stop the GPS unit by turning the car's ignition switch.

nb. i know some GPS units have auto on/off functionality and are designed for usb only power, but id rather save some money by modifying my existing unit, disassembled pictures attached.
Attached Images
gps.jpg  
Roy33
Would connecting the (+) and (-) do the trick?
Not sure if all I have todo is connect the (+) to the (-) at the top left of the pic (which is the battery connector) to complete the circuit.. any ideas..
Marvin Hlavac
Hi Roy33,

Welcome to Laptop GPS World.

If the GPS receiver doesn't start without the battery, then just leave the battery there. The life span if the battery will be shortened by it being constantly charged, but I don't think you will mind that.

Try it like that, and see if it causes any issues.

If you are not happy with that, then perhaps buy a simple USB GPS receiver. They can be bought quite inexpensively these days.
Ken in Regina
Marvin, if he leaves the battery in the circuit and the battery has any charge, that won't accomplish what he wants. He wants the GPS receiver to turn on and off when he turns the ignition on and off. It won't do that if the battery provides any charge at all. And it will run the battery flat if he leaves it in the vehicle with the receiver turned on.

I'm not familiar enough with the device to guess how to make the connections. It should be really simple to do but the pictures don't provide any detail of the area(s) where the battery and external power connectors are. It should be as simple as jumping across the battery connectors to complete the circuit so the receiver will see power only when the external connector provides it. But without seeing the device in hand or the detailed circuit diagram I can't recommend it because it might also be bypassing some built-in protection circuitry. All Lithium batteries (lithium ion and lithium polymer) have an overcharge/overvoltage protection circuit right on the battery itself. This usually results in extra connectors in the device so the battery can control the external power/charger circuitry. Making the wrong connection will surely be bad for the GPS receiver.

...ken...
Marvin Hlavac
Yes, to leave it on all the time is not what Roy33 asked for, but it is something that I would try to do (since I cannot think of anything better ). I think there is no harm in leaving the GPS receiver on even 24/7/365.
Strabo
the battery looks like it says 3.7v on it, USB outputs at 5v so you could run it from the usb if you connected it right (with or without a resistor, it MIGHT not mind having 5v but of course, it might react badly if its more than its expecting)

An alternative to that is running wires from the battery to the GPS via the ignition? so that it only makes the circuit when the engine is running.
diredesire
are you any good at soldering?

If the gps unit ONLY requires a 3.7v input (i'd guess 3.3v would be OK) you could mount a small voltage regulator to split the 5v input and use it as a dummy load. I doubt the issue is "connecting +/-" This would effectively short your power rails.

I really doubt it's an impedance issue (resistor/wire). I'd try with a dummy voltage load. The most common voltage regulator i see used is the LM317, requires a few resistors to use. You could alternatively buy a very small SMD (SOIC) fixed regulator chip that will take 5v down to 3.3 w/ no biasing resistors and use that instead.

You've got options, but some more research is needed.
Marvin Hlavac
Hi diredesire,

Welcome to Laptop GPS World.

That sounds like a suggestion worth a try.
diredesire
Good luck! I wish I could be of more help, but I'd need to take a close look at the actual module to give you a definitive answer.
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