Ultimate GPS Beakout Coin Cell Question

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fredstout
 
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Ultimate GPS Beakout Coin Cell Question

Post by fredstout »

I have the Ultimate GPS Breakout (PA1616S, #746).
I have wired it according to instructions and connected it to my Metro. It works just fine.
I added the coin cell holder and a CR1220 coin cell battery. Nothing happens. I used my meter and determined that the coin cell holder was not shorted out and that I had 3.1 volts GND to VBAT.
Is there some indication that it is working? What should I be looking for?

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adafruit_support_carter
 
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Re: Ultimate GPS Beakout Coin Cell Question

Post by adafruit_support_carter »

What do you mean by "nothing happens"? Adding the coin cell holder caused the GPS breakout to stop working? And it was previously working?

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fredstout
 
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Re: Ultimate GPS Beakout Coin Cell Question

Post by fredstout »

The GPS Breakout works well with or without the battery. I thought the purpose of the battery was to keep the GPS system "warm" for faster acquisition of a fix. It appears to do nothing.
Perhaps a better question is what is the purpose of the coin cell battery?

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Re: Ultimate GPS Beakout Coin Cell Question

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fredstout
 
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Re: Ultimate GPS Beakout Coin Cell Question

Post by fredstout »

I read the information suggested. Apparently there is no outward sign the backup power is available or not.

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Re: Ultimate GPS Beakout Coin Cell Question

Post by adafruit_support_carter »

Does that need to be known for some reason?

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Re: Ultimate GPS Beakout Coin Cell Question

Post by adafruit_support_carter »

@3BK Please start a new thread for your issue.

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fredstout
 
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Re: Ultimate GPS Beakout Coin Cell Question

Post by fredstout »

In response to: Does that need to be known for some reason?
I think the answer is yes. Coin cell backup is an important feature of the product. I installed a new battery and the the GPS breakout worked just fine but there is no apparent speedup in acquiring a fix which is , probably, the main reason to use a coin cell battery in the first place. So, is there some way to determine if it is working or is there a way to tell when its time to replace it if there is no obvious change in performance?

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Re: Ultimate GPS Beakout Coin Cell Question

Post by sj_remington »

there is no apparent speedup in acquiring a fix
If the battery-backed satellite information is too far out of date, the entire process has to start over, and you won't see a speedup.

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Re: Ultimate GPS Beakout Coin Cell Question

Post by adafruit_support_carter »

I thought maybe there was something burried in the NMEA sentences that would give an indication of battery state, but I'm not finding anything.

There is something like that for external antenna:
https://learn.adafruit.com/adafruit-ult ... al-antenna

So don't think there is anyway to query the battery state via software.

While the battery can help reduce start up time, there are also lots of other factors that can affect this. Like sky coverage, current satellites in view, etc.

The other function of the battery is to preserve settings, like baud rate. Otherwise, those would return to factory defaults with every power cycle.

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