Hello

I would like to understand why the GPS every time I unplug the battery do a new procedure to find sat ?

Doing like that I fly for 2 minutes without GPS and also the hot start with the 1s lipo don't work in this way.

I don't know how is possible ?

Is there connected a battery on the drone, the drone is new...is there the risk that that battery is uncharged ? Should be charge considering is a new GPS.

if i'm not wrong, after that do the first sat fix it should keep always the sat fixed right if im in the same place when i plugin the new lipo ?

or is necessary use the 1s always before a fly with that procedure:

1 i connect the 1s to gps, do the sat fix

2 after that i saw the sat fix light i keep connected the 1s and i plugin also the 4s that give power to fc

3 i disconnect the 1s and i connect the gps to the jst and it recive power using the fc and 4s lipo.

----
because even if ihave keep the 1s for 10 minutes, after i have disconnected that, connected the 4s after some minutes and sat fix was again 0

The BN220 has a small cell onboard to store settings and that cell can drain out over time which may result in the GPS doing a cold start everytime since it can’t store previously tracked information.

Those batteries are soldered into place and can be tricky to replace.

It sounds like the backup battery on the GPS either needs to be charged or replaced. Try leaving the GPS powered on connected to a %v supply for several hours to see if the battery takes a charge. Otherwise you can try to replace the battery or just get a new GPS.

https://intofpv.com/t-gps-problem

(13-Apr-2022, 09:09 PM)kafie1980 Wrote: The BN220 has a small cell onboard to store settings and that cell can drain out over time which may result in the GPS doing a cold start everytime since it can’t store previously tracked information.

Those batteries are soldered into place and can be tricky to replace.

(13-Apr-2022, 09:14 PM)V-22 Wrote: It sounds like the backup battery on the GPS either needs to be charged or replaced. Try leaving the GPS powered on connected to a %v supply for several hours to see if the battery takes a charge. Otherwise you can try to replace the battery or just get a new GPS.

https://intofpv.com/t-gps-problem

But my gps is new, buyed some times ago and first fly test is been least week !

What kind of battery they use and why they have soldered ?

The GPS modules use button cell batteries that have solder tabs on and are soldered to the circuit board so they make a good reliable contact and aren't at risk of falling out.

While your GPS module is "new", you have no idea how many years it might have been sitting in the stock cupboard for. You might also have been unlucky enough to end up with a GPS module that had a faulty battery fitted to it at the factory. Beitian likely have no real QC procedures.

I have used many Matek M8Q-5883 GPS units and have never had any issues or problems.

I also like using an external 1s battery to get a sat fix prior to flying in a new location which
has worked amazingly well for me.  That said, I am finding the JST connectors harder to use
in the field in this fashion. Consequently, all future and retro fit GPS connectors will be the 
BetaFPV BT2.0.  Personally, I like these connectors and the "keying" method makes them
easier to use in the field...at least for me.

(13-Apr-2022, 10:53 PM)SnowLeopardFPV Wrote: The GPS modules use button cell batteries that have solder tabs on and are soldered to the circuit board so they make a good reliable contact and aren't at risk of falling out.

While your GPS module is "new", you have no idea how many years it might have been sitting in the stock cupboard for. You might also have been unlucky enough to end up with a GPS module that had a faulty battery fitted to it at the factory. Beitian likely have no real QC procedures.

But should back to work if I recharge using a 1s lipo at 3.80v ?

Understand all but they could find a better solution for these battery to can be replaced much easier...

Now i have connected the 1s lipo

(14-Apr-2022, 03:28 PM)Rosssiiii Wrote: But should back to work if I recharge using a 1s lipo at 3.80v ?

Understand all but they could find a better solution for these battery to can be replaced much easier...

Now i have connected the 1s lipo

As far as I know standard (not-rechargable) button cell batteries are used on the GPS modules that will eventually run out after a few years. So they won't get recharged by applying voltage to the module.

It would be better if the required data was stored in NVRAM but maybe the MCU they generally use for GPS modules doesn't have that feature.

(14-Apr-2022, 07:00 PM)SnowLeopardFPV Wrote: As far as I know standard (not-rechargable) button cell batteries are used on the GPS modules that will eventually run out after a few years. So they won't get recharged by applying voltage to the module.

It would be better if the required data was stored in NVRAM but maybe the MCU they generally use for GPS modules doesn't have that feature.

But really I don't have words...how stupid is that system 

They should had put battery that you can connect and disconnect every time you want to be replaced !

A battery like that should be very cheap...more then the entire GPS that I bought new but is with a dead battery already 


You can't go at random

Now i have put the lipo 1s connect to the GPS from 4.30v it will drop at 3.85 but I don't think will work and is not fair that...

Even if difficult I would like try to replace the battery if necessary if is a standard one !

Could be necessary put the tip of the soldering iron on the top plate and desolder the battery

That is a close look of the GPS battery: https://i.imgur.com/OVkm9eU.jpg

(15-Apr-2022, 10:23 AM)Rosssiiii Wrote: That is a close look of the GPS battery: https://i.imgur.com/OVkm9eU.jpg

Hi Rosssiiii,

That looks like a "TAC" weld which is different than solder. Using a soldering iron
to heat it up will likely NOT work. You might have to physically break it loose.
If you can get the battery out without damaging anything, then you might be able 
to replace it. 

Go easy with it and be careful. Send pics.  

Heating a battery that size with a soldering iron will be damaging which is why spot welding is preferred.

I will suggest to try and connect the GPS unit to a controlled 3.3-5v power source for a few hours to try and charge the battery. Worst case you can power the GPS with a 1s lipo for several hours.

Now here is a bizzare thought 

Just power the GPS separately with a 1S lipo attached to the quad.
When you get to the fly location, just plug it in and leave it. By the
time you are ready to fly, it should have sat locks. Go ahead and
fly with the 1S battery attached. Yeah, this means that you would
need to have a secure mounting method for the 1S battery. Now 
this might be a good application for the Dual Lock hook and loop 
stuff that many pilots are fond of. Given your situation, this might
actually be a viable solution.

Or...just buy another GPS...maybe a Matek this time 

(15-Apr-2022, 09:24 PM)iFly4rotors Wrote: Now here is a bizzare thought 

Just power the GPS separately with a 1S lipo attached to the quad.
When you get to the fly location, just plug it in and leave it. By the
time you are ready to fly, it should have sat locks. Go ahead and
fly with the 1S battery attached. Yeah, this means that you would
need to have a secure mounting method for the 1S battery. Now 
this might be a good application for the Dual Lock hook and loop 
stuff that many pilots are fond of. Given your situation, this might
actually be a viable solution.

Or...just buy another GPS...maybe a Matek this time 

Is there some smaller lipo then a 1s lipo more easy and light to place on the quad ? Like for example the lipo used by many buzers...I don't know how many voltage give a smaller one, but could be interesting.

The 1s 300mah is not that heavy for a wizard I think but take lot of space ...