BU-303 ! I have found the problem for all!

**Enforcer** · 02-24-2005, 02:35 PM

Placing a bookmark.

Strange I posted in this forum earlier to mark it so I get update on replies. Now I get the replies but there is no post

**rubicon** · 02-24-2005, 02:53 PM

Originally Posted by mox

Should the BU-303 have contained a regular battery, the manufacturer would have mentioned so, or would at least have made it user serviceable.

Kind of like the old "Legend of Zelda" NES cartridges? No mention of a battery inside (that I can recall, anyway) - but I doubt that they used NVRAM or the like for savegames

Ahh, memories.

**Grayscale** · 02-24-2005, 03:00 PM

So what would be the difference between using a watch battery and running a regulator off of the car battery into it!?!

I thought we couldn't use a watch battery and we had to use a supercap?

**ddogg_777** · 02-24-2005, 03:15 PM

Maybe if someone took pictures of these things we would know for sure.....

**Pilt** · 02-24-2005, 05:01 PM

Originally Posted by Grayscale

So what would be the difference between using a watch battery and running a regulator off of the car battery into it!?!

I thought we couldn't use a watch battery and we had to use a supercap?

Well all the supercap is doing is basically being charged via USB when the PC is on then it is slowly drained while your PC is off to keep data on satalitles. Im sure you could just use a battery providing its the same voltage and you use a diode so the gps thing doesnt try to charge the battery (which would be bad)

If you used a watch battery it would eventually run out, where as a regulator would take quite a while to flatten the whole car battery!!

**ddogg_777** · 02-24-2005, 05:10 PM

Here are your answers for the supercap/battery question: http://www.gpskit.nl/supercap-en.htm

Browse around, there is more info there.

**Enforcer** · 02-24-2005, 05:26 PM

On the GPS module is volatile memory and a real-time clock circuit. When the power supply is removed from the module, and no special precautions are taken, the clock will start at "0" and the memory will be flushed at the next power-on. The result is that the module needs more time to get a correct position and time fix the next time it is switched on.

This time can be shortened by:

creating a backup voltage by soldering a supercapacitor on the GPS module PCB, or
+ =

creating a backup voltage by mounting a 3,6V NiCd cell on the PCB.

well that's cleared that up then

**ddogg_777** · 02-24-2005, 05:56 PM

You forgot to paste this part:

The backup with a supercapacitor has enough energy to bridge a 48 hour period of no supply. When you use the 3,6V NiCd cell option, this period is several weeks.
Everyone buy some NiCds!

**Grayscale** · 02-24-2005, 06:57 PM

Good info.

So it HAS to be a NiCad? Why can't it just be a typical Lithium Ion watch battery? Isn't that the kind of battery a typical watch battery is?

Also, I'm assuming the regulator with car battery trick would still work fine, we would just need to make sure we put a diode on the positive side from the regulator to the positive trace on the board, right?