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

**Grayscale** · 02-21-2005, 08:44 PM

yep, there is. So Radioshack sells watch-sized batterys with leads or connectors to be soldered onto already? I think watch batteries are too slick or something to solder directly onto. I think I vaguely remeber trying to solder onto one. I should be looking for one that puts out 3.5 volts? I still have my battery I ripped off, and it even has part of the metal thing that is soldered onto it, so I may try to just resolder it. Yeah, just checked and I just have to resolder the metal pieces into the circuit board again.

You think the battery on there is going to help me get a faster lock? Hopefully you can get a battery to try it with at Radioshack, and let me know if I don't get a chance to test it out. In fact I know I won't since my screen needs a new VGA controller and is dead currently

EDIT: My post was intended to reply to chuckctv, didn't expect so many people to reply before me

**chuckctv** · 02-21-2005, 09:02 PM

you wont be able to solder onto a battery, you must either get a battery with leads on it, or mount a tiny battery holder in the unit. the imprinted voltage on the battery is 3.3volts. Also just incase anyone is interested- a battery metal material on the outside is not solderable, the leads you see on the battery if you look close at it arnt soldered but tac-welded on... I will find out tommorrow what is the best plan of action for a replacement battery, when i go to radioshack and see what they have on hand.

chuck

**chuckctv** · 02-21-2005, 09:07 PM

Also if anyone has opened up the gps unit yet, they will see the RS-232 unit and USB unit are the same. I viewed the circiut diagram on-line, it has a 3.3v battery and the wiring for both connections, also it has 2 larger solderable leads to wire up the battery next to the onbaord battery, their also labeled + & - ....

chuck

**Grayscale** · 02-21-2005, 09:26 PM

Can you link me to this circuit diagram plzkthnx

?

**Scouse Monkey** · 02-21-2005, 09:28 PM

You can solder to the battery but you normally have to rough up the surface 1st. The solder tags are welded on. I would get a battery with tabs on so you don't damage the cell keeping the iron on too long.

**bry21317** · 02-21-2005, 09:36 PM

Why not just make an external case to hold the battery or something else, that makes it easy to replace?

This could be done pretty easy, I would think and you could then mount it into something that held it outside the case. I know it wouldn't be the prettiest thing, but it would be easily changed.

Also, you would only have 2 wires to come out of the GPS unit.

Later,
Bryan

**Grayscale** · 02-21-2005, 09:43 PM

That'd work. Mine is easily visible, though, so I want mine to be pretty

**StationRocket** · 02-21-2005, 09:48 PM

you can stick a screwdriver in an electrical outlet as well but it's a pretty bad idea

There are a couple of reasons why I would try to talk anyone attempting to solder directly to watch battery out of it.

First as someone above pointed out the surface of a watch battery is not made of an appropriat metal for the solder to adhear to. Roughing it up will help this but not fix it. It is still very likley going to fail after some period of time in a vibrating automotive environment.

Second the heat you would have to subject the battery internal chemestry to in the process of soldering to face would be well outside of a safe range. At a minimum you are going to alter it so it likley won't make the propper voltage or last very long and more likley you are going to have it leaking all over the place.

It's not to hard to get ahold of a battery with tabs for cheap so it's just a silly thing to concider doing.

**chuckctv** · 02-21-2005, 10:20 PM

http://www.globalsat.com.tw/english/...n_id=5&p_id=13

this is a near duplicate of the bu-303

http://www.globalsat.com.tw/english/...n_id=5&p_id=12

this is the specs.

**westscape** · 02-22-2005, 01:04 PM

Well last time I looked I was sure the "battery" inside the BU-303 is not a battery but is actually a super capacitor. Not sure what soldering a battery in would have though!