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

**Grayscale** · 02-24-2005, 07:41 PM

what?! we want 3.3 volts, not 5. Why couldn't you just use a diode and not have a rechargable battery?

**ddogg_777** · 02-24-2005, 07:51 PM

Nicads are forgiving, a 5v charge to a 3.6v nicad probably won't harm it (hmm, this my guess anyway, don't take as scripture). Besides, until someone tests the voltage at those leads we don't know for sure if the pcb board has a regulator built in to drop it to 3.3v...
Go ahead and do your regulator and diode idea, there is nothing wrong with it and should work just fine. It just might be more cluttered than others want.

**naveedh** · 02-24-2005, 08:17 PM

u can buy rechargable pcb batteries from maplins. Btw the Rikaline does not have something like what is posted on that website, it is a proper raw uncovered watch like battery.

**Enforcer** · 02-25-2005, 04:29 AM

Originally Posted by Grayscale

what?! we want 3.3 volts, not 5. Why couldn't you just use a diode and not have a rechargable battery?

to recharge a battery you need to put in a higher voltage than what it outputs

**westscape** · 02-25-2005, 01:48 PM

I'm no expert on batteries but having worked in the electronics and instrumentation field for 22 years I have picked up a bit of pigeon info.

The important thing with Ni-Cads is to limit the charging current to a safe value otherwise it will overheat. The simplest way is to use a higher voltage and a resistor using a basic ohms law calculation. Connecting 3 nicad cells (3.6v nominal to a unlimited 5V supply will give a very large charging current only limited by the internal cell resistance) and is quite likely to cause damage.

I would think the main advantage of the supercap is that it can be charged extremely quickly compared to a nicad.

I did some digging; this is the closest data sheet I can find from the manufacturer.
http://www.elna.co.jp/en/ct/pdf/dlce.pdf

**Grayscale** · 02-25-2005, 02:52 PM

How about a 9v battery or a couple of AA's hooked up to a 3.3v regulator, that would take forever to drain! And it'd be less cluttered if you hid it somewhere

**ddogg_777** · 02-25-2005, 03:51 PM

Nah, they would be drained in a month or two according to the website.

**djmickyg** · 02-25-2005, 11:11 PM

here's my background

ive had the gps for about a month but i havent used it much in this time..
when i first got it used to put it on the roof and it worked fine, but i only did this a few times.
last week i mounted it on the windshield, up the top corner, and its velcro'd on. the first time i used it it worked fine.. but since then i havent been able to lock onto a sat and it finds a max of 3 sats and thats after a little wait..
so i figured i may aswell hack out this lil cap.

as soon as i pluged it back in it found 2 sats instatly and after a a few mins i got a lock again.. but it was having truble holding the lock.
i also figured if i put my hand around it, it was able to lock on to a sat.. and i was locking onto 8+ which i i think is the most ive locked onto.

so im gona make a little metal box togo around it and see how that goes.

**djmickyg** · 02-26-2005, 10:03 AM

i put some foil around the back of it too see if it would make a differrence.. and yep again i locked on more sats.. this is looking good.

**mattress** · 02-27-2005, 01:59 PM

wow very interesting find... let me try to understand what you're saying. you have the GPS inside the car, mounted to the top corner of your windshield with velcro. is it upside down? where did you put the foil?

I've already dumped my GPS unit in some plasti-dip to make it weatherproof. I'd love to make it more accurate/faster... I'm gonna have to take my cap out and put foil around it and redip it...