Sat Nav fault help

[Shinigami]

Right tech boffins, i've a cheapie 5" sat nav that was having battery issues and not powering on/weird lines on screen when it did.

i've spliced a new battery from a different nav (3 wires soldered to board) and matched the wires, on original were white black and red, on new are yellow black and red so matched yellow to white.

now it turns on fine, no lines on screen etc and operates/tracks fine.

However the battery won't charge properly, plugged into a usb port it got upto 4 out of 5 bars but when used only lasted 15 minutes.

Plugged into mains to charge for a few hours only got to 2 bars and was at 1 bar without using by morning.

Is the whole thing fooked? what's the 3rd battery wire for? imagine it would work fine if connected to bikes battery while in use as it does stay on while 'charging'
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Current: Honda City Fly CLR125 2003 Honda CB600F Hornet 2008 Yamaha FZ6 S2 + 1991 Kawasaki GPZ500
"Once you realize what a joke everything is, being the Comedian is the only thing that makes sense.

[T1z3R]

are the old and new batteries rated the same?
if not then the gps could be calibrated for the old one. if they are then maybe theres a charging issue which was the cause of the previous failure.
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duck my sick!

[Shinigami]

no idea on the rating of the old one, cheap chinese shite the battery was completely unmarked, replaced with what seems to be pretty standard in sat navs (3.7v)

will test it plugged in, may end up being vehicle bound if it only runs when plugged in, as long as it doesn't explode then I can probably deal with that
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Current: Honda City Fly CLR125 2003 Honda CB600F Hornet 2008 Yamaha FZ6 S2 + 1991 Kawasaki GPZ500
"Once you realize what a joke everything is, being the Comedian is the only thing that makes sense.

[WD Forte]

I spect the 3rd wire is temp sensor
LI-Ions are fussy about how they're charged
As for your snags, not sure
The screens are the main culprit for poor battery life
With a good, properly charged battery, turning down/off the backlight can extend battery run time but as the very limited internal space
dictates a weeny battery, its never going to be great.
Even if you fit a new battery,you never really know how good the charging circuitry is on these things anyway so its bit of gamble.

My £50 7" satnav works damn well but only gave about an hours run time on internal battery when new
Now, who knows?
Its always used in the van so not really an issue

If I wanted to walk about with it I'd consider patching in a 6V lantern battery (PPJ i think ?) or 6V rechargeable pack.
You could use a diode or two in series to drop the forward voltage a bit if you felt it was needed

Edit:
Just checked, a PJ996 was what i was thinking about but on reflection, its a bit chunky to stick in yer pocket
I'd probably use one of these instead and AA nimhs
https://i.ebayimg.com/t/RC-4-x-AA-Battery-Holder-With-Futaba-Plug-For-Receiver-Cars-Planes-Boats-UK-/00/s/NTAwWDUwMA==/z/jlgAAOxyGstSC90t/$T2eC16hHJIkFHSY0gspfBSC90thE1w~~60_12.JPG
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bikers smell of wee

[stinkwheel]

If you use an M-ap, you'll get a much bigger user interface AND reduce battery use to zero. Gets a full signal everywhere in the UK too.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.