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Satnav battery discharging
RazMan - 20/4/07 at 04:29 PM

I recently put my satnav in the dash, connecting the power lead permanently connected at both the satnav end (mini usb) and the cigar lighter plug too. I have noticed that the internal battery now discharges overnight so I contacted their technical support who said "Pull the plug out then" As I want the satnav to come on all the time (handy for those pesky speed cams ) I fitted a switch to enable me to control the power from the dash - no fiddling about with ciggy lighter plugs.

The damn thing is still discharging and seems to need the mini usb plug to be pulled out to stop it doing this.

As the drain seems to be happening in the lead & plug assembly, can I just simply put a 5V diode in the positive feed of the ciggy plug?

[Edited on 20-4-07 by RazMan]

Chippy - 20/4/07 at 10:30 PM

Cant you just wire it so that its on all the time, not the satnav but the power to it. That way battery would always be on top line, as I think they charge while turned of. Just a thought. Ray
PS: the one I purchased from you works great,

RazMan - 20/4/07 at 11:07 PM

I don't really want it on 24/7 - probably won't do the battery any favours as they have a 'memory' and like to be discharged occasionally to keep minty fresh. I will experiment a little more and try to pinpoint where the drain is.

Glad yours does the trick for you

Hellfire - 20/4/07 at 11:28 PM

Razman,

My TomTomOne is usually plugged in during typical business driving. I noticed some time ago that even though power is being supplied to it, it doesn't use it. It uses the battery until the level drops low, then it automatically switches on the recharge facility. Crazy as it will degenerates the battery quicker, maybe?
It's a company one so if it needs a new battery I wont be paying but I wonder if they are all like this...?

Steve

RazMan - 21/4/07 at 07:27 AM

You could be right there Steve. The Navman shows a green led when fully charged and an orange one when charging - its nearly always orange when I'm on the move.

Bloomin' new fangled technology

MikeRJ - 22/4/07 at 05:22 PM

quote:
Originally posted by RazMan
As the drain seems to be happening in the lead & plug assembly, can I just simply put a 5V diode in the positive feed of the ciggy plug?


If the internal battery discharges through the charger when it's powered down it's a bit of a poor design.

Wether you can use a diode depends on if the charging control is within the ciggy lighter plug, or within the module. Putting a diode in series with the output of the charger will drop it's voltage by 0.6-0.7volts which might cause problems.

One possibility is to use a double pole relay, (or two single pole relays) to isolate the input and output of the charger when the igntion is switched off.

[Edited on 22/4/07 by MikeRJ]

RazMan - 22/4/07 at 06:40 PM

I hadn't thought about using a relay but surely my switch would do the same thing - isolating the feed...... or do you mean between the ciggy plug and the usb plug?

I agree that it looks like a shoddy bit of design and I voiced my opinion when I emailed Navman's technical team. I am still waiting for their latest response.

MikeRJ - 24/4/07 at 12:32 PM

quote:
Originally posted by RazMan
I hadn't thought about using a relay but surely my switch would do the same thing - isolating the feed..


If your switch is a double pole switch then that should work fine as well, one pole used to break the feed between car battery and the charger, the other pol used to break connection bwteen output of charger and Satnav.

The reason I suggsted a relay is you could power it from an igntion circuit so the satnav would be automaticly isolated when you turn ignition off, and would automaticly start charging with igntion on.

RazMan - 24/4/07 at 04:45 PM

Ah I see what you mean now - cunning