Nuvi 255W totally dead

You need to let it charge for at least 1/2 an hour before trying to turn it on even though it is connected to a charger. A lot of these units require some battery charge as part of their startup diagnostics.

Charge the unit overnight. Make sure you are using the proper A/C charger or vehicle power cord. Then hold the power slide switch to the left in the on position for at least 10 seconds.

This procedure works on my 265W (A 255 with traffic cable) when it occasionally locks up.

recently with my ancient 265WT. Turned out the battery was toast. Did a search on replacement batteries, found one (newpower99.com) and within a week I changed it and was up and running again. There are many videos on You Tube showing how easy it is to replace the battery. They even included all the tools that you need to make the switch.

Hope that helps.

George

I have always charged using a computer and usb cable. In fact I have used the same cable for years. Presumably the 255W had a dead battery but when connected to the computer it did not charge or connect. I tired bdhsfz6’s suggestion of using a different charger and it promptly came to life and charged normally. Thinking the usb cable must have failed, I plugged in a cable powered disk drive and it worked properly.

So now I have a known good usb cable that seems to work for everything except a 255W with a dead battery. Next step is to partially discharge the 255W and then see if it will charge using the usb cable.

The USB cable is probably all right. A dead 255 can draw more current than a USB port can supply. The 120 volt charger can supply more current but it still takes at least 5 hours for a full charge.

If the battery is original, gcurran's idea about replacing it makes sense. Older batteries could have only 50% of their new capacity.

dobs108

After fully charging the 255W on a stand-alone charger I turned it on to check battery life. 2 ½ hours later it is still showing two battery bars (out of four). Clearly the battery is in good condition. I then return the unit to the same computer and cable as before – it charges promptly.

So it would seem that if the battery is completely dead the computer refuses to charge it. But if the battery is only partly discharged it charges fine. Seems like a classic Catch-22 problem.

I know that modern usb devices have the ability to negotiate charging currents. Maybe if the GPS is completely dead it cannot negotiate and the computer then refuses to supply any current. But that seems illogical. After all how would usb devices without a battery work? Obviously they are also dead when plugged in. So still confused but the 255W seems back to normal.

Your computer USB Port will shut down when asked to provide too much current. When your battery is dead it will easily need more current than USB Port will provide, your USB Port shuts down, and you get the symptoms you posted.
If you have an AC USB Charger, it will probably provide more current than the computer USB Port could.

You best bet is to let it charge an evening or overnight on an AC USB Charger....

My 660 on it's original 6 year old battery acted the same as yours did.

This is obviously what happened. But the strategy of supplying a low current as opposed to none seems more desirable. That allows dead devices to eventually recover. Perhaps there are portable disk drives that behave baddy if current starved.

Not so obvious to me. The 255W is reported to use a lithium ion battery. Lithium batteries generally require careful management of charge current so not clear why a dead battery would draw more than a half charged battery.