Nuvi 2599LMTHD Faulty Battery

It is possible a new battery would fix your nuvi, but it is also possible that there is a hardware failure in the USB port or charging circuitry. If that is the problem, a new battery won't help.

When you say "it won't turn on" do you get any messages. flickers, images on the screen at all or is it completely dead?

Screen remains completely blank/dark...no sign of life whatsoever.

USB port is not loose...as you suggest it might be something in the charging circuitry. Probably not worth having repaired.

Too bad as I treat this unit with "kid gloves". I've talked with Garmin tech support. Not much help other than offering to sell me refurbished unit (same model) for $99.

If you never see anything on the screen it could be a faulty screen or other part of the hardware or even a cable fault. Normally you'd expect it to work when plugged in even with a faulty battery.

Sometimes when Li-Ion batteries have been left dead for too long, their voltage is low enough that even after plugging in a charger, the voltage won't increase fast enough for the charging circuit to recognize it, and the charger will cut back out.
I've revived a couple of forgotten old drill batteries and the like by plugging them in, letting them sit on the charger for a couple of minutes (usually until the charge indicator light on them would start flashing an error, though I imagine you can just guesstimate it with a Garmin) then unplugging and doing it again. After a few cycles of that, it'd charge normally.
Of course, it did no big favors to the battery to let it completely die to begin with, so I'd make plans to replace it anyway. Replacements are cheap on amazon and ebay, and it doesn't take anything more than a few torx screws to open the case to replace.

I've had my Nuvi on and off the charger so many times in attempt to jumpstart it that I've lost count...still no sign of life !!

Hate to invest even $15 on replacement battery as it's not a sure cure.

Probably better to spend the money towards another unit than a replacwement battery.

Like to hear your thoughts on how Nuvi should be prepped for storage that might extend past a week.

Here is something to try that won't cost a penny. Take the nuvi apart and remove the battery, then try to boot it up plugged into the power supply with the battery removed.

If it works that way, there is a good chance that a new battery will fix it ... if not, it is probably toast. If you have given up on it, you have nothing to lose by trying this test.

I'm not convinced that these thing are a delicate as some believe.

I have a Nuvi 50 that is more than 5 years old, maybe more. I used to leave it mounted to a vent in the car, summer & winter, and it powered up whenever the car was running. Never really ran on battery.

A year or so ago I was given a "better" model and I semi-retired the 50. Now I only charge it when a map update is ready. I charge it in the car, take it off charger, plug in to USB, and download map then back to storage.

Since I NEVER use it as a hand-held device (it was never designed to be used that way anyhow) I don't see any battery charging problems with the 50 that does not get charged regularly.