I'm interested in preserving my Go 920's internal battery. Various terms are used when discussing the 'OFF' state a TomTom unit can be in. I've come across these terms in connection with the operation of a TomTom.

Suspend
Standby
Hibernate
Sleep
Power down
Switch-off state
Fully shut down state

How many 'OFF' states can the Go 920 be in?
What are they?
And how do they rank for battery power consumption?

And hence advise what state my Go 920 is in...

1. after the pin hard-reset is used?

2. after the ON/OFF button is held down until the monochrome screen of text appears, and then switched off by pressing the ON/OFF button again but briefly? (The 'Sleep' and 'Power down' terms appear in that text screen)?

3. when, after use for navigation, it's turned off by pressing ON/OFF button briefly...
3.1. when an Auto-on navcore is installed?
3.2. when a normal navcore is installed?

4. when, after use for navigation, the USB power is removed and the battery saving feature is activated in the setup menu...
4.1. when an Auto-on navcore is installed?
4.2. when a normal navcore is installed?

I hope some-one can help clear up my confusion! Please!

I don't really understand why you are so concerned about the state of your device when it is off.
As far as I know there is no auto on navcore, there is only a battery saving setting, with that choice your device switches off after 10 seconds with power off, rather it goes to sleep and after restoring the power it starts again automatically .

That is a very handy option, there is only a small objection to it, because of the sleep mode the device continues to consume a very small amount of power, eventually the battery is completely empty.

Of course, the device will not start automatically the first time.
A great danger for a battery that has been completely discharged and is not charged within a certain period of time is the chance that it will even reverse polarity, then negative becomes plus and plus becomes negative, which cannot be repaired.

Now there is a small piece of software, suicide, which turns your device in battery saving mode off after about half an hour, power consumption to zero.

What you only have to deal with now is the internal resistance of the battery, how old is it, how was it mistreated in the past, that now determines how quickly the battery drains itself.
But in principle you can work very well without a battery, after all there is a very large one in the car or your motorcycle, only then it is really off and no more auto start.

Get your Suicide from here:
ftp://All_Available_Goodies_and_Info:Av ... uicide.rar

Thank you pe1agp. But I feel I should apologise: I didn't make it clear why I was asking. Sorry. And I should have mentioned that I'm a retired electronics engineer; with, at it happens, a good knowledge of and experience with the Li-Po (Li-Ion) battery and its operation and characteristics.
Now with the supply of good replacement batteries for my satnavs becoming more problematic in my experience as the years go by, I want the ones that I have, to last as long as possible.
Covid lockdowns have resulted in our family cars being left unused for lengthy periods. Our cars (mine and my wife's) each has a Go 920 in it, plugged-in to USB 5v derived from the car's ignition-switched 12V. Those Go 920s are the same as each other - each running the same Auto-on navcore (see the thread https://www.navitotal.com/navcore-510-with-auto-power-t13728.html, that utilises the shut-down file suicide.dat set to 90-minutes).

Over the last year (since the pandemic began) I've observed that when one car is used while the other is laid-up for a week or more, and neither Go 920 is used (they're not switched on - familiar short local journeys only), it is the Go 920 battery in the used car that loses its charge. The unused car's Go 920 battery keeps its charge. Quite the opposite of what I was expecting. And it doesn't matter which car is used. It's always the Go 920 battery in the used car that loses its charge, usually to the point where it won't turn on without being placed on-charge.

I am interested in understanding what shut-down modes the Go 920 has. Are they wholly controlled by software (eg the navcore)? Or are firmware (eg bootloader) as well as hardware (eg uP ICs) involved? Hence my post.

The only answer I can give you I have already given you, and yes the electronics are not entirely unknown to me, about 50 years ago I took my exam for my radio amateur license.
But that knowledge is entirely hobby-based.

Indeed, you would expect that the battery used will last the longest of the device used, but on the other hand, you have no guarantee that all batteries will have exactly the same properties and lifespan from the factory.

So as I have already answered, a special navcore developed by the very famous Downunder, I do have a number of his on my server, but never immersed myself in this special one, and the only setting known to me is that of the battery saving.

I don't have the slightest idea how that is processed via the electronics in the devices of TomTom, the boot loader is nothing more than the BIOS in your PC and starts up all the hardware, possibly that the secret is located there.

Incidentally, there has been a persistent story in previous years that you can only upgrade that bootloader and never downgrade, that has been rumored for a long time and it is possible that what Downunder is writing about the exe file that, and then I have to guess, something changes in the boot loader.
What is certainly true is that if you are going to use a different navcore then pay attention to the file "system" which is the boot loader because if it is of a higher version than already installed it will be installed the first start which is not too bad but if at that moment you end up with an empty battery, you can use the TomTom as a bookend.
But even for that problem I once gave someone a indeed a special navcore including boot loaders, who later wrote that the device was working again, but it never became clear to me what state the device actually got into and whether the problem was caused by the failure of the boot loader upgrade.

Furthermore, I never worry about the battery, I never leave my GO 950 connected in the car, sometimes on the motorcycle my Rider v2, but it is in the backyard, it is from 2009 when I retired, I have I suspect that the full battery will last for half an hour, but for portable navigation I have my Galaxy S8.
I have sometimes wondered what the use is of a battery in those devices, in my opinion a button cell, just like in the PC, would have been sufficient to hold certain settings, only when such a device is used without on-board voltage it has its usefulness, but that's my thoughts on that.

Something completely different, I have a number of GoPro's, 2 old Hero 2 and 2 old Hero 3 plus a small Session for the helmet, even all those devices only have such a small battery that never last longer than about 45 minutes, now you may wonder why is there a battery that only lasts 45 minutes, in 45 minutes you can record quite a nice piece of video, but if I ride around on my motorcycle all day, that battery is not at all important , for the session I have a pretty large power bank in my pocket that lasts for more than 6 hours on a 64GB SDHC card, I thought, so here too my question, why should there be a special battery in there, they can never are large enough to provide the device with power for a day like the TomTom's

Best regards

Go920s running with Navcore 9.510 with auto-power-on - Measured battery discharge currents:

Information that could be useful to somebody else (apart from me!)

Background: Found that none of my Go 920s was holding its battery charge while in car. But OK when out-of-car.

Set-up: Go 920 fitted with a good (1300mAh) fully charged battery with its leads modified by a 3-core ribbon cable that interrupted the +ve (red) wire and tapped into the -ve (black) wire. That cable ribbon was extended through the body of the Go 920. This enabled the battery current (discharge and charge), battery voltage and load voltage to be measured externally on digital multimeters.

Normal in-car Mode -
1) USB 5v input,
2) Go 920 fully turned-on to normal navigation screen: battery charges at a few tens of mA.

Portable Mode -
1) No USB 5v input,
2) Go 920 fully turned-on to normal navigation screen: battery discharges at around 500mA, giving theoretical maximum battery operation of 2.6 hours.

Sleep Mode 1 –
1) USB 5v input,
2) Go 920 fully turned-on, (Battery Saving Preferences option must be enabled in the Go 920 menu settings), and then
3) USB 5v input removed; or
Sleep Mode 2 –
1) No USB 5v input,
2) Go 920 turned-off,
3) ON/OFF button held down until B/W text appears, and then
4) ON/OFF button pressed briefly: in both Sleep modes, battery discharges at 490 microamps, giving a theoretical maximum battery operation of 110 days.

Hibernation Mode –
1) No USB 5v input, and then
2) Go 920 RESET operated with a pin: battery discharges at 2.6 microamps, giving a theoretical storage life of many months.

Rogue Mode –
1) USB 5v input,
2) Go 920 turned off, and then
3) USB 5v input removed: battery discharges at 45mA, giving a theoretical maximum battery operation of only 29 hours.
Problem found!

When the Go 920 is kept plugged-in to the car’s USB ignition switched 5v, AND it’s not turned on/used while the car is driven, its battery will discharge rapidly after the ignition is switched off.
If however, the Go 920 is always turned on (for use) while the car is driven, its battery will keep its charge after the ignition is switched off.
This rogue excessive discharge effect seems to be caused by an unfortunate bug in the auto-start navcore.