Nano-3 will not charge

[Tony]

Hey all, my Nano-3 is up to date and worked fine a few weeks ago.

Trying to charge it for tomorrow, it continues to DISCHARGE when plugged in to factory wall charger, brand x wall charger, and through PC/USB, both with unit shut down and while up and running.

Started at over 20% battery but it only goes down. 2 LEDs.

I am going to let it crash and try charging from that state, any other udeas?

[Tony]

So finally the discharge is reversing. I did not let it crash, decided that would be risky. Just kept unplugging/replugging and shutting down. Room temperature for three weeks and around 40% charge, apparently that falls under the cautions? Had this thing for about 7 years and new battery last year, looks like I have to treat it with suspicion and kid gloves from now on!?

[Martin Gregorie]

What sort of batteries does it use? If its on AA or AAA cells, they're
probably NiMH, which are pretty much junk. Replace then with Sanyo EneLoop
and you'll see a big difference.

The other point, particularly a problem with NiMH chemistry, is that they
self-discharge quite rapidly - and this process is speeded up if the
device using them has any type of soft-touch switch rather than a
mechanical power switch. The former makes the device permanently 'on'
because soft-touch switches burn battery power while they are watching
for somebody to press the on switch.

As a result, when you aren't using the PNA/PDA/logger which has a soft-
touch power switch they are still using battery power.

Example: I have a fairly old EW Micro logger, which uses a set of four
NiMH AA cells to power it when it isn't connected to the glider's 12v
supply. It also has a soft-touch power switch. Consequently, if it isn't
recharged at least once a month during winter, when we aren't flying, the
NiMH cells will be destroyed, and must be replaced and the logger will
have also loose its configuration settings.

My Medion S.3747 PNA, which runs LK8000, has the same issue, a touch-
sensitive power switch, and also needs to be recharged each month over
winter, while by contrast the even older Binatone PNA that the Medion
replaced has a mechanical power switch and only needs charging every six
months or so.

I've never used a Nano, but I have a strong suspicion that it has a soft-
touch power switch and so will flatten its batteries relatively fast.
Keep an eye on its charge state during the winter and recharge as needed
and its batteries will last a lot longer. Fortunately modern hybrid
battery chemistry (or Li-ion) has a much lower self-discharge rate than
NiMH batteries.


--
Martin | martin at
Gregorie | gregorie dot org

[Matthew Scutter]

I believe it uses an 1800mAh LiPo that is not user replaceable. I have seen one swell up like an old laptop before so they are not immune to failure. I would guess yours has failed and needs replacing.

[stephen...@sympatico.ca]

Nano and Nano 3 are user replaceable and without worrying about the seal.

[John DeRosa OHM Ω http://aviation.derosaweb.net]

You may want to ask about this on the LXNAV Google group.

[Stéphane Vander Veken]

This is from the Nano³ manual:

4.11 Replacing battery
The battery can be replaced by user. You will need a screwdriver with cross head (Phillips).
Unscrew three screws.
Open the cover and remove the battery.
Insert a new Nokia 3310 battery (Li-Ion). Make sure that the contacts are properly aligned.
Close the cover and screw back three screws gently.

So no problem there. It could be that your new battery is less resistant than your first one, especially when getting very low on charge...

The only problem I had with my Nano³ (original battery - 2014) was that it disconnected in flight, interrupted the log and restarted the Nano. I solved this by putting some padding behind the battery, to keep it in place.

[kinsell]

Have you tried different USB cords? They can become intermittent.

One long shot is USB sockets can become contaminated with dust and
pocket lint after years of use, plugging in the connector pushes a
little bit of gunk into the socket each time. If it happens again, try
holding the plug into the unit. Can be cleaned out with something like
a flat wooden toothpick.

[Tony]

Thanks, everyone. I think Martin may be on the right track. Situation resolved after multiple tries. LXNAV recommended charging without shutting down which I will try tonight. Also going to assume the "extended period" warning applies to weeks, not months!

[Martin Gregorie]

I didn't realise it has Li-ion batteries: using any power switch other
than mechanical is bad news for those: if you don't check their charge
state regularly the batteries WILL self-destruct if their voltage falls
below 2.5v per cell or they're charged above 4.2v. On top of that a Li-
ion battery self-discharges at about 2% per month, even when not
connected to anything.

If the Nano's charger (external or built-in) has an automatic cutoff at
full charge and can 'float' when the battery reaches full charge, I'd
leave it permanently on charge when its not being used. This style of
charger has been common for years for SLA batteries and is often supplied
with the device. My camera chargers (both built-in and separate) do this
and so does the charger for my Yaesu FTA-250 hand-held radio.

[Moshe Braner]

On 4/30/2021 6:01 AM, Martin Gregorie wrote:
> ...

>
> I didn't realise it has Li-ion batteries: using any power switch other
> than mechanical is bad news for those: if you don't check their charge
> state regularly the batteries WILL self-destruct if their voltage falls
> below 2.5v per cell or they're charged above 4.2v. On top of that a Li-
> ion battery self-discharges at about 2% per month, even when not
> connected to anything.
>
> If the Nano's charger (external or built-in) has an automatic cutoff at
> full charge and can 'float' when the battery reaches full charge, I'd
> leave it permanently on charge when its not being used. This style of
> charger has been common for years for SLA batteries and is often supplied
> with the device. My camera chargers (both built-in and separate) do this
> and so does the charger for my Yaesu FTA-250 hand-held radio.
>

Right in theory, but in reality it seems that many of those
push-button-to-start devices hold their charge for many months, even
years, with no problem. I have several such devices, including rarely
used old smartphones and tablets, e-readers, goTenna gizmos,
flashlights, etc. The circuit of such on/off buttons can be designed to
use mere microamps *. LiIon batteries usually have a protection circuit
built in to prevent them from over-discharging.

The PLB I carry with me when flying has a push button to turn it on, and
its non-rechargable lithium battery pack is officially good for 5 years
- and then is still supposed to be strong enough to transmit (in pulses)
for 24 hours.

And I've read warnings in various places NOT to use a "float" charger on
lithium batteries. E.g., if you use a 12V LiFePO4 battery instead of
SLA in your glider (highly recommended!) do not leave it on a float
charger designed for SLAs when not flying. Ideally you'd use a charger
designed for LiFePO4, and it shuts the charge off completely when it
decides that the battery is "full". You can use a charger designed for
SLA, the battery will be mostly but not fully charged, and you should
manually disconnect it after it thinks the charge is done.

* Math appendix: if the battery capacity is 1 amp-hour and the
pushbutton circuit uses 10 microamps it will take 100,000 hours to
discharge the battery. That is more than 10 years.

[Dave Nadler]

On 4/30/2021 6:01 AM, Martin Gregorie wrote:

> ... On top of that a Li-

> ion battery self-discharges at about 2% per month, even when not
> connected to anything.

Please, there are MANY different kinds of Li-ion batteries,
and some of them have MUCH lower self-discharge than 2%/month...

[Martin Gregorie]

On Fri, 30 Apr 2021 08:42:58 -0400, Moshe Braner wrote:

> On 4/30/2021 6:01 AM, Martin Gregorie wrote:

> Right in theory, but in reality it seems that many of those
> push-button-to-start devices hold their charge for many months, even
> years, with no problem. I have several such devices, including rarely
> used old smartphones and tablets, e-readers, goTenna gizmos,
> flashlights, etc. The circuit of such on/off buttons can be designed to
> use mere microamps *.
>

I was quoting from my own experience from using apparently similar PNAs:
one has a mechanical power switch, the other a soft sensor power switch.
But I take your point: an even old Pentax Optio snapper uses a soft
switch, but holds charge much better than the newer Medion PNA I run
LK8000 on.

> And I've read warnings in various places NOT to use a "float" charger on
> lithium batteries.
>

I was not recommending using an SLA charger for Li-ion or LiPO batteries.
Maybe I should have been clearer about that.

This could well be a case for recommending devices that charge via a USB
connector - I don't recall seeing any of these that don't stop accepting
charge when its battery is full.

> * Math appendix: if the battery capacity is 1 amp-hour and the
> pushbutton circuit uses 10 microamps it will take 100,000 hours to
> discharge the battery. That is more than 10 years.
>

Sure, but in a race to the bottom on competitive pricing, what's the
likelihood that the device will contain the best soft switch rather than
the cheapest?

[Tony]

I'm glad this thread has been expanded upon...by the way when the Nano reversed the discharge and started charging, it ended up at over 107% before I unplugged it!? Can't swear I never saw that before but the discharging while trying to charge was definitely a new thing...

[Richard Pfiffner]

Start by just replacing the battery. If that does not work buy a new NANO or send to LXNAV for repair.

Richard

[Tony]

On Friday, April 30, 2021 at 10:03:29 PM UTC-4, Richard Pfiffner wrote:
> Start by just replacing the battery. If that does not work buy a new NANO or send to LXNAV for repair.
>
> Richard

Battery is one year old. Will monitor behaviour.

[Paul Agnew]

>>>
Resurrecting this Nano3 battery thread...

Does anyone know where to source the 1700mAh battery specified? All of the Nokia 3310 3.7v batteries I can find online are much lower capacities. The best I could find is a 1500mAh on Ebay, but I'm wondering if there is a compatible battery out there that we can use.

My Nano3 sat for many months and when I went to charge it today it won't accept any of my chargers. I can boot it, but it shuts down for low battery in about 45 seconds. No indicator lights when I plug it in.

Yes, there are replacement instructions in the NANO3 Manual and also under the cover once you remove it. The label under the back cover says:

3.7v 1700mAh Li-Ion BATTERY TYPE (NOKIA 3310 or similar)

It's the "or similar" that has me wondering what other batteries are compatible.

PA

[BobW]

If you haven't already, you might try batteriesamerica.com, where I sourced
not-only some - gasp! - ni-cad batteries for a 1990's-ish AM Futaba RC control
box and long-disused RC sailplane receiver (originals corroded/long-dead).

Pretty astonishing source in terms of "general battery availability" IMHO...

[Richard Pfiffner]

Battery Available on this page


https://www.craggyaero.com/lxnav_accessories.htm
Part number 1055039

Richard

[Paul Agnew]

Thanks, Richard! Can you confirm the amp hour rating for this battery?

PA

[Tony]

I'm sure Paul Remde has the battery. Also, bad idea to let any of these gadgets sit untouched over the winter - even the Florida "winter". That being said, it's always a goat rodeo for me to get spooled up on the individual systems, buttons , file locations &c. if I do.

[Richard Pfiffner]

It is a LXNAV battery so I suspect it is 1700 mAH.

Richard,

[Paul Agnew]

On Monday, March 27, 2023 at 9:59:45 PM UTC-4, Richard Pfiffner wrote:
> It is a LXNAV battery so I suspect it is 1700 mAH.
>
> Richard,

Thanks, Richard. With shipping being almost 50% of the cost of the battery, I'll have to look around the website to see if I need anything that can be combined to spread out some of the expense over several items.

Now, the plot thickens...

I pulled the existing battery and was surprised to find it had 3.1v remaining. The unit will power up normally, but shuts down with a low battery warning a few minutes later. I've checked the USB port for debris and have tried several compatible chargers and USB cables to no avail. The battery bumped up to 3.6v with a quick two minute direct connection to a 5v 1amp charger, so I'm starting to suspect the unit is the problem. No matter what I connect to it, I get no lights indicating charging or power connected. NanoConfig last showed the battery voltage as 3.57v before it auto-shutdown, so I don't think it's a problem caused by the full-discharge voltage protection circuit (or whatever it may have built in.)

Hopefully, LXNAV will respond to my inquiry on Monday and they'll know what to do. Batteries can be fickle, so it still may be that, but the lack of any lights when turned on or charging is puzzling.

PA

[Tony]

Hey Paul, have you tried shutting it down after connecting charger? Not the preferred method but just thinking of different approaches.