Zumo User Forums

I bought my Garmin Zumo XT in June of 2021. Lately I have been using it on bike rides on the internal battery. In warmer weather the battery lasts the entire ride. Lately, the temperatures have been about 18 to 20 degrees Fahrenheit and the battery doesn't last as long. I know that the colder weather does affect battery performance.

How much does it affect battery life? How can I determine if the battery needs replacement?

I would imagine the capacity of the battery would be 1/2 to two thirds of what it would be at 80F. You will find out if it needs to be replaced next summer I expect! Failing that maybe power it?

If you press the battery symbol at the top right for about 10 seconds you enter the developers / diagnostics pages. One of the pages includes battery capacity / charging status, and it might give you some answers.

Temperature affects battery =capacity= not life. Life is determined by how many charge cycles the battery experiences. A cycle is the =equivalent= of one full discharge to the safety shutoff point and one full charge. A cycle is not equal to how many times you discharge/charge a partial amount. IOW, two half discharge/charge events equal one cycle. After a couple hundred cycles, battery capacity is reduced by about 20%.

So if your battery is three years old it may only have about 80% or less of its original capacity under ideal conditions. Add in those very low temps and capacity may temporarily be a lot less. I would not replace it until it shows signs of low capacity under more normal temps. If you do get a new one, keep in mind that it takes a few cycles for the full capacity to be usable.

The only way temp can affect battery life is if you expose it to very high temps, which will shorten its life (as will letting it discharge to the safety shutoff point and letting it sit without charging for a long time (weeks)).

-dan

all batteries prefer cold temperatures and not high heat temps, like car batteries in Florida that need replacing earlier than up North snow belt cars, its the heat that causes batteries to die sooner. I don't think there's a fix except to buy a new battery if you live in high heat places.

I would let it go flat and then charge it from a good power source with the screen turned off for 24 hours.

See if that improves how long it lasts.

If you have been using the Zumo while connected to a USB charger - it is actually using up battery - at a much slower rate, but it requires more power to run than it is getting from the USB socket. So it slowly leaks power. I think that I have a full battery, but it is way down.
I have a spare cradle and a 4A transformer and when its on my desk it sits in that to avoid this from happening. (It doesn't need 4A, but it has plenty for me to use and it still be charging).

Sometimes the software 'guesses' the capacity from its use and its charge and it gets it wrong. But it behaves as if it is correct.

I often have to do this with my Cardo headset. The Cardo gives a rough indication of battery remaining through the earphones when I turn it off. Sometimes I will leave it to charge, test it, turn it off and it says 75% full. And then it dies much earlier than it should. If I leave it switched on for a day to let it fully discharge, then charge it, it reports 100% full when I turn it power off, and lasts for much longer.

Oop North John wrote: ↑Mon Dec 02, 2024 7:46 amIf you press the battery symbol at the top right for about 10 seconds you enter the developers / diagnostics pages. One of the pages includes battery capacity / charging status, and it might give you some answers.

I have that screen up now and it shows:

Batt Capacity 100

Jim1348 wrote: ↑Tue Dec 03, 2024 2:02 am

Oop North John wrote: ↑Mon Dec 02, 2024 7:46 amIf you press the battery symbol at the top right for about 10 seconds you enter the developers / diagnostics pages. One of the pages includes battery capacity / charging status, and it might give you some answers.

I have that screen up now and it shows:

Batt Capacity 100

I'll guess then the XT thinks the battery is ok? But I have no idea of what a bad batteries value would be, or the rate of deterioration.

I'll also guess that the battery will fail at the most inopportune time!

I don't think Garmin really expects a Zumo to be used for extended periods without a power supply. The battery is fine for picking destinations, previewing a route, etc., before setting out, but life is simpler if you connect the powered mount. The screen will not dim because it is operating off the battery, and the reduction of battery life because of temperature extremes will not be a concern.