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Can I convert a 3.6V battery into 4V? Answered

Hello everyone,

I am planning on using an A9G GPS tracker, whose working voltages are 3.5-4.2V. I have a mobile phone battery that would be perfect to power the A9G, but it's voltaje is 3.6V, so if it goes down a little bit, the A9G won't work.

So my question is: Can I convert the battery voltage to constant 4V or so? Because I feel like if I connect them as they are, once the battery goes below 75% or so, the A9G won't work.

Thanks

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Downunder35m
Downunder35m

1 year ago

I am stating the same here, it should work with just a single cell.
And as the tracker operates WITHIN the limits of a li-Ion cell there should be no problem with the voltage drop.
Once the battery is too low to operate the tracker has the same problem, assuming it will let you know the battery is empty and shut down.
Only question would be what shuts down first - protective circuit of the battery or tracker...

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Orngrimm
Orngrimm

1 year ago

I can only confirm the post of Jack A Lopez.

However, if you want to step up the voltage, you will need a DC/DC-Converter. Ideally a SEPIC as the raise of maybe only a little can be a problem for a classical DC/DC Boost.
SEPIC = Single-ended primary-inductor converter
https://en.wikipedia.org/wiki/Single-ended_primary...

The normal Asia-based sellers have lots of SEPIC (They often call it buck-boost) based on the XL6009 from XLSemi (http://www.xlsemi.com/)
https://www.banggood.com/DC-DC-Boost-Buck-Adjustab...

However, those things pull a VERY high sleep-current (in the 10-20mA-Range!) and are not very good for battery-sipping projects.

If you want to buld your own, i suggest checking out the lineup of Analog
https://www.analog.com/en/parametricsearch/11516#/
or TI
http://www.ti.com/power-management/non-isolated-dc...
Very often, those Controllers are also availabe on a demo-board where they use the reference design to have it all already made and well. For a price of course...



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Jack A Lopez
Jack A Lopez

1 year ago

I think the actual voltage, seen across the terminals of a lithium-ion cell, is in the range from approximately 2.8 volts to 4.2 volts, and often there is a protection circuit thrown in, to disconnect the cell, at around 2.8 to 3.0 volts or so.

I mean, if I look at the graph, in Figure 1, on this page, "BU-501a: Discharge Characteristics of Li-ion" at batteryuniversity.com,

https://batteryuniversity.com/learn/article/discha...

I dunno. Are they lying to me?

To me, this specified voltage range of 3.5 to 4.2, for your tracker toy, makes me think it was possibly designed to run from a single Li-ion cell. Like, that is really the kind of battery it wants.

I am going to humbly suggest, trying your tracker toy, with just a 1-cell mobile phone battery, like you suggest, connected across its input leads, without a power converter in between the two of them.

By the way, I am kind of wondering what does happen with the tracker toy, at 3.5 V, the low end of its specified voltage range. Maybe it just shuts itself down gracefully? That would be nice.

If you have a bench type DC power supply, the kind with some knobs to adjust the current and voltage limits, you could use that to test what happens; i.e. turn a knob, and observe what the GPS tracker gizmo does when its supply voltage reaches 3.5 volts, or lower than that.