How to increase the battery charging voltage

Bridges

8/30/24, 9:50 AM

I plugged in a LiPo battery into my single board computer running Ubuntu 20.04.1 LTS. The Power Statistics shows the battery is 7.4V but the actual battery voltage is 7.6V. Now, when the battery is 100% charged, it can only be used for 10 minutes.

I would like to ask if there is a way to increase the battery charging voltage? It will save me from buying a 7.4V battery.

I am using a LattePanda Alpha board, it can support 7.2 to 8.4V battery. The battery that I have is 7.6V. The Ubuntu system seems to recognize it as a 7.4V battery and stops charging at 7.4V. I think that's why I am getting 10 minutes of use time. I would like to increase the battery charging voltage so the battery can charge to its real capacity.

The highest charging voltage that the battery can sustain is 8.65V.

Is there a way to change the battery voltage? The system thinks it is a 7.4V battery, is that a way to configure it as a 7.6V battery instead?

Looking at https://www.kernel.org/doc/Documentation/power/power_supply_class.txt, it seems that the "voltage_max_design" is to set the battery full voltage. But this attribute is not available on my Ubuntu.

VOLTAGE_MAX_DESIGN, VOLTAGE_MIN_DESIGN - design values for maximal and minimal power supply voltages. Maximal/minimal means values of voltages when battery considered "full"/"empty" at normal conditions. Yes, there is no direct relation between voltage and battery capacity, but some dumb batteries use voltage for very approximated calculation of capacity. Battery driver also can use this attribute just to inform userspace about maximal and minimal voltage thresholds of a given battery.

Is that mean writing a battery driver is the only solution? If that is the case, I may buy a 7.4V battery instead as I have no knowledge about it.

Screenshot of my BAT0

I managed to probe the battery connector and the charging IC on LattePanda Alpha is actually delivering 8.4V. So I guess the battery is deteriorated and I will try to get a new one.

Thanks for all the help!

0 + 7

battery-charging-threshold

Luuk

8/30/24, 10:32 AM

Increasing the charging voltage will not increase it's life time, and not increase the time you can use power from that battery. Power is measure in [Watt](https://en.wikipedia.org/wiki/Watt), not in Volts.

Sam O'Riil

8/30/24, 12:01 PM

You should use exactly that type of battery the system was meant to use, otherwise what you are getting now is just the smallest of possible troubles. It's not clear what's your situation though, can you elaborate more on it?

FedKad

8/30/24, 12:49 PM

Please, put any extra information into the question and not in comments.

Luuk

8/30/24, 1:06 PM

Please read about [battery capacity](https://www.pveducation.org/pvcdrom/battery-characteristics/battery-capacity), and find out that increasing voltage does not increase the the usage time.

Bridges

8/30/24, 1:50 PM

Thanks for answering! But if a 7.6V battery is charged at 7.4V only, I don't think it will reach its real capacity.

Thomas Ward

8/30/24, 1:54 PM

@Bridges your charge voltage is regulated at a hardware level. 7.6V vs. 7.4V has no effect, it's the **Wattage** that determines if the computer can charge. Case in point my XPS laptop uses a 130W charger. My XPS Folio tablet uses a 45W charger. 90W can *charge* my XPS but slowly. 90W is faster-charger for the XPS Folio tablet but can also charge my XPS laptop at a *slower* rate. 135w is overkill for the Folio, but it only pulls what it can handle. Watts is power measure, not Voltage.

Bridges

8/30/24, 3:18 PM

Thanks for the reply! But it is difficult for me to understand how we can pump energy into the battery if your charger voltage is lower than the battery voltage. To charge a 4.2V lithium battery, the charging IC needs to be at a slightly higher voltage which is around 4.325V (it depends on the battery).

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: How to increase the battery charging voltage

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