Why do I get an over voltage warning at 3V and 4V.

[anon8380037]

I have been charging and posting in a coffee shop with a free new Power Bank thingy from EE for about an hour.

I then get a bell about 3 times in a minute. I can't catch the notification at first before it disappears. I finally see and catch it.

The portable charger is rated at 5V 1A.

I am using a Note 3 which I can charge from a 0.7A car charger or its 2A mains adaptor. (pc usb is 0.5A ?)

Why does it warn me that it's overcharging at 3V and 4V, and what is the danger. I opened GSam and the temperature is fine.

This happened when the 2600mah charger is down to 25% or less (1 of 4 lights remaining).

I don't understand or forget the significance of voltage. I thought all chargers were 5V.

Thanks.

 

[Rukbat]

The power bank is a lithium battery, not a mains-powered charger. (You may be charging it with a mains-powered charger as you're using it to charge the phone, but you're still charging the phone from a lithium battery.) As you use it to charge the phone's battery, the power bank's battery voltage drops, unless the mains-powered charger can supply enough current (and the power bank can draw enough current) to keep the voltage up.. When you get down to 3 Volts on the power bank, you're destroying the power bank. (No lithium battery should be discharged below 40%, which will give you about 3.5 Volts at the terminals, depending on the load.)

GSam is giving you the wrong indication - it should be giving you an undevoltage warning - "Battery Under Voltage (3.0 V)".

 

[anon8380037]

Ah the warning was from Gsam, not the Note 3.

I wasn't using AC as well.
The Power Bank came with about 60 - 70 % (flashing 3rd light of 4) so I had charged that up earlier in the day.

So if I didn't have GSam I wouldn't have known?

Below 3V at under 40% will damage the charger. I accept what you are saying but if that applies to all portable chargers there's no info out there, or on this leaflet.
I am a currently a skinflint cheapskate and these were free from the carrier, and going forward, customers can recharge their own, or exchange them for a charged one in a store for free. This sounds like a fly in that ointment. I may just try to disable the GSam warning, but I will read this again later.

Do the big name portable chargers have a cut off or warning on them, I don't know.

Awesome as usual Rukbat. Thanks.

On Edit : The Note 3 was between 17 - 21% when I connected it (scold me later). I know it's easier to charge a battery @ around 40 - 60% when there's less resistance, or whatever.