Tricking circuit that detects li-ion battery temp/gauge?

[caphair]

Sometimes when I'm using a bench supply connected to the battery terminals of an iPhone (or any device that normally measures battery temp/gauge) the phone will display a message saying it's too hot and needs to cool before using.

If I remove bench supply and plug in a known good battery the message goes away. So I'm guessing sometimes the internal circuitry of the device looks for a temp/gauge reading and if it's missing throws that message.

Could I add a resistor to the pins on the device terminals to trick the circuit into seeing an acceptable value for a battery fully charged at room temperature or it wouldn't work? If so how do I determine the resistor value to use?

[sam_sam_sam]

Re: Tricking circuit that detects li-ion battery temp/gauge?

Sometimes when I'm using a bench supply connected to the battery terminals of an iPhone (or any device that normally measures battery temp/gauge) the phone will display a message saying it's too hot and needs to cool before using.

If I remove bench supply and plug in a known good battery the message goes away. So I'm guessing sometimes the internal circuitry of the device looks for a temp/gauge reading and if it's missing throws that message.

Could I add a resistor to the pins on the device terminals to trick the circuit into seeing an acceptable value for a battery fully charged at room temperature or it wouldn't work? If so how do I determine the resistor value to use?

First off you can not fool it that way ----> if you take the protection board off the battery and hook up power supply to the protection board

Be very careful removing the protection board from the battery you can start fire doing this

HOWEVER you need be real careful when doing you can fry the phone and protection board if you are not real careful with the voltage that you put to it

[RJARRRPCGP]

Re: Tricking circuit that detects li-ion battery temp/gauge?

Sometimes when I'm using a bench supply connected to the battery terminals of an iPhone (or any device that normally measures battery temp/gauge) the phone will display a message saying it's too hot and needs to cool before using.

If I remove bench supply and plug in a known good battery the message goes away. So I'm guessing sometimes the internal circuitry of the device looks for a temp/gauge reading and if it's missing throws that message.

Most thermal probes=If shorted, you get a false high reading.

Open=Will think it's cold! 0C and the like...

Thus, if you get an overheat complaint, it almost always means a temp probe short.

[caphair]

Re: Tricking circuit that detects li-ion battery temp/gauge?

First off you can not fool it that way ----> if you take the protection board off the battery and hook up power supply to the protection board

Be very careful removing the protection board from the battery you can start fire doing this

HOWEVER you need be real careful when doing you can fry the phone and protection board if you are not real careful with the voltage that you put to it

I don't mean fooling the protection board of the battery itself.

I'm referring to the circuitry on the device AFTER the battery and it's protection circuit.

Connecting a bench supply directly to the logic board minus anything to do with the battery/protection circuit in the battery

[sam_sam_sam]

Re: Tricking circuit that detects li-ion battery temp/gauge?

The way this person is making it sound there talking out the battery out of the phone and trying to run on a power supply and if that is the case then what I said would be true

Now if the battery that is supposed to in phone is in there then what you have here would be true

[sam_sam_sam]

Re: Tricking circuit that detects li-ion battery temp/gauge?

I don't mean fooling the protection board of the battery itself.

I'm referring to the circuitry on the device AFTER the battery and it's protection circuit.

Connecting a bench supply directly to the logic board minus anything to do with the battery/protection circuit in the battery

You can not do it that way the the phone's power management will not work with out the protection board in place power management is looking for the signal
from the protection board with out this signal the phone will either not come or keep rebooting or give some kind of error

I know I have done this before and like I said if you are not careful you can burn up phone and or the protection board