Charging mobile phone battery without phone

[williamwright]

Some phones ask you to OK the data link. If you did that you could simply download the pics onto a PC.

Bill

[Brian Gaff (Sofa]

More likely I think is a dodgy connection somewhere which will probably go again just when it has lulled you into believing its OK. Brian

[Theo]

I don't know the resistance curve of a torch bulb, but I'd want to make sure I never put more than 4.2V across the lithium cell. If the cell isn't taking much charge current I'd expect the cell voltage to rise above 4.2V which is likely to damage the cell (not in a fireworks kind of way if the current is low, but in terms of reduced cycle life). The torch bulb also won't back off the current as it reaches top-of-charge.

However, it's likely this cell has a protection circuit in it so you might get away with it, but personally I'm not sure I'd want to risk it.

Theo

[Theo]

I had something similar recently - brought old phone (Galaxy Note 4) out of storage, battery flat. Left it on charge in a pile of stuff, went out for half an hour. Came back, said it was fully charged - that was quick.

But, while the phone would power on, but was stuck in a bootloop. Tried various things with reflashing the firmware (which all went through successfully), still bootlooping.

Eventually I noticed the back cover was slightly loose. Took it off, noticed the battery had puffed up. Evidently the battery only had a few seconds of charge in it and as soon as it started to power on the phone would brownout and reboot.

Mr Amazon supplied me with a new (Ravpower) battery and it was all fine again.

Theo

[The Natural Philosopher]

I think it is worth emphasising that this is indeed one way a LIPO battery dies. Puffing and/or vastly reduced capacity. And vastly reduced ability to supply current

In general, also, if you have gotten 5 years out of a lithium, you have done well,

It is probably worth investing in a new one at that point anyway as you are likely to have lost more than half the capacity.