Hi!
I would like to know if any USB power port for cigarette lighter socket is functional to plug in the the FF4 USB power cable, and to recharge it safely.
What is that
and
I don’t undestand
I use a car charger, plugged into Lighter socket which is connected to my 12V system
What I mean is : As the FP4 require a special charger (not any brand works), when I’m in my car, is any of these devices ok to charge the FP4 safely?
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A charger for the cigarette lighter socket needs to meet the same requirements, as the ones for the mains socket. So if you want to benefit from fast charging, it needs to be PD compatible and deliver at least 20W.
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I can’t have this information because I don’t even know the brand of the cigarette lighter socket I have. So my question is, if it’s not a compatible charger, and I try it, can it damage my phone?
No, if it is somehow standard compatible, it should only deliver 5V and 500mA.
But we cannot guarantee, that a random, unknown to you and us product meets all standard requirements. Did you use it with any other device yet?
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I’m using a “random” 12V lighter socket supply for a long time now. Apart from the possibility of you having a really strange device, it should work perfectly fine. Depending on the exact specs it might only charge your phone relatively slowly, though. Mine does 2A@5V (10W) and that is totally fine for me.
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I think that it has to be QC4 or PPS not PD
Should be fine. With no specs it has to provide a max of 5V at a max 0.9A so will take some hours to charge the phone.
For more info on QC4 and PD see
On a PC the USB have either a blue or black insert. You can read about them
Charger and cable specifications
Fairphone uses a Qualcomm SoC. It supports Qualcomm’s QuickCharge protocol:
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Yes I used it with my Iphone
Then there should be no worry.
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Sorry I meant FP4 charger
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So a USB A charger output will only give 5V at a max of 0.9A if there is no comms with the device.
USB A with QC3 or QC4 will allow rapid charge as it can negotiate a higher voltage
PD2 is a similar protocol, mostly for PCs, giving up 100w PD3 to 240W
PPS can provide for QC3 and PD2
All these get update protocols to communcate with the devices charging chips.
No protocol > No lanugage > No communication > Fall back to 5V
Easier to buy a new car type charger with QC3 and PD2 for a laptop too.
I have an 85W that I can run my laptop (using PD at 60W) and QC3 for my FP at 18W
http://217.155.51.23/unveiled/index.php/linkon-85w-12-to-pd-qc-pps?blog=5
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Qualcomm’s QC4 (which is what the Fairphone uses) is compatible with USB-PD, which is the standard. I personally always look for PD gadgets because they’re universal, and every PD-compatible charger I have worked well with my FP4 so far. AFAIK a QC4 gadget can only pull 27W from a PD charger (likely 9V 3A) but that should be plenty, especially given most chargers intended for phones output 18W (9V 2A). I go for the big stuff on chargers, 65-90W because I’m charging laptops too, but if that’s not a use case for you you can go for a smaller wattage one, the Fairphone can only pull 20W. (If you wanna charge your laptop too you need to verify the presence of a 20V option, but phones don’t care about that, and there’s no way to go above 15W in the USB-PD spec without going to 9V at least.)
TL;DR: go for anything that says USB-PD (Power Delivery) and offers at least 18W. That will let you fast charge not just a Fairphone, but any relatively recent phone as well.
If you really want to, you can go for Qualcomm’s special proprietary solution, but I can’t recommend it unless you have a very good reason. There is no advantage with the Fairphone, and the only real drawback of USB-PD is that the spec only supports USB-C plugs, but many gadgets break that anyway and offer a USB-A receptacle, and even if they don’t you’ll need a cable regardless.
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A USB power port for cigarette lighter socket should behave like a USB port of a PC.
I assume the FP4 can be charged at any USB port of a PC (like the FP2 I own). 
On the downside, charging will be quite slow as it is limited to 5V / 500mA by default. On the upside, slow charging prolongs battery liefetime 
There are several different protocols for charging via USB and they can all be supported by a cigarette lighter charger. So it’s not just like a USB port of a PC.
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I was referring to the picture by Natha13 which shows a typical one. I own a smiliar device which simply converts 12V to 5V. And 5V / 500mA is the smallest common denominator in USB charging which every device should be able to handle …
Of course, there may be more sophisticated chargers for the cigarette lighter plug.
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Good to know! 
The one I use
http://217.155.51.23/unveiled/index.php/linkon-85w-12-to-pd-qc-pps?blog=5
Heat is the killer so slow charging has it’s place, but a low charge is also to be avoided as the battery has to work harder at a lower voltage to provide the same power. I try to keep my battery between 40% and 90% but I’m less worried about it reaching 100% than I am 10%
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That also is good to know! I already read that in another topic but it’s always good to remember!
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As others already said, yes.
I had a cheap no-brand Chinese one in my car, and I kept using it for the FP4 by just buying a small micro-USB to USB-C adapter to put on the cable. Works perfectly, and avoids me to have to throw it away just because the FP4 had a different USB socket.
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