When I charge my three M3P batteries at home they seem to take an age to charge.

Yet when I've been on the road taking photos and using the drone, when I plug it into my USB charger in the car to top them up for the next flight they seem to charge much more quickly.

Why does this happen and I'm sure there must be a logical explanation ?

Regards

different power outputs and charging protocols on the respective charger perhaps.

maybe type of charger? usb-c will charge MUCH faster than usb-a. you can tell if it's usb-c by how fast the lights blink.

Yes there is...

The wattage in your home charger will be less than the USB wattage output in the car...

I bet, the green LEDs do also blink faster when you charge the battery in the car....

But remember, faster charging time = less battery life (especially if they get hot while charging)

Hi there,

Thank You for reaching out. We are truly sorry for the inconvenience you are experiencing. It is recommended to use the charging devices provided by DJI, such as the DJI Mini 3 Pro Two-Way Charging Hub, DJI 30WUSB-C Charger, or other USB Power Delivery chargers. The DJI Mini 3Pro Two-Way Charging Hub and the DJI 30W USB-C Charger are
both optional accessories. Visit the official DJI online store for more information.

When you charge the battery mounted to the aircraft or inserted into the DJI Mini 3 Pro Two-Way Charging Hub, the maximum charging power supported is 30 w.

I hope this information has helped to clarify your inquiries. If you have any other questions, kindly let us know. Thank You!

There are 3 types of charging
Normal old usb 5V
QC (quick charge)
PD (power delivery)

The newer types negotiate a voltage 5, 7, 9, 12, 15, 20

You have to pay attention to what's written on the side of your elcheapo charger. It will be something like
5V/2A. 9V /2.22A, 12V/1.67A - that would be a 20W charger. You are aiming for 30W, 12V 2.5A.

It may quote a maximum for PD or QC. Cheap chargers generally lie. Car chargers are mostly rubbish, but i found one a few days ago at a chemist, that works 20W 9V2A, but at a lousy 10W on my Mini 2SE.
For reliable charging, you need a GaN charger with a QC(orange) and PD(blue)
Mini 3 Pro charges on PD only.

You can find multiport chargers that arent GaN, that still work.
You can also watch with a reliable usb C ammeter, like the white kowsi/kewesi one with rounded corners.

You also need a cable that's rated at 3A, unless you want to slow it down

Thank you for all your replies, much appreciated.

I was away for over 24 hours flying the drone, and yes it does charge significantly quicker in the car USB, and this is using DJI three battery charge point.

Cheers