Car charger intermittent - is it my car?

[AlanTheBeast]

I was driving to a site the other evening and one battery wasn't fully charged - so plugged it into the DJI car charger. At a stop it wasn't charging. Pulled over checked the connections, did the usual jiggling, etc and it worked. Drove off ... and it stopped charging again.

It struck me that when the car's VR stops taking power from the alternator, that the voltage would drop to 12-ish and then keep dropping until the VR kicked in again. As a result, the MP car charger, needing closer to 13 or so volts quits until the car voltage kicks up to 14.x again.

Does that sound right - or does my car need a new alternator/VR?

 

[BD0G]

You could connect a multimeter (even a cheap harbor freight one) to the output (center lug and outer barrel) on the cigarette lighter plug and determine what actual voltage level is being supplied. The alternator is still supplying voltage/ current at a stop as the belt is still turning the alternator pulley even at idle. Yes it is spinning it at a lower RPM which in turn may be supplying less voltage than needed, but the cars battery should be sustaining its voltage.

Its a question of fact so measure and see what you are working with.

 

[SeaComms]

No it doesn't sound right... even at idle your electrics in the car should be way over 13 volts.

However it may be cheaper to get a voltage booster for the Mavic car charger than fixing the car! On ebay you can get 9-15v input and 13.8 v output boosters for around $20 or so. Wire up a cig plug one end and socket the other and then you can charge the Mavic battery all he time, even with engine not running. Obviously being careful not to charge it 30 times in a day and running the car battery flat!

 

[KDog]

Car electrics are a curious thing - and filled with inconsistently from experience. Ohms law states that current is directly proportional to voltage and inversely proportional to resistance, so a drop in voltage results in a drop in current and an increase in resistance. 12v DC electrical circuits can be wired with any range of fuses (even within the same vehicle), and the cigarette lighter has a fusable link immediately before it as a redundancy to the fuse in the box. These factors and any other built in logical protections (depending upon age of vehicle) could combine to cause the resistance to become too high to supply the charger. That said, there's no way of diagnosing the problem via a forum - electrical design in vehicles is so inconsistent that two different cars could have completely different causes for the same issue. If it's a significant problem, the easiest way is to shell out a bit (usually not that much) for an autoelec and have them diagnose it. Those guys are usually wizards, and could potentially save you some expensive and time consuming self-diagnostics, IMHO.

 

[Cut.Aussie]

There is a lot of discussion about the DJI car charger, seems the choose to have a rather high and unrealistic input voltage threshold below which it cuts off charging to protect your car from getting a flat battery so you really need the engine running to insure enough voltage.

A second issue is if your a smoker and use the cigarette lighter, the contacts in the socket are probably corroded.

A third issue is the long and often thin gauge wiring to the cigarette socket adds a lot of voltage drop. I cut the plug off my charger and fitted it with two Crocodile clips and clip it directly to the car battery terminals

 

[idiogenic]

A third issue is the long and often thin gauge wiring to the cigarette socket adds a lot of voltage drop. I cut the plug off my charger and fitted it with two Crocodile clips and clip it directly to the car battery terminals

^this!

Cigarette sockets really weren't designed for carrying much current and the wiring, particularly in slightly older cars, isn't either.

The DJI car charger wouldn't work in the factory socket in my 2000 Toyota Hilux even with the engine running. Works fine in my wife's 2016 Lexus though - I think that cigarette socket is actually rated for 100w or something.

Just want to reiterate as well, that the DJI car charger is a piece of **** and should stop selling them.

 

[F6Rider]

A resting battery (engine off) once the surface charge has dropped will normally be at 12.6-12.8 VDC, with the engine on the voltage will be from 13.8-14.2, unfortunately the older DJI charger had a low voltage cutoff of 12.8, which would only allow it to work for a short time after the engine was turned off and the batteries surface charge dropped off to 12.6. The new car chargers have been changed to work with a voltage range of 12.3 to 16 volts so it should work fine with the engine off. I got rid of my old (read first version) for a new one and it works much better.

 

[idiogenic]

Interesting, I didn't know they'd changed the voltage cutoff. When did they make this change? I wish I could return mine but I've cut the plug off and attached a voltage regulator already.

 

[MrMavic]

I used my 12v charger for 2 days on my camper system and it worked flawlessly. Check your battery voltage to make sure it is up to par. Batteries can drop voltage quickly after the charge voltage stops if the battery is junk. A good battery will normally stay at 12.4v to 12.8v when the battery is good. Modern vehicle charge regulators charge at 13.8v when the car is running. Take your car to Napa and have them do a load test on your battery. It's a free service.

 

[matth1000]

Just has this problem on my latest trip.
My dad is mechanic so I asked him what the go is.
I have a 2016 model car, he said on newish cars the computer actually controls the alternator.
It will ramp down the voltage when the battery is fully charged.
I have volt read out on the dash and after a 4 hour drive to get to holiday spot the voltage was 12.3v, not enough to run the DJI car charger which needs a min of 13v.

Put my headlights on and because of the extra load, the voltage goes up to 14.2v.

This won't be the same on every car.
I think the dc to dc converter will be the best option.

 

[Clinton1]

Same happened to me yesterday. Drove for 45 min. with charger showing it is charging the battery. But just 2 lights on battery was flashing. Same as where i discharged it. Randomly switching of, then have to fiddle to get it going. At the end, it didnt take any charge.

 

[normr]

Sounds like it's better to buy an inverter and run the ac charger instead

 

[Lifted Chevy]

I flew a battery down to 40% and plugged it in my work vehicle. Works great. Flew again and charged the battery on the way home. Maybe I got a good one? 45 minutes and it's charged.

 

[bakerboy]

Mavic car charger has a rather high "low voltage" cutoff, most new cars won't run it unless the car is running

 

[Kilrah]

unfortunately the older DJI charger had a low voltage cutoff of 12.8,

Strange, mines needs 12.5 to start charging and will stop at 12, and I've got a first batch Mavic combo.

 

[DroneTone]

My experience with the car charger so far-
Worked consistently good in my Acura, no disconnects and charges batteries rapidly, dependably.
However, on vacation in a late model rental Toyota Rav 4, I had frequent disconnects. No amount of adjusting or tweaking the plug connections would help.
(Because sometimes I didn't notice the disconnects right away, it and it took a couple hours to get one battery charged).
I finally had to give up on the other batteries, the power just would never stay connected...

 

[Lapeer20m]

I use the factory 110 power outlet in my jeep with the wall charger plugged in and it works perfect.

I also have a cheap 140w inverter that plugs in cagarette outlet in other vehicles and both options work very well with dji wall charger.

 

[bakerboy]

I use the factory 110 power outlet in my jeep with the wall charger plugged in and it works perfect.

I also have a cheap 140w inverter that plugs in cagarette outlet in other vehicles and both options work very well with dji wall charger.

They're talking about the car charger not the wall charger

 

[bakerboy]

Try running this inline if you're having issues
uxcell Voltage Converter Regulator DC/DC DC8-40V to DC13.8V 10A 138W Transformer | eBay

 

[Mako79]

I userd this on my phantom 3 and 2 when i was out in the field.
Car Power Inverter 12V DC to110V/220V AC Converter USB Charger Cigarette Lighter | eBay