Hi guys,

This is the second time I'm trying this without success...
After flying my batteries I wanted to use the car charger.
Last time I had it connected to my lighter jack in my car. When the car's motor was not running the charger had no green light and did not charge ... (the utilities inside the car worked so ignition switch was on). Btw, car's battery is 65Amps.
This time we had a dedicated car battey just for that.
A 46Amps battery.
It had two phantom 3 chargers, running together just fine. But again the Mavic's charger didn't operate at all, even when it was running solo on this battery.
Any ideas?
It's not always possible to leave the car running...
Thanks

Anyone? ...

Seems to only work when the motor is running (To get voltage above 13v.) Makes the charger pretty much useless for me. Can't charge off the deep cycle battery in my camper.

megove Posted at 2017-4-17 05:35
Seems to only work when the motor is running (To get voltage above 13v.) Makes the charger pretty much useless for me. Can't charge off the deep cycle battery in my camper.

Wouldn't your camper have a 110 outlet inside?

Gilur Posted at 2017-4-17 05:25
Anyone? ...

Per website "The Mavic Car Charger is used to charge the Intelligent Flight Battery through a car's cigarette lighter port. It comes with low-voltage protection to ensure enough starting battery voltage for the car. Overheating protection will automatically cut off charging if your cigarette lighter port exceeds a certain temperature."

So it looks like yes it needs to be running, the other chargers may work because they are older technology.

FrequentFlyer Posted at 2017-4-17 06:14
Per website "The Mavic Car Charger is used to charge the Intelligent Flight Battery through a car's cigarette lighter port. It comes with low-voltage protection to ensure enough starting battery voltage for the car. Overheating protection will automatically cut off charging if your cigarette lighter port exceeds a certain temperature."

So it looks like yes it needs to be running, the other chargers may work because they are older technology.

As Megove said, it's actually useless in that case.
Leaving the car on 40-50 minutes for each battery is not practical.
I'm wondering if there's a fix/mod/whatever to solve this.. .. (besides getting more batteries LOL)

It could be a case where your cars battery is due for a change, or at least a night on the charger.

Same goes for your lower amp battery.

This behavior has been noted several times and I don't think there is anything you can do.  I just started using an inverter and the regular charger.

FrequentFlyer Posted at 2017-4-17 06:11
Wouldn't your camper have a 110 outlet inside?

Sure, when it's plugged in to outside power.. But that doesn't work when you're away from any utilities. The ac charger works fine off power inverter. The car charger is still just as useless.

You are right.  I just tried it in three different cars and it only works in only one of them with the ignition off.  

How ironic is it that it is the only one that can't go offroad.

Xman1 Posted at 2017-4-17 07:18
You are right.  I just tried it in three different cars and it only works in only one of them with the ignition off.  

How ironic is it that it is the only one that can't go offroad.

It should work while the car is running or driving, if not driving you can get a inverter and use your regular charger.

I was more interested in it working without the car on.  Granted, maybe after a long drive, this would work as the battery has been fully charged....  

Note:  I don't hate this feature as I think my car starting properly is more important, but I might be in agreement that it may be a little sensitive.

I can always throw a genset in the back if I need to I guess.

My car doesn't charge when turned off. I wouldn't want it on and drain my car battery. I haven't use the car charger once. I just purchased more batteries.

I run dual batteries in most of my rigs and it will charge on battery before shutting off.

Beezzzzy Posted at 2017-4-17 09:28
My car doesn't charge when turned off. I wouldn't want it on and drain my car battery. I haven't use the car charger once. I just purchased more batteries.

One of my locations has no street power so I would need a lot of batteries.

Do remember that you are pulling a few amps when charging your batteries.  It's never a good idea to run on battery only when doing so.  However, there is a device these days that will take care of what you want.  It costs a few bucks, goes between your battery and the charger or other device.  It will keep the output voltage up and will shut down at a settable battery voltage to keep you from running it all the way down.  The ones I've seen are good for pretty good current, but I don't have a reference handy right now.  Expect to pay well over $100, if I remember correctly.  There are many different ones, but here's a link to a high current version from MFJ.  This sort of thing would be excellent for a separate battery used to power ham radio and other things, such as chargers that normally require a minimum voltage.   http://www.mfjenterprises.com/Product.php?productid=MFJ-4416C

Guys,
I'm into RC flying and FPV for a couple of years... During that whole time I've been charging batteries every Saturday at the field. never had a problem with my car's battery in my life and to be honest, in days when I did some massive charging I ran the motor for half an hour during charging, but, that was my responsibility.
I truly don't need DJI to be my Car's keeper. I'd rather have a charger that does the job, and charges my batteries when I need it to do so, and If I'll make mistakes ... I'll learn from them.
This is actually the 1st 'con' I can find in my Mavic. I cannot really see how DJI can solve it with the existing chargers as this sounds like electronic design (and not some software issue that a firmware will solve),
But maybe it will be useful for them on the next models or for a new charger for the Mavic.
If a new charger will not cost to much and will adress this issue - I will buy it

Thank you all
I thought my car charger were broken, now I know that the engine has to run to charge...
I am also in he RC world since long years and started only the engine when needed; after some couple of packs :-)
(especially if the car has a 110Ah battery)

The charger shows clearly that it takes in 13v.  Output is also clearly 13.05v 6a.  Maybe the battery needs 13.05v or close to it.

Just checked the wall charger and it is also 13.05v output.

AG0N-Gary Posted at 2017-4-17 09:55
Do remember that you are pulling a few amps when charging your batteries.  It's never a good idea to run on battery only when doing so.  However, there is a device these days that will take care of what you want.  It costs a few bucks, goes between your battery and the charger or other device.  It will keep the output voltage up and will shut down at a settable battery voltage to keep you from running it all the way down.  The ones I've seen are good for pretty good current, but I don't have a reference handy right now.  Expect to pay well over $100, if I remember correctly.  There are many different ones, but here's a link to a high current version from MFJ.  This sort of thing would be excellent for a separate battery used to power ham radio and other things, such as chargers that normally require a minimum voltage.   http://www.mfjenterprises.com/Product.php?productid=MFJ-4416C

Or just buy an inverter ($37 from amazon for a 300w sine wave) and run the regular charger. $180 to bump the voltage to use the car charger is beyond ridiculous.

megove Posted at 2017-4-17 15:03
Or just buy an inverter ($37 from amazon for a 300w sine wave) and run the regular charger. $180 to bump the voltage to use the car charger is beyond ridiculous.

Try $110 or so.

A.  Cig lighter socket cannot produce 300 watts.  The highest rated ones will output 150 Watts max.  Most cars only have 10 Amps here so expect a lot less power than even 150 Watts.
B.  Electronics probably require a Pure Sine Wave output without damaging them over time.
C.  You will never find a Pure Sine Wave inverter for $37 unless they are lying.

Xman1 Posted at 2017-4-17 15:47
Try $110 or so.

A.  Cig lighter socket cannot produce 300 watts.  The highest rated ones will output 150 Watts max.  Most cars only have 10 Amps here so expect a lot less power than even 150 Watts.

Here's 2:
https://www.amazon.com/MicroSola ... ires/dp/B00F4TBW6S/
https://www.amazon.com/BESTEK-Po ... pter/dp/B01DP9JE18/

Conveniently the mavic ac charger runs around 55w according to the kill-a-watt. No problem for a 10-15a lighter plug. Some extra load due to inverter inefficiency, would use less battery if the car charger actually worked on battery voltage instead of requiring 13+v.
The only thing I've ever run into that had a problem with a modified sine wave inverter was a cpap machine.

megove Posted at 2017-4-19 11:14
Here's 2:
https://www.amazon.com/MicroSolar-300W-Peak-Inverter-Wires/dp/B00F4TBW6S/
https://www.amazon.com/BESTEK-Power-Inverter-Smart-Adapter/dp/B01DP9JE18/

Microsolar is not pure sine wave if it is doing this so this is a fake:  

This is the noisiest power inverter I have ever used. The AC coming out is 118V but VERY noisy. I used this for charging a laptop while tuning my car and it creates so much noise that it would actually change bits in the code on the ECU! I will try a power conditioner in line with it but I should have purchased a more expensive inverter to save time and money (signal conditioners are a little pricey).

The Bestek one is terrible.  Look at Pushkins scope.  If you want to fry your electronics, these are good fake pure sine wave inverters to do it with.  They would be great for motorized electrics, but terrible for electronics.



Bestek review:

The  inverter has a fan that is always on.  It's ridiculously loud.  You are  not going to be sleeping in the same room with this thing on and  running.  When the inverter is on, it uses about 6 watts even if nothing  is plugged into it.  I tested the efficiency with a 43 watt load and  got a 12 V side power reading of 61 W, efficiency of about 70%, which is  not great.
The output is 110 V which is OK for most applications.

Then  I decided to test how clean the output waveform actually is. And it  turn out it's extremely noisy.  I made a 100 to 1 voltage divider  (100kOhm to 1 kOhm) and hooked up my scope to it.  It has crazy voltage  spikes that are ginormous: (6V x 100 = 600 V) at a frequency of about 50  to 100 kHz.

I've attached the scope traces of what my mains power outlet looks like and the waveform output of this piece of junk inverter.
When you look at those traces remember that they were run through a 100x voltage divider.

Also,  i have not tested the USB outlets, but they must be noisy as well  because they caused my phones touchscreen to go crazy when it is  connected to them and charging.

Gilur,
       The threshold voltage for the Mavic car charger is above 13 volts --- when a car is not running it's battery output would just barely be 13v when the car is running the output voltage of the alternator bumps the car battery and electrical system to around 14+volts
        As far as using an inverter you will drain your cars battery really quick --- you need the power for the inverter also the power to operate the Mavic's charger
         The only Efficient way to charge the Mavic batteries by car not running with the DJI car charger is for DJI to lower the Threshold turn ON voltage --- Which means in short new electronic circuitry  design for the DJI charger  

SkunkWerxs Posted at 2017-4-20 05:52
Gilur,
       The threshold voltage for the Mavic car charger is above 13 volts --- when a car is not running it's battery output would just barely be 13v when the car is running the output voltage of the alternator bumps the car battery and electrical system to around 14+volts
        As far as using an inverter you will drain your cars battery really quick --- you need the power for the inverter also the power to operate the Mavic's charger

Hi SkunkWerxs,

I must say that in all my years, I never drained my car's battery while charging at the field, and - true: it was my responsibility to pay attention how mutch I'm charging.

If DJI would post a "fixup" for that "mistake" (that would probably involve the replacement of 2-3 parts) - I personally will do it, though I doubt if they will encourage people to open the car charger.
Furthermore, If there will be a new charger that solves this issue - I will buy it.

Leaving it as is (with all the nice words on taking care of by ca'rs battery etc etc) simply makes the mavic less usable and less enjoyable Sad but True..
I will not but additional 2-3-4 batteries just to have these flights

DJI may already have addressed this problem, on my car charger it states input  13/26v if you look at the specs for the charger in the DJI store it says 12.3/16v for the charger with the same model number as mine, if this is the case then DJI have  basically said a big screw you to all of us with a car charger that is  useless in the real world.

Gilur Posted at 2017-4-21 03:15
Hi SkunkWerxs,

I must say that in all my years, I never drained my car's battery while charging at the field, and - true: it was my responsibility to pay attention how mutch I'm charging.

Gilur,
        It is sad but true -------------- There are aftermarket lipo car chargers that claim to balance the battery cells, I just don't trust them --- I don't blame you for not buying more Mavic batteries , They Are Expensive
FlySafe

Can an admin confirm if DJI have changed the  input voltage spec of the car charger as it now states an input of 12.3v  on the DJI store.

I would like to know if this is true too.  Did DJI update the car charger design to support 12.3v?  

I have the same issue you are experiencing with the Mavic Pro Car Charger not charging with the vehicle off.  The input voltage drops to around 12.5 volts on my car with the engine off.  The cutoff on my car charger is somewhere around 12.6 volts where the status light begins to blink and eventually turn off.  I plan on contacting DJI to see what options they offer.