Charger mystery

sydnsue

sydnsue

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Here's one for the electricians. I charge DJI drone batteries in the van. I have one DJI charger with input 12V, output 17.6V. The 12V socket it is plugged into is connected to twin leisure batteries. The charge alternately switches on for 10 seconds, off for 5 seconds.
I also have a DJI mains charger for the drone batteries. I connect a small inverter to a 12V socket which then runs the mains charger which also outputs 17.6V. This runs continuously, no issues.
Why is the first scenario with the dedicated 12V charger switching out? Surely the inverter is pulling more power from the leisure batteries than the 12V charger.
Bottom line - how do I charge the drone batteries directly from 12V.
I asked this before and someone said the 12V feed from the van wasn't man enough, so the 12V socket i have now installed is direct to the leisure batteries with heavy cable.
 
sounds to me like the 12V charger is suspect.
 
There is no option or cable to run from USB. Both chargers have 17.6V output which I imagine would not be ideal using a 5V input. The drone is Mavic 2 Pro so batteries may be larger than yours.
 
sydnsue said:
There is no option or cable to run from USB. Both chargers have 17.6V output which I imagine would not be ideal using a 5V input. The drone is Mavic 2 Pro so batteries may be larger than yours.
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The Mini Mavic has a USB charger connection and I think there is an assumption that what one has is what the others have :rolleyes:

I think the USB PD setup can actually boost a USB output to beyond 18V in fact but that again is not relevant as you don't have that connection either, but a standard 12V.
Try running something else off that 12V socket and see what happens (TV maybe?). And try the charger off the cab 12V socket as a process of elimination.

If the charger does multiple batteries simultaneously (like the Mini Mavic does 3 for example), try just having one battery and see what happens. Maybe one battery is playing up causing odd things to happen?
 
Can you try the charger in the van's cab cigarette socket? As David, it could be faulty.

The socket and wiring not being up to the job is also possible, measuring the voltage at the socket while trying to use the charger would prove. You might see it drop significantly as the charger comes on. It would be the socket not making a good connection I'm talking about, so you'd have to measure the actual cable to the charger. Maybe not easy....
 
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This gets weirder. Other things including TV run fine from the 12V socket. Just tried the 12V charger on the cab socket and that runs fine. So why does it run on the vehicle battery but not on the leisure batteries?
 
St3v3 said:
Can you try the charger in the van's cab cigarette socket? As David, it could be faulty.

The socket and wiring not being up to the job is also possible, measuring the voltage at the socket while trying to use the charger would prove. You might see it drop significantly as the charger comes on. It would be the actual socket not making a good connection I'm talking about, so you'd have to measure the actual cable to the charger. Maybe not easy....
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Difficult to test right now as we are on holiday. I have tried it on the habitation 12V socket and I also made a separate charging station with 12V socket that connects directly to the leisure batteries. I think it was 2.5mm cable I used which should be ample. Unlikely for 2 sockets to be faulty. It is almost as if the leisure batteries cannot supply what is required which seems impossible. Twin 110ah batteries and new.
 
wildebus said:
The Mini Mavic has a USB charger connection and I think there is an assumption that what one has is what the others have :rolleyes:

I think the USB PD setup can actually boost a USB output to beyond 18V in fact but that again is not relevant as you don't have that connection either, but a standard 12V.
Try running something else off that 12V socket and see what happens (TV maybe?). And try the charger off the cab 12V socket as a process of elimination.

If the charger does multiple batteries simultaneously (like the Mini Mavic does 3 for example), try just having one battery and see what happens. Maybe one battery is playing up causing odd things to happen?
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I am charging one battery at a time.
 
Some of the sockets are pretty poor quality, I'm thinking it's just not making a good connection.
 
sydnsue said:
Difficult to test right now as we are on holiday. I have tried it on the habitation 12V socket and I also made a separate charging station with 12V socket that connects directly to the leisure batteries. I think it was 2.5mm cable I used which should be ample. Unlikely for 2 sockets to be faulty. It is almost as if the leisure batteries cannot supply what is required which seems impossible. Twin 110ah batteries and new.
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TBH, you seem to be ignoring the possibly that the only common factor - the charger itself - could be faulty.
 
My first stop with issues like this is usually Google....

Google "intermittent DJI charger"

There's a heap of folks in the DJI world with the same issue.
 
mistericeman said:
My first stop with issues like this is usually Google....

Google "intermittent DJI charger"

There's a heap of folks in the DJI world with the same issue.
Click to expand...
needs a minimum of 12.8V? that is pants! I guess they work on the assumption that the car charger is used when driving (same as you would a 12V coolbox) and then when arrived you plug into mains for charging?

I would get one of these probably - https://www.ebay.co.uk/itm/191981725032
I use these for the Chinese Diesel Heaters which are suspectible to cutting out on generally acceptable voltages.
Or just use the Inverter and Mains charger combo. probably easier :)
 
wildebus said:
needs a minimum of 12.8V? that is pants! I guess they work on the assumption that the car charger is used when driving (same as you would a 12V coolbox) and then when arrived you plug into mains for charging?

I would get one of these probably - https://www.ebay.co.uk/itm/191981725032
I use these for the Chinese Diesel Heaters which are suspectible to cutting out on generally acceptable voltages.
Or just use the Inverter and Mains charger combo. probably easier :)
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Where did 12.8V come from? I don't follow you. Your step up could be good but I may as well use the inverter.
 
I have had another look at the 12V charger and the small print states 14V input so presumably the vehicle can supply that but not the leisure batteries, even though the standing charge on the leisure is 12.7V and the vehicle battery is 13.1V. Maybe just enough to make the difference. Or maybe there is some technical difference between the battery types that creates the problem.
 
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wildebus said:
I did a search as suggested and that is what owners were saying. I'm not an owner of this charger so I don't know the spec.


Exactly so.
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Actually the 12.8V idea could make sense following the voltages I have on the leisure and vehicle batteries. The leisure are on solar which presumably cannot get them as high as the alternator does with the vehicle.
 
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