Small battery charging issue

[sydnsue]

I have a DJI drone that uses quite meaty batteries and I charge them via the 12V socket in the living area in my van. (Not the dash sockets). When I connect the 12V charger, the lights on the battery illuminate to show it is charging but they light for a few seconds, then go off for a few seconds, then light for a few seconds etc, etc. I assumed this meant that the socket was unable to supply the required current and the charger was switching in and out. However, if I plug an inverter into the same 12V socket and then run the 240V charger from the inverter, the lights on the battery remain on. Surely the load is the same for both chargers. In fact I would have thought the inverter would have been worse due to the inefficiency of the inverter.
So what is happening? The numbers on the chargers are as follows:
Mains charger - INPUT 240V 1.8A. OUTPUT 17.6V 3.41A
12V charger - INPUT 14V 6.5A OUTPUT 17.6V 4.54A
On the face of it, it seems obvious that the 12V charger is a higher current, hence the overload problem, but surely it is the battery that draws the current. The figures on the chargers are only what they are capable of. I thought the battery would draw the same current whichever charger was used. In which case why is the 240V charger through the inverter not flashing on and off.
The bottom line is - how do I use the 12V charger?

 

[QFour]

Its the DC - DC Converter thats causing your problems. The circuit is not getting enough power. You maybe getting a voltage drop through the wiring. You are trying to get 91w from a 12v cig lighter socket that is probably only rated at 100w. They were never really designed to take large loads. A better bet would be to have a connection straight to the battery with something like a Hella plug and socket. If the DC - DC Converter is housed within the socket then get a decent socket and try wiring it straight to the battery.

DC - DC Converters work by switching the DC voltage on and off rapidly using various methods. You cannot just put DC voltage through a transformer as it would not work. If however you switched the DC voltage on and off you would then generate a field within the transformer and get an output. This is the basic way your inverter works.

You could also try a different 12v charger. If you find one with a lower output Amps then the input Amps will be lower. Which is why the 240v one works as its not using as much power.

 

[sydnsue]

Thanks for the reply. What and where is the DC-DC Converter? The socket is just the standard cigarette lighter type socket. Also, what is the difference between a Hella and standard socket? They look the same.

 

[wildebus]

The reference to the DC-DC converter is the 12V Charger (it's converting 12V to 17V, hence the DC-DC description)

 

[trevskoda]

Use a heavy duty cig socket wired from battery with a inline fuse.
Can be mult or single sockets all from ebay.

 

[sydnsue]

Thanks everyone. Looks like a new socket is required.

 

[Mark135]

I have a DJI drone that uses quite meaty batteries and I charge them via the 12V socket in the living area in my van. (Not the dash sockets). When I connect the 12V charger, the lights on the battery illuminate to show it is charging but they light for a few seconds, then go off for a few seconds, then light for a few seconds etc, etc. I assumed this meant that the socket was unable to supply the required current and the charger was switching in and out. However, if I plug an inverter into the same 12V socket and then run the 240V charger from the inverter, the lights on the battery remain on. Surely the load is the same for both chargers. In fact I would have thought the inverter would have been worse due to the inefficiency of the inverter.
So what is happening? The numbers on the chargers are as follows:
Mains charger - INPUT 240V 1.8A. OUTPUT 17.6V 3.41A
12V charger - INPUT 14V 6.5A OUTPUT 17.6V 4.54A
On the face of it, it seems obvious that the 12V charger is a higher current, hence the overload problem, but surely it is the battery that draws the current. The figures on the chargers are only what they are capable of. I thought the battery would draw the same current whichever charger was used. In which case why is the 240V charger through the inverter not flashing on and off.
The bottom line is - how do I use the 12V charger?

As Froodie says, looks like there is too big a voltage drop in the cables. If you have a lead acid battery, fully charged this will give 12.6 v at the battery terminals. You say your 12v charger is 14v input. I suggest you try connecting your 12v charger as close as you can to the battery using a12v socket with short leads to croc clips first to see if the charger works before you spend too much on new sockets etc.