Battery Charging

InspiredOne · Feb 1, 2015

I was reading the “Intelligent Flight Battery Safety Guidelines” (English language version) that came with the Inspire 1. On page one, top of second column, it states, “Do not charge the Intelligent Flight Battery and remote controller at the same time, otherwise the charger may overheat.”

However, on DJI’s Inspire 1 microsite in the “Features” section under “Lightbridge Equipped” it says, “Users can… recharge both flight and remote control batteries simultaneously.”

Ed, could you, please, clarify which one is correct?

Thank you!

Jon R. · Feb 1, 2015

I have also wondered. There is a video on the forums where someone tested both scenarios with a heat probe and found no real temp difference. However, from personal experience, the charger does get super hot if charging both.

InspiredOne · Feb 1, 2015

Hi, Jon. Thanks for the reply. I did this the first time (seeing the dual connections), charging both at the same time. Unfortunately, I don't recall the charger getting particularly hot, but that doesn't mean it didn't. Some do get warm with regular use. I just can't recall and I don't want to damage anything.

But the contradiction in their literature (printed and web) is confusing at best,

InspiredOne · Feb 2, 2015

Received this from DJI Support this morning:

Dear Jay,

Thank you for contacting DJI Technical Support.

So sorry for the confusion.

Please follow the instruction on the User Manual for better maintenance for your battery: “Do not charge the Intelligent Flight Battery and remote controller at the same time, otherwise the charger may overheat.”

Vulle · Feb 4, 2015

Hi,

I had the same question and decided to investigate it my self. First I measure the output from the charger, it is a CC CV charger, which means the output will be about 26,1 voltage when it is unloaded. When you charge the battery it will give max 4 amp, and the voltage will be the current battery voltage. If you have a battery discharge to about 20 % the voltage from the charger will be about 23 voltage. The load on the Charger is limited by the CC CV control output from the charger.

I my testing the load on the charger does not change if you are charging a battery, and then plug the transmitter charge plug. I have cut the wire between the charger and the charge plugs to measure this. No matter what combination of charging battery and transmitter I have tried, I never measure more load on the charger, than when it is charging the battery alone. Charging the transmitter alone will use about 1 amp from the charger.

My conclusion is that it not a problem for the charger to charge the battery and the transmitter at the same time. I don't know why the DJI support is saying it is not a good ide to charge them both at the same time. I have measured the temperature on the charger when charging the battery alone, and it gets very hot. In my opinion it is not a very good design. I always try to make sure the is air all around the charger to keep it cooler when charging.

Just my 5 cents

InspiredOne · Feb 4, 2015

Humm... My charger doesn't heat up charging batteries.

Cacou · Feb 4, 2015

My charger stays pretty cool when charging the battery, but it get very warm when charging both a battery and the remote. I can understand that in certain conditions, this could become a safety hazard.

My advice would be, if you can monitor the charging closely, go ahead and charge both simultaneously, but otherwise stick to charging one or the other.

Mazz · Feb 5, 2015

Cacou said:
My charger stays pretty cool when charging the battery, but it get very warm when charging both a battery and the remote. I can understand that in certain conditions, this could become a safety hazard.

My advice would be, if you can monitor the charging closely, go ahead and charge both simultaneously, but otherwise stick to charging one or the other.

I am with you. Cold for one hot for both. I charge the batteries almost daily and my controllers are charged barely weekly. They can wait for safety.

Kilrah · Feb 6, 2015

Vulle said:
I had the same question and decided to investigate it my self. First I measure the output from the charger, it is a CC CV charger, which means the output will be about 26,1 voltage when it is unloaded. When you charge the battery it will give max 4 amp, and the voltage will be the current battery voltage. If you have a battery discharge to about 20 % the voltage from the charger will be about 23 voltage. The load on the Charger is limited by the CC CV control output from the charger.

I just cut my charger's cable and added inline plugs to do some measurements, and yes it is a CC/CV charger but mine seems to have the current limit set to 4.5A. With a battery that is sufficiently discharged to pull that, if I connect the remote voltage drops but current stays spot on, which confirms it.

The charger is rated as 100W and 3.8A (which matches with 26.3V, seems correct). IMO the issue is that current limit is set a bit crudely and will vary by a lot between units. People with one set rather low will have a cool charger, those set higher will heat more but it will be the case whether or not the remote is connected at the same time. The only thing is that with the remote it will take a bit longer to reach the CV phase where the pressure on the charger is released... but if that was a problem it's not the dual charging we should worry about.

DustyVisor · Mar 25, 2015

Is there a percentage the controllers should be discharged to? I have been charging mine when they get down to one light, or about 25%. Do they need to be run to 0% every 20 cycles like the inspire lipos? Any care tips beyond what manual says is much appreciated. Thanks.

sirnikolas · Mar 25, 2015

Apparently the RC automatically discharges aswell. But as for discharging it to 0%, that would be a good question for @blade strike .

DustyVisor · Mar 26, 2015

@blade strike @Tahoe Ed ,
What kind of discharge/charge cycles do you guys do with your controllers? Do they need to be run to 0% every 20 cycles like the inspire lipos?
Thanks.

InspiredOne · Mar 26, 2015

DustyVisor said:
@blade strike @Tahoe Ed ,
What kind of discharge/charge cycles do you guys do with your controllers? Do they need to be run to 0% every 20 cycles like the inspire lipos?
Thanks.

Excellent! I've been wondering the same thing,

just never got around to asking.