Can anyone suggest an off-the-shelf power inverter I can buy that will have the current to charge 2 batteries using the 100watt DJI chargers at the same time, even if I have to clamp it directly to the car battery and leave the car running?

I am searching for a lost horse for a freind this Sunday and don't have time to order one on-line.

Any suggestions are welcome.

Thanks

Hi Mr Menace,

Not as simple as it seems. I gave up on it for now.

Let me see if I can explain...

First, any inverter you use, please go after the "pure sine" ones or you might burn your batteries.

So, to charge 1 battery, using the DJI wall charger,  it draws a ton of current from your car battery. The main issue is how to connect the battery with the inverter... for 2 batteries at once, the lighter won't do it... too much.

Also, even for 1 charger, the inverter will eat up your car battery very quickly, be careful.

I have heard from a ton of people that they are using a single charger from the lighter, directly to the battery. That makes sense as it is Pb to Pb charging.

They have one in the DJI store but it is for P2.

Most people are getting the lighter charger from email for less than $20.

Here is my similar post on the same subject:
http://forum.dji.com/thread-32557-1-1.html

Cheers.

Paniza Posted at 2015-11-13 08:13
Hi Mr Menace,

Not as simple as it seems. I gave up on it for now.

Pure Sine invertors are a big con and not needed as you are using your charger it is regulating the power supply then sending it to the smart  battery which regulates the charge of each cell.

Thank you. I managed to find an inverter. It is a 400watt modified Sine Wave Inverter. It does have cables to connect directly to the battery. I do plan to leave my car running while charging my batteries.

I have looked into this Modified vs. pure sine wave issue and what should run on it and what shouldn't and the only thing close to what I'm doing that might be a problem is if I am using some battery chargers for power tools, and specifically Makita is named as the one that has trouble with this.

I feel confident I will be OK with this, but I will certainly report back here if I experience problems.

Phantom Menace Posted at 2015-11-12 19:26
Thank you. I managed to find an inverter. It is a 400watt modified Sine Wave Inverter. It does have  ...

ah cool.

I had purchased one of the normal inverters as well but sent back.

Some users said it was risky and one even said that burned 2 batteries doing just that.

I didn't want take the risk.

Rocket_Aus Posted at 2015-11-12 17:33
Pure Sine invertors are a big con and not needed as you are using your charger it is regulating th ...

Hit Rocket,

Perhaps they are a big con... I just didn't want to take the risk.

Try an APC product. They make some great supplies and readily available.

Big difference between the P2 and the P3 batteries.

The P2 battery was only 11.2 volts, so DC charging from a 12 volt source wasn't a problem. The P3 battery being 15.2 volts shouldn't be charged with a lower voltage power source. The 100 watt charger out puts 17.4 volts which is close to 8 amps current.

The P3 100 watt charger is very tolerant of frequency and voltage as it switches between 50 and 60 cycles and 120-240 volts.

An inverter generates cleaner power than a coil wound generator does and holds frequency.

I have a Peak 2000 watt inverter in my truck that I use to charge my lap top computer and run a laser printer. I'd use a inkjet, but the ink freezes in the winter. The lap top doesn't cause the engine rpm to increase. The laser printer causes the engine to gain 500 rpm. I on occasion check the frequency and voltage using a P2 Killowatt plug, and it produces 118 v and 60 cycle juice.

Ignore the pure sine trend... Get a 3-400 watt inverter form a local automotive shop.. They work fine. You will only be powering transformer that is commonly called a charger. The trendy purists will act as if a non pure sine wave inverter will "Fry your electronics" This is not true... Exercise common sense and steer away from the internet myths.

Just keep in mind,  whatever you intend to use the inverter for,  you must know the power requirements of the gear you want to power. Ohms law and the power formula is very useful  Power, measured in Watts is calculated by multiplying Voltage x Current, measured in amps.  So P=I x E  .  P = Power.  I = Amps or Current and E = Volts or Electromotive force.  Example:  1 volt times 1 amp = 1 watt.
I knew that basic electronics theory would come in handy one day.

Rocket_Aus Posted at 2015-11-13 08:33
Pure Sine invertors are a big con and not needed as you are using your charger it is regulating th ...

Any recommendations for a invertor

I have a Duracell 130 watt continuous inverter with two plugs and it handles two chargers without issues.  I also have a Belkin 300 watt continuous and it cannot even charge one of them.  Anyone have any ideas why the the stronger Belkin cannot even charge one of them?

exmeaguy Posted at 2016-3-27 13:23
I have a Duracell 130 watt continuous inverter with two plugs and it handles two chargers without is ...

It is probably because the Belkin unit is not a pure sine wave converter. The DJI charger is actually a switch mode power supply, not really a charger as such, and switch mode power supplies hate non-sine wave supplies.

Geebax Posted at 2016-3-27 04:56
It is probably because the Belkin unit is not a pure sine wave converter. The DJI charger is actua ...

That's why I believe you're better off just getting one of the $25 car chargers off ebay.  They are specifically designed for the P3 battery terminals and they pump out the right voltage and amps.  All the charging and protection circuitry is in the battery itself; you only need a simple power supply to do the job.

I have been using one for several months and they work flawlessly...

wellsi Posted at 2016-3-27 19:45
That's why I believe you're better off just getting one of the $25 car chargers off ebay.  They ar ...

'I have been using one for several months and they work flawlessly...'

Yes, me too. Mine costs $16 and was delivered from China for free. I have been using it without any problems, One of the best cheap purchases I have made for ages. It takes a little longer to charge the battery, but still does it quickly enough.

I recently purchased a £20 "fit in a cup holder" 200W inverter charger and I did not even think that it may cause a damage to any of my equipment. I have charged my P4 battery twice since I bought it and it has charged it fully without any issues. As long as you're driving it charges without any problems. When engine is stopped it struggles.