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12 volt power inverter to charge batteries from my car?
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Interesting how they magically start talking about modified square wave in place of modified sine wave as the article progresses without explanation.... Modified square wave of adequate rating should not be a problem with the DJI charging supply, the input is rectified to DC at the input, the biggest problem will be the voltage rating of any capacitors.
I agree with those who suggest just using the DJI car charger. It's specifically made to charge your $169 batteries. Any inverter that costs less is not going to be very good quality. A more expensive inverter will do the job, but as the responses indicate, you could wind up spending hundreds of dollars buying and installing a good inverter. Seems unnecessarily expensive to me, but then again that's what my wife thought when i bought my P4P.
Thank you. That's actually better than I anticipated and quite reasonable. Thanks!
I don't know what some of you guys are missing but, I'm not charging the battery with the inverter I actually plug in a " DJI " charger to charge the battery.
My charger and your charger are the same thing.
How do you know that the alternating current coming from the alternator and electrical system in the car isn't messing with your charger that you plug into cigarette lighter. If anybody's got any scientific evidence please enlighten me.
My charger and your charger are the same thing.
How do you know that the alternating current coming from the alternator and electrical system in the car isn't messing with your charger that you plug into cigarette lighter. If anybody's got any scientific evidence please enlighten me.
The unit I purchased runs off the car battery via the plug in cigar lighter socket. It will charge two Phantom batteries at once, a Phantom controller as well as recharge an Apple i-Pad mini screen either individually or all at once. If you are in Australia you can purchase the unit from EBW Unit 4/26-32 Cosgrove Road New South Wales Post Code 2136. They are a well built unit with very good connectors. While the batteries are running down during flight so is the other electronic equipment. I found this to be a very practical unit and not expensive at all.
Everything isn’t equal in your assumption- you need to look at the battery capacity and charge rate. The P3 battery is 68Wh and charges at 1C so to charge in one hour (fastest possible time) from 0% you need 68W from the supply plus some overhead for switching efficiency in the converter, loss through the pack bleed resistors and efficiency of the charging process. At 5A the car charger already has 28% overhead, you won’t see anywhere near you claimed time difference. Same wouldnaoply if the supply could deliver 200A or any greater figure, the pack will only draw what it needs from the load.
I recently got a Bestek Model MRI1511LU. It's pretty heavy duty... even has a fan in it. Charged up my batteries just fine.
One advantage of the Bestek is that it's less than 20% the cost of the DJI charger, and you can take the charger cable and plug it into the Bestek... Just sayin'
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I used a 12kVA genset in one of my trucks to keep the cameras running, the one downside is that a lot of gensets are made for the American market and produce a 60Hz output, where I needed a 50Hz output for UK/Europe as most of the 240V ac cameras/VCRs use the mains frequency for locking the video signal to, and 50Hz gensets are as rare as hens teeth.
I had the same problem looking for a 12V to 50Hz 240V inverter and eventually settled for an online pure sine wave computer UPS with it's 12V battery pack charged from a split charging system on the SUV.
The biggest problem was the VCRs as they all used the mains frequency to lock the time signal for recording, and tapes recorded on 60Hz won't playback properly on customers 50Hz VCRs Lucky you don't have to deal with that as well
I had the same problem looking for a 12V to 50Hz 240V inverter and eventually settled for an online pure sine wave computer UPS with it's 12V battery pack charged from a split charging system on the SUV.
The biggest problem was the VCRs as they all used the mains frequency to lock the time signal for recording, and tapes recorded on 60Hz won't playback properly on customers 50Hz VCRs Lucky you don't have to deal with that as well
Not to worry, I'll have a real life comparison of my two chargers by the end of today. Two batteries, starting at the same point, 35%... and each connected to the respective chargers at the same time. I'll be watching each closely and note the time it takes to charge to 100%
Meanwhile, would you mind answering the question I was replying to?
Thank you
Yesterday morning I flew my #4 battery down to 30%, let it cool, put it on a DJI Factory 100 watt charger, and happened to be standing in front of it when the last light went off... it took 50 minutes and some seconds.
This morning I flew the same battery down... landed at 30% but it flipped down to 29% before I could power it down. Using the no-name cig lighter charger I have, it took ~61 minutes... the charger never got hot or even over-warm, my work van was not running, and TBH the battery in the van is not even very healthy... 12.42v no load, 12.22v with the charger plugged in.
61 - 50 = 11
11 / 50 = .22
So 22% longer, not 14 %... 11 minutes more.. and with the van running, it might have been even less?
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I said mine was LIKE that one, I didn't say that's the one I bought... sorry.
I read all the reviews on the one I finally bought, but that was way over a year ago... and it works great for me
The output from an automotive alternator is DC, not AC. It starts out AC in the stator coil but it is rectified to DC before the output.
If you measured the voltage at the battery terminals the resting voltage indicates a battery somewhere above 75% state of charge (12.4V = 75% for a SLA 12V battery from memory). If measuring at the lighter socket the voltage drop might be largely attributed to IR losses in the cable. In any case, and as you might know, true indication of battery health could only be reliably assessed by loading it significantly to compare the CCA or RC to manufacturer specs.
Interesting result on the charge time comparison. What is your take on this? Over enthusiastic power delivery quoted by the maker?
Higher supply voltage to the charger should not make an appreciable difference as long as it is within the input range or the buck converter. It may prove relavent if the wiring gauge to the lighter socket was marginal and IR losses proved significant.
The alternator output is dirty DC (contains a significant ripple component). The battery provudes a significant role in smoothing the output (similar to that of the reservoir capacitors that follow the rectifier or switch mode section of a DC power supply).
Hey DOC.........are you some what confused to the s i m p l e q u e s t i o n that you had asked....I sure would be and i'd sure Not know what to do....have you By Now come Up to a conclusion to the need ?
You make a good observation here no question- there is no simple answer. You either make a considerable investment (unit cost, dual battery supppy in the vehicle and associated wiring) in a sine wave inverter from a reputable manufacturer or go with a cheaper modified square wave unit that other forum members have actually used and know performs acceptably. If you have no need for for AC power in the field the DJI car charger is probably the best option.
In terms to allow the person thats placed a question here....i agree the answers can sure vary........your quite Right "with"......Yep a simple DJI charger would " Keep it S i m p l e " Louder Cheers ))))) )))))
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