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Way to solve the 12 volt charger issue

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#41
My 2014 Honda CRV turns off the acc. outlets if the car is not running. On a couple of occasions my wife was cleaning the car with the dome lights and radio on and when I got home she tells me that the car won't start. Had to put the charger on the battery both times. Makes me afraid of trying to charge the Mavic batteries in the middle of nowhere.
 

dwallersv

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#42
My 2014 Honda CRV turns off the acc. outlets if the car is not running. On a couple of occasions my wife was cleaning the car with the dome lights and radio on and when I got home she tells me that the car won't start. Had to put the charger on the battery both times. Makes me afraid of trying to charge the Mavic batteries in the middle of nowhere.
Rest easy. This was not because dome lights for an hour or so will discharge the battery. It's because you needed a new battery.
 
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Kilrah

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#43
Can you validate this with some actual evidence?

The fact that below an input voltage of 13V the output voltage tracks input down would seem to strongly dispute your claim.
It doesn't, as mentioned earlier that "fact" isn't one, only a fluke due to measuring output with no load.


20170512_213053.jpg
 

AlanTheBeast

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#44
My 2014 Honda CRV turns off the acc. outlets if the car is not running. On a couple of occasions my wife was cleaning the car with the dome lights and radio on and when I got home she tells me that the car won't start. Had to put the charger on the battery both times. Makes me afraid of trying to charge the Mavic batteries in the middle of nowhere.
Note that Honda have been putting really small batteries in cars in recent years. Doesn't take much to drain them. In our winters you have to be very wary. Used to have manual and my driveway is downhill to the street - so I could easily start it. Now automatic.
 

JustinVV

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#45
I flattened all the batteries today, 3 x bateries and the controller, and will test charge on the motorbike tomorrow with the engine stopped.
 
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#46
Exactly what I needed! Order from amazon for $26 10Amp version. I have to use a splitter in my car and that makes the voltage too low even when running. Hope this will fix that problem. :)
 

MilesTHD

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#47
You can easily charge three Mavic batteries from your car battery while its stopped with no problems at all.
Three (3) Mavic battery's at 15% flatt = roughly 3000mha or X3 9000 mha or 9amps.
The average car battery, Small is 400amp, large 600amp.
So even after an hour charging 3 Mavic batterys 9 to 10 amps from 400 amp battery isn't going to flatten it. And a five minute idle with a good alternator will replace that back into car battery.
Now the DJI car charger seems to need a full 13.8 volts to provide the battery circuit an even current to charge the cells.
The problem is the car battery is an lead acid and at peak charge per cell of 2.3 is 13.8 but once that float discharge is removed the nominal voltage per cell is 2.1 or 12.6 volts.
And 12.6 is not enough to hold open the input gate on the Mavic car charger.
So you have to use a Buck Converter which takes a lower voltage of between 8 to 12v and supplies a steady output of 13.8 volts. They come in flavors of 5,8,10or15 amp so you would need at least 10 amp minimum for 3 batteries at once.
Or you could go the 12v to 240v inverter route and use your home charger plugged into the inverter.
A little more inefficient but still a cheap fix as you already have home charger and a 12v to 240v 300w can or gigarette plug inverter is only $15 to $20.
You guys have way too much time on your hands.
 

AlanTheBeast

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#48
You guys have way too much time on your hands.
Nothing like running out of power 100 km from home. I'll be ordering the DC-DC's shortly and I'm going to go look at batteries today. Won't take me 30 minutes to cobble a neat package together for this.
 

Matchlock

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#49
Not many Mavic owners know this but the black brick that you get with the Mavic Pro is NOT a charger. It is ONLY a power supply. The actual battery charger is in the battery itself.

Bud

Maybe, but the battery has smarts to protect it, but why didn't they put a proper power supply in it that would regulate to the correct voltage. Like everyone else does. Its all about price.

The regulator I used will supply a rock solid regulated 13.6 volts, no matter what you throw at it. Just what the charger needs.

Is there a limit switch in the power supply? or is it just the battery that has the smarts.. I will check, but I bet its the battery that has the smarts. I bet the power supply only regulates on the high end.
 
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quick_dry

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#50
Not many Mavic owners know this but the black brick that you get with the Mavic Pro is NOT a charger. It is ONLY a power supply. The actual battery charger is in the battery itself.

Bud
I haven't had the Mavic long and haven't checked, but are Mavic batteries similar to Solo in that they're allowed a max Voltage and if you supply over X amps the battery shuts off ? (ie you need a current limited power supply)
 

JustinVV

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#51
I just set up the motorbike (2016 KLR 650) and charger 3 x batteries and the controller, the bike battery was stable at just under 13 volts (its an AGM battery). By the time the batteries and the controller were fully charged the battery voltage was just above 11, and the engine would barely turn over. its warm here so I could have got it started, but on a cold morning, it would be a no go. Also the engine may not have turned over quick enough to release the de-compressor to allow the engine to fire.

So I will only be charging the batteries. as I rise, which is what I normally do.

PS I could charge one while stopped to get me out of trouble if I needed to.
 

AlanTheBeast

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#52
I haven't had the Mavic long and haven't checked, but are Mavic batteries similar to Solo in that they're allowed a max Voltage and if you supply over X amps the battery shuts off ? (ie you need a current limited power supply)
The battery has it's own control circuitry and will stop charging the cells when they are fully charged. They also have over current protection during charge.
 

AlanTheBeast

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#53
I just set up the motorbike (2016 KLR 650) and charger 3 x batteries and the controller, the bike battery was stable at just under 13 volts (its an AGM battery). By the time the batteries and the controller were fully charged the battery voltage was just above 11, and the engine would barely turn over. its warm here so I could have got it started, but on a cold morning, it would be a no go. Also the engine may not have turned over quick enough to release the de-compressor to allow the engine to fire.

So I will only be charging the batteries. as I rise, which is what I normally do.

PS I could charge one while stopped to get me out of trouble if I needed to.
This is why I'll be getting a separate battery to throw in the trunk. Deep cycle.
 

quick_dry

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#54
The battery has it's own control circuitry and will stop charging the cells when they are fully charged. They also have over current protection during charge.
Is that by disconnecting the charge circuit, or using the discharge circuit? I have a bunch of DC-DC modules with current and voltage limiting I was going to use for my own quick charger
 

AlanTheBeast

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#55
Is that by disconnecting the charge circuit, or using the discharge circuit? I have a bunch of DC-DC modules with current and voltage limiting I was going to use for my own quick charger
Can't answer that specifically - I would assume it simply disconnects to protect. The discharge circuit automatically engages in 10 days (or per settings) of no use.
 

Lelantos

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#57
... if I had to guess the capacity of my battery, it would be about 672 Ah. I would say the average battery has about 400 Ah, considering mine is a high end.
Wouldn't that be nice... True deep cycle batteries have the highest amp hour capacity. A deep cycle battery the size of a large car battery has about 110 amp hours of capacity. The capacity of a hybrid or starting battery of the same physical size will be much less. The difference is that a starting battery can deliver more amps for cranking than a deep cycle can.

Most capacity ratings of deep cycle batteries are based upon a 20 hour discharge. If you discharge at a slower rate, you will get more total capacity out of the battery. Discharge at a higher rate and the capacity will be less.

When shopping for a deep cycle battery, do not get a hybrid. If is says anything about cold cranking amps, move on. You want a true deep cycle, AGM. Vmaxtanks, available from Amazon have a good reputation and are available in many sizes.
 
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Cyberpower678

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#58
Wouldn't that be nice... True deep cycle batteries have the highest amp hour capacity. A deep cycle battery the size of a large car battery has about 110 amp hours of capacity. The capacity of a hybrid or starting battery of the same physical size will be much less. The difference is that a starting battery can deliver more amps for cranking than a deep cycle can.

Most capacity ratings of deep cycle batteries are based upon a 20 hour discharge. If you discharge at a slower rate, you will get more total capacity out of the battery. Discharge at a higher rate and the capacity will be less.

When shopping for a deep cycle battery, do not get a hybrid. If is says anything about cold cranking amps, move on. You want a true deep cycle, AGM. Vmaxtanks, available from Amazon have a good reputation and are available in many sizes.
I have no complaints with my battery. I have 3 devices plugged into the outlet that draws on the battery and they all took an entire week to drain my car's battery. I'm estimating that they all consume 4 amps total.
 

idiogenic

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#59
Dude, a genuine 600 amp hour battery would be about the size of a medium portable generator. Like old mate above you, I have a 120 amp hour deep cycle 2nd battery in my truck to power the fridge and it's the size of a very large car battery.

There's no way your battery capacity is 600 amp hours - the biggest I've seen us a 400 amp hour lithium battery that costs more than some cars.

Also, on the topic of the charger, I was the guy that took the plug apart. I can't comment on its exact function as it's not my area of expertise but I left it in when I wired in a DC converter and everything works great.
 

Matchlock

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#60
I'm sorry I don't know the answer to that question. Perhaps someone with more electrical and battery knowledge than I can help you.

Bud

I haven't had the Mavic long and haven't checked, but are Mavic batteries similar to Solo in that they're allowed a max Voltage and if you supply over X amps the battery shuts off ? (ie you need a current limited power supply)
 

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