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Better Charger for Mavic 2,

bumper

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Frankly, I was a bit concerned that an aftermarket charger might trash my expensive M2P batteries. After playing with this, I think it's both safe and a lot better than the stock charger. Not perfect, but certainly a good deal ($55). My review below.

https://www.amazon.com/Hanatora-Battery-Controller-Charging-Discharging/dp/B07Y9V4GTR/ref=cm_cr_arp_d_product_top?ie=UTF8

Note: Referring to cell balance, I'm sure it's not the discrete balance (as might be achieved with a separate plug with leads to each cell), rather this is a timed, low current finish charge of about 20 minutes, during which time or after, the battery is ready for use. The low current prevents overheating and damage to the already full cells - - at least that's the basic premise.

Review:

My background is in electronics, this review will be "gently" technical. This is more than just a great charger, it has 3 important and discreet modes:
1) Full charge with cell balance
2) Storage charge with cell balance
3) Full discharge to zero.

1) Charging: Plug in up to 4 batteries and they will all charge simultaneously. Note that when charging 4 batteries, station 4 will initially not charge at a 2 to 3 amp rate as do stations 1 - 3. This is due to max power considerations. As soon as the 1-3 receive a significant charge, station 4 will start to catch up. At about 99% charge, the finish charge will be low current to balance the cells (the battery can be removed at this point if needed.

2) you can plug in your discharged or charged batteries and depending on their individual state, they will be discharged down, or charged up, to 15.4 to 15.8 volts for long term storage. Storing at this charge level prolongs battery life and should be considered if you won't be flying your drone for a few days or more. Storing lithium batteries fully charged stressed them, so this is a useful feature. This is also why Mavic 2 batteries (and probably others) are programmed to initiate a slow self discharge when stored in a charged condition for a set number of days (I believe the default is 10 days, I changed mine to 5 days). But really, it's better not to store them fully charged for any appreciable length of time if it can be avoided - - overnight for flying next morning, no problem. But if flying late morning, then this charger makes it quick and easy to charge 'em all while having breakfast!

3) Another feature is discharge mode . The will discharge a fully or partially charged battery down to zero (0%) which is recommended after every 20 or so charge-discharge cycles for maximum battery longevity.

Note that when using the car charging cord, the vehicle's engine will need to be running before plugging in the charger. Otherwise, due to the high current demand, the charger's input voltage will be too low and you will get an error indication on the display..

Noise: Not objectionably at all. Both the AC power adapter and the charging cradle have small muffin style cooling fans to dissipate heat, a necessary design feature when charging with this much power. BTW, no smell noted.

All in all, a reasonably priced and far more convenient upgrade compared to the DJI provided charger.

Minor cons (communicated to mfg): Add an on/off rocker switch on AC power adapter so one does not have to unplug cord between uses.
Add a bit more length to the DC (car charger) cord. Note that due to fairly high current demand, wiring loss (voltage drop across wiring) can be an issue - that's the reason they kept the cord fairly short. As a result, on some vehicles, this leaves no convenient place or rest the charger with batteries - especially when driving (and who wants to sit parked with engine running for an hour to charge batteries?). They could increase wire thickness and add a foot or so to the length with no net loss.
I'm very happy with this charger.
 

hactick

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Thanks for the detailed review.. glad to see it can charge in a car too.
 

bonmot

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Thanks for the detailed review.. glad to see it can charge in a car too.
I got a car charger with fly more kit. Never used it.
But I found the stock charger works very well. And 5 days discharge setting (the default for my Mavic 2 Zoom) is just at the sweet spot.
“Discharge to zero” might be tricky. What is the min voltage of each cell at the end of this process?
 

romko1

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3) Another feature is discharge mode . The will discharge a fully or partially charged battery down to zero (0%) which is recommended after every 20 or so charge-discharge cycles for maximum battery longevity.
What is 0% discharge? Discharging the cell below 3V will irreparably damage the LiPol battery. Thanks.
 
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Bramavic2

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I just got mine, will do some tests. Are you sure it only charges with the car on? I bought it to be able to charge it from stationary 12v batteries. The ad says it will charge from 11v to 14v:
 

bumper

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I just got mine, will do some tests. Are you sure it only charges with the car on? I bought it to be able to charge it from stationary 12v batteries. The ad says it will charge from 11v to 14v:
When I tested it in my FJ Cruiser, it gave me an error signal on the display with the engine not running. This was with 3 & 4 batteries. I did not check the input voltage at the receptacle when testing. Due to the vehicle's wiring size, there's probable enough voltage drop get the charger's input voltage below the acceptable limit.
 

bumper

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What is 0% discharge? Discharging the cell below 3V will irreparably damage the LiPol battery. Thanks.
Have a look at the last line on page 6, where DJI says to fully charge and discharge the battery at least once every 3 months to maintain battery health.
https://dl.djicdn.com/downloads/Mavic_2/20180823/Mavic_2_Intelligent_Flight_Battery_Safety_Guidelines_EN.pdf

There are other references to completely discharging the batteries to zero every 20 charge discharge cycles. I have 5 batteries for my two M2's, I have not accumulated enough cycles to require trying this yet . . . so I'm only going by what I've read.
 

Camino Ken

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Have a look at the last line on page 6, where DJI says to fully charge and discharge the battery at least once every 3 months to maintain battery health.
https://dl.djicdn.com/downloads/Mavic_2/20180823/Mavic_2_Intelligent_Flight_Battery_Safety_Guidelines_EN.pdf

There are other references to completely discharging the batteries to zero every 20 charge discharge cycles. I have 5 batteries for my two M2's, I have not accumulated enough cycles to require trying this yet . . . so I'm only going by what I've read.
I think that statement is misleading. I have read in multiple sources that discharging a LIPO battery to zero can cause permanent damage. Maybe it meant “fully charge and discharge to 10% every three months.
 

bheiser1

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I think that statement is misleading. I have read in multiple sources that discharging a LIPO battery to zero can cause permanent damage. Maybe it meant “fully charge and discharge to 10% every three months.
Airdata says to discharge to 8% as their instructions below explain. I’ve been reluctant to follow their instructions because so many people here have said not to deep cycle them this way. I’m also disinclined from running the motors without props or just letting it sit and run. What to do, what to do... 🤔

Battery Deep Cycle Discharge

When you deep cycle the battery, it also re-initializes the battery's internal software. Always allow a LiPo battery to cool completely before any recharge to help protect your battery and extend its life.

Slower Deep Cycle Method:
Fly until battery level reaches 25%-30%
Allow battery to cool completely to room temperature
Put battery back in and turn on aircraft (optionally starting motors with no propellers) and allow battery to discharge until it gets down to 8%, or until the battery can no longer be turned on. Launch the DJI GO app to check battery levels.
Important: NEVER fully discharge the battery to 0% - it can cause permanent damage
Tip: With engines stopped, the battery seems to drain about 1% every 5 minutes or so
Allow the battery to cool completely again to room temperature
Recharge battery normally

Rapid Deep Cycle Method:
Fly the aircraft outdoors until there is less than 8% of power left, or until the battery can no longer be turned on.
Allow the battery to cool completely again to room temperature
Recharge battery normally
 
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bumper

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I haven't been brave enough (or have batteries old enough) to try the discharge mode lower than 8%. From that point, using "storage mode" (which either discharges or charges battery to about 50% automatically), the Hanatora charges the battery at half the normal rate, 1.5 amps, until almost 50%, then it switches to a lower pulsed charge for maybe 20 minutes before stopping.

On a couple of larger LiFePo4 batteries I have, like the Mavic 2 batteries, there is no separate balance plug. The balance procedure there is also a finishing pulsed charge, the idea being this prevents the fully charged cells from overheating with with additional charge, while allowing the lower charges cells to "catch up". The Hanatora seems to use a similar protocol.

When I get enough cycles on a M2 batt, I'll let the Hanatora charger discharge it to zero (while keeping an eye on it) and report back. Either it'll stop at zero, s advertised, or the on-board smart charging circuitry will stop it from going that low.
 

Bramavic2

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The thing is zero percent might refer to very different voltages in dji go (as people have flow well past it) and to the discharger.

Regarding balance, I thought it was done by the battery pack itself, as it is "intelligent", not by the slower charging method. Any further info on that? First I thought all those multiple contacts in the conector were for each individual cell so to allow the factory charger to take care of balancing.
 

bumper

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The thing is zero percent might refer to very different voltages in dji go (as people have flow well past it) and to the discharger.

Regarding balance, I thought it was done by the battery pack itself, as it is "intelligent", not by the slower charging method. Any further info on that? First I thought all those multiple contacts in the conector were for each individual cell so to allow the factory charger to take care of balancing.
According to DJI, balance is done internally to the battery. The pin-outs are 1 thru 4 - negative, 5 & 6 - ? probably data, 7 thru 10 - positive.
 

Mike4884

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I would not do your number "3" on that list.... You just do not do that with any lipos I don't care what DJI says or what smart technology they have I have never done that with any of my heli lipos and I have big stick packs 12s ....14s....6s.... Have many years of experience with lipos....back in the day phantom 3 day DJ I just wanted you to discharge it to around just under 10% to calibrate the smartboard to read more accurately that's what that was for.... Like I said and it's very bad to discharge to 0%..... Just follow the 80/20 rule and you will always be good 80% out ....leaving 20%.... If you are not flying just store your batteries at 3.7 or 3.8 volts each cell which is 1 and half light blinking.... I have had every single DJI aircraft except for the inspire 2 and have never had a problem from not discharging to 0% I've never done that once. I can only cringe to think about doing that with one of my stick packs that would be five hundred bucks down the tube lol and yes the DJI packs have smart boards in them but sometimes taking them down that low you can't revive them you actually have to take the battery apart and put it on a regular lipo charger so it's just not advised to go to 0% all the time like suggested
 

Bramavic2

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When I tested it in my FJ Cruiser, it gave me an error signal on the display with the engine not running. This was with 3 & 4 batteries. I did not check the input voltage at the receptacle when testing. Due to the vehicle's wiring size, there's probable enough voltage drop get the charger's input voltage below the acceptable limit.
I tested my unit and it does indeed charge from the car 12v battery without the car on, so between 12 to 13 volts. Well bellow the DJI charger in the flymore kit. I haven't yet tried the 11v advertised, but no reason to doubt that.
 
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bumper

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I tested my unit and it does indeed charge from the car 12v battery without the car on, so between 12 to 13 volts. Well bellow the DJI charger in the flymore kit. I haven't yet tried the 11v advertised, but no reason to doubt that.
I don't typically drive my FJ on more than short trips, not enough to replenish the battery - and it was low. After charging the battery, it functioned properly with the Hanatora just fine.
 

romko1

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For your information: I have watched the battery cells voltage through DJI GO in the envy at percentages.
So: 10% = 3.72V/cell
9% = 3.71V/cell
8% = 3.70V/cell

I did not go below so purely theoretically 0% battery (apl. DJI GO) would not have to be less than 3.5V / cell.
 

Bensherrard1

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Frankly, I was a bit concerned that an aftermarket charger might trash my expensive M2P batteries. After playing with this, I think it's both safe and a lot better than the stock charger. Not perfect, but certainly a good deal ($55). My review below.

https://www.amazon.com/Hanatora-Battery-Controller-Charging-Discharging/dp/B07Y9V4GTR/ref=cm_cr_arp_d_product_top?ie=UTF8

Note: Referring to cell balance, I'm sure it's not the discrete balance (as might be achieved with a separate plug with leads to each cell), rather this is a timed, low current finish charge of about 20 minutes, during which time or after, the battery is ready for use. The low current prevents overheating and damage to the already full cells - - at least that's the basic premise.

Review:

My background is in electronics, this review will be "gently" technical. This is more than just a great charger, it has 3 important and discreet modes:
1) Full charge with cell balance
2) Storage charge with cell balance
3) Full discharge to zero.

1) Charging: Plug in up to 4 batteries and they will all charge simultaneously. Note that when charging 4 batteries, station 4 will initially not charge at a 2 to 3 amp rate as do stations 1 - 3. This is due to max power considerations. As soon as the 1-3 receive a significant charge, station 4 will start to catch up. At about 99% charge, the finish charge will be low current to balance the cells (the battery can be removed at this point if needed.

2) you can plug in your discharged or charged batteries and depending on their individual state, they will be discharged down, or charged up, to 15.4 to 15.8 volts for long term storage. Storing at this charge level prolongs battery life and should be considered if you won't be flying your drone for a few days or more. Storing lithium batteries fully charged stressed them, so this is a useful feature. This is also why Mavic 2 batteries (and probably others) are programmed to initiate a slow self discharge when stored in a charged condition for a set number of days (I believe the default is 10 days, I changed mine to 5 days). But really, it's better not to store them fully charged for any appreciable length of time if it can be avoided - - overnight for flying next morning, no problem. But if flying late morning, then this charger makes it quick and easy to charge 'em all while having breakfast!

3) Another feature is discharge mode . The will discharge a fully or partially charged battery down to zero (0%) which is recommended after every 20 or so charge-discharge cycles for maximum battery longevity.

Note that when using the car charging cord, the vehicle's engine will need to be running before plugging in the charger. Otherwise, due to the high current demand, the charger's input voltage will be too low and you will get an error indication on the display..

Noise: Not objectionably at all. Both the AC power adapter and the charging cradle have small muffin style cooling fans to dissipate heat, a necessary design feature when charging with this much power. BTW, no smell noted.

All in all, a reasonably priced and far more convenient upgrade compared to the DJI provided charger.

Minor cons (communicated to mfg): Add an on/off rocker switch on AC power adapter so one does not have to unplug cord between uses.
Add a bit more length to the DC (car charger) cord. Note that due to fairly high current demand, wiring loss (voltage drop across wiring) can be an issue - that's the reason they kept the cord fairly short. As a result, on some vehicles, this leaves no convenient place or rest the charger with batteries - especially when driving (and who wants to sit parked with engine running for an hour to charge batteries?). They could increase wire thickness and add a foot or so to the length with no net loss.
I'm very happy with this charger.
Awesome thx!