Balance plug for Mavic pack

[Balmybaldwin]

Now showing fully charged... recon it took about 1h30 in all

 

[Ill]

I'm new here, but not new to RC, Mutirotors, Drones, or LiPo batteries. Been flying electric for 20+ years and have been around the block more than a few times building and flying LiPoly packs.

I recently bought a Mavic from eBay and it came with 4 batteries and a ton of other stuff. Seemed like a great deal and in fact it flies great! I also own a couple of 3DR Solos and the Mavic is a clear winner when it comes to gimbal smoothness and flying range.
.....

BTW- Do you have any idea what is the RST-contact in circuit board?

 

[Ill]

The led one is blinking ~16 times in 6 sec. and then ~7 sec break.
The battery has been connected to charger long periods but there are no changes to battery behavior.

 

[UAV Aerial]

Will this
B6/B6AC Converting Fast Charging Cable Balance Charger Adapter Plug for DJI Mavic Air Battery

work like this?

 

[UAV Aerial]

Nevermind I just noticed its for Mavic AIR. **** I already ordered it.

 

[stberlin]

Nevermind I just noticed its for Mavic AIR. **** I already ordered it.

I see a lot of B6 to mavic air cable + charger combo on ebay or amazon that says "balancer."

I don't think a B6 cable can actually balance a Mavic Air battery.

 

[Memphis3]

Almost any LiPo charger will balance charge any DJI battery. You do have to connect the balance lead and connect the power leads.
and
That charger is one of the nicer ones even the knock off or clone B6 will work. The charger can partial charge storage charge discharge trickle charge a whole slue of different battery types.
Your good to go.

 

[KDan]

I'm revisiting this thread because I just started flying my Mavic Pro again this spring. Guess what? I have another Mavic pack with the dreaded battery error and a low cell - which refuses to fly

This time I got the battery pack apart more easily with basically Zero cosmetic damage. The key is to use the right tool for the job. I used a thin 6 inch metal ruler which allowed me to get beside several of the snap catches on the battery case at once. I also carefully got a scalpel under the front and rear edges where the label is located on the bottom of the pack. There are adhesive strips here which if separated first, makes it much easier to get the pack apart.

I'd like to comment on the past couple messages above. There is NO balance charger and cable that will balance charge a Mavic pack through the standard connector. It's impossible because individual cells are NOT brought out to those pins. The only way to do it is pull the pack apart, carefully install a balance plug, and use a cell discharge balancer or balance charger to bring the cells back into balance. Using the discharge balancer is most effective when used on a nearly depleted pack - that is when cell voltage differences are most exaggerated.
Significant charging or discharging through this balance plug will effect the battery calibration. I've just reconfirmed that fact. After re-balancing your pack in a nearly discharged state, put it back into the Mavic and turn it on. Watch the cell voltages in the DJIGo4 app to confirm the cell voltages are very close. When it shuts down, let it rest a few minutes and then go ahead and put it on the DJI charger and charge it fully. Don't use the balance charger again unless you absolutely need to re-balance the pack again.

 

[KDan]

Wow, this is becoming an epidemic! A friend called me over the weekend and told me he was getting this battery cell broken error on his Mavic Pro (refurb) just bought last year. He only had one battery and was dead in the water. I told him I could fix it and he dropped it off Sunday afternoon. I had the pack apart, balance plug installed, and on the cell discharge balancer that evening. By Monday morning the cells were perfectly balanced. I snapped the pack back together and put it on the DJI charger before I went to work. Last night I put the pack in my Mavic Pro and flew around for about 20 minutes and the pack performed 100%. The cells are still in perfect balance.
Geez, maybe I should start a business fixing these things

 

[gmarg]

Hello, i am also having a problem with my Mavic Pro battery (11 charging cycles but out of warranty and 0.2V difference between cells) and after a lot of reading i understand that i have to open and balance the cells. I have no problem opening it as i am good with electronic repairs but i have no experience at all in LiPO charging. Can you suggest a good (but not very expensive) balancer-charger to use? Looking at the photos i can see that you are using hobbyking hk-010 which can balance the battery by discharging it at the lowest cell value (if i can understand correctly in the manual) - is it OK or there is a better way to balance the cells?

 

[Texas Mavic]

I'm revisiting this thread because I just started flying my Mavic Pro again this spring. Guess what? I have another Mavic pack with the dreaded battery error and a low cell - which refuses to fly

This time I got the battery pack apart more easily with basically Zero cosmetic damage. The key is to use the right tool for the job. I used a thin 6 inch metal ruler which allowed me to get beside several of the snap catches on the battery case at once. I also carefully got a scalpel under the front and rear edges where the label is located on the bottom of the pack. There are adhesive strips here which if separated first, makes it much easier to get the pack apart.

I'd like to comment on the past couple messages above. There is NO balance charger and cable that will balance charge a Mavic pack through the standard connector. It's impossible because individual cells are NOT brought out to those pins. The only way to do it is pull the pack apart, carefully install a balance plug, and use a cell discharge balancer or balance charger to bring the cells back into balance. Using the discharge balancer is most effective when used on a nearly depleted pack - that is when cell voltage differences are most exaggerated.
Significant charging or discharging through this balance plug will effect the battery calibration. I've just reconfirmed that fact. After re-balancing your pack in a nearly discharged state, put it back into the Mavic and turn it on. Watch the cell voltages in the DJIGo4 app to confirm the cell voltages are very close. When it shuts down, let it rest a few minutes and then go ahead and put it on the DJI charger and charge it fully. Don't use the balance charger again unless you absolutely need to re-balance the pack again.

View attachment 69402

View attachment 69403

View attachment 69404

Can you tell me the best place to solder in the balanced 3S cable into the Mavic battery?

 

[___]

Wow, this is becoming an epidemic! A friend called me over the weekend and told me he was getting this battery cell broken error on his Mavic Pro (refurb) just bought last year. He only had one battery and was dead in the water. I told him I could fix it and he dropped it off Sunday afternoon. I had the pack apart, balance plug installed, and on the cell discharge balancer that evening. By Monday morning the cells were perfectly balanced. I snapped the pack back together and put it on the DJI charger before I went to work. Last night I put the pack in my Mavic Pro and flew around for about 20 minutes and the pack performed 100%. The cells are still in perfect balance.
Geez, maybe I should start a business fixing these things

What's the cost for a rebalance?

 

[Texas Mavic]

I can’t quite see where it’s soldered, that’s why I asked. Looks like the underside of where the board 3S is. I assumed it was at the cell terminal.

 

[KDan]

The discharge balancer I have (hobbyking hk-010) has been around a long time. There are certainly other alternatives. I prefer to use a discharge balancer rather than a balance charger because balance chargers only balance when the cell is at full charge (and most don't charge HVLipo cells cells correctly anyway). Discharge balancers apply more load to higher voltage cells immediately upon connecting them, so you get the voltages equalized faster. It also has much less effect upon the battery calibration.
I prefer to solder the balance lead onto the terminals on the bottom side of the BMS board. This allows you to rebalance the cells without disconnecting power from the BMS circuit. You could just pull the plug at the end of the battery pack (inside font), but I suspect that disconnects the BMS and resets it. That is not what you want to do if you want to preserve historical battery data (cycle count) and calibration data.

 

[Texas Mavic]

The discharge balancer I have (hobbyking hk-010) has been around a long time. There are certainly other alternatives. I prefer to use a discharge balancer rather than a balance charger because balance chargers only balance when the cell is at full charge (and most don't charge HVLipo cells cells correctly anyway). Discharge balancers apply more load to higher voltage cells immediately upon connecting them, so you get the voltages equalized faster. It also has much less effect upon the battery calibration.
I prefer to solder the balance lead onto the terminals on the bottom side of the BMS board. This allows you to rebalance the cells without disconnecting power from the BMS circuit. You could just pull the plug at the end of the battery pack (inside font), but I suspect that disconnects the BMS and resets it. That is not what you want to do if you want to preserve historical battery data (cycle count) and calibration data.

So the battery is giving me the blink, not wanna charge led signals. How can I reset this, or have I just bricked the battery and need to make a 3S pack out of it?

 

[KDan]

So the battery is giving me the blink, not wanna charge led signals. How can I reset this, or have I just bricked the battery and need to make a 3S pack out of it?

Look at the first picture on the first message of the thread to see the correct terminals to connect the balancer leads. Make sure the cells are balanced. Then if you are still getting an error, you could try to reset the BMS circuit. If you look at the same picture you will notice a pad marked RST. This should be the reset. I'm guessing that grounding this pad briefly will completely reset the board. I haven't needed to do this myself, but if the battery voltages are good and it still won't charge, you have nothing to loose...

 

[Texas Mavic]

Look at the first picture on the first message of the thread to see the correct terminals to connect the balancer leads. Make sure the cells are balanced. Then if you are still getting an error, you could try to reset the BMS circuit. If you look at the same picture you will notice a pad marked RST. This should be the reset. I'm guessing that grounding this pad briefly will completely reset the board. I haven't needed to do this myself, but if the battery voltages are good and it still won't charge, you have nothing to loose...

How would I ground to that RST pad? Or how would you recommend I ground to it?

 

[Texas Mavic]

Look at the first picture on the first message of the thread to see the correct terminals to connect the balancer leads. Make sure the cells are balanced. Then if you are still getting an error, you could try to reset the BMS circuit. If you look at the same picture you will notice a pad marked RST. This should be the reset. I'm guessing that grounding this pad briefly will completely reset the board. I haven't needed to do this myself, but if the battery voltages are good and it still won't charge, you have nothing to loose...

The cells are all fine. It’s the board shutdown about 10 seconds after powered on that is the problem. I believe I shorted the leads when I installed the balanced cable. I remember a small spark, I think I touched two positives together for a split second. Then the board wouldn’t keep the battery powered up.

 

[Texas Mavic]

How would I ground to that RST pad? Or how would you recommend I ground to it? From the + lead of all 3 cells? Or 1 cell? I have combed the battery mod threads, and there is some great work there, I don’t remember anyone finding the reset, cudos!! Maybe I missed it...but that’s a solid catch @KDan

 

[Texas Mavic]

Well I accidentally destroyed the whole thing. The 4 pin connector crumbled, The whole front board came off, it’s useless now. I can smell the dreaded lipo candy stink. All the cells still have 4.23 volts!!! So I just bricked it. Hopefully I can figure out how to throw it away.