Eachine Battery Charger HELP!!

Eachine98379872 · Feb 8, 2021

I have the Eachine battery charger which I use to charge my XT60 75C 4S battery for my Eachine Wizard X200S drone - Eachine Wizard X220S FPV Racer RC Drone Spare Part 4S 14.8V Battery Charger

When I plugged my battery into it there was a spark and a burning smell and the charger no longer works. I have opened it up and it looks like a diode has blown. I got another one and used a different battery and the same thing happened again. I had used the new charger and the battery several times without an issue before it broke. Does anyone have any ideas as to why this is happening? I have the wall switch turned off when I plug the battery in but I can’t imagine that making a difference. There is a USA – UK plug adapter that came with the charger aswell. Also do you think that the battery that blew the charger is still safe to use? It had a slight burn mark on one of the terminals. The other battery that I blew it with has no marks at all.

Thank you

droneguy · Feb 8, 2021

There are a few issues in the picture you provided. The diode that burned in the pic is a Schottky diode used as a clamping/rectifier diode. The power resistor to the right in the image also demonstrates signs of overheating and potential damage. These types of component failures are often due to over current situations. Also, the battery balance lead had a melted pin on the connector due to excessive current. That cell may be damaged or had significantly lower voltage than the rest when you plugged it it to charge. Uneven cell voltage causes the current to rush across the cells when charging in order to balance the cells. This would appear to be your situation.

The safest course of action moving forward is to replace the charger and test the suspect battery(ies).

For testing, I'd start with the battery since it is the device you will likely want to keep using moving forward if it's ok. You can perform simple tests with a multi-meter checking voltage of each cell and total voltage. If there is a failed cell, you could have a short causing the high current condition on the battery. Given your situation, my suspicion is a damaged battery. I would also recommend a good battery checker like the ISDT BattGo BG-8S Battery Meter or even a cheap one like the DROK voltage indicator or FlyRC capacity checker etc. Knowing the individual cell voltage is important in order to see battery health. The ISDT has the added benefit of a cell balance function that will balance the voltages across the cells.

I would take this opportunity to look at a newer smart charger with balancing and storage functions. There are many reputable brands on the market. I like the ISDT chargers myself, but there are many good ones to choose from. Smart charger often show you the cell impedance as well which is great for tracking long term battery health. Also good chargers, charge through the main power lead (XT60 etc.) and use the balance leads to monitor and adjust the balance the voltage accross the cells. This charger charges each cell through the balance lead and a failed or uneven cell(s) will cause high current draws like what you are experiencing. These types of chargers are dangerous and I would avoid them at all costs for anything larger than a small 2 cell battery.

If you chose to repair the charger, you will need to independently test all the devices involved (AC adapter, charger) as well as source the replacement components of the charger. To troubleshoot the charger, I'd start with the AC adapter that us plugged into the charger. The power brick is converts the 110vAC to 19vDC for the charger. Use a multi-meter to check the output voltage of the brick. Next you would want to load test the brick. Given it's a 19v output with a 850mA max current your load should not exceed 23ohms. Given your charger is now damaged you may opt to attempt repairing it or likely you will opt to replace it.

Hope this helps in some way and fell free to respond with further questions and we can see if we can help.

droneguy · Feb 8, 2021

One more thought, are you powering a Gopro or other camera off the balance lead cable?

Eachine98379872 · Feb 8, 2021

Thank you for your reply that's really helpful. The only thing I'm powering is the drone itself. Do you have any other good battery tips? I heard something about not draining them to 0% but it looks seem to be a bit of a dark art. Thank you

droneguy · Feb 8, 2021

LiPo batteries are designed to run from 4.2v (full charge) down to 3.2v or 3.3v. For a 4S (Like the battery in your pic) you will see 16.8V on a full charge down to 13.5 -14v on a discharged battery. You can use your transmiter or OSD in your goggles to keep track of you battery voltage while you fly. You should probably be thinking about landing when you reach around 13.5v or 3.3v per cell as the voltage tends to drops quickly anything below 14v and after that and you could get into trouble in a hurry and drop dangerously close to dropping below 3v. Lipo batteries should never be discharged below 3v. It permanently alters the chemistry and charging a battery that has dropped below 3v can be dangerous as it will draw really high amperage if you don't limit it and potentially light themselves on fire in the process. The charger you are using offers no intellegence or visibility into the state of the battery and therefore can be dangerous.

As I mentioned in my earlier post, balance charging is important in order for all cells to have the same capacity and when used current is drawn equally across the cells, otherwise some cells will wear much quicker leading to a damaged cell and useless battery. I suspect that the battery you connected to the charger has either one or more cells that have dropped below 3v and cause a high current draw on the charger when you attempted to charge it. A smart charger and a battery tester would help you mitigate those risks.

droneguy · Feb 8, 2021

Check out my other post for more battery management tips.

Battery Storage

So I need some info from the more experienced pilots here. I flew 12 4s packs today. I probably won't fly more than 2 or 3 this week or maybe not at all. If the weather is good this weekend I might get a dozen or more flights. If the weather is crap(it's definitely winter here in the northeast...

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