Just inside the Q500 Battery, there is a BLACK circuit board marked "DLX-690 RoHS" (see picture). Can anyone tell me what it does?
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What is the black board inside a Q500 Battery for?
- Thread starter WTFDproject
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I haven't opened a battery myself, but, as a tech I would assume that this board is involved in balance charging of our batteries. The charger has to sense when the cell are out of balance and apply extra current to a low cell. Once again, this is just an opinion as a technician. As Yuneec warned me not to leave my batteries in the charger for more that 1 hour I don't think it has anything to do with over-charging protection. Without seeing the IC numbers this is the best guess I can give you. I am a little concerned with the look of the solder connections, but then, working as an Equipment Installer for a phone company (retired), everything had to be perfect, or it's not right.
Yeah, the solder looks a little odd for something that you would expect to be machine soldered. It didn't look quite as bad after I cleaned off the blue sealant, but each point is mechanically clipped off. Maybe excess wire? And the amount of solder on each joint differs a little bit. The strangest thing is a blue color that does not seem to be a residual of the sealant. It looks just like steel that has been heated up to bluing temperature. But how in the world would you ever get solder to that temperature without melting everything around it. And does solder even turn blue anyway? I've seen a lot of solder. Never saw any blue solder before.
I'm guessing the batts are manually soldered. The batt for the H looks similar and most multi-cell lipos are likely to have a connection board.
Thank you Steve for showing us the inside of an H battery. If you look at it, you see heat shrink on the connector ends effectively insulating them. For the cost of our batteries and drones, this is what I expect to see. But, I have known many companies to cheap out to save money. Adding heat shrink probably add 5 cents and 30 seconds construction to a battery, but if you add the cost over a million batteries, the cost starts to show. Most of the solder connections look fine. Just a few that I would consider suspect. They are most likely fine, just being finicky. The connection board, as you said would be common to multi-cell batteries. Whether it has anything to do with the balance charging is, as I said, a guess. The original Q500 chargers are not very intelligent so I would expect some intelligence in the battery.
The Yuneec batteries are simply Lipos with no smart boards. I'm happy with that. It keeps the cost down and makes it possible to use aftermarket batts.
Yeah, it's not a smart board, but it also isn't just a straight connection board. The back side, under the sticky tape, has a thick coating of black epoxy. The Q500 version has about 12 evenly spaced "lumps". The ground wire has a huge resistance value to it. The other wires don't, but I suspect they do something to assist the balance charge. I'm trying to use this thing as part of a project to turn a Breeze charger into an adapter so I can use my normal charger. I'm trying to decide whether to use the Q500 board and tie in downstream of the Breeze board altogether, or not use the Q500 board, and tie in upstream of the Breeze charger equivalent. Can always take a guess, and keep a fire extinguisher handy, but would rather it be an educated guess. For that, I need to figure out what this board actually does for the balancing process. And yes, I know it would be easier to buy an adapter, but no one in the US seems to have one for the Breeze. Kinda got interested in this anyway, and would like to see if the idea works.
Good luck with your project. As a tech, I would be interested in your projects success, as well as confirmation of what the black board does. With the high resistance on the ground lead and the 12 lumps, I do suspect it has something to do with balance charging. It doesn't need to be a smart board as regular circuitry can achieve the same results by separating the cells voltages and comparing them.
Have fun with this!
Have fun with this!
Thanks. I'll do that. Especially if I mess something up while trying.
This is a picture of the backside of the board, showing the epoxy and the "lumps".
This is a picture of the backside of the board, showing the epoxy and the "lumps".
You have the most important first step already. That is to map out how the wires connect to the board. So may people, techs included, get eager to start and miss this step. When I was a young student in college studying telecom, our instruction brought in a bunch of older phones for us to open. We all happily dug into the phones and checked them out, disconnecting to our hearts content. After a while he told us to put them back together, so they worked. No one managed to do this. Lesson learned!
Hey, @ChuckBridges. The Breeze charger mod is done. The case looks terrible, due to difficulties in getting it apart. (It doesn't look as bad as the pictures below, that was just bad photography. But it's pretty scratched up.)
The mod itself went very well, and seems to be working perfectly. I did some charging with it as a standalone charger, more charging using it as an adapter for a Venom ProDuo, and then let the Venom put the battery into storage mode. Then charged it up again. House isn't on fire yet, so I guess it was a success.
Here are some pictures and a drawing. I used blue shrink rap so it would be obvious in the photo where the connections were made, but you still have to look hard to see the two in the middle.
I gave up on the black board. I figured that if the breeze battery needs anything to assist the balance charge, then it would have some version of the board already in the battery. Seems to be a correct assumption, because everything works perfectly. You may note the mod LOOKS more complicated than it is. I originally intended to simply solder all the new stuff directly to the existing charger connection, and in fact did most of that. But I didn't like the crowded appearance when I put it in the case to check the spacing, and I didn't like the idea of using a higher power charger through wires that were only sized for balance charging currents. I took everything part, used bigger wires for the main charge, and then rerouted the existing harness wires to take advantage of the proximity of the adapter. Pretty interesting project. Just with I hadn't messed up the outside of the case so badly.
Here are some Pics:
Awesome. I love it when a challenge is overcome. You are most likely correct about the balance board inside the breeze battery. Yuneec's site states that it is a 3S, so 3 cells. Having drawn up a schematic not only will help yourself, but anyone else who might be encouraged to try something similar. Congratulations.
As previously mentioned my thought is the same - its a balance board for each cell, I actually got rid of this board When i swapped my battery cells with off the shelf hobbyking zippy cells. Works goods, quad does still alarm when the battery is getting low etc.
h-elsner
Premium Pilot
Now I have disassembled a Q500 battery and a Typhoon H battery . Both have protecting boards in.
Q500: DLX-690.
It is between balancer cable and battery. All wires are connected 1:1 except the 0V (ground). There is an MOSFET inbetween.
Usually those are protects all 3 cells against over-voltage and under-voltage. It's only the balancer cable, not the main power cables - no risk during flight.
I have testet this circuit, but it protects only against over-voltage. The MOSFET cuts the 0V balancer line at 4.22V. The charger will indentify this as error and stops charging.
The Typhoon H has a similar circuit for 4 cells. The switch is now at the red (+ 16V) line and consists of 2 p-channel MOSFETs AO4407 in parallel. This is the horizontal-pin.
I'm on to check if it protects only against over-voltage too (as Q500 batts) or if it is better and will also cut the line in case of under-voltage. DLX-6118:
br HE
Q500: DLX-690.
It is between balancer cable and battery. All wires are connected 1:1 except the 0V (ground). There is an MOSFET inbetween.
Usually those are protects all 3 cells against over-voltage and under-voltage. It's only the balancer cable, not the main power cables - no risk during flight.
I have testet this circuit, but it protects only against over-voltage. The MOSFET cuts the 0V balancer line at 4.22V. The charger will indentify this as error and stops charging.
The Typhoon H has a similar circuit for 4 cells. The switch is now at the red (+ 16V) line and consists of 2 p-channel MOSFETs AO4407 in parallel. This is the horizontal-pin.
I'm on to check if it protects only against over-voltage too (as Q500 batts) or if it is better and will also cut the line in case of under-voltage. DLX-6118:
br HE
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Thank you for your valuable investigation into this. Now we know for certain. I am curious why Yuneec warned me not to leave my batteries on the charger for more than 1 hour if this circuit prevents over-charging.
@h-elsner,
Thanks for the time you spent, and the results of your work. I have a few older batteries set aside for a future "salvage the good cells" project. I am sure that during this project the idea "why not just leave the board out" would have crossed my mind. Your work shows that this would not be such a good idea. You provide good information.
Thanks again,
WTFDproject
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