Rehab1 Posted April 29, 2017 Share Posted April 29, 2017 Omg I just tried to reconnect the batteries on my ACM 1600 to give them a charge and all hell broke loose! Burned my hand, melted the connector! All of the cale connectors are simple plug and play. What the hell happened? Link to comment Share on other sites More sharing options...
Tilmann Posted April 29, 2017 Share Posted April 29, 2017 Could it be that you connected a (mostly) full battery pack to a (mostly) empty one? That would explain a very high current flowing and causing the burns. Hope you did not seriously hurt yourself? Link to comment Share on other sites More sharing options...
Rehab1 Posted April 29, 2017 Author Share Posted April 29, 2017 6 minutes ago, Tilmann said: Could it be that you connected a (mostly) full battery pack to a (mostly) empty one? That would explain a very high current flowing and causing the burns. Hope you did not seriously hurt yourself? I have no idea! This project is getting me down! I am ok. Just a slight electrical burn. Could be worse! At first I was afraid to look at my hand but most of the black soot came off. Feel sorry for those that suffer 2nd and third degree burns all over their bodies! Link to comment Share on other sites More sharing options...
Tilmann Posted April 29, 2017 Share Posted April 29, 2017 That looks much better (sigh of relief). Explanation: Our batteries have a very low "internal resistance" and deliver a very high current when shortened. Connecting two battery packs with a significantly different charging state is very close to a short circuit. Say, at 60V and some 35A flowing, there's a sudden heat source worth >1000 Watt - concentrated at a tiny spot where the pins of your XT60 connectors touch. As a result it gets so hot, that the metal pins just melt away and sparks are flying all over the place. Meaning: you did not connect the wrong wires or magically plus and minus got reversed. Most likely, the connection you tried to close is exactly how it is meant to be wired. Just somehow between disassembly and re-assembly one of the packs was charged up or discharged while the other(s) maintained their charge level. Or did you buy a new pack and connected it the first time? Link to comment Share on other sites More sharing options...
esaj Posted April 29, 2017 Share Posted April 29, 2017 Were you connecting the packs to the mainboard or the packs together? @Tilmann's suggestion of the voltage difference would make sense if it was two or more packs being connected together. In the mainboard case it could be that the capacitors drew a big spike charging up... Either way, looks nasty, good to hear you're ok(ish). Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted April 29, 2017 Share Posted April 29, 2017 Yikes those batteries pack a wallop. Glad to hear you're okay and that the pack didn't flame out... I would wear like rubber gloves next time... Is there a certain sequence of reconnecting the wires? Are the motor wires not connected on the other side? What wire did you connect the battery to? Is there like a Y connector or something? Link to comment Share on other sites More sharing options...
Tilmann Posted April 29, 2017 Share Posted April 29, 2017 10 minutes ago, Hunka Hunka Burning Love said: Yikes those batteries pack a wallop. Glad to hear you're okay and that the pack didn't flame out... I would wear like rubber gloves next time... Is there a certain sequence of reconnecting the wires? Are the motor wires not connected on the other side? I don't think, sequence matters. What matters is, that connecting parallel battery packs must only be done when all packs are at the same charge level. So, we need to meter the voltage of every individual pack first and as long as we find any significant difference, they must be charged to a similar level individually before connecting them. I'd be worried with any voltage difference >0.2V between the packs (hi experts, please correct me). EDIT: If you don't have a volt meter but you are desperate to put your wheel back together, you can connect the first pack (and only the first one), charge it to green light, disconnect the first pack and repeat that individual charging with all other packs - one after the other. Only when all packs are charged to green, start connecting them in parallel. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted April 29, 2017 Share Posted April 29, 2017 I wonder why though would the packs be at such different levels if they are from the same wheel? There should be that much of a difference after being unplugged, should there? Maybe there is another reason... Link to comment Share on other sites More sharing options...
Tilmann Posted April 29, 2017 Share Posted April 29, 2017 5 minutes ago, Hunka Hunka Burning Love said: I wonder why though would the packs be at such different levels if they are from the same wheel? There should be that much of a difference after being unplugged, should there? Maybe there is another reason... Upgrading to higher capacity with new/more packs? Link to comment Share on other sites More sharing options...
US69 Posted April 29, 2017 Share Posted April 29, 2017 @Rehab1 At first: Good that you are OK,!! i would like to know i which sequence you connected the packs? First paralleling them, then plugging to the board? And....the extra connection between the packs...has this been established before? that is the second time i see such a short on a newer GW ACM...Someone who received a new one, with batteries send seperatly, had the same kind of short and reported here! I would guess that the packs and their extra connection has to be done in a specific row....i can not see why one of rehabs pack should have drained more than the other while working on his ACM? Link to comment Share on other sites More sharing options...
US69 Posted April 29, 2017 Share Posted April 29, 2017 7 minutes ago, Tilmann said: Upgrading to higher capacity with new/more packs? No.....he has been just working on his ACM and had disconnected all batteries....and now after finishing put the same packs on.... Link to comment Share on other sites More sharing options...
Rehab1 Posted April 29, 2017 Author Share Posted April 29, 2017 29 minutes ago, Tilmann said: That looks much better (sigh of relief) Why all of the black soot? Do LiPos emit some form of gas when is happens? Trying to keep my wife from seeing my hand (blistered index finger). I was suppose to be doing dictation at work! 29 minutes ago, esaj said: Were you connecting the packs to the mainboard or the packs together? One pack was connected to the main board and I the joined the connector that serves both packs. 26 minutes ago, Hunka Hunka Burning Love said: I would wear like rubber gloves next time... The rubber would have melted around my hand! This hurts bad enough! 20 minutes ago, Tilmann said: So, we need to meter the voltage of every individual pack first and as long as we find any significant difference, they must be charged to a similar level individually before connecting them. I'd be worried with any voltage difference >0.2V between the packs (hi experts, please correct me). I need to go to work tomorrow so so will do that! 20 minutes ago, Tilmann said: EDIT: If you don't have a volt meter but you are desperate to put your wheel back together, you can connect the first pack (and only the first one), charge it to green light, disconnect the first pack and repeat that individual charging with all other packs - one after the other. Only when all packs are charged to green, start connecting them in parallel. Not desperate just wanted to keep the batteries from depleting too much. I will try that but a bit worried! 17 minutes ago, Hunka Hunka Burning Love said: I wonder why though would the packs be at such different levels if they are from the same wheel? There should be that much of a difference after being unplugged, should there? Maybe there is another reason... I don't have an answer? All I know is that these battery packs are powerful!! Link to comment Share on other sites More sharing options...
SuperSport Posted April 29, 2017 Share Posted April 29, 2017 There was likely some draw on the packmleft on the Control Board. That cause the uneven voltage. Now that the connectors are burned, you need to be careful with those. If they don't make a good connection, it can be a source of heat moving forward. I'm comfortable changing the XT60 plugs, if you are, it'd be recommended. But, if you aren't comfortable, beware of this as you already know. Link to comment Share on other sites More sharing options...
Rehab1 Posted April 29, 2017 Author Share Posted April 29, 2017 14 minutes ago, KingSong69 said: i would like to know i which sequence you connected the packs? First paralleling them, then plugging to the board? As I gather my thoughts... wife knows now... I first connected both packs together, no problem, then I connected the battery pack to the pig tail connector coming from the main board. This was a small burst of sparks but nothing like this! I quickly disconnected the batteries from the board. I then disconnected both battery packs and only reconnected one pack to the board. Everything was fine until I made the final connection of both batteries together. Link to comment Share on other sites More sharing options...
Rehab1 Posted April 29, 2017 Author Share Posted April 29, 2017 4 minutes ago, SuperSport said: There was likely some draw on the packmleft on the Control Board. That cause the uneven voltage. Now that the connectors are burned, you need to be careful with those. If they don't make a good connection, it can be a source of heat moving forward. I'm comfortable changing the XT60 plugs, if you are, it'd be recommended. But, if you aren't comfortable, beware of this as you already know. I will need to change out the connector. Any ideas where to purchase them. I don't feel comfortable charging the packs through the main board. What would be the best alternative? Link to comment Share on other sites More sharing options...
esaj Posted April 30, 2017 Share Posted April 30, 2017 16 minutes ago, Rehab1 said: I will need to change out the connector. Any ideas where to purchase them. You can get the XT60's from RC-shops or Aliexpress... there's also anti-spark -versions available, but even with those, you should check that the pack voltages are very close to each other before connecting the packs together, they are meant to suppress any spark caused by charging of capacitors or such, not to equalize the packs if the voltages are more different. Oh, and I'd first connect the packs together, then to the mainboard... although it shouldn't make that big of a difference, the mainboard probably pulls very little current after the caps are charged, so I don't think it should change the pack voltage much. 16 minutes ago, Rehab1 said: I don't feel comfortable charging the packs through the main board. What would be the best alternative? I don't know how the wiring works in the ACM (if the charging indeed goes through the mainboard), in most wheels the charge-port is connected to the battery packs directly, so you shouldn't need to connect the packs to the mainboard just for charging? You could also build something like a GX16-3 -> XT60 connector to go directly between the charger and the packs. If money wasn't an issue, what I'd do is get one of these: http://www.keysight.com/en/pd-839012-pn-6675A/2000-watt-system-power-supply-120v-18a?cc=US&lc=eng But I don't suppose you have around $5K (or maybe around "only" $1K + shipping used) laying around, especially if you only need it for charging the packs... Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted April 30, 2017 Share Posted April 30, 2017 I was thinking these heavy duty nitrile work gloves... but maybe they would melt? https://ca.hach.com/gloves-chemical-resistant-10-size/product?id=14534001810&source=googleshopping&locale=en-CA&_bt=182095578162&_bk=&_bm=&_bn=g&gclid=CIWa7bnwytMCFQEEaQodvbsD4w All that black soot is possibly ignited and vaporized plastic from the inside of the yellow connector and end terminals. The huge spark flashes quite a lot of heat energy searing whatever is next to it. Now why it would do that is strange. You would think there is 84 volts on the line when adding the other 84 volt battery pack so there would be not much differential. Very weird. Is your control board motor wires connected to anything or touching each other? Link to comment Share on other sites More sharing options...
meepmeepmayer Posted April 30, 2017 Share Posted April 30, 2017 Wow you really have no luck with this wheel!!! Hope the packs themselves are ok (you seem to be ok at least). -- If it was the batteries, a question for those who know: is it better to store the batteries with the two smaller (inter-battery) connectors connected? I assume these are for balancing? Should they be stored with all 3 cables connected (so the main one too)? Also, after you disconnect the battery (and touch parts of the wheel electronics), and before you connect them again, press the power button until the system is drained of electricity. The wheel boots up for a second (and balances) even with no battery connection! Link to comment Share on other sites More sharing options...
esaj Posted April 30, 2017 Share Posted April 30, 2017 2 minutes ago, meepmeepmayer said: If it was the batteries, a question for those who know: is it better to store the batteries with the two smaller (inter-battery) connectors connected? I assume these are for balancing? Should they be stored with all 3 cables connected (so the main one too)? I can't think of any harm storing them connected together could cause, on the contrary, then the voltages should stay equal even if one of them would "try" to self-discharge slightly faster. 2 minutes ago, meepmeepmayer said: Also, after you disconnect the battery (and touch parts of the wheel electronics), and before you connect them again, press the power button until the system is drained of electricity. The wheel boots up for a second (and balances) even with no battery connection! There's probably enough charge left in the capacitors to boot the wheel, and maybe even balance a short while with no load (ie. no person on top). But, if the capacitors are empty (like they usually are) when you connect the battery to the mainboard, the ones directly connected to the main power lines will charge fast to the same voltage as the batteries... the thing is, they also draw a huge current spike to do that, and that's likely to cause sparking. Capacitors do have some internal resistance, but it's very low (typically something like tens or hundreds of milliohms, I think). I have a capacitor-bank -based spot welder under work (still waiting for the caps, that have been delayed for months), that can give up about 1000A in spikes... Link to comment Share on other sites More sharing options...
Rehab1 Posted April 30, 2017 Author Share Posted April 30, 2017 10 minutes ago, esaj said: You can get the XT60's from RC-shops or Aliexpress... there's also anti-spark -versions available, but even with those, you should check that the pack voltages are very close to each other before connecting the packs together, they are meant to suppress any spark caused by charging of capacitors or such, not to equalize the packs if the voltages are more different. Oh, and I'd first connect the packs together, then to the mainboard... although it shouldn't make that big of a difference, the mainboard probably pulls very little current after the caps are charged, so I don't think it should change the pack voltage much. Very good! Thanks! 12 minutes ago, esaj said: I don't know how the wiring works in the ACM (if the charging indeed goes through the mainboard), in most wheels the charge-port is connected to the battery packs directly, so you shouldn't need to connect the packs to the mainboard just for charging? I will look at the CB to see if the wiring coming from the charging port is directly linked to the battery packs. If so I would just to charge them with the GW charger. What should I do about the 2 secondary wire connectors coming out of each pack? Link to comment Share on other sites More sharing options...
US69 Posted April 30, 2017 Share Posted April 30, 2017 3 minutes ago, Rehab1 said: I will look at the CB to see if the wiring coming from the charging port is directly linked to the battery packs. If so I would just to charge them with the GW charger. What should I do about the 2 secondary wire connectors coming out of each pack? Yes...they are direcly connected to the charge port...and not over the board! You should connect those extra wires! they are for balancing/communication between the packs! and if they were not connected before your plug in/out and spark....that perhaps was the reason! Link to comment Share on other sites More sharing options...
esaj Posted April 30, 2017 Share Posted April 30, 2017 9 minutes ago, Rehab1 said: I will look at the CB to see if the wiring coming from the charging port is directly linked to the battery packs. If so I would just to charge them with the GW charger. What should I do about the 2 secondary wire connectors coming out of each pack? The image won't show up in quote for some reason, but the smaller black connector looks like the same one the Firewheel -packs had between the packs and the charge port (ie. the charge-port connects directly to the packs, not through the mainboard). Check if that's the case, then you should be able to charge the packs normally, no mainboard connection is needed. Have you measured the pack voltages? I wouldn't charge them to full if there's a chance that they're not going to be used in a while, storing them with less charge is better. Unless you really, really need to get them connected or something... The voltages can be equalized over a resistor, although I don't know if you have any handy... ie. connect the negative wires of the batteries directly and put the resistor between the positive wires... something like at least a 100 ohm power resistor should work well, the bigger the resistance, the slower the voltages will equalize, but also the resistor will heat up less as there's less current flowing. Since I don't know how much difference there is between your packs, I'd go with larger than 100 ohms though, to be on the safe side... 1k? Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted April 30, 2017 Share Posted April 30, 2017 I wonder if this same thing happened to that one guy who received his wheel with the black markings on the connectors. I bet someone at the customs agency tried to plug in the battery to the Y connector and then the other to see if they could turn the wheel on which ended up frying it. Do you remember that thread? Maybe connecting to the control board drops the voltage enough that adding a different pack in at a higher voltage results in the electroboom...? Link to comment Share on other sites More sharing options...
Rehab1 Posted April 30, 2017 Author Share Posted April 30, 2017 19 minutes ago, Hunka Hunka Burning Love said: I was thinking these heavy duty nitrile work gloves... but maybe they would melt? We have asbestos gloves at work but they bulky. I may need a burn bandage for the interim as blisters are forming. This sucks!! 23 minutes ago, meepmeepmayer said: If it was the batteries, a question for those who know: is it better to store the batteries with the two smaller (inter-battery) connectors connected? I assume these are for balancing? Should they be stored with all 3 cables connected (so the main one too)? Perfect question! 19 minutes ago, esaj said: I can't think of any harm storing them connected together could cause, on the contrary, then the voltages should stay equal even if one of them would "try" to self-discharge slightly faster. So connect both the batteries along with the inter/ battery connectors? What are the inter- battery connector used for? Well I am going to soak my hand, thanks for all the help! Link to comment Share on other sites More sharing options...
Rehab1 Posted April 30, 2017 Author Share Posted April 30, 2017 9 minutes ago, KingSong69 said: Yes...they are direcly connected to the charge port...and not over the board! You should connect those extra wires! they are for balancing/communication between the packs! and if they were not connected before your plug in/out and spark....that perhaps was the reason! Just caught this! Thanks for the explanation! Yes they were connected. Link to comment Share on other sites More sharing options...
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