@Namasaki Just to make sure, if I alter your scheme to this, it should work fine charging the lipo’s with the BMS and discharging them without.
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@oriol360 Bro! Thanks so much for this post 
You and @Namasaki have the most straight forward explanations for the BMS. Bookmarked 
I have never bypassed the BMS on discharge myself but I think it will work the way you have it. I was mainly showing how to connect the balance wires. Note: Some BMS’s have a ground port in the balance plug in which case you would use the the black balance wire from pack number one. Note: I’m not sure about port N- never seen that before. Just make sure that is for charge neg. if not, I think you’ll need to connect charge neg to B- Then again I’m not positive about bypassing. Frankly I don’t recommend bypassing but rather spend the money for a BMS that will handle discharge. You’ll be glad you did. My advice is, never skimp on batteries or electronics.
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The red wire is always the balance wire for the last cell in pack. The black wire is always ground, not a balance wire. Most BMS’s use main ground for balance. That’s why they don’t have the extra pin. Although the red and black wires are connected between packs in series, use the red wire for balance and omit the black wire for a more direct route to the cell being balanced. It’s better to discharge through the BMS because the Vesc only monitors total pack voltage so you could possibly have one cell drop bellow safe voltage before the Vesc would shut down. A BMS monitors the voltage of each cell or parallel cell group providing better over discharge protection. Not only that, it will also protect against over charging by regen braking. I’m not sure that’s the case when you bypass. Also the BMS will protect against shorts if use for discharge. I did actually short my battery once wile the BMS was on and it’s short protection tripped and shut the system down in an instant so nothing was damaged. Not the BMS, not the Vescs, not even the battery. This is why I say, don’t skimp, buy a quality BMS with high amp capability and wire it for charge/discharge. In the long run you’ll be glad you did. Or, you can buy a cheap BMS like this guy.
This is what I’ve been using since last summer and I have had no problems at all with them. http://bestechpower.com/37v10spcmbmspcbforli-ionli-polymerbatterypack/PCM-D223V1.html
how to order on bestechpower ?
Send an email to [email protected] Requesting to purchase the BMS by model number. They will complete the transaction by email. They accept Paypal and their minimum order requirement is 2. Total cost for 2 of the bms’s I use with shipping to USA was about $136 It’s really a good deal considering that they have a built in HV e-switch saving up to $60 on your build And they easily handle 80a continuous and up to 240a peak current discharge and 20a charge. Note: I’m pretty sure they ship to EU as well.
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@Namasaki
Thanks for the advice, only too late for me 
My BMS is already broken.
I have the BMS from battersupports.com (12S 60A) which is used a lot here with positive feedback. I already have a high voltage switch. If I new about this BMS with build in switch before, I would have definitely gone for that.
I use my BMS now with three 4S lipo’s. I wired my cables and connectors and tested the BMS with a volt meter. Black on B- and than I’ve tested the balance wires one by one.
At the sixt pin (in the middle of the connector for battery two) it didn’t measure any current. All further pins no current either. I’ve tested my wiring and those are good for 100% sure. Really think it came in broken, never even used it. I will open a dispute at AliExpress and I will ask them to send me a new one. Right now I will use my Turnigy balance charger (1S to 6S) to charge the battery’s balanced in parallel till I receive my new BMS.
The balance current on the Bestech is only 126ma I’d imaging that’s it’s similar on the battery supports. Possibly your meter isn’t set for that low of a reading. Therefore showing zero Also balancing happens at the end of charge cycle so there may be nothing wrong with your BMS
Note: I just checked and the Battery Supports BMS balances at 60ma
What was ur quoted price
$136.50 for 2 with shipping and PayPal fee.
Hmm alright thanks man!
Hey man, Why is your charger connected in parallel to the VESC? Is that correct? I think the VESC’s negative should be connected to B- and the chargers’s negative is the only thing that should be connected to P- Am I correct? Have you figured it out yet? Thanks!
Hi, i am reading you for a long time and finally decided to make my electric skateboard.
About BMS i have some questions if anyne is so kind to reply or to redirect me to the topic where you already talked about it: 1- In a configuration of 2 3S Battery to create a 6S battery can i use 2 separate 3s BMS for each battery connected in parallel to the charger port? ( for time reason, I can not find on ebay europe a 6s bms)
2- When i will connect the power suply/charger to the bms, it will automatically drain the max current the bms can take and /or the charger can give? ( to estimate charging times)
3- What voltage power supply should i get for a 3s BMS ?
and what voltage power supply 6s BMS if i decide to take this one?
i can not find the max voltage the bms board take, only max current …
4- Anyone know where to buy cheap BMS and power supply in europe?
If i said some eresy please forgie me 
Does anyone know why a bms might drop voltage? I have mine wired up like in this post but it for whatever reason my bms drops voltage accross it now (it did not a week ago) to the point where it cannot even get my vesc to turn on. I thought about bypassing it by simply running a wire from the B- to the P-. Does anyone know if that wold work?
Does the e switch mean I can easily hook up a on off switch to it without adding anything else?
If you are referring to the BeaTech BMS’s then yes. They come with leads to connect a switch.
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any 12v 2 pole automotive switch will work as long as it is not a momentary switch
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Well, technically you could use momentary switch but you will have to hold it pressed while riding 
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Looks like it’ll take forever to get hose adaptors. Can I do it without them?
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