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Weak link in V1.5 kits pertaining to amperage draw per cell?  

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BigJohn
(@bigjohn)
Street cred = 10 mAh
Joined:5 months  ago
Posts: 2
12/07/2018 4:00 pm  

Would running a common copper bus bar be beneficial to allowing a tad more current to be safely drawn from the v1.5 kits? I am building a 13s4p battery for my 1500w ebike. It's using a 35a +/- 1a controller and the vruzend sold 48v 30a BMS.


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BigJohn
(@bigjohn)
Street cred = 10 mAh
Joined:5 months  ago
Posts: 2
12/07/2018 4:05 pm  

P.s. I'm using new Panasonic / Sanyo NCR18650GA


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Micah (Vruzend Rep)
(@admin)
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Posts: 433
16/07/2018 2:13 am  

It would help, but it wouldn't remove the next bottleneck of the internal contact. The V2 kits are designed with all conductors made from pure copper or copper alloys for this reason.


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esust
(@esust)
Street cred = 10 mAh
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Posts: 2
23/08/2018 1:36 pm  

Vruzend / Micah. I would be very interested to know some facts and figures of the actual resistance of the caps and associated bus bars of both versions. i can't find any thing on the internet which will actually help me calculate a rough voltage drop of both versions of the kit.

Are you guys able to divulge what the 3.5 and 20 amp ratings are based on? i am currently putting 15 amps through each cell on my current older Vruzend pack giving me roughly 12v voltage drop across 14 cells. bearing in mind that 18650s have roughly 0.05 ohms resistance then that works out to be roughly 14 x 0.05 x 15 = 10.5 volt drop through just the batteries. so it looks like i'm only getting roughly a 1.5 voltage drop through my current vruzend kit. so if i am only getting a 1.5 v drop through it with 15 amps then it doesn't make a huge difference if i bought the new version of the kit right?

again what's the 3.5 amp based on. i'm looking to get more power through my ebike by improving my battery and if the new kit will only shave of some of 1.5v then it doesn't seem worth it to me?

i would be very interested to hear your thoughts. what's the incentive?


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esust
(@esust)
Street cred = 10 mAh
Joined:4 months  ago
Posts: 2
23/08/2018 2:36 pm  

I take that back! i just tested the voltage whilst in a high gear from start so to draw the most current and it dropped from 56 down to 28V so nearly a 30v drop.

therefore i think I'll definitely be needing the new Vruzend kit.

however i would definitely be interested to know the rough figures for resistance of the new and old kit if possible?

thanks.


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Micah (Vruzend Rep)
(@admin)
Street cred = 5 Ah Admin
Joined:2 years  ago
Posts: 433
26/08/2018 5:40 pm  

The current ratings are based on temperature. As you saw, it is possible to pull more than 5 A from the V1.5 kits, and many people do. But the voltage drop you are experiencing is resulting in power loss. That power is going somewhere, and the somewhere is heat. That heat buildup is what you want to avoid.

Every battery will create some heat during discharge, but lower resistance connections result in less heat. The more current you pull, the higher the losses and thus the higher the heat buildup which is essentially robbed power. 


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Ritchieward
(@ritchieward)
New Member
Joined:7 months  ago
Posts: 1
11/09/2018 4:03 pm  

I made a vruzend 48v 6p 13s when i use for a block all the lights with the power cuts off before i added a vruzend bms and soon as i turned it on to work it cut off. It use to cut off while riding it it cuts off while still ride it will keep going and when i try to charge the light will light up green and not red.any help thanks.


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