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  1. D

    Corrosion on 0.1mm copper sheet?

    I just googled what you said (copper acetate) and it’s definitely this , colour is identical. In future I’ll opt for something that states non corrosive or neutral cure as mentioned but for now I’ll just remove all the copper plating and cut out some fresh pieces, also leaving it for 7-14 days...
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    Corrosion on 0.1mm copper sheet?

    It didn’t get wet but I’ve rid it in cold weather maybe the pack got warm and was cold in the outside and caused condensation under the tape Or possibly I’ve drawn to the fact that the glue I used releases acetic fumes as I’ve used a silicone RTV and I believe vinegar also promotes corrosion I...
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    Corrosion on 0.1mm copper sheet?

    I’ve just removed the fish paper insulation from my pack to make a horrible discovery… My copper sheet has corroded quite significantly and I’m unsure of the cause. I understand copper oxidises but I’ve had some scraps off copper on my desk from when I cut out my plates 2 weeks ago and they’re...
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    Fault in pack , possibly unbalanced

    Ok so the balance light came on for 5 minutes or so and then began repeating as before , charger shuts off and so does balance light , then turns back on again along with the light , off and on repeatedly in progressively slower and slower segments Sent from my iPhone using Tapatalk
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    Fault in pack , possibly unbalanced

    Some interesting results after a 5 minute ride full throttle , here’s the voltages 1-3.93v 2-7.77 , 3.84v 3-11.6 , 3.83v 4-15.43 3.83v 5-19.28 3.85v 6-23.1 3.82v 7-26.9 3.8v 8-30.8 3.9v 9-34.6 3.8v 10-38.4 3.8v 11-42.5 4.1v 12-46.5 4v 13-50.3 3.8v It appears the majority of the pack is...
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    Fault in pack , possibly unbalanced

    If you mean that one group isn't draining (discharging) while riding...that can't happen because they are in series. All seriesed groups (cells) discharge at the same current, same "rate". They end up at different states of charge afterward because they have differing capabilities and...
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    Fault in pack , possibly unbalanced

    So far I’ve done 5 charge cycles at most when I’ve plugged it in took it off once it had a green light and hammered it probably pulling around 30-45 amps on average. I like that idea though , I’ll have a little ride around the woods take it back and test the groups again and see if it’s possible...
  8. D

    Fault in pack , possibly unbalanced

    Ok I’m definitely going to have to pick one of those up because my bms is balancing at 20-30mah. Hopefully it’s a case of being badly balanced from the get go and progressively worsening under load and cycles. Maybe I’ll also need too choose a better bms with more balancing capability or opt for...
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    Fault in pack , possibly unbalanced

    I personally haven’t conducted any tests regarding capacity however the YouTube video I watched did and linked this supplier in the description. It is possible they’ve sent an off batch off cells however id like too hope not as they are in the top 10 suppliers for Alibaba. You would be...
  10. D

    Fault in pack , possibly unbalanced

    Model3-NCR21700 what is stated on each cell , I have watched a video of these cells being tested and they are a genuine 4700-4800mah capacity which is amazing for the price Sent from my iPhone using Tapatalk
  11. D

    Fault in pack , possibly unbalanced

    Hi ebuilder , thanks for the reply. yesterday after taking it off the charger it read 51.4v , as of today taking it off the charger it reads 50.6v which has made me realise this will only get worse and I’d imagine quickly. Originally I was leaving it on charge until the charger stopped and...
  12. D

    Fault in pack , possibly unbalanced

    After dismantling the pack and testing the voltages at the bms wiring harness these are the results for each of the 13 groups 1 - 4.05v 2 - 3.87v 3 - 3.86v 4 - 3.86v 5- 3.89v 6- 3.77v 7- 3.9v 8-3.9v 9- 3.9v 10- 3.8v 11- 4.2v 12- 4.1v 13- 3.9v It appears cell group 11 is hitting the 4.2v...
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    Fault in pack , possibly unbalanced

    Hi guys , I recently finished my 13s8p pack using Tesla 21700 cells (4800 mah each) supposedly giving me 48v (54.6 fully charged) and 38.8ah , BMS limited to 120A but has never pulled more than 45 due to controller , there’s no hotspots on the pack when charging or discharging only slightly...
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    6 AWG cable to QUCC bms?

    Great news , I’ll pick some up and use a washer to rise the terminal slightly to keep it away from the PCB , thanks for the info :) Sent from my iPhone using Tapatalk
  15. D

    6 AWG cable to QUCC bms?

    Thankyou , I’d assume so too and judging by another post on the forum it’s a common technique for thicker gauge wires , thanks again! Sent from my iPhone using Tapatalk
  16. D

    6 AWG cable to QUCC bms?

    hoping it will look a little something like this. Any feedback? Sent from my iPhone using Tapatalk
  17. D

    6 AWG cable to QUCC bms?

    Just a quick one wondering if anyone can help , here I’ve got some 6 AWG cable and I’m trying to determine the best way to connect it to my BMS. Would it be easier if I bought some crimp connectors and bolted it to the bms through the hole or is it still more ideal to solder it? Thanks! Sent...
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    13S8P 21700 honeycomb battery design/diagram

    So I remade the design, and moved some cells around after reading the information provided on the thread above and believe I have rectified the issue being the old design would have only allowed 4 connections in the middle for the series e.g too much juice so I’ve made sure there’s a minimum of...
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    13S8P 21700 honeycomb battery design/diagram

    Ok so I’ve had a peak at the mentioned thread about common design mistakes and I understand the logic being this is an 8p pack , 15A per cell x 8p = 120A. The below chart I have found states that 0.2mm x 0.7mm is optimal for 13A current , I would be planning on using 0.2 x 0.8mm strip so roughly...
  20. D

    13S8P 21700 honeycomb battery design/diagram

    Thankyou for taking a look , I’ll check that thread and make any changes necessary, better safe than sorry!
  21. D

    13S8P 21700 honeycomb battery design/diagram

    Hi guys , so little rundown I’m wanting to create a 48v 40ah+ battery for my e bike , I’ve mocked up a design on some paper creating 13 groups of 8 cells and was wondering if anybody on here could clarify weather this is a possible design. And also if someone could add if it’s ok the connect...
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