Samsung 30Q hard voltage drop under load?

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DasDouble
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Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 10, 2018 12:09 am

My Samsung 30Q pack is dropping hard from about 3.9 to ~3.35v at the lowest when pushing it to 10A while it could theoretically get to 15A (says the supplier). Is that a normal thing today? Because in such case my Adaptto Controller says the battery is empty and stops giving me more current :roll: ..

What is better in this case:
1.) Cooling the cell down to whatever temperature I want (I would suggest about ~8°C?) so the resistance of the pack gets lower

or

2.) Welding more nickel on the complete pack so the resistance also get lower. I have got 0,15mm x ~10mm Nickel at the weekest point but have a temperaturesensor on it so I know when it becomes too hot.


What do you think?
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Re: Samsung 30Q hard voltage drop under load?

Post by liveforphysics » Feb 10, 2018 6:20 am

Cooling the cells will give you more voltage drop from slowed ionic motion rates inside the cell.

Maybe fake 30Qs, maybe stored at high SOC and high temp until impedance climbed, and that's pretty light busing likely causing at least a few tenths of a volt drop.
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Re: Samsung 30Q hard voltage drop under load?

Post by Punx0r » Feb 10, 2018 10:15 am

You can see what the voltage should be for the 30Q at different discharge currents over the discharge cycle in the chart on page 6 here:

https://eu.nkon.nl/sk/k/30q.pdf

See if it matches up with your observations

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Re: Samsung 30Q hard voltage drop under load?

Post by Hillhater » Feb 10, 2018 8:00 pm

DasDouble wrote:
Feb 10, 2018 12:09 am
My Samsung 30Q pack is dropping hard from about 3.9 to ~3.35v at the lowest when pushing it to 10A ....
How and where are you measuring this ?
..At the controller
...At the pack terminals ?
...At the cell end caps with a mMeter ?
What size pack and what max pack current draw. .
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Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 12, 2018 9:36 am

I measure this at the Adaptto Max-E Controller. I have a 20s 15p 300 cells Samsung 30Q pack. Maybe it is because of my poor nickel strips with its 0,15mm x 10mm x 3 for 15 cells in parallel?
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Re: Samsung 30Q hard voltage drop under load?

Post by Pedrodemio » Feb 12, 2018 12:53 pm

If possible post a picture or a schematic of how you wired the back, but if only 3 nickel strips are used for the serial connections there is your problem, and if it is, I recommend you stop using the pack until fixed, the least that can happen is these 3 nickel strips melt, the worst they melt and short circuit something and make a big fira ball

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Re: Samsung 30Q hard voltage drop under load?

Post by brumbrum » Feb 12, 2018 6:12 pm

DasDouble wrote:
Feb 12, 2018 9:36 am
I measure this at the Adaptto Max-E Controller. I have a 20s 15p 300 cells Samsung 30Q pack. Maybe it is because of my poor nickel strips with its 0,15mm x 10mm x 3 for 15 cells in parallel?
What mohm resistance reading are you getting on the adaptto statistics screen?

Make sure your series connections are beefed up with either extra nickel strips or copper wire.

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Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 14, 2018 5:07 am

Pedrodemio wrote:
Feb 12, 2018 12:53 pm
If possible post a picture or a schematic of how you wired the back, but if only 3 nickel strips are used for the serial connections there is your problem, and if it is, I recommend you stop using the pack until fixed, the least that can happen is these 3 nickel strips melt, the worst they melt and short circuit something and make a big fira ball
yeah I hoped that this would not be the issue, but I guess you are right there. I have to level that stuff up.. (will be a ton of work yeeey.. :roll: :pancake:

Thanks
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Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 15, 2018 1:33 pm

brumbrum wrote:
Feb 12, 2018 6:12 pm
DasDouble wrote:
Feb 12, 2018 9:36 am
I measure this at the Adaptto Max-E Controller. I have a 20s 15p 300 cells Samsung 30Q pack. Maybe it is because of my poor nickel strips with its 0,15mm x 10mm x 3 for 15 cells in parallel?
What mohm resistance reading are you getting on the adaptto statistics screen?

Make sure your series connections are beefed up with either extra nickel strips or copper wire.
I have searched for it. Where can you read that?
Thanks in advice :)
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Re: Samsung 30Q hard voltage drop under load?

Post by brumbrum » Feb 15, 2018 3:30 pm

It’s at the very bottom of a the screen that tells you the max speed you’ve pulled,, along with other statistics such as ah used and average voltage etc

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