Samsung 30Q hard voltage drop under load?

Batteries, Chargers, and Battery Management Systems.
Post Reply
User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 10 2018 12:09am

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?
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
liveforphysics   100 GW

100 GW
Posts: 13951
Joined: Oct 29 2008 1:48am
Location: Santa Cruz, CA, USA

Re: Samsung 30Q hard voltage drop under load?

Post by liveforphysics » Feb 10 2018 6:20am

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.
Each carcinogen vapor exposure includes a dice roll for cancer.

Each mutagen vapor exposure includes a dice roll for reproductive genetic defects in your children.

Each engine start sprays them into a shared atmosphere which includes beings not offered an opportunity to consent accepting these cancer experiences and defective genetics life experiences.

Every post is a free gift to the collective of minds composing the living bleeding edge of LEV development on our spaceship.

Punx0r   10 GW

10 GW
Posts: 4822
Joined: May 03 2012 8:16am
Location: England

Re: Samsung 30Q hard voltage drop under load?

Post by Punx0r » Feb 10 2018 10:15am

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

Hillhater   100 GW

100 GW
Posts: 9248
Joined: Aug 03 2010 10:33pm
Location: Sydney ..(Hilly part !) .. Australia/ Down under !

Re: Samsung 30Q hard voltage drop under load?

Post by Hillhater » Feb 10 2018 8:00pm

DasDouble wrote:
Feb 10 2018 12:09am
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. .
This forum owes its existence to Justin of ebikes.ca

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 12 2018 9:36am

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?
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

Pedrodemio   10 W

10 W
Posts: 82
Joined: Jun 30 2015 8:38pm
Location: Brazil

Re: Samsung 30Q hard voltage drop under load?

Post by Pedrodemio » Feb 12 2018 12:53pm

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

User avatar
brumbrum   100 kW

100 kW
Posts: 1253
Joined: Oct 30 2010 3:29pm
Location: Wales U.K

Re: Samsung 30Q hard voltage drop under load?

Post by brumbrum » Feb 12 2018 6:12pm

DasDouble wrote:
Feb 12 2018 9:36am
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.
My NYX and cromotor build
viewtopic.php?f=6&t=74615
My LMX 161 dirt bike build
viewtopic.php?f=6&t=94074

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 14 2018 5:07am

Pedrodemio wrote:
Feb 12 2018 12:53pm
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
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 15 2018 1:33pm

brumbrum wrote:
Feb 12 2018 6:12pm
DasDouble wrote:
Feb 12 2018 9:36am
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 :)
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
brumbrum   100 kW

100 kW
Posts: 1253
Joined: Oct 30 2010 3:29pm
Location: Wales U.K

Re: Samsung 30Q hard voltage drop under load?

Post by brumbrum » Feb 15 2018 3:30pm

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
My NYX and cromotor build
viewtopic.php?f=6&t=74615
My LMX 161 dirt bike build
viewtopic.php?f=6&t=94074

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 26 2018 3:56am

It says 73,2 aVg on the left side and 117 mOhm at the right side. Damn, that used to be way more less.. Maybe because I have pushed that max. current a bit in the past? Im sure I have to add some more nickel / other material on my cells..
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
ridethelightning   1 MW

1 MW
Posts: 1778
Joined: Jul 21 2013 9:48pm

Re: Samsung 30Q hard voltage drop under load?

Post by ridethelightning » Feb 26 2018 5:27am

i just made a 10p 30q pack. looking for 150-200A. i used 10X 0.2mm strip for the serial connections and still think its borderline..

User avatar
brumbrum   100 kW

100 kW
Posts: 1253
Joined: Oct 30 2010 3:29pm
Location: Wales U.K

Re: Samsung 30Q hard voltage drop under load?

Post by brumbrum » Feb 26 2018 8:08am

The voltage sag you are seeing on the pack is about 11volts in total(if using 20s configuration). With a 15p pack it should be less than half that number..... depending on how many amps being pulled by the motor.
I have just built a 30Q pack 20s 9p. I have only cycled the pack twice but this is what I have seen...
Adaptto recording resistance as 50mohms.
Battery from full charge sags up to 4v at 85amps
Battery near empty (60v resting) sags 6v
Each cell is having 9 to 10 amp discharge
My NYX and cromotor build
viewtopic.php?f=6&t=74615
My LMX 161 dirt bike build
viewtopic.php?f=6&t=94074

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 26 2018 8:15am

Well I guess we would have to compare that at more equal circumstances. My pack is now maybe about 1.5 years old, I supercharged it like 5 times in total (but only 3 (180 cells) of them, two of them were not) and its -11°C outside right now here in Germany.. When I have more time I will take some hours and finally upgrade all of them to 16,2kW output. :)
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 26 2018 8:23am

ridethelightning wrote:
Feb 26 2018 5:27am
i just made a 10p 30q pack. looking for 150-200A. i used 10X 0.2mm strip for the serial connections and still think its borderline..
Just have a look at that table. I made a formular for calculating that once but it ended up being too complicated to post it on the forum. :) https://endless-sphere.com/forums/viewt ... 14&t=68005

For 150-200 Amps you would need a bit more then 0,2mm x 10mm being one single strip from one to the other cell. I would recommend to go with this single strip to one big connector like a copper busbar or something like that.
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
brumbrum   100 kW

100 kW
Posts: 1253
Joined: Oct 30 2010 3:29pm
Location: Wales U.K

Re: Samsung 30Q hard voltage drop under load?

Post by brumbrum » Feb 26 2018 8:38am

DasDouble wrote:
Feb 26 2018 8:15am
Well I guess we would have to compare that at more equal circumstances. My pack is now maybe about 1.5 years old, I supercharged it like 5 times in total (but only 3 (180 cells) of them, two of them were not) and its -11°C outside right now here in Germany.. When I have more time I will take some hours and finally upgrade all of them to 16,2kW output. :)
Maybe then you have answered your own question.
Some of the cells are different age. Pack is getting old. Very cold temperatures. All three would definitely add up to ooor performance.
My NYX and cromotor build
viewtopic.php?f=6&t=74615
My LMX 161 dirt bike build
viewtopic.php?f=6&t=94074

User avatar
brumbrum   100 kW

100 kW
Posts: 1253
Joined: Oct 30 2010 3:29pm
Location: Wales U.K

Re: Samsung 30Q hard voltage drop under load?

Post by brumbrum » Feb 26 2018 8:45am

DasDouble wrote:
Feb 26 2018 8:23am
ridethelightning wrote:
Feb 26 2018 5:27am
i just made a 10p 30q pack. looking for 150-200A. i used 10X 0.2mm strip for the serial connections and still think its borderline..
Just have a look at that table. I made a formular for calculating that once but it ended up being too complicated to post it on the forum. :) https://endless-sphere.com/forums/viewt ... 14&t=68005

For 150-200 Amps you would need a bit more then 0,2mm x 10mm being one single strip from one to the other cell. I would recommend to go with this single strip to one big connector like a copper busbar or something like that.
Here is a 4s 9p I made for my adaptto. I made 5 of these modules and put them in series. Nickel for parallels is .15mm, copper series connectors are 2mm diameter
Image
My NYX and cromotor build
viewtopic.php?f=6&t=74615
My LMX 161 dirt bike build
viewtopic.php?f=6&t=94074

User avatar
ridethelightning   1 MW

1 MW
Posts: 1778
Joined: Jul 21 2013 9:48pm

Re: Samsung 30Q hard voltage drop under load?

Post by ridethelightning » Feb 26 2018 4:09pm

brumbrum wrote:
Feb 26 2018 8:45am
DasDouble wrote:
Feb 26 2018 8:23am
ridethelightning wrote:
Feb 26 2018 5:27am
i just made a 10p 30q pack. looking for 150-200A. i used 10X 0.2mm strip for the serial connections and still think its borderline..
Just have a look at that table. I made a formular for calculating that once but it ended up being too complicated to post it on the forum. :) https://endless-sphere.com/forums/viewt ... 14&t=68005

For 150-200 Amps you would need a bit more then 0,2mm x 10mm being one single strip from one to the other cell. I would recommend to go with this single strip to one big connector like a copper busbar or something like that.
Here is a 4s 9p I made for my adaptto. I made 5 of these modules and put them in series. Nickel for parallels is .15mm, copper series connectors are 2mm diameter
Image
my bad. i meant to write 10 x 10mm X 0.2mm for the series connections. basically maxing out the nickle strip welds for the config.

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Feb 27 2018 4:30am

brumbrum wrote:
Feb 26 2018 8:45am
DasDouble wrote:
Feb 26 2018 8:23am
ridethelightning wrote:
Feb 26 2018 5:27am
i just made a 10p 30q pack. looking for 150-200A. i used 10X 0.2mm strip for the serial connections and still think its borderline..
Just have a look at that table. I made a formular for calculating that once but it ended up being too complicated to post it on the forum. :) https://endless-sphere.com/forums/viewt ... 14&t=68005

For 150-200 Amps you would need a bit more then 0,2mm x 10mm being one single strip from one to the other cell. I would recommend to go with this single strip to one big connector like a copper busbar or something like that.
Here is a 4s 9p I made for my adaptto. I made 5 of these modules and put them in series. Nickel for parallels is .15mm, copper series connectors are 2mm diameter
Image
Wow, that looks like a hell of a pack.. And I thought my 300 Amper variation would arleady be crazy..
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Mar 06 2018 10:51am

Have just disscharged the complete pack down to 3.2 volts. The one of five packs I have upgraded some time ago went back to 3.5v quite fast. Seems like Im gonna have to do the same with the other ones too. For sure this will help.
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Mar 07 2018 2:16pm

DasDouble wrote:
Mar 06 2018 10:51am
Have just disscharged the complete pack down to 3.2 volts. The one of five packs I have upgraded some time ago went back to 3.5v quite fast. Seems like Im gonna have to do the same with the other ones too. For sure this will help.
Damn, I just calculated the lost range of 0,2v difference. Its 0,1666% (1/6%) of the range I do get right now (44km) means (44km * 1/6%) 7.3km of range! Wow and just all because of bad series connection. :o :shock:

Edit: 73 meters, not 7.3km :pancake:
Last edited by DasDouble on Mar 08 2018 1:40pm, edited 1 time in total.
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

Punx0r   10 GW

10 GW
Posts: 4822
Joined: May 03 2012 8:16am
Location: England

Re: Samsung 30Q hard voltage drop under load?

Post by Punx0r » Mar 07 2018 2:55pm

You're off by a couple of decimal points:

0.167% of 44km is 0.073km = 73 metres!

User avatar
DasDouble   100 kW

100 kW
Posts: 1091
Joined: Jul 12 2015 1:35pm
Location: GERMANIA :D

Re: Samsung 30Q hard voltage drop under load?

Post by DasDouble » Mar 08 2018 1:40pm

Punx0r wrote:
Mar 07 2018 2:55pm
You're off by a couple of decimal points:

0.167% of 44km is 0.073km = 73 metres!
Oops.. thats a thing :pancake:
"..the crazy kid exploring hipower ebike world ^^"
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

User avatar
TheBeastie   1 MW

1 MW
Posts: 1745
Joined: Jul 28 2012 12:31am
Location: Melbourne Australia

Re: Samsung 30Q hard voltage drop under load?

Post by TheBeastie » Mar 08 2018 11:21pm

It can't be said enough that the max discharge claims of 18650 cells have to be taken with a grain of salt.
This video that tests a cell at 8a discharge shows it gets much hotter than it claims its supposed to be at 80c for the claimed possible discharge of 10amp, listen to what the guy says after the test.
https://youtu.be/an9-i23mGqc?t=4m29s
This is a consistent theme with 18650s, everyone wants to treat them like lico but I don't think they have as much cobalt in them to be treated in such fashion.
Another way to look at ideal 18650 usuage is Tesla battery modules, where the wire to each cell is tiny, almost so thin you can't see it easily in the pictures, in other words the draw from each cell is comparatively tiny.
Image
Speed Kills Range, 10mph = 46 miles range, 20mph = 20 miles, 30mph = 8 miles range https://goo.gl/1JNL53
Over Charging Kills ur battery bit.ly/1hzWKl4
Consider PAS as your only throttle https://goo.gl/Kg1F8F
Fuel-Cell is the ultimate battery coupled with 4th-gen Nuclear https://goo.gl/ZhFFot
https://goo.gl/gfa215
10 Square Miles of solar panels = 0.12GW average power! https://goo.gl/Ub1S39

Post Reply