Anyone have experience with Samsung 50e or Samsung 40t cells?

Raylinguo

1 mW
Joined
Nov 13, 2022
Messages
10
I'm looking at new cells for a battery build, the samsung 50e are quite attractive with their high capacity, but I'm unsure if their cont. discharge rating will be enough for my application.

I would likely build 14s5p, I don't know if I would have room for any larger. This gives me 49amp continuous discharge. My motor is 1500w, and controller is rated to as being 22amp with a 45amp max draw.

I basically want to know if 49amp is enough headroom for a 45amp max controller, i realise it's not much headroom, but if I'm just going to 45amp for a few seconds while accelerating and then cruising after that, then the batteries would mostly be operating at 1c ish. I live in a fairly flat area too.

A second option is the samsung 40t at 14s4p but that provides much more amps than I need and im a bit reluctant due to the lower cycle life and smaller capacity.

Does anyone have experience with either of the two cells, as they've been out for a few years now, and can recommend one over the other?

The 50e makes sense, with more capacity and seemingly longer cycle life, so long as they aren't worked too hard in which case cycle life may actually be less right? And so long as voltage drop isn't too bad. The 50e spec sheet says they should work in this application but unsure if that necessarily translates in the real world

Or would I be better off going 40t and playing it safe with having high discharge and no voltage sag at the cost of smaller capacity and lower cycle life?

Its my first ebike build so I'm kinda working with all theory at this stage.

Would be great to hear from someone who has used either of the cells for a good length of time and might be able to suggest one over the other,

Cheers!
 
We run both as 52 volt E Bike batteries. The 50E's we run as 14S3P @ max 20A's so far without any sort of issue. We tried to run them as 14S2P but the voltage sag at the later stages will trigger the BMS early. The 40T as a 14S2P has been really good and absolutely no problems with handling 20A's.

Both cells seem better than specs and will run out almost to max W/hs as per the specs whilst still holding better volts. Good cells. Do remember that the chances of you recharging 3000 times or more is going to be slim.
 
I had bicycle motor works make me at 72 volt Samsung 40t 20s 6p pack and only got 18.5 ah when it was rated at 24 ah
It has a BT BMS. I run it at 50 amps Max and has always been in balance whether I drain it all the way which I rarely do or when it comes to top charge before they be in the BMS starts balancing.
I can only come to the conclusion that he bought counterfeit sales I have talking to Matthew at bicycle motor works and he won't answer the phone or talk to me about my pack as I first had to return it because it wouldn't fully charge the 84 volts but only 82 volts but that was before he put the Bluetooth BMS on I had a regular BMS.
My lessons learned I'm going to buy a k welder and make my own battery packs from now on as it's hard to trust people out there and who they might be buying their cells .from
 
Waynemarlow said:
We run both as 52 volt E Bike batteries. The 50E's we run as 14S3P @ max 20A's so far without any sort of issue. We tried to run them as 14S2P but the voltage sag at the later stages will trigger the BMS early. The 40T as a 14S2P has been really good and absolutely no problems with handling 20A's.

Both cells seem better than specs and will run out almost to max W/hs as per the specs whilst still holding better volts. Good cells. Do remember that the chances of you recharging 3000 times or more is going to be slim.

Ok great, thank you good to know! Have you noticed the 40t loose capacity faster than the 50e? As the specs say the capacity goes to 60% after 250 charge cycles, when the 50e reduces to 80% after 1000 cycles, so seems quite the difference!

Yeah if I got 3000 cycles I would be very happy, and probably 10 years older 😂 but 250 to 1000 is realistic so it seems 50e is better in that regard. So long as the voltage drop is ok and they don't degrade when used at 1c and 2c for short burst, which you have confirmed
 
999zip999 said:
I had bicycle motor works make me at 72 volt Samsung 40t 20s 6p pack and only got 18.5 ah when it was rated at 24 ah
It has a BT BMS. I run it at 50 amps Max and has always been in balance whether I drain it all the way which I rarely do or when it comes to top charge before they be in the BMS starts balancing.
I can only come to the conclusion that he bought counterfeit sales I have talking to Matthew at bicycle motor works and he won't answer the phone or talk to me about my pack as I first had to return it because it wouldn't fully charge the 84 volts but only 82 volts but that was before he put the Bluetooth BMS on I had a regular BMS.
My lessons learned I'm going to buy a k welder and make my own battery packs from now on as it's hard to trust people out there and who they might be buying their cells .from

Ah really that's a shame.. Sorry to hear that! expensive thing to be cheated on. Does it charge to 84 volts now? Perhaps those 2 volts are where some of the missing capacity is.

And yeah, I have a spot welder and all the other fixings to build a battery, just have to source some legit cells.

Cheers!
 
I sent it back to him Matthew and he took out the BMS and put in a Bluetooth BMS with the little blue elephant and then it charged to full. He kept telling me that when he got it back that he was able to charge it to 84 volts but I have three different 72 volt chargers and they all work on my other batteries at the time it's about two and a half years old now and it cost me $1,100.

This makes me have to buy a Kweld .
I guess I had money and I was lazy and it cost.

72v 12ah Samsung 40T Lithium ion E-Bike Battery
$799.99 $679.99 :flame:

Here's a link to the guy he doesn't stand behind his products
So I never buy from him again he has a nice wife who try to help but she just got in trouble for helping. But mine was custom made in a triangle and it costs $100 and he didn't stand behind it
 
999zip999 said:
I had bicycle motor works make me at 72 volt Samsung 40t 20s 6p pack and only got 18.5 ah when it was rated at 24 ah
The 40T is only 4Ah. At 6p you get 24Ah only if you fill it all the way and drain it all the way to completely empty, which means the cells wont' last as long (fewer cycles) and will be more sensitive to voltage sag under load near LVC.

Normally the BMS will be set to limit discharge to somewhere above the actual completely empty point of the cells, so you wouldn't get the full capacity from them, to help them be less stressed and last longer. If you set the BMS to that completely empty point as it's LVC, you'll usually need to lower the current you pull from it by a fair bit as it gets toward that point so it doesn't sag in voltage as much so that you can get every last bit from the cells before LVC engages.

The controller LVC is also usually a lot higher than the BMS limit, so unless you change that to be below the BMS limit so the BMS is what does the shutdown, you also won't get the full capacity. (normally the BMS is only used as emergency shutdown, and controller does the everyday LVC at anywhere from 3v/cell up to 3.4-3.5v/cell x however many series cells there are).
 
Yes and I have a BT BMS to see and monitor voltage capacity ect. But 6x 4,000mah is 24ah and new I got 18.5 as best and as you know I hate to use my battery to lvc and never leave it charged iat hvc. Just a bad batch ?.
It acts like a 5p pack will take apart after it died.
He had a hard time making it and he will not make custom size packs again. I guessing he had a hard time making series connections.
He also repair 6 cells.
 
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