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SMC Battery Case Popped Open

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mumbles

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Hi All. I have had an SMC 4S 5000mah battery that recently the case has popped open. Is this caused by the battery swelling? I can't really open it all the way so I can't tell. I noticed that the cells have been sitting at around 3.7v, could this be the cause of the swelling, if it is swelling? Thanks for your help.
 
Hi All. I have had an SMC 4S 5000mah battery that recently the case has popped open. Is this caused by the battery swelling? I can't really open it all the way so I can't tell. I noticed that the cells have been sitting at around 3.7v, could this be the cause of the swelling, if it is swelling? Thanks for your help.

Just thought I would mention that it's a hard case in case it wasn't clear.
 
This is very common for a battery that has been damaged from excessive heat, any number of reasons can cause this swelling to occur, especially if you charge the battery inside a cool air conditioned room and then take the battery outside in extreme heat which will cause the voltage to spike, etc...

I would check the IR of the cells and depending on the severity of the swelling it may be time to replace the pack. I've seen someone damage a brand new pack that they charged and placed their rc in the trunk of their car and drove over an hour to the beach and the pack overheated during the drive.

If your charger doesn't have an IR meter, then I would encourage you to consider one:
Which charger is the best?

Good Luck!
 
Hi thank you for your response. The IR readings are as follows:

1: 2 2 3
4: 5 0 0

Does anything look off there?
 
Sounds like your 4th cell is reading 5mΩ which in itself is what I would personally consider acceptable, I feel that anything below 7mΩ is "healthy", however there is a problem in that there is a disparity of more than 2mΩ difference between your best and worst cell readings which shows that 1 cell is not matched and will continue to degrade more quickly. While your pack may still be acceptable to continue using (for now), it is quickly approaching the end of its reasonable service life. I would keep a close eye on that bad cell and chances are you will see the swelling of the pack continue to expand as the IR increases.

If you continue to use the pack when the cell is above 15mΩ then that will make me nervous.
 
Bill, thank you so much for your help! I'll probably look into getting a new pack soon. Cheers!
 
Bill, thank you so much for your help! I'll probably look into getting a new pack soon. Cheers!
How many SMC packs have you owned? I bought 4 packs a couple of years ago that were rated at 5400mah and actually delivered around 4100mah. SMC graciously credited me for those packs, and in good faith, I promptly bought 4 of their upgraded packs. Guess what, they were all short of their capacity rating, by a lot! In addition, every single pack has opened up the case from swelling. IR readings aren't terrible, and I have read that SMC lipos are packed tightly into their cases, so swelling is more obvious, but none of my other packs have been this obvious. LOL! I respect SMC, but won't be risking a purchase there again.
 
I've probably bought about half dozen or so SMC packs over the years, I have no beef with the brand, they are just as good as any other budget brand out there. I used to buy whichever brand was the least expensive and had what I needed in stock when it was time to replace my packs, pretty much every budget brand was comparable in performance and longevity.

I make it a point these days to only select a brand which is rated to handle 3C charge rates as a minimum, if they don't state what charge rate they support, then I keep on searching for another brand to consider.

I'm currently running Trinity White Carbon series right now and plan to stay with them indefinitely, they are more expensive up front but have proven to be more cost effective over the long haul because they last considerably longer than most budget brands before the IR degrades.
 
I've probably bought about half dozen or so SMC packs over the years, I have no beef with the brand, they are just as good as any other budget brand out there. I used to buy whichever brand was the least expensive and had what I needed in stock when it was time to replace my packs, pretty much every budget brand was comparable in performance and longevity.

I make it a point these days to only select a brand which is rated to handle 3C charge rates as a minimum, if they don't state what charge rate they support, then I keep on searching for another brand to consider.

I'm currently running Trinity White Carbon series right now and plan to stay with them indefinitely, they are more expensive up front but have proven to be more cost effective over the long haul because they last considerably longer than most budget brands before the IR degrades.
Thanks for the insight on the Trinity packs. I know with the amount of racing you do, that your recommendations come from real-world use. My earlier comment was mostly for the original poster, and anyone else who might be seeing some swelling in their SMC packs. I only play with my RC cars, so it's usually budget batteries for me, however, within that range I wouldn't buy anywhere else but Hobbyking. I have dozens of lipo packs, and the ones that have lasted the longest (10+ years) are Turnigy. I have gotten a couple of lemons from them before, but Hobbyking has always made it right. I recently bought some Rhino 4s and 6s packs from Hobbyking and not only was the IR right around 1milliohm, but after running the 4s packs in my Xmaxx, I was shocked at how cold they were! I mean cold! So far, I'm extremely impressed with them. I tested the 6s packs in my Tekno MT410, running a Tekin 1550kv in there, and the results were the same. Ice cold after 15 minutes of bashing around the yard non-stop and end voltages almost exactly the same across the entire pack.
 
EBaltazar, thank you for the response. I really appreciate it. I have been extremely careful with my SMC 5200 mah pack, always make sure to store it at proper storage voltages, and never draining below 30% and never charging above 85-90%. Moreover, I've probably used this pack less than a dozen times and never in extreme weather. So to see it already swelling and the case popped open, I was really disappointed. Had me start questioning if I had been maintaining it right. I bought this back in 2018 and it wasn't cheap. I'm in Canada so it's harder to get budget lipos around here, and this one I bought from a reatailer who happened to carry stock so I'm not sure if I have any recourse at this point.

Could you link some Turnigy packs that you've had success with?
 
EBaltazar, thank you for the response. I really appreciate it. I have been extremely careful with my SMC 5200 mah pack, always make sure to store it at proper storage voltages, and never draining below 30% and never charging above 85-90%. Moreover, I've probably used this pack less than a dozen times and never in extreme weather. So to see it already swelling and the case popped open, I was really disappointed. Had me start questioning if I had been maintaining it right. I bought this back in 2018 and it wasn't cheap. I'm in Canada so it's harder to get budget lipos around here, and this one I bought from a reatailer who happened to carry stock so I'm not sure if I have any recourse at this point.

Could you link some Turnigy packs that you've had success with?
Hey there! Yeah, I was shocked at how poor my SMC batteries were. Here are the most recent batteries that I bought from Hobbyking. I always wait for their big battery sales. I got these at the sale prices a couple of months ago. https://hobbyking.com/en_us/turnigy-graphene-5000mah-4s-75c-lipo-pack-w-xt90.html
https://hobbyking.com/en_us/rhino-5000mah-4s-50c-lipo-pack-w-xt90.html
https://hobbyking.com/en_us/rhino-4000mah-6s-50c-lipo-pack-w-xt90.html

Those Rhino packs flat out impressed me! I see one of them is currently out of stock, but I'm sure that will be sorted out as the world normalizes.
 
Hey there! Yeah, I was shocked at how poor my SMC batteries were. Here are the most recent batteries that I bought from Hobbyking. I always wait for their big battery sales. I got these at the sale prices a couple of months ago. https://hobbyking.com/en_us/turnigy-graphene-5000mah-4s-75c-lipo-pack-w-xt90.html
https://hobbyking.com/en_us/rhino-5000mah-4s-50c-lipo-pack-w-xt90.html
https://hobbyking.com/en_us/rhino-4000mah-6s-50c-lipo-pack-w-xt90.html

Those Rhino packs flat out impressed me! I see one of them is currently out of stock, but I'm sure that will be sorted out as the world normalizes.

Thanks for those links. I'll try them out. Approx how much runtime do you get out of your 4000 and 5000 mah packs?
 
Thanks for those links. I'll try them out. Approx how much runtime do you get out of your 4000 and 5000 mah packs?
Runtime is relative to the motor, esc, vehicle weight and driving style of the user. In my Xmaxx, two 4s 5000mah packs get around 20+ minutes of park bashing. The 4000mah 6s packs get 18 to 20 minutes in my MT410 with a 1550kv tekin system. Your mileage will most certainly vary. ??
 
I've probably bought about half dozen or so SMC packs over the years, I have no beef with the brand, they are just as good as any other budget brand out there. I used to buy whichever brand was the least expensive and had what I needed in stock when it was time to replace my packs, pretty much every budget brand was comparable in performance and longevity.

I make it a point these days to only select a brand which is rated to handle 3C charge rates as a minimum, if they don't state what charge rate they support, then I keep on searching for another brand to consider.

I'm currently running Trinity White Carbon series right now and plan to stay with them indefinitely, they are more expensive up front but have proven to be more cost effective over the long haul because they last considerably longer than most budget brands before the IR degrades.
Hi Bill, I am also running a Trinity White Carbon 2S 7700mah battery and noticed on the very first run (at 3.1V cutoff per cell) the battery was swollen after the run. I checked the IRs and they are both 1.3Ohm to 2.2Ohm depending on the battery temp. The IRs seem really reasonable and both cells are extremely close, varying by 0.2Ohm at most, but the battery swells. One run the swelling was substantial. The swelling goes down almost to none (the case barely doesn't close all the way) after the battery cools and is charged to storage voltage. I am guessing I am running the battery too hard and maybe overheating? I am not sure what I'm doing wrong, or if the battery is defective.
 
Hi Bill, I am also running a Trinity White Carbon 2S 7700mah battery and noticed on the very first run (at 3.1V cutoff per cell) the battery was swollen after the run. I checked the IRs and they are both 1.3Ohm to 2.2Ohm depending on the battery temp. The IRs seem really reasonable and both cells are extremely close, varying by 0.2Ohm at most, but the battery swells. One run the swelling was substantial. The swelling goes down almost to none (the case barely doesn't close all the way) after the battery cools and is charged to storage voltage. I am guessing I am running the battery too hard and maybe overheating? I am not sure what I'm doing wrong, or if the battery is defective.

Batteries are really hard to consistently get right. Some puffing is normal especially with 2s packs. They tend to be more stressed than larger 4s batteries. Also many packs don't like going as low as 3.1V.

My observations so far:
  • High end batteries with high C rating most of the time wear out quicker than some lower end stuff
  • 2s batteries suffer more than 4s+, they puff quick. C rating makes more of a difference in performance
  • 4s batteries have enough voltage to be less of a "power bottleneck". C rating is less important on those larger packs
  • Puffing is not a big deal
  • Internal Resistance is what matters when making diagnostics on a battery
  • Internal connections can also become a problem in multi-cell batteries
  • Battery cells batches are inconsistent from one batch to another
  • Manufacturers will "dump" whatever quality (good or bad) cells to their customers
  • Some of the best batteries I ever had are the Turnigy batteries mentioned by @EBaltazar
 

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