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SMC 28C 4000/5000 Hardcase Lipo part 2

SMC 28C 4000/5000 Hardcase Lipo part 2

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Old 04-09-2008, 12:38 AM
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Hello everyone,

just ordered an smc5000 lipo. reading back in a few pages I read that the 5000 lipo is a 4 cell pack.

I own an Ice charger. my question is what balancer should I look into purchasing? I was looking at the checkpoint pro car lipo balancer but upon further inspection noticed that it can only balance 3 cells. Am I misunderstanding how this balancer works?

Looking forward to going lipo.

cheerz all.
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Old 04-09-2008, 02:48 AM
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Originally Posted by Obsidian View Post
Hello everyone,

just ordered an smc5000 lipo. reading back in a few pages I read that the 5000 lipo is a 4 cell pack.

I own an Ice charger. my question is what balancer should I look into purchasing? I was looking at the checkpoint pro car lipo balancer but upon further inspection noticed that it can only balance 3 cells. Am I misunderstanding how this balancer works?

Looking forward to going lipo.

cheerz all.
have you looked into the astroflight blinky balancer?
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Old 04-09-2008, 03:53 AM
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Here is my cycle tonight. I'll cycle again next week after race day.

Pack 1;
420 seconds 7.34v
4083 mAh 7.2 IR

Pack 2;
416 seconds 7.33v
4044 mAh 7.2 IR
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Old 04-09-2008, 10:16 AM
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Originally Posted by Obsidian View Post
Hello everyone,

just ordered an smc5000 lipo. reading back in a few pages I read that the 5000 lipo is a 4 cell pack.

I own an Ice charger. my question is what balancer should I look into purchasing? I was looking at the checkpoint pro car lipo balancer but upon further inspection noticed that it can only balance 3 cells. Am I misunderstanding how this balancer works?

Looking forward to going lipo.

cheerz all.
Our 5000 pack is a 2S2P which means it's 2x2500mAh cells in parallel to get 5000mAh and then both of those are put into series to get 7.4 volts.

So any balancer that can do a 2S pack will be fine. Just make sure you have the proper adapter for the balance connector.
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Old 04-09-2008, 10:23 AM
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Originally Posted by JimmyMac View Post
Here is my cycle tonight. I'll cycle again next week after race day.

Pack 1;
420 seconds 7.34v
4083 mAh 7.2 IR

Pack 2;
416 seconds 7.33v
4044 mAh 7.2 IR

Thanks for the info. I see similar results with my packs. When I cycle them after a raceday and then cycle them again I get a bit better IR and voltage.
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Old 04-09-2008, 10:24 AM
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Originally Posted by Danny/SMC View Post
Our 5000 pack is a 2S2P which means it's 2x2500mAh cells in parallel to get 5000mAh and then both of those are put into series to get 7.4 volts.

So any balancer that can do a 2S pack will be fine. Just make sure you have the proper adapter for the balance connector.
Danny

Would a 2S1P configuration using your SMC 28C lipo cell produce more power or lower IR? I've read on some of the Lipo threads that going to 2S1P set ups for Lipo is the best way to go since it lowers IR and gets more power out of the packs, and you can make them lower profile, too...what do you think about this?

thanks

Yohan
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Old 04-09-2008, 10:50 AM
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Originally Posted by yyhayyim View Post
Danny

Would a 2S1P configuration using your SMC 28C lipo cell produce more power or lower IR? I've read on some of the Lipo threads that going to 2S1P set ups for Lipo is the best way to go since it lowers IR and gets more power out of the packs, and you can make them lower profile, too...what do you think about this?

thanks

Yohan
In theory it should be better but in my testing I haven't seen a big difference between a 2S and a 2S2P. To get 2S1P 5000/28C the pack would need to be longer than the ROAR specified rules so a 2S2P is needed.
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Old 04-09-2008, 11:20 AM
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Originally Posted by Danny/SMC View Post
In theory it should be better but in my testing I haven't seen a big difference between a 2S and a 2S2P. To get 2S1P 5000/28C the pack would need to be longer than the ROAR specified rules so a 2S2P is needed.
Hmmm I think the CORE5000 packs are 2S1P but they are 20C rated. So your're saying that your SMC 28C cells in 5000mah are a bit longer than the CORE5000 20C rate cells, and their length is over the ROAR limit? Just curious...
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Old 04-09-2008, 11:43 AM
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Hello all

this was stated earlier in the thread by danny:

To specify the C rate the industry standard is that a cell must be 90% of it's rated capacity at maximum C rate discharge.

The 2500 cell is 93% at 30C and the 4000 is 88% at 30C so the cells used in our packs do have a true 28C rate as advertised.

Im not quite understanding what all this means: for instance, what is 28c?

thank you for any clairifcation
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Old 04-09-2008, 05:32 PM
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Originally Posted by Danny/SMC View Post
Our 5000 pack is a 2S2P which means it's 2x2500mAh cells in parallel to get 5000mAh and then both of those are put into series to get 7.4 volts.

So any balancer that can do a 2S pack will be fine. Just make sure you have the proper adapter for the balance connector.

PM
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Old 04-09-2008, 06:55 PM
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Originally Posted by yyhayyim View Post
Hmmm I think the CORE5000 packs are 2S1P but they are 20C rated. So your're saying that your SMC 28C cells in 5000mah are a bit longer than the CORE5000 20C rate cells, and their length is over the ROAR limit? Just curious...

A 25C/5000 from our supplier is 8.5mm x 44mm 152mm. The hardcase is 1.5mm all around plus you need to allow enough room on the ends for the wires so the pack would be 160mm or more in length.
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Old 04-09-2008, 06:57 PM
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Originally Posted by Obsidian View Post
Hello all

this was stated earlier in the thread by danny:

To specify the C rate the industry standard is that a cell must be 90% of it's rated capacity at maximum C rate discharge.

The 2500 cell is 93% at 30C and the 4000 is 88% at 30C so the cells used in our packs do have a true 28C rate as advertised.

Im not quite understanding what all this means: for instance, what is 28c?

thank you for any clairifcation
C rate is the ability of Lipos to give out constant current. For example a 5000 pack at 20C can deliver a constant 100 amps. A 28C/5000 can deliver 140 amps. If the C rate is better it means the pack will have better performance.
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Old 04-10-2008, 06:59 AM
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Originally Posted by Danny/SMC View Post
C rate is the ability of Lipos to give out constant current. For example a 5000 pack at 20C can deliver a constant 100 amps. A 28C/5000 can deliver 140 amps. If the C rate is better it means the pack will have better performance.
If I understand right C rating is like IR in NMH packs, so you would get more punch with a higher C rating what is the highest C rating? and if the C rating go to say C50 then why not go for the highest C rating for RC racing.
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Old 04-10-2008, 09:23 AM
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C rate will have an impact on the size of the cell and it also adds to the cost of the pack. Since there is a maximum size for Lipos to be ROAR legal it will be tough to go much higher in C rate while retaining 5000 in capacity. The materials used by the manufacturer is also important to make high performance Lipos.
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Old 04-10-2008, 10:49 AM
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Will this packs fit in T2'008? Which will be better, 4000 or 5000 in a T2'008 without modification?
Thanks in advance!



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