Think about it... How many different battery manufactures do you think there are? For example. Protek, an a main brand, do you think a main hobbies manufactures their own batteries in their warehouse? No. And as for max amps, They have some crazy high amp ratings... Is it possible that their batteries are tested on a different higher reading machine? as there is no real sanctioning body to regulate testing that im aware of. ive personally never had an issue with smc batteries and honestly I never balance them, or discharge them. Whatever the voltage is at after a heat/main is where it stays till next week.

yeah, I get that. I was more concerned with pushing 14 maps into the esc. And power on or off, still an issue. plug the battery in backwards even with it off. It will most likely still smoke. Anyway, back in the brushed days when we soldered the packs in, I tried to charge with the battery connected and the esc melted. never tried it again.

All lipos probably come from the same couple manufacturers and are relabeled, cool thing about smc is if you have an issue/question Danny is on this forum daily with answers and testing results. You don't see that with many other batt companies

I have never messed up any pack since I returned to the hobby a year ago. Several years ago I bought a lipo and forgot to unplug it front the esc after a race and needless to say, 8 months later it was toast. 2 years later it puffed. a year after that I cut the deans off it and tossed it in the trash. That is the ONLY lipo I have ever messed up. I see people puffing packs non stop locally, but I think they just do it wrong. Like leave the packs in the car when its 110 outside. Some fast guys are doing overcharging to get more kick from the packs, and they puff a few months later. And sc4x4 loves to eat packs. Almost any pack with puff on a sc4x4 if geared wrong or constantly run down to 3v/cell cutoff. The SMC packs are fine. Are they the best on the market? I dunno, but I will say you cant beat the performance for the price. why would nayone buy the chinese packs that cost the same or more. First off, supporting SMC supports a local small business and the owner supports the packs on these forums. Show me the turnigy/gens ace thread where the owner of the company is on the forums daily answering question. When you purchase an SMC pack, your not only getting a solid pack for a low price, your getting Danny's support with it and his commitment to a good product.

Agreed

If the label said 120 for burst it was a typo but if you have read my Info & Tips section on our website C rates and burst rates have pretty much become useless in the past 2-3 years. There is no standards and every factory/reseller in China seem to claim what they feel like. Very sad but this is the current state of RC batteries.

I believe that everyone has learnt allot in the past years on what to do and what not to do with Lipos. Lipos when treated properly will last many cycles. When you don't follow the guidelines they will get damaged and have a lower cycle life. Another thing to note is we sell high performance packs with low IR and there is a fine line between performance and reliability. I believe the factory we use has learnt allot in the past years and have a better understanding of what they can or can't do. I think this is also applicable to other factories as well. When Lipos first came out and flight guys would use them they would get 30-50 cycles now they can get 150-300 cycles out of a good pack.

Ok thanks. i did read it but i forgot that part of the info thanks for being so honest all the time it really tell us what to look for and what a great guy you are. Rob

Not 100% sure how many Lipo factories are in China but there is only a few that make what I consider high end cells. By high end cells I mean low resistance cells as this is what makes a cell drop less under load.

I'm sure there is plenty of factories making lower end cells and lower C rate cells.

Here is something that might be shocking to some of you but I will say it anyway. 90% of the cells used in RC packs are 15 to 25C if you were to use a good standard method of testing for C rates. The very best materials can yield around 40C but the draw back is the mAh would be lower and in most cases it wouldn't be much stronger than a higher mAh cell with lower C rate.

You can check out this video as I show how C rate is tested.

http://www.youtube.com/watch?v=rqdLCV2goCI

I'm glad to share info with those who want to learn and better understand Lipos. For over 25 years I've been testing and selling race packs to the RC market and my goal has remained the same which is to sell the best possible packs to my fellow RC racers.

okay thank you for your help. ill definitely be buy 6 or more lipos once you guys get them back in stock

Seems like 5mm inboard style packs are becoming more popular and it seems that this is the latest attempt by companies to get you to buy new packs. 8 months or so ago I tested 5mm vs 4mm and actually found the 5mm connector had higher IR. I'm really not sure why this is the case and in theory it makes no sense but my test was done properly. I decided to do the test again today and it confirmed my original findings.

The test is done by using one cell and soldering a 4mm female tube with 12AWG wire and a 5mm female tube with 12AWG wire on the cell. I then use the ESR meter to measure the IR of the cell through the connector and wire.

As you can see the 5mm setup provides 0.20 mOhm higher than the 4mm connector. The 4mm connector and 5mm connector are manufactured by the same company.

SMC has always been all about selling the best possible packs and this is the reason why we're not jumping on the 5mm bandwagon yet. I will study this some more as I'm really perplexed as to why the 5mm wouldn't at least equal to the 4mm.

Did you normalize for fit or insertion force? Same total contact force would mean 4/5s unit force (but bigger contact area)? 5/4 if you assume line contact around the circle.

Not sure what you mean by this.

I used 4mm male connectors and 4mm female tubes and measured the IR of the cell through the connector. I did the same with the 5mm connectors. The fit of both connectors are nice and tight.

I must admit I would of expected the 5mm to be equal or possibly better but it isn't and this is why I never pursued 5mm inboard packs. Also my 4mm adapter has been used a good amount and normally this increases the resistance. The 5mm adapter uses brand new 5mm connectors.

Assume you were to measure the force to push in the 4mm, then measure the force to push in the 5mm, and they both require the same force. The 4mm would in theory have higher force at a microscopic contact spot than the 5mm. However, there are more microscopic spots (contact area) with the 5 mm than the 4mm.

Seems like a good trade off (more spots/area), but as you've measured funny non-linear things happen with contact resistance. Maybe contact force is more important than contact area?

If all else fails... Make more measurements!

PS - Believe your result; just fun engineer speculation trying to justify/quantify above.
PPS - I run a Shorty SMC pack. It's great! Keep up the great work!

Thanks for the explanation. I'm very confident in my results but really have no idea why they are as they are. Guess your info might be why. At the end of the day I know that resistance is key to performance and for my SMC packs I really can't justify using 5mm connectors just to sell more packs especially if this will increase the resistance.

I do plan to do more detailed testings eventually but I only have so much time to test such things.

Glad to hear you like the 4670 shorty.