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-   -   SMC LIPO BATTERY THREAD (https://www.rctech.net/forum/radio-electronics/674886-smc-lipo-battery-thread.html)

Danny/SMC 06-11-2013 08:22 AM


Originally Posted by Tim3 (Post 12245473)
Hi Danny
When do you think we will see shorty lipos go to 5000 mha?
Do you see the packs going from 4mm female tubes to 5mm?
Thanks, Tim


Increasing the mAh is possible but this will come at the expense of IR which will impact the voltage curve and punch of the pack. The current 4600s cycle out at 4500 or so at 35 amps but have very low IR. I believe keeping the IR as low as possible is the way to go.

As far as 5mm tubes go in my testing I couldn't see a difference in the data of the pack. Since most customers are already equipped with 4mm connectors switching to 5mm really makes no sense at this time.

Danny/SMC 06-11-2013 08:31 AM


Originally Posted by DarthRacer (Post 12245737)
Do you have a graph of the discharge curves for any of your batteries? I'm curious to know how much capacity I can use up before coming close to LVC. From using the pack I have I can use 2500 from a 5000 2S pack and still have the voltage at 8.0V.


Typically the mAh is at the rated spec or within 5%. As the factory makes a model at first they give us the estimated mAh it will reach. Then after a few batches the mAh settles in and can be lower or a higher this depends on the IR. Also there is some fluctuation in cells. So if they make 5000 cells rated at 5000 the lowest one maybe 4750 and the highest ones may reach 5250.

The best thing to do is to set your cutoff on the conservative side. Something around 3.50v per cell is a good start. Run the pack until the cutoff kicks in and then measure the voltage of the pack. If your cutoff is working properly the voltage of the pack should be at 7v or a bit over. If it's 7.2v or so you should drop it to 3.4v per cell as this means your cutoff isn't accurate. This depends on how the ESC senses the voltage which has allot to do with resistance and voltage drop.

Recently I had a customer who had is cutoff set at 6.7V and after a run the pack had a cell at 2.9 and the other at 3.4 this means his cutoff isn't working properly. The voltage should always equal the cutoff or be a bit higher.

Danny/SMC 06-11-2013 08:33 AM


Originally Posted by gawith0413 (Post 12245757)
Hey Danny,
I would like to check on my buddies order also #2195. Thanks!

His order will ship at the same time as yours.

Minor delay in getting packs shipped this week as it seems China is on a 2-3 day National Holiday. I expect our next shipment to ship on Friday.

gawith0413 06-11-2013 08:38 AM


Originally Posted by Danny/SMC (Post 12245915)
His order will ship at the same time as yours.

Minor delay in getting packs shipped this week as it seems China is on a 2-3 day National Holiday. I expect our next shipment to ship on Friday.

So....They will ship from China on Friday?

JoshC90 06-11-2013 08:53 AM


Originally Posted by Danny/SMC (Post 12244861)
Not exactly sure. Were in the process of switching these packs over to the factory that makes our Race Formula packs. I believe by the end of June or first week of May we should get more of these in but will have a better idea in a few weeks.

Well i went ahead and pre-ordered them :batman: Not like im going to find a better pack for a cheaper price

Danny/SMC 06-11-2013 09:13 AM


Originally Posted by gawith0413 (Post 12245927)
So....They will ship from China on Friday?

Yes that is what they told me. Originally they told me the 10th but then yesterday they told me they we're going on a National holiday and my order can only ship on Friday.

If nothing changes this means they will be in by the end of next week.

Danny/SMC 06-11-2013 09:14 AM


Originally Posted by JoshC90 (Post 12245973)
Well i went ahead and pre-ordered them :batman: Not like im going to find a better pack for a cheaper price

We will honor the pre-order price but once the packs comeback in stock we will increase the price by 5 dollars. The new model we will offer will be 5100-40C and the IR will be lower so expect better performance out of the new pack.

mxgregg 06-11-2013 09:22 AM

Just got my Race Formula 7.4V 7200mAh 70C Inboard. Fast shipping and even faster battery!

PetRock 06-11-2013 02:35 PM


Originally Posted by Danny/SMC (Post 12244879)
Yes I do have IR measurements but they are useless as we use the ESR IR meter with a controlled temperature. Unless you own this meter and test at the same temperature we use the data is useless. The IR is lower than the Turnigy packs.

I've been measuring the IR of my new SMC and Turnigy nano-tech batteries, and SMC has shown significantly lower numbers when new. I have about 20 full charges through 3 of my nano-techs and their IR hasn't really changed yet, but I'm keeping an eye on them.

Once I get about 20 charges through my 2 new SMC's I'll measure them again.

Danny/SMC 06-11-2013 03:00 PM

Glad to see your putting the ESR meter to good use. A few things you might want to consider is testing the IR at storage charge then charging the packs at 2C and testing the IR at the end of charge. You should notice that certain packs drop more in IR as they are made using different formulations.

tony montana 06-11-2013 04:45 PM

Danny, I ran my shorty 4600 the other day till it hit LVC. I have it set at 3.2. But when I went to charge it the next day the cells where pretty off balance. Eventually they balanced out ok with them being at 4.18 and the other at 4.17. But it took them a long time to charge. Case is not swelled one bit. Just wanna make sure I didnt do any damage. And this was the first time that I have hit the LVC with that battery

Danny/SMC 06-11-2013 05:14 PM

What was the voltage of each cell when you put it on the charger? Assuming your ESC does cutoff at 3.2v per cell that is on the low side. I've seen a pack be as low as 5.9v with the cutoff set at a 3.2v.

I don't recommend going below 3.4v per cell.

If the pack took charged up and didn't swell it should be fine.

Wildcat1971 06-11-2013 06:00 PM


Originally Posted by tony montana (Post 12247266)
Danny, I ran my shorty 4600 the other day till it hit LVC. I have it set at 3.2. But when I went to charge it the next day the cells where pretty off balance. Eventually they balanced out ok with them being at 4.18 and the other at 4.17. But it took them a long time to charge. Case is not swelled one bit. Just wanna make sure I didnt do any damage. And this was the first time that I have hit the LVC with that battery

That normal. The cells seperate close to 3.4ish volts. It really not a good idea to run till lvc.. It hard on the cells.

george919 06-11-2013 06:07 PM

What is the main difference between the race formula and the factory? Also will I tell the difference when driving my tekno sct?

fq06 06-11-2013 06:18 PM


Originally Posted by george919 (Post 12247559)
What is the main difference between the race formula and the factory? Also will I tell the difference when driving my tekno sct?

Not a tech answer like Danny may give but I'll chime in...

Lower internal resistance, more punch, can handle a power hungry setup better than the factory pack.
Yes, you want the race pack for the heavier conversion truck.


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