Danny/SMC

iTrader: (2)

We should get the answer on ROAR approval by the end of this week.

I also got some info about ontrack testing that was done this past weekend. It seems like our 5000 pack was .15 to .20 seconds per lap slower than EnerG 4600s. This is only the first test and we will get more testing done this coming weekend.


Here are some random pack numbers on our 4000s.

sec - av - mAh - IR
421 7.33 4093 7.3

431 7.34 4190 7.1

419 7.33 4073 7.1

432 7.34 4200 7.0

421 7.34 4093 7.2

419 7.33 4073 7.5

brians11

iTrader: (40)

Danny, what type of racing was this?

Danny/SMC

iTrader: (2)

Foam TC. I guess it will take us some more testing to figure it out and that was with pack not being heated. I think we need to do more testing before we can come to a conclusion.

CRCDUDE

iTrader: (50)

After readin all of this topic, I had come up with my own lipo warmer.
i use a ceramic heater that has adjustable heat / fan. then i place a rack that holds batteries 8" away. I place them on the "warmer for about 10 min before a run and this gets them up to around 125-140* (case temp)

i have definatly seen a difference by getting them warm before a run, although i dont have solid lap times as i struggle with consistecy still (off-road) I have made believers while running my 13.5 BL in 2wd mod and hangin with them on the back striaght. And yes my car is ROAR legal weight for those who were wondering.

Although, i see a big improvement I still get the "dud" run every other charge cycle.

I do not discharge after a run as we hardly have enuff time.

Great thread and i hope we all can learn more on how to make these work safely.

Scottrik

iTrader: (261)

Unfortunately I don't believe this is actually benefitting you. Probably not hurting either. This amount of time at this comparatively low heat level just isn't enough to warm the cells, you're just warming the case. As an experiment (since doing this with cells isn't practical)...put a steak in the oven and set it at, say, 150 degrees. Come back after 10 minutes and measue the inside temperature with a meat thermometer. I'd wager it's still at the original temperature, and it doesn't have the plastic insulator that the case on our batteries represents.

If I knew the temp delta at a given degrees C (or F) I'd give this problem to my Calculus students...kids eat these kinds of practical problems up. Then we could find out how long to get to the center of a Tootsie Pop (oops, wrong problem. Who's old enough to remember those ads?). We could find the length of time at what temperature to get a pack thoroughly heated X degrees above ambient.

Anything that is going to effectively warm the batteries EXTERNALLY (as opposed to Danny's method of heating INTERNALLY via aggressive cycling) is going to require a lengthy period of constant exposure to the moderate heat we'll be limited to (can't damage the case) if you want to see even a 140 degree temperature through the pack. Just guessing...an hour plus if we can use 200-ish degree (measured at the case) external heat source.

oXYnary

iTrader: (4)

A friend and I were discussing using high powered infared LEDs in a box system (facing inwards towards the pack) that would fit inside a lipo sack with a small fan to circulate the hot air. If possible, it would be much more power efficient than thermal pads or wires (safer as well from shorts).

It all theory at this time.

By cycling that hot air, it should help warm the pack faster than just letting it sit or being wrapped up inside a thermal element.

Davidka

iTrader: (86)

I don't think heating the cells is going to be worthwhile in the long run. Unless you're running mod or something that draws a ton of amps the cells aren't under enough stress to maintain the heat anyway. It defeats the purpose of LiPo anyway which is to have batteries that a racer can charge and race. No cycling, no balancing, no heaters, etc.

Jack Rimer

We just received confirmation that our hard case 5000 and 4000 packs have been legalized by ROAR. It should be on the ROAR site very soon.

syndr0me

iTrader: (32)

Congratulations guys, that's a strong testament to the quality of your packs.

Davidka: The things you said about LiPo will likely remain true for the average person. For the "serious" racers in classes that value voltage, you're going to see guys do anything they can to get more power for free. Heating packs is really pretty simple, though it does remove some of the simplicity of LiPo. Multiple manufacturers have stated that it won't affect the cells, and it really does bring cold LiPo to life. They can feel very flat for the first run or two otherwise.

yyhayyim

iTrader: (26)

Con

Are the Dementions the same as posted in the first post in this thread?

Danny/SMC

iTrader: (2)

Yes same dimensions.

I'm currently at JACO/SMC Canadian Challenge at Fastcats and were testing our new Lipos and as soon as I have info I will post it.

Gitsum

iTrader: (1)

Am I looking on the wrong place or what? All I see approved are all the Orion lipos and the Checkpoint.....ummmmm.....where are the rest?

Marman

iTrader: (10)

I just finished reading the ROAR lipo rules and it says the pack shall be 2 cells in series. I originally thought this must mean the pack had to be 2S1P but if the SMC 5000 pack 2S2P is legal I guess it doesn't?? Does this then mean there are no limits on the number of cells as long as they are configured with 2 cells in series and the whole thing fits within the case dimeansions?

Danny/SMC

iTrader: (2)

They will be on the list once ROAR updates the list.