LowDrag

iTrader: (10)

I'm new to foam tires... what is the best foam type for black carpet. K Foam, T Foam, shore hardness?

simple

iTrader: (2)

Wrong forum for this information - GT12- RT (stands for Rubber Tire) -
You are better served by reading the Wiki at the top of this forum - 1/12 forum
IT has quite a bit of tire information already posted, and specific information relevant to Black carpet.

LowDrag

iTrader: (10)

Perfect, thanks for the info "simple"

TonysScrews

iTrader: (13)

Question on batteries....

For example, looking at the Trinity website they have:

White Carbon: (LiPO)
7400mah 135C 3.7v 1S pack
8000mah 130C 3.7v 1S pack

RevTech: (LiHV)
8600mah 140C 3.8v 1S pack

What's the preferred battery in 12th scale racing? In this class most folks run the USGT fixed-timing motor. Other classes they run whatever from 21.5 to 13.5 to Mod. I'd imagine most places tech batteries to 4.2v per cell so whether running 1S or 2S packs, you'd have to charge the packs to the required "tech" voltage. So not sure if charging a 3.8v LiHV pack makes any sense to only 4.2v instead of 4.35v. Curious if anyone has done any testing on this?

BullFrog

iTrader: (4)

Trinity White Carbons (7400) and everyone charges to 4.2 that's the ROAR rules. CRC also has batteries.

Billy Kelly

iTrader: (9)

A chaotic Main from Wednesday. Short on marshals and a 10 lap difference from first to last

https://youtu.be/wJoAis356LI

Greg Holford

iTrader: (1)

I bought one of the CRC Rocket Fuel 7500 mah. Seems pretty good so far and a little more "punchy" if that's a term. I was surprised how quickly it charges over the Reedy Zapper I was using. Reedy takes 23minutes or so and the CRC only takes 10-11 minutes.

old_dude

iTrader: (1)

Just be careful with them. They do not like high charge rates and they really don't need them. 15A is probably tops and no external heating. They will puff if you do. Keep them low and they are great.

Greg Holford

iTrader: (1)

My charger only goes to 14 amp and I never used a heater for my batteries. I've never felt comfortable with those high charge rates, even back in the old nicad days. Once you see a couple packs go up in flames it kinda teaches you to play it safe.

Regarding the heater pads. Has anyone really seen an improvement using one in 21.5 rubber tire? There is so little power to work with anyways, I wouldn't think they offer much improvement.

mrreet2001

iTrader: (9)

Low power / stock type racing is when you get the MOST improvement from the best IRs.

BullFrog

iTrader: (4)

Always charge at 20amps and discharge at 30amps. Store batterys when not using in the Refrigerator- Have never seen a puffed battery in years!

Sabin

iTrader: (1)

I disagree. This is old and outdated information. Charging them at 20 amps puts too much wear on the batteries and you'll end up replacing batteries faster than you need to. Why? A charge rate that high causes the internal temperature to rise too fast, leading to accelerated cell wear.

Charge at 2C max (8 amps if 4000mAh). Storing in the fridge is now unnecessary. The better way of doing it is to keep them at room temperature and make sure they're not in a hot environment. IR is now your yardstick. Good cells should be under 5 milliohms per. If they start rising to 6 or above, then consider replacing the cells. 10 or higher means the cells now have degraded and that's when you should retire the pack.

BullFrog

iTrader: (4)

You have your way and I have my way. I have had ZERO puffs in many years. I also store regular batteries in the fridge.

mr.rev

It just doesn't make any sense. It has some aditional risks (for the batteries and for your health if you're using the kitchen fridge) and for a regular person this practice brings absolutely 0 benefits.

old_dude

iTrader: (1)

These new ones are way more sensitive. The 20A number may be to high. Even our local battery guy (Power Push) put out a warning on them. Something very unusual for him.
Interesting side though. Our track has handout batteries for GT12. You get one for the day. These things are routinely charged at 30A and heated. I don't think any have puffed. After a year a couple of them were weeded out due to IR's that were over 2. Different brand and probably a different cell maker.