I've gone almost a full season in some cases. Or one race after getting in a wreck. Depends on cleanliness of track, how often crashing happens or quality of the bearing itself.

Stock CRC bearings, and a few good tumbles so far, one of which was a bit of cartwheeling. I'll order up some extras.

I suppose that answers my questions.

I bought a pack of 10 rear bearings to carry in the spares. My son was breaking one every other weekend when he first started. I noticed that it often came from side slapping the wall in the sweeper at the end of the straight. So I started putting an o-ring between the stack of 1/4" axle spacers on the left rear of the car. If your car has enough space on the right side, you could do that as well. He can now make it a whole season or more on one set.

I too use o-rings as track width spacers on the rear axle to cushion the rear bearings from side impacts. It works great. On thing though - I don’t ever let the o-ring ride directly on the bearings. I put a thin metal shim on first so there’s no chance of the rubber rubbing on the bearing cage under compression.

Funny you both mention this- I'm running a CRC MetriCKs chassis, and it actually has 2 bearing o-rings built into the design(#3062 in the diagram). Despite all that I still killed a bearing. And yes, as MC Hamilton mentioned, it's on the sweeper side. I bought a sleeve of Protek replacements, but they're noticeably more draggy despite also being metal shielded. I suspect they're greased and the CRC bearings are oiled. I probably ran that bearing dry in the last week two with how much practicing/racing I've been doing. I'll use the greased bearings for practice/club racing, and I ordered up some more oiled bearings and oil from Avid.

My first day of practice with the car was rough to say the least, and I had some gnarly tumbles as I got more confident and pushed it. I can't say I'm too surprised, now that I think of it.

I'm back with more questions after racing yesterday

I seem to be dealing with a little more fade than most on race day. Towards the end of the main I'm definitely losing time compared to a few of the faster drivers. I've got a Protek 8800 LiHV, Hobbywing XR10 1S, 17.5T G4R, and my rollout is right around 89mm (65/45, 41.0 tire). Car comes off the track after a heat with a motor temp of ~150 degrees. My litmus test is someone I had a very close race with pulling away from me in the end, thanks to having what looked like more power, with the same chassis and electronics setup save for the battery. They're running the new CRC 150C cell. Can a modern battery really have that much impact? I'm operating on the assumption that, like, 3 companies make all of these batteries and it's just different stickers and cases.

If not, where should I start to look to help reduce fade throughout the main? Right now it seems I'm gaining roughly .3-.5s in average lap time by the end of an 8 minute heat.

A battery can absolutely make that much of a difference. While you're correct in assuming there aren't that many actual manufacturers of batteries out there, you get what you pay for in terms of battery chemistry and quality control. The current EAM packs seem to be the industry standard, followed by the latest CRC packs.

The other thing to play with is your motor timing and gearing. You'd be surprised how much a couple degrees less timing and one or two more pinion teeth can affect fade while not reducing overall speed.

The CRC 7500 150c batteries are very good. The two I have show .8-.9 ir. A friend who recently purchased the same battery is getting .7 ir. It being $30+ cheaper than other top batteries is an added bonus. Regarding fade, the batteries remain strong with only a .1-.2 second drop off at the end of the run.

It might be the battery. I'd be interested to have you and the other racer put each of your batteries on one of your chargers after the race and compare voltage and then do a charge from that point to see how many mAh go back into each of your batteries. If you are running the same motors/timing and rollout, it could be that his driving style is a little easier on power consumption and at the end of 8-minutes he has just a bit more voltage than you do. On a 17.5 motor, a 0.1v difference in voltage is going to translate into an RPM discrepancy of about 250-300RPM at the motor. If he's willing to swap batteries for a run, try that.

I've tested a few different 1s batteries with the same case design and they performed virtually identical under a 40-amp discharge, giving some credence to your theory about many of these coming from the same source (CRC, EA, Tekin, eXcelerate, Fido, etc.). I'm not sure who makes the Protek batteries, but they are certainly different than the others I mention simply based on the orientation of the +/- and size of the terminals. They look very similar to a Reedy.

Are you running a motor fan?
Are the others at your track running a motor fan?
Motor fans can help reduce that last two minute fade, but I also agree with the comments from others about running a good, low IR battery.

Perhaps I’ll initially start with some timing. I will totally admit that I never have really been competitive enough for it to matter to me(aka - motor is not the limitation in off-road classes). I was entertaining the idea of a Tunalyzer, but that’s probably not enough ROI for me. I’ve currently got about 42 degrees of timing as this G4R. I’ll back it off to 40 and re-tune gearing.

This is a pretty good idea, and next time I actually plan to try and borrow a battery for a heat, just for the science. I just checked my battery from the main yesterday, and it’s sitting at 3.9v. That seems barely off from a full charger of 4.2v, but I could be very wrong. I’ll charger it back up and see how much charge it actually takes. I actually talked to Team EAM support earlier today, and they mentioned that the Protek batteries sort of cheat their capacity rating on the 8800mAh LiHV because it’s 8800 charge at 4.35v, and more like 7200 charge at 4.2v. That right there could be my entire issue and I plan to discharge and recharge to test it. Also had no idea how much voltage contributed to motor RPM. That’s massive. I placed second, and the guy in first definitely has been doing this a lot longer than I. I’m sure he’s a bit easier on power with his driving style.He also runs a car in 13.5 so I’m sure 17.5 is like a walk in the park.

I am running a fan, as was everyone else in the A. We also all had very similar rollout (+/- 5mm). This is definitely looking more like driving style/battery.

This is good to hear about the CRC batteries. I have definitely heard good things about them, and am strongly considering it since they seem very cost effective as well. I’d kill for a .1-.2 drop off with fade.

This is going to be part of your issue, at least long term. Letting a battery sit for any length of time at a "charged" voltage (ie: overnight) is going to permanently raise the iR. You really want to make sure and discharge your batteries down to 3.6-3.7v when not in use. The increased iR will lead to overall diminished pack performance, as well as contribute to an increase in fade over a 5-8 minute run.

Don't be fooled by this. Unless everyone is on the same motor and timing, rollout can vary wildly, especially depending on the size of the track. I've seen locally others running a rollout 15-20mm higher and are basically at the same speed over a run, and I was actually fading more than they were.



Just remember, advice is always a guide, and VERY rarely is it a definitive answer. Don't be afraid to experiment and try new things.

I typically bring the car home and put batteries in storage the next morning. We race a lot of classes, even on club nights, so I usually don't get home until it's very late. I just had intentionally left this one so I could measure it and record voltage. I was always under the assumption that overnight wouldn't be a battery killer. Good to know I was wrong! I discharged and recharged at 20A to get it hot and IR dropped to about 1.7ohm... so not amazing but seemingly acceptable?

As far as motor setups - it just so happens the entire podium was running XR10 1S, 17.5T G4R motors, and 65t spurs- one MetriCKs, one CK25AR, and an A12WC. Closer comparison than most, but like you said, still not perfect. I'm not sure of everyone's tire diameters and motor timing.

I ordered a CRC Rocket fuel battery, and I might get the EAM cell to try as well. Next I'm at the track(won't be for a few weeks as I'll be traveling) I'll play with dropping timing and seeing how motor temps and lap times change!

You'll probably be fine storing them at 3.9v. That is close to prescribed storage voltage and far better than leaving them at 4.2V for any length of time. Personally, I would not sweat leaving them at 3.9v for a day.
1.7mohm on a warm battery on the Toolkit charger (I believe that is what I saw you were using) is... not good. For comparison, my M8D shows 0.5 - 0.7 on all of my fresh 1s race packs. My iCharger on the same packs shows 0.8-1.2 mohms.
Don't overlook SMC. From my testing, it was the only battery that stood out, holding 0.05v+ higher voltage across a 40-amp discharge cycle. I do have a brand new CRC 7500 arriving today that they are touting as "the best 4.0V numbers they've seen," so I'll be comparing that against my SMC, Fido and Tekin batteries.

Yep, ToolkitRC M8 and M8D chargers. I didn't know they typically read lower than iChargers. I considered it to be okay because my good Motiv packs(back in, like , 2018) never read below about 1.2 and they were the punchiest I've ever run. Relative to your findings... this Protek pack has more than double the IR. That's pretty bad. I'll be interested to see what the CRC reads when I get it. I did look into SMC, but they only have a single clearance 1s battery on their site and are very clear that is has subpar specs compared to their last batch.

Share your findings when you test those batteries! I'd definitely be curious to know.