glennhl

iTrader: (16)

I always love the standard response, "no need to optimize this or that because the rest of your car or your driving is junk."

malkiy

iTrader: (10)

90 degrees isn't very high. Cycling at 10 amps will get it to that temperature. The ones cycling at 40amps are quite a bit over 100 I'm guessing.

DirkW

iTrader: (1)

It's not wrong though. The advantage you gain is quite small and you are likely to lose as much (or more) by a myriad of other things that could happen. If these are the odds, I'm not betting my batteries on it.

Once again it's not about the extreme positions. Neither does it "not work at all" nor does it make a "world of difference" in stock racing. It does provide a (very) small edge that most racers cannot even exploit properly - yet they are (more than) willing to damage their batteries prematurely. One could of course simply make rules (or a gentleman's agreement, yeah in RC racing, right? Good one! ) and all just settle for a lower max. amperage while charging. But of course that would make the pay-to-win crowd unhappy (if you cannot beat them on track you can at least try to outspend them, right? ). After all it's not like one couldn't have as close and competitive stock racing when everyone uses say 20 A as with 40A. 40A is only (slightly) better if you use it against guys who don't. Doesn't give any advantage when everyone does it, right? But that's typical in today's RC world: "as long as I get a (temporary) advantage, I don't care whether it's good for the hobby!"

Roelof

Because more than 90% of the drivers just follow what their hero's are doing not knowing if it will work for them. Drivers who can not run 5 minutes straight the same laptimes within a 0.5 sec window will not use any gain of a heated battery and even if they say they can I still doubt that, for sure with 21.5 and 25.5T motors.
The same is with the endless whining for setups, as if a setup from another driver will work for you.

Goof

iTrader: (81)

It seem again this thread is off topic to the OP thread
Like I said the lipo mentioned r lower quality packs so without knowing how much puffing is really happening we can't help
The cases r built small as possible and a little puffing will happen
Here is a pic off SR page changing out his 2s for off road and I know he is using his lipos more then any of us. So do more reading and u should figure it out

glennhl

iTrader: (16)

My point is this thread is about optimizing batteries. Even if it's just a little, it still counts. I charge at 12 amps, not because I don't believe charging at 40 amps would give me a little more punch, I believe it will. I don't do it because I'm cheap and I want my batteries to last.

Sabin

iTrader: (1)

Well, you haven't raced me. I know I can give you a run for your money because I'm able to keep up with the fastest guys at our local track. They do all the battery shenanigans, like pumping, cycling and other unnecessary steps that just kill their packs. And I just charge my batteries at 1.5c, keeping an eye on mAh consumed. My packs recover quicker and run longer because I'm not smashing them with that metaphorical hammer.

Sabin

iTrader: (1)

This part here. See, when you see a lower IR, it's due to the packs' internal temperature. If you let the pack rest for five minutes, letting it cool, the IR will be higher. Cycling a pack just leads to a placebo effect. What you're actually witnessing is its ability to deliver voltage under load. I gave a buddy a pack of mine to race with and he was commenting about it being really fast. It was a thirty dollar CNHL pack that sat for twenty minutes.

Sorry for the double reply, phones are ass for responding on a forum.

Alexv2024

iTrader: (2)

I bought 4 Reedy 6100mah SG3 shorty packs in feb 2020. I just threw away the last ones this fall, and they spent the first whole year nearly every cycle at 40a charging, with lots of 18a or 40a discharging in there as well. The next 2 years was a mix of 15-20a and 40a charging with 40a discharging for series races and big races I was running stock. I was running stock and mod at the time, and in mod I was doing 4.1v/cell to reduce initial punch, and help reduce wear on the batteries, along with 15-20a charging and no discharging. Stock I'd do 4.2/cell and 40a charge as normal. Practice I'd usually do 20a for everything max, as I had time to wait.

End of days I'd make sure the cells were 3.7-3.9v and also hit "balance pack" to make sure they were even. I also made sure to always have good charge leads, which really helps pack life.

I had and killed a bunch of thin packs, 4000-4400s usually for wheeler. But that was mostly accidents of over discharging from leaving them connected and stuff like that. But also the same charge numbers (40a/15-20a) are much higher C rates so are more abusive. I had a few of them last a good 8-12 months.

Will 40a charging shorten battery life? Sure. But I still have 1 of the 6100's on my rc shelf with no puff. IRs are high from insane amount of cycles and its capacity is roughly 4000mah now but its 3.5 years old. 2 of them did die last year but the other two lasted till now. Its also sitting next to my 5000mah fantom that I bought in 2019 thats in the same condition. I've talked to a lot of guys about how they treat their stuff. Lots of truth in this thread, however high quality packs that are 5000-6000mah will easily handle 40a charging for 2 years if not done every single cycle. Also high amp discharging is much easier on packs than high amp charging. For a while I was doing 40a discharging and 20a charging. I'd consider trinity, reedy, fantom, r1, muchmore the highest quality packs commonly in racing. I had and seen lots of failures with protek and gensace. I had 2 gens ace packs (5800mah? redline) fail 3 months after I bought them from broken cell tabs internally. Proteks Ive heard also have cell tab issues, or quality issues in general but never seemed to have great IRs. Their pricing should be like 20% lower, that seems more in line with their quality. But lots of people have good luck with them, but lots of people have complaints. SMC seems pretty good, and very cheap. I feel like they buy the cells that perform well but are just lower mah rated than the big brands, so they cell them cheap. But they other wise seem good. I have talked to a few guys that have bought trinity packs in the last few months and they say they dont seem as good, so who knows if they're still a safe bet. But I just bought 5 new fantom packs, so I'll be set for 2 years.

TLDR- I'd consider trinity, reedy, fantom, r1, muchmore the highest quality packs commonly in racing. Ive had the best luck with Fantom and Reedy, but also never go over rated charge voltage (4.2 or 4.35/cell) but never go below 3.2v/cell if you can manage it, but 3.0 and below is for sure cell degredation. Either diminished charge capacity or higher IRs but usually both. With an Icharger and good leads and storage inside the house those listed packs should last a long time. I did over discharge one of my new 4400 Fantoms running 4wd mod, it got down to 2.9v on one cell, so we'll see how it ages compared to the other 4400mah I bought with it. But the 6400mahs I expect 2 years out of with half the cycles being 40a for stock racing.

disaster999

iTrader: (1)

I think the newer batteries now arent what they used to. Ive used Nosram Graphene 2 and 3 batteries previously and those were the best batteries Ive ever used up till now (in terms of puff resistance). They were charged at 12A with an iCharger, run 8+min runs on them, and stored at 3.85v after use. They experienced some sort of over discharge once or twice when I thought they were charged but werent and went out on track at storage voltage levels. Despite some abuse, they lasted me 2+ years with minimal puffing.

Ive replaced them with some other brands by recommendation from LHS or local racers and those packs didnt even last a year before they puffed. Same charging and storage practices, Ive even shortened the run time to 6 mins to prevent draining them too much but still puffed. just seems like its "the norm" now a days. Im currently trying out some new packs from a local racer to see how they hold up.

Shorty packs seem to puff up a lot more and easier for me also. I have not had a shorty pack that didnt puff up yet.

slappomatt

I used to run shorty packs and I have thrown away all of the ones I had. it was mainly a decade ago racing a B5m. most were budget batteries, but I did try one or two higher end packs. they also puffed in less than 6 months so I lost the will to spend $100 on something I would be throwing out. I am willing to try again. once. whats a good stick pack with 5mm bullets for ~$100 or less.

gigaplex

iTrader: (2)

Emphasis on temporary. As soon as the battery cools, the IR increases again. The battery will cool between charging and hitting the track, so the actual impact on lap times is negligible, and you've harmed the batteries in the process. And the temporary difference in IR between a pack charged at 10A vs a pack cycled at high amps is pretty small.

Good luck reliably cycling it to peak just before the race starts without exceeding the temperature limits (if any) and not missing your race or having to go out with a partially charged battery.

PDR

iTrader: (31)

I always like to see data. Has someone got IR numbers before/after their preferred cycling?

Last time I checked at the track, my year-old LRP packs were showing "1mΩ 0mΩ" on my icharger with my standard "let them rest after a run and then balance charge at 10A".

staiguy

iTrader: (7)

technically a battery is something that HAS to get thrown out eventually. It’s just a matter of how long it lasts. I really like my R1 batteries. Out the box and on its first chargers it read about 3 ir.

HOTROD716

Beside the discussion of cycling, I have had SMC batteries puff. I have been using Trinity White LP. carbon with great results, I have used Fantom's LP with great result, now I am trying Exalt's LP to see.

I store my batteries in my basement, where my rc workshop is. I do charge and discharge at a high rate, and I am not the best driver, but my batteries do not puff. I would try different brands and see what results you have. I do use Icharger chargers.