What am I doing wrong with my lipos?

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Wheels007

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Location
Hopkinton, MA
Arrma RC's
  1. BigRock 4x4
  2. Granite
I posted here a few months ago about my lipos not packing a punch in the beginning of a run, but after 10 minutes my truck is fine. Some of you warned me that lipos sold on Amazon can be hit or miss in quality. I decided to buy a decent 3s 90c 5000 mah lipo from SMC. It was a night and day difference from the other lipos I had...until yesterday. It started doing the same thing as the others. No punch for 10ish minutes then it woke up for the rest of the run.
Here are my charging habits. I ALWAYS balance charge my batteries. I charge at a 1C charge rate. I charge up to 4.2 volts. If I'm not going to use them for a week I leave them charged around 3.6-3.8 volts. Is there anything I'm missing? Or is it something with my truck?
 
Seems like your charging routine is ok. But it sounds like the pack may be dieing.

Were these the True Spec 135a 90c packs? I bought a pair of them about a year ago, never got to run them much (maybe a dozen cycles) and this summer they both failed.(puffed). Do the math on 135a, and that SMC 90c pack is really about 25c. Guess that is not enough power...
 
Seems like your charging routine is ok. But it sounds like the pack may be dieing.

Were these the True Spec 135a 90c packs? I bought a pair of them about a year ago, never got to run them much (maybe a dozen cycles) and this summer they both failed.(puffed). Do the math on 135a, and that SMC 90c pack is really about 25c. Guess that is not enough power...
It was this pack https://www.smc-racing.net/index.php?route=product/product&path=67_99&product_id=463
 
I assume you have tried powering off the truck and back on when it behaves this way?
It sounds more to me like the ESC.

I cannot imagine any reason why a battery would start to behave significantly better 10 mins in other than heat helps electron flow.
You are in the summer season, so its not like the batteries are cold initially right? You don't store them in the fridge or something!?
 
It's about 75-80 F out when I run it. And no I don't store them in the fridge hah. The batteries are never hot. maybe a little warm at the end of a run.
You mentioned storage charging them if not using them for a week, but you really should storage charge them after every use. Only fully charge them just before use.
Ya, I meant to say I do it after each run.
 
More likely to be esc related. I doubt its your Lipos. If they were damaged enough to lack punch they wouldn't miraculously recover like that.
Not sure what esc you are using or if yours limits amperage based on temp or not but I'd monitor your esc temps just incase there was a correlation.

Another thought.. Not 100% on this but I'd probably also check the Lipo/ power lead connectors. The bullets gradually close and loosen over time and connection cycles. If there is a loose connection and are arcing, resistance builds up and available amperage might be affected and vary due to connection movement?

Or... cold solder joint somewhere?
 
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Ok, I need to be educated. It says 90C on the battery. How did you get 20?
More likely to be esc related. I doubt its your Lipos. If they were damaged enough to lack punch they wouldn't miraculously recover like that.
Not sure what esc you are using or if yours limits amperage based on temp or not but I'd monitor your esc temps just incase there was a correlation.

Another thought.. Not 100% on this but I'd probably also check the Lipo/ power lead connectors. The bullets gradually close and loosen over time and connection cycles. If there is a loose connection and are arcing, resistance builds up and available amperage might be affected and vary due to connection movement?

Or... cold solder joint somewhere?
It's the blx 100 in the BRCC
 
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Ok, I need to be educated. It says 90C on the battery. How did you get 20?

I don't get that either. All I ran for 2 years were SMC 2S 7200 or 7400 lipos, 90C. They did fine paired up in my brushless revo, savage flux hp and outcast. I never noticed a dip in performance until the very end or them getting much over 105F unless it was hot out.
 
I can't see the new battery acting like the old ones. No punch then 10 minutes later no problem makes no sense

Makes me think esc problem not lipo.
 
I’m the worst when it comes to lipo maintenance and all (have a lot) of mine are fine and have never done that. Can you swap out the esc or try the lipos in another rig, maybe a buddies and try his batteries. I agree with the guys above most likely the esc likes to get warmed up first...might be time for a new one. Arrma has a 2 year warranty if you have your receipt. Hope you get it sorted.
 
Can you test your batteries in a different vehicle perhaps? I'm going out on a limb and thinking a dodge capacitor in the ESC.....I hope it doesn't become a nightmare to RA under warranty for you if that is the case. Really hard to be definitive without dropping another one in
 
I would start with checking and resoldering your connectors, especially the one on the esc since your problem occurs with different lipo's. It's just a guess but after 10 min the connections get warm and better.
 
Ok, I need to be educated. battery. How did you get 20?

It's the blx 100 in the BRCC
It says right on the battery, 97a max. So maths-
90a/5ah=19.4c

Seems back when SMC had their Factory spec Packs, their 90c packs were very good. Does not seem that way anymore. I've seen a lot of people complaining that the new packs don't measure up anymore. And personally I've had 100% failure rate with relatively short number of Cycles.
 
I’m the worst when it comes to lipo maintenance and all (have a lot) of mine are fine and have never done that. Can you swap out the esc or try the lipos in another rig, maybe a buddies and try his batteries. I agree with the guys above most likely the esc likes to get warmed up first...might be time for a new one. Arrma has a 2 year warranty if you have your receipt. Hope you get it sorted.
Bah, unfortunately I run solo around here so I don't have anyone around to try my batteries. I contacted Horizon Hobby. Hopefully everything will work out.

It says right on the battery, 97a max. So maths-
90a/5ah=19.4c

Seems back when SMC had their Factory spec Packs, their 90c packs were very good. Does not seem that way anymore. I've seen a lot of people complaining that the new packs don't measure up anymore. And personally I've had 100% failure rate with relatively short number of Cycles.
Ahh I see. Thank you!
BTW, what lipos do you all use and have good luck with?
 
My longest lived lipos are all Hobbyking brand. Zippy compact for my minis, Turnigy Nano-tech and Turnigy Graphine for my big cars. I did get some regular Turnigy (grey label) and they all failed.

My oldest/most cycles lipo is an old 4s SPC lipo. Too bad they stopped selling lipos...
With both my SMC 4s packs failing this summer, I need more packs. My next buy will probably some more Turnigy Graphine. Unless I see something on sale. I am a sucker for a good sale... lol
 
It says right on the battery, 97a max. So maths-
90a/5ah=19.4c

Seems back when SMC had their Factory spec Packs, their 90c packs were very good. Does not seem that way anymore. I've seen a lot of people complaining that the new packs don't measure up anymore. And personally I've had 100% failure rate with relatively short number of Cycles.
I haven't bought any SMC's in over a year. As it was, when I ran nearly every weekend I'd cycle the packs 4-5 times a weekend and I'd get about 1.5yrs out of them before they became hard to balance. They never seemed to have an issue supplying power though.

I've been running hrb 5000mah 50C and hobbystar 6200mah 50C packs the past 9 months now that I run 6S. I run 2x3S since 2 out of my 3 trucks use saddle packs. The hobbystar's seem to be a bit more punchy.
 
I've been running hrb 5000mah 50C and hobbystar 6200mah 50C packs the past 9 months now that I run 6S. I run 2x3S since 2 out of my 3 trucks use saddle packs. The hobbystar's seem to be a bit more punchy.
The Hobbystar 6s 6200mah is a nice battery. little on the heavy side though. it will go on sale from time to time.
 
The Hobbystar 6s 6200mah is a nice battery. little on the heavy side though. it will go on sale from time to time.
Yep, heavy. Not so noticeable on my outcast and savage flux, but I really feel it on the ERBEv2. I think they are on sale this week again for $40 with traxxas plugs. That's when I usually buy a couple, but between those and the hrb's, I have 8 3S packs for my big trucks. No point in buying more to have them sit on the shelf.
 
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