New Battery Issues - Lectron Pro

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ShadyD

ShadyD

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Arrma RC's
  1. Kraton 6s
So having some battery issues, and not sure what to think.

I have 2 Lectron Pro 3S 5200 mAh batteries I bought after Christmas and have used 4 times total.

I was out at the local BMX pump track thrashing my Kraton when the LVC kicked in. It seemed a bit odd, since I hadn't been out there too long and was running at 50% throttle. I thought maybe I had just lost track of time, and my son had just broken his suspension arm on his Slash, so I put it out of my mind and packed up.

When I got home, I put the batteries on the charger to storage charge, and the charger immediately beeped and told me they were good to go. All cells read 3.8v. This seemed off, so I decided to check the cell resistance (which I had not yet done). Using my charger (Passport Ultra P2, purchased at the same time as the batteries), the 1st battery read a solid 29 milliOhms across the cells. The second battery read 30/35/27.

For shits and giggles, I used my portable Tenegry volt checker, which has a resistance feature. It read much lower, but still wildly different resistances per cell, between 5 milliOhms and 19 milliOhms.

Anyone have any ideas what's going on here? Are these batteries just junk? I've literally had then less than a month, and they've had 4 charge/use cycles. These are my first lipos, so not sure what I should do here.

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Is this new behavior for these batteries, the short run time?

How are they stored, like at storage voltage, or fully charged? It's bad for the batteries to store them fully charged. But even so, I don't know if they could degrade THAT quickly.

The charger's IR measurement may be inaccurate. But still, if they ran much-shorter than usual, and were at 3.8V when hitting LVC, that's a separate symptom from what the charger is measuring.

What was the ambient temperature when you were out playing? Cold LiPos do not perform as well. So if it was 20F, and you weren't keeping the batteries warm before use, that could be part of the weak performance.
 
I have the same batteries. Plenty of runs with my UDR and they are fine with that, but they are absolutely terrible for speed runs in my limitless.
 
Did you check IR when you first purchased them? That would be your best bet for whether something has changed. Even if your charger is reading high IR at the beginning, it should provide a consistent baseline to check against cell degradation. Meaning, if they were high initial and performed well, and then nothing has changed, i wouldn't be worried. Also, you can check cell IR against a known good Lipo (that you know is a good performer) and see if the charger reports good IR.
 
LibertyMKiii said:
I am actually questioning the charger in this scenario.
Any friends that you could try thier's? Or maybe try at the hobby shop their charger?
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I'm unfortunately the only person I know in my area that does RC as a hobby. The hobby shop I got these from is an hour away, but I do need to make a run, so I can bring them along to get a reading. The Tenegry seems to list different IR every time I use it, so not sure of its accuracy either. The charger has been consistent each time.
RedOctobyr said:
Is this new behavior for these batteries, the short run time?

How are they stored, like at storage voltage, or fully charged? It's bad for the batteries to store them fully charged. But even so, I don't know if they could degrade THAT quickly.

The charger's IR measurement may be inaccurate. But still, if they ran much-shorter than usual, and were at 3.8V when hitting LVC, that's a separate symptom from what the charger is measuring.

What was the ambient temperature when you were out playing? Cold LiPos do not perform as well. So if it was 20F, and you weren't keeping the batteries warm before use, that could be part of the weak performance.
Click to expand...
It was very cold out, which is what I chalked the performance up to initially. I checked the IR mostly because I realized I had not yet done that with these batteries.
aroberson77 said:
I have the same batteries. Plenty of runs with my UDR and they are fine with that, but they are absolutely terrible for speed runs in my limitless.
Click to expand...
I've seen some folks use these forever, and other have the same issues with them being dead out of the box. I bought them only because that's what my shop had.
Hector_Fisher said:
Did you check IR when you first purchased them? That would be your best bet for whether something has changed. Even if your charger is reading high IR at the beginning, it should provide a consistent baseline to check against cell degradation. Meaning, if they were high initial and performed well, and then nothing has changed, i wouldn't be worried. Also, you can check cell IR against a known good Lipo (that you know is a good performer) and see if the charger reports good IR.
Click to expand...
I did not check them right off, but I will start tracking them now.
 
ShadyD said:
I'm unfortunately the only person I know in my area that does RC as a hobby. The hobby shop I got these from is an hour away, but I do need to make a run, so I can bring them along to get a reading.

It was very cold out, which is what I chalked the performance up to initially. I checked the IR mostly because I realized I had not yet done that with these batteries.
Click to expand...

2 things worth noting. Usually, you want to check the IR when fully charged. Also take readings at a consistent temperature.
A cell might show 9 milli Ohms at 70 Fahrenheit and only 4.5 ohms at 100 Fahrenheit in the summer.

IF the cells are truly at 20+ milli ohms they are just about dead. Usually you can tell because those high cells wont take a charge well. The healthy cell will get to 4.2 volts and the other will sit there for 30+ mins trying to get those last few 10ths or hundredths of a volt.

Another trick I learned is to power cycle the cells a few times before hammering them hard in the RC car.
Charge and discharge them a few times at home before using them hard. This generally will also bring down internal resistance.
 
ShadyD said:
I'm unfortunately the only person I know in my area that does RC as a hobby. The hobby shop I got these from is an hour away, but I do need to make a run, so I can bring them along to get a reading. The Tenegry seems to list different IR every time I use it, so not sure of its accuracy either. The charger has been consistent each time.

It was very cold out, which is what I chalked the performance up to initially. I checked the IR mostly because I realized I had not yet done that with these batteries.

I've seen some folks use these forever, and other have the same issues with them being dead out of the box. I bought them only because that's what my shop had.

I did not check them right off, but I will start tracking them now.
Click to expand...
Do you have any other lipos you can check against to get a better feel for whether it's the charger acting up? (ie, if you have any, what is the IR for your other lipos?)
LibertyMKiii said:
2 things worth noting. Usually, you want to check the IR when fully charged. Also take readings at a consistent temperature.
A cell might show 9 milli Ohms at 70 Fahrenheit and only 4.5 ohms at 100 Fahrenheit in the summer.

IF the cells are truly at 20+ milli ohms they are just about dead. Usually you can tell because those high cells wont take a charge well. The healthy cell will get to 4.2 volts and the other will sit there for 30+ mins trying to get those last few 10ths or hundredths of a volt.
Click to expand...
I agree that high IR predicts cell health, however, I would make an important caveat. Change in cell IR is the best indication of cell health. A battery with higher IR (in the 20-30 range) can still be used in the right applications. If continuously used in such applications, and 1) the IR doesn't take any drastic changes when you're frequently monitoring them (like after every run), 2) the batteries aren't getting super hot after every run, and 3) the performance on your truck is satisfactory for you, then I'd say the application is appropriate for those lipos and i would continue using them.

With any battery, you really need to be frequently monitoring them. It's free and doesn't take too much time, so there's really no downsides to it.
 
I have found IR to vary even with charge level, never mind temperature. But with them at some repeatable voltage (charged is good for this, since they'll be balanced) it's worth getting a baseline for the current IR. You could recheck a pack after getting it cold, like put it in the fridge overnight, to see the difference.

25-30 sounds really high to me. My packs are 4100s (smaller cells generally have higher IR, I think), and are almost 10 years old. They were showing 6-7 mOhms per cell, while charging them recently. And they were probably still chilly.
 
Hector_Fisher said:
Do you have any other lipos you can check against to get a better feel for whether it's the charger acting up? (ie, if you have any, what is the IR for your other lipos?)

I agree that high IR predicts cell health, however, I would make an important caveat. Change in cell IR is the best indication of cell health. A battery with higher IR (in the 20-30 range) can still be used in the right applications. If continuously used in such applications, and 1) the IR doesn't take any drastic changes when you're frequently monitoring them (like after every run), 2) the batteries aren't getting super hot after every run, and 3) the performance on your truck is satisfactory for you, then I'd say the application is appropriate for those lipos and i would continue using them.

With any battery, you really need to be frequently monitoring them. It's free and doesn't take too much time, so there's really no downsides to it.
Click to expand...
I don't have any other batteries....yet. I'm planning on grabbing a couple of Zeee 3s batteries to supplement these two.
 
aroberson77 said:
I would take a good look at CNHL, better than Zeees from what I have read
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Yeah, I had looked at them as well. Biggest problem is simply most of their stuff is out of stock in US warehouses.

I've read good stuff about zeee as well, especially for the price point.
 
So quick update. I have 2 new Zeee 3s 6000mAh. I checked them under the same conditions and temp as the Lectron packs in thr original picture, and where as the Lectrons read up in the 29-35 range, the new Zeees read 4 milliOhms across the board. So at this point, I would discount the charger.

I'm driving out to the hobby shop today so my sin can buy new suspension arms for his Slash, so I'll probably bring these batteries along.
 

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