Is this lipo bad?
10-12-2012, 05:49 PM
#1
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Is this lipo bad?
So I got two Turnigy 180mAh small lipos from Hobbyking and when they arrived, both were at storage voltages.
I didn't charge them before I started using them. After the cut off, both lipos seem to be bad. If you look at the picture below from my logger.
The voltage on the first cell is too low but it climbs back up slowly.
I've bought two Rhino version couple months back for my Losi Micro SCT and they had the same problem.
I didn't charge them before I started using them. After the cut off, both lipos seem to be bad. If you look at the picture below from my logger.
The voltage on the first cell is too low but it climbs back up slowly.
I've bought two Rhino version couple months back for my Losi Micro SCT and they had the same problem.
10-12-2012, 05:59 PM
#2
RE: Is this lipo bad?
should have balance charged em fully
also what amp rating is the micro SCT? 180mah seems extremely small for anything. My radio would even destroy those in minutes
also what amp rating is the micro SCT? 180mah seems extremely small for anything. My radio would even destroy those in minutes
10-12-2012, 07:12 PM
#3
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RE: Is this lipo bad?
If this is a 2s pack then the only thing we can know is that cell 1 is smaller OR just had lower voltage. If the voltages started out equal then it is smaller. May not be bad at all.
10-15-2012, 02:06 AM
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RE: Is this lipo bad?
The difference between 2.92 and 3.36v in a lipo might be 2% of capacity. Your pack is fine. Try charging it (slowly from voltage that low) and you'll find they are both close to 4.2v.
You shouldn't run packs down to LVC though, you will damage them. They will livw much longer if you stop at 20% capacity remaining.
10-15-2012, 06:45 AM
#5
RE: Is this lipo bad?
yeh, the difference between the 2 isnt that huge, and the lower is still high enough that it should take a charge.
Id balance charge these packs every time tho.
Id balance charge these packs every time tho.
10-17-2012, 07:42 AM
#7
RE: Is this lipo bad?
ORIGINAL: SuchIsLife
Thedifferencebetween 2.92 and 3.36v in a lipo might be 2% of capacity. Your pack is fine. Try charging it (slowly from voltage that low) and you'll find they are both close to 4.2v.
Thedifferencebetween 2.92 and 3.36v in a lipo might be 2% of capacity. Your pack is fine. Try charging it (slowly from voltage that low) and you'll find they are both close to 4.2v.
You shouldn't run packs down to LVC though, you will damage them. They will livw much longer if you stop at 20% capacity remaining.
10-17-2012, 07:54 AM
#8
RE: Is this lipo bad?
ORIGINAL: EXT2Rob
Huh? Really? I thought that's why we HAVE LVC, to prevent damage.
ORIGINAL: SuchIsLife
The difference between 2.92 and 3.36v in a lipo might be 2% of capacity. Your pack is fine. Try charging it (slowly from voltage that low) and you'll find they are both close to 4.2v.
The difference between 2.92 and 3.36v in a lipo might be 2% of capacity. Your pack is fine. Try charging it (slowly from voltage that low) and you'll find they are both close to 4.2v.
You shouldn't run packs down to LVC though, you will damage them. They will livw much longer if you stop at 20% capacity remaining.
LVC works fine if its set right, the pack is balanced, and the packs cells discharge in a uniform matter as it just takes a total of the packs voltage, and judges it off that.
If one cell in the pack is weak you can literally end up with 2.5volts on one cell while the other is at 3.7volts, and it will still allow you to run if you set the LVC to 3 volts per cell(seems standard setting on a lot of ESC's) as the battery voltage would be 6.2 volts. That kind of situation is also why I set my LVCs on the higher conservative side of 3.4volts per cell so even if one gets out of whack it should stop prior to it hitting below 3 volts
I think it would be neat if ESC manufacturers put balance ports on the ESC's so they can monitor actual battery voltage, and not just estimate it
10-30-2012, 04:13 PM
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RE: Is this lipo bad?
ORIGINAL: SuchIsLife
The difference between 2.92 and 3.36v in a lipo might be 2% of capacity. Your pack is fine. Try charging it (slowly from voltage that low) and you'll find they are both close to 4.2v.
The difference between 2.92 and 3.36v in a lipo might be 2% of capacity. Your pack is fine. Try charging it (slowly from voltage that low) and you'll find they are both close to 4.2v.
You shouldn't run packs down to LVC though, you will damage them. They will live much longer if you stop at 20% capacity remaining.
I have a Lipo that does that. It Climbs all the way to 8.16V and stops (if you combine both cells together).
My charger did save the Lipo thou and now its going to 8.40V. I usually run the car for 10-15 mins and stop.
7.60V is the storage charge voltage.
12-09-2012, 01:53 AM
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RE: Is this lipo bad?
ORIGINAL: EXT2Rob
I thought that's why we HAVE LVC, to prevent damage.
I thought that's why we HAVE LVC, to prevent damage.
Same logic as your car - it has a redline you shouldn't rev over or you will do damage. That doesn't mean it's fine to keep it up near the redline the motor every trip. You'll shorten it's life.
When I first started in RC I ran my turnigy LiPo's to LVC. They lasted about a hundred cycles. Now I land at 3.6v per cell, and they last 2 or 3 hundred cycles. Plus, if my approach is not perfect I have a few minutes to go around and make a good one. And land more gracefully.
