Kraton Lipo batteries

[ChemEng]

1C is the lipo industry norm for RC rechargeables. Charging less than 1C will add better longevity to the lipo cells. How much more is questionable. With the way we beat the crap out of these lipos I cant see getting much more out of them charging at 1/2C for instance. But it cant hurt. May be a nuisance for most though. Getting multiple packs ready for a bash day and all. 1C is perfectly fine. Some packs are labeled 2C and higher. I never do that. I just never have and wont. MAh is rated to a 1 hour scale. Who is to say the cells of a particular brand allow a higher than 1C charge? I know some guys, who race and do just that even though the cells are not rated for higher than 1C. But they don't care about their lipos, the warranty and the liability. They want a hot lipo for that next race. And it makes a difference for them. And it works, but the Lipo industry states a lipo shouldn't be charged Hot/warm. The industry considers a lipo cooled down after one hour at rest. I wait about that long for my lipos to get to room ambient temps at rest before I full balance charge again or Storage charge them. Whether I bashed in freezing temps or in 90F+ temps. Fire risk and cell puffing is minimized. We all have our own lipo habits.
Just my thoughts.

Most of the C ratings on LiPo packs are marketing hype. There is no good standard for testing.

You can charge your lipos as fast as you feel comfortable, but I would recommend that you don't leave them unattended and charge them in a LiPo bag or in the middle of your garage floor. I would hate to read a "i burned my house down and killed my family charging toy car batteries" thread.

 

[nomis38]

What brand and C rating of lipo do you usually run?

Various C ratings. Glacier/Gens/Goldbat/hrb/ovonic/Tattu/Zee/Spectrum and a few off brands for Airsoft.


More to the topic, as I love lipo discussion.

Anyone can check the health of their batteries with an IR check. 90% of aftermarket chargers have this function, no need to wonder. When cells start going bad they will have upwards of 50 mili ohms per cell. To me anything under 20 is a good cell, under 10 is an exceptional cell. Also pay attention to how many mah's are put back into a cell when charging.

I've had lipos go up on me and it just gave me a better understanding of how to handle them properly. If you haven't pushed something to its limit you will never truly know its limit.

Pushing the envelope is what R&D is all about lol.

 

[RCBro80]

Various C ratings. Glacier/Gens/Goldbat/hrb/ovonic/Tattu/Zee/Spectrum and a few off brands for Airsoft.


More to the topic, as I love lipo discussion.

Anyone can check the health of their batteries with an IR check. 90% of aftermarket chargers have this function, no need to wonder. When cells start going bad they will have upwards of 50 mili ohms per cell. To me anything under 20 is a good cell, under 10 is an exceptional cell. Also pay attention to how many mah's are put back into a cell when charging.

I've had lipos go up on me and it just gave me a better understanding of how to handle them properly. If you haven't pushed something to its limit you will never truly know its limit.

Pushing the envelope is what R&D is all about lol.

I often check my IR values, and I know they fluctuate with charge level, but they are always below 10 m ohms.

That said... I have 2 batteries that clearly have damaged cells - when they get low (like 3.5V), they drop FAST (need to run voltage alarms because waiting for LVC puts them at risk of dipping below 3V). And when they are storage charged, that cell always sags more than the others at rest.

Is this a common experience?

 

[nomis38]

I often check my IR values, and I know they fluctuate with charge level, but they are always below 10 m ohms.

That said... I have 2 batteries that clearly have damaged cells - when they get low (like 3.5V), they drop FAST (need to run voltage alarms because waiting for LVC puts them at risk of dipping below 3V). And when they are storage charged, that cell always sags more than the others at rest.

Is this a common experience?

I would agree that those cells are on their way out. And yup i have had a few cells like that.

 

[SrC]

I often check my IR values, and I know they fluctuate with charge level, but they are always below 10 m ohms.

That said... I have 2 batteries that clearly have damaged cells - when they get low (like 3.5V), they drop FAST (need to run voltage alarms because waiting for LVC puts them at risk of dipping below 3V). And when they are storage charged, that cell always sags more than the others at rest.

Is this a common experience?

^^^Yeah this is common. IR's are great for reference. I always check IR's and all parameters of NEW lipo out the box un charged. I make reference of the storage volts and IR's. Write on the pack what was new out the box. But, I also found many Lipos out the box with very bad IR's and extremely unbalanced with a cell or 2 out of tolerance. Those lipos I warranty immediately. Maybe 1 out of 8 lipos are bad from my exper. Even a few expensive ones. I even had one Gens-Ace Crawler lipo out of spec. Gens-Ace USA was excellent about it. Had a new one air shipped right away. A 5 minute phone call is all it took. Replacement was spot on.
BTW, IR's are most accurate and important in a Fully charged state. That's the best reference to go by.
New high quality lipo cells are usually below 5 milliohms (Ir's). I notice when they get old IR's of 16-20, mean they are getting tired. They are still usable, but I do start to see a small performance hit. If my lipos sit for more than a month and more unused, I top off the storage volts. 3.8-3.85v. As lipos get older, they lose volts faster sitting idle unused. I have 28 lipo packs. All kinds, brands.
I find all lipos can be a mixed bag. That's why I don't really recommend a particular brand personally. There are many flavors of the month that are good.
Lipo's are Mfr. by a minimal few companies. From the raw materials to assembly. Better $$ lipo packs just have better cell matching standards and numerous "Lots of cells" to do that matching. Better Lipo packs have identically precisely matched cells. Better consistent amp delivery. What separates the men from the boys. Just my thoughts.
Edit: Lipos when new perform optimally after a minimum of 3 charge/discharge cycles. And it is at this point where the Ir's and how well the cells are balanced to each other will tell you if you got a "good one".
If I don't bash my packs when new. I use my dedicated dischargers to cycle them 3 times. I allow 1 hour rest between each charge and each discharge.

 

[RCBro80]

^^^Yeah this is common. IR's are great for reference. I always check IR's and all parameters of NEW lipo out the box un charged. I make reference of the storage volts and IR's. Write on the pack what was new out the box. But, I also found many Lipos out the box with very bad IR's and extremely unbalanced with a cell or 2 out of tolerance. Those lipos I warranty immediately. Maybe 1 out of 8 lipos are bad from my exper. Even a few expensive ones. I even had one Gens-Ace Crawler lipo out of spec. Gens-Ace USA was excellent about it. Had a new one air shipped right away. A 5 minute phone call is all it took. Replacement was spot on.
BTW, IR's are most accurate and important in a Fully charged state. That's the best reference to go by.
New high quality lipo cells are usually below 5 milliohms (Ir's). I notice when they get old IR's of 16-20, mean they are getting tired. They are still usable, but I do start to see a small performance hit. If my lipos sit for more than a month and more unused, I top off the storage volts. 3.8-3.85v. As lipos get older, they lose volts faster sitting idle unused. I have 28 lipo packs. All kinds, brands.
I find all lipos can be a mixed bag. That's why I don't really recommend a particular brand personally. There are many flavors of the month that are good.
Lipo's are Mfr. by a minimal few companies. From the raw materials to assembly. Better $$ lipo packs just have better cell matching standards and numerous "Lots of cells" to do that matching. Better Lipo packs have identically precisely matched cells. Better consistent amp delivery. What separates the men from the boys. Just my thoughts.
Edit: Lipos when new perform optimally after a minimum of 3 charge/discharge cycles. And it is at this point where the Ir's and how well the cells are balanced to each other will tell you if you got a "good one".
If I don't bash my packs when new. I use my dedicated dischargers to cycle them 3 times. I allow 1 hour rest between each charge and each discharge.

Only if 28 packs?

 

[SrC]

After you get up there with many lipos, you see that they are all a mixed bag. Lipos are costly. I see many want the best for the $$ when starting out. I thought that way also. But in the end, it can be hit or miss brand wise. At least for me. Some hot brands that did well for a while peter out because of production changes etc. Resting on the name they made prior and then cutting costs with poor Cheaper cell matching. The lipo industry is weird in this way.
So yeah, they are mixed bag for me at least. I find Gens-Ace a consistent brand. Well known for their Tattu line of lipos for the Drone crowed. The Drone RC crowd dominates and drives the lipo industry first and formost. Then the RC (air) Plane crowed second. RC Surface is a smaller niche segment of the lipo industry by comparison.

 

[jkflow]

Just careful with the IR and comparing 'mine is bigger than yours'

All my 6S 5000mAh packs (and higher are in the 2mOhm range). At 10mOhm they would be trash compared to what they are doing today.
Key is though that the pack 'goodness' if the cells are equal with respect to each other (probably 50% at these low values vs 10-20% at higher values).

My smaller packs are above 10mOhm but these are 2S, low C and sub 1000mAh (300, 500 etc)

Never seen anything above 20mOhm in my use of Lipo's.

 

[RCBro80]

After you get up there with many lipos, you see that they are all a mixed bag. Lipos are costly. I see many want the best for the $$ when starting out. I thought that way also. But in the end, it can be hit or miss brand wise. At least for me. Some hot brands that did well for a while peter out because of production changes etc. Resting on the name they made prior and then cutting costs with poor Cheaper cell matching. The lipo industry is weird in this way.
So yeah, they are mixed bag for me at least. I find Gens-Ace a consistent brand. Well known for their Tattu line of lipos for the Drone crowed. The Drone RC crowd dominates and drives the lipo industry first and formost. Then the RC Plane crowed second. RC Surface is a smaller niche segment of the lipo industry by comparison.

One of my "bad" ones is a gensacearespammers, but admittedly I didn't know enough about them when I got it (relying on LVC instead of using voltage alarms).

Is there a difference between batteries for the surface and air markets?

Just careful with the IR and comparing 'mine is bigger than yours'

All my 6S 5000mAh packs (and higher are in the 2mOhm range). At 10mOhm they would be trash compared to what they are doing today.
Key is though that the pack 'goodness' if the cells are equal with respect to each other (probably 50% at these low values vs 10-20% at higher values).

My smaller packs are above 10mOhm but these are 2S, low C and sub 1000mAh (300, 500 etc)

Good point, size does matter

 

[SrC]

Size ( dimensions), capacities and C ratings are somewhat different. But do overlap to RC surface to some extent.
The average Drone guy is not running 8-9k Mah packs. They need smaller packs with consistent C ratings. Drones are a different animal.
They don't consume higher amps than RC Surface. If you notice hard core drone guys want light packs and fly for 5 min max before they need to land. Lipo requirements are different. C ratings are more important but in lower Mah capacities. Different in this way.
Drone guys are very much in tune with lipo performance. Its easily distinguished for them. They can easily tell from fight to flight if the pack was good or not compared to the next pack. I have drone friends. With surface, it's usually the hardcore speed run guys that see lipo performance affect their runs. Just bashing around its hard to tell. Run times is what we go by when just bashing.

 

[nomis38]

Just careful with the IR and comparing 'mine is bigger than yours'

All my 6S 5000mAh packs (and higher are in the 2mOhm range). At 10mOhm they would be trash compared to what they are doing today.
Key is though that the pack 'goodness' if the cells are equal with respect to each other (probably 50% at these low values vs 10-20% at higher values).

My smaller packs are above 10mOhm but these are 2S, low C and sub 1000mAh (300, 500 etc)

Never seen anything above 20mOhm in my use of Lipo's.

Then test some severely puffed, or bad lipos lol. Ones that show bad signs and have bad performance. Cause it shows it every time.

For some reason in my home state and here in TN, so I guess most flight clubs lol, people in my flight clubs I attend have a lot of puffed packs. Ive tested a bunch of different peoples packs. I've seen a lot of 40 to 60mohm on badly puffed lipos. Makes me laugh every time, cause they run them anyway. But yeah IR and how many miliamps go back in the pack always tells me the state of the battery. Other than obvious looks lol.

 

[jkflow]

Ok, I never have puffed packs because I treat them too well
I believe the high values but those packs are garbage on performance. Still useable for less demanding applications.

 

[ih8nixon]

5 inch (prop size) quads eat lipos. The average acrobatic flight is about 3 minutes. In terms of amps my 2750kv 4s setups will spike at 130A on punchouts and settle down to 110A on a 1500mah battery. The high amp draws cause a lot of voltage sag towards the end of the flight which is part of the reason a lot of pilots have gone to 6s. Some pilots can go absolutely nuts and can drain a pack in about 2 minutes on a high speed race course.

Personally think the hardest abusers of the larger cells are the guys flying 90mm+ Electric Ducted Fans (EDF). Basically electric jets. The ducting, small fan blades, and high RPMs make them horribly inefficient. I've seen them referred to as "flying welders" due to their high amp draws.

IR is related to cell size. So a pack from the same series and manufacturer will have lower IR as the mah increase.

As to charging manufacturers will usually specify a maximum charging rate. Anymore almost every battery I see recommends a maximum charge rate of 3-5C. A lot of drone/plane pilots charge at 2-5C and say that there is no cell degradation. With that in mind I've heard that some of the cheaper chargers will not properly charge through the constant voltage part of the charge if the amperage during the constant current is above 1c. So the charger will say it's done, but the battery is only partially charged. Personally I pretty much charge everything below 2C as I group everything up in parallel and my charger wattage is the limiting factor.

After you get up there with many lipos, you see that they are all a mixed bag. Lipos are costly. I see many want the best for the $$ when starting out. I thought that way also. But in the end, it can be hit or miss brand wise. At least for me. Some hot brands that did well for a while peter out because of production changes etc. Resting on the name they made prior and then cutting costs with poor Cheaper cell matching. The lipo industry is weird in this way.

Definitely seen that happen with some brands.

On a side note there was one old thread I remember that some guy tried to destroy a graphene pack by charging it at 15c with a fan to cool it and said that there was no noticeable cell degradation after 100 or so cycles.

 

[SrC]

^^^ I believe that. Pro racers do that to warm up the cells. They like to charge at super high/ fast charge rates. Amp delivery increases exponentially. They don't care if they get 3 or 4 months out of a lipo. At the track they have sand barrels all over for compromised lipos for that reason. But the lipo industry sets the standards. Anyone can deviate from them. Govern yourself accordingly in your home.

BTW, overvolting a lipo will make them explode, not so much the charge "C" rate
Fully charged lipos shouldn't sit around for long unused in your house. They are very volitile in that state. (4.2v) compared to storage volts of 3.8v a benign state of charge.

 

[crisantos102]

Does anyone know what the charge rate of a gens 6000mah 6s Lipo is. I’ve been charging at 1c rate but takes forever.

Spoke to a hobby tech with the same question im new to all this so he told me the safest would be 5amp

Spoke to a hobby tech with the same question im new to all this so he told me the safest would be 5amp

I meant 5c* lol

 

[jkflow]

@crisantos102 if you can point me to the manufacturers recommendation showing 5C I would do it. I can't find anything and therefore default is 1C. Not willing to risk my investment to cut down charge time to 15 min from 45min. At 5C the balancing will take up most of the charge time and that is always limited to ~1-2A no matter what you set the charge rate at.

 

[SrC]

Spoke to a hobby tech with the same question im new to all this so he told me the safest would be 5amp

I meant 5c* lol

The person recommending below a 1C as safest, makes no sense. And safe in what way????
I could also say charging at .001C is even safer. Will take you 3 days to charge.
1C IS the industry norm for Lithium Polymer Chemistry. Just a fact.
I spoke with many Hobby techs. I can get a different answer every time. I can call my self a Hobby tech. But am I? Even Google info has much misinformation.
The best information comes from reading the Mfr. White Sheets published in/for/by the Lipo industry.

EDIT:
I notice many apply charging knowledge of Nimpacks and Nicads of years gone by. Referring to Lipo Balance cycles as Trickle charging etc. Using wrong terms and logic. Be careful.
99% of Lipos are labeled 1C for a reason. Because it means 1C.

5000Mah is charged at 5amps, 5500 at 5.5 amps,6000 at 6.0 amps. Those are all 1C rates.
If your charger cant provide a 1c rate, then it just charges at less than 1C. Not tragic. Just takes longer. But 1C is a good and correct target. Having the correct charger for your lipo capacities is important.
SO much misinfo. out there

 

[WestOz RC]

If you want to charge fast then I think more batteries is the answer as well as a parallel charging board and a beefy charger and power supply. I have the isdt Q8 charger maxed out at 20 A charging almost 40,000 mah worth of 4s batteries here which works out to 0.5C. It takes less than 1 hr to go from storage at 3.85V to 4.2V. It would take about 3 hours to charge them each separately and that is if you are on top of changing them out as they are done:

View attachment 126000

Are you charging a 9700mah, 5000mah, 5700mah with 2 others on the same charge? I thought you’re only able to charge the same mah batteries together. I never charge my 8000mah with my 7200mah, or am I wrong?

 

[SrC]

Charging several lipos on a Parallel Balance Board is ok if all the lipos are the same volts each pack, Same cell count, and all balanced well before charging.( 2,3,4 or 6s) You add up all the capacities and set your charger to the appropriate amps based on total of all capacities. That's fine. Make sure and use only a QUALITY bal. Board. The Chinesium stuff will fire up/ burn. trust me, Been there.
I use a Joshua Bardwell Signature bal. board (Fused). ISDT makes a decent one also.

Maybe others do it differently?? Most of my 6s packs are between 5500 and 6500Mah. They are fairly close in capacity anyway. Using a 24 400wat PSU D6 Duo. 2 of them to get many packs done faster.

 

[WestOz RC]

Charging several lipos on a Parallel Balance Board is ok if all the lipos are the same volts each pack, Same cell count, and all balanced well before charging.( 2,3,4 or 6s) You add up all the capacities and set your charger to the appropriate amps based on total of all capacities. That's fine. Make sure and use only a QUALITY bal. Board. The Chinesium stuff will fire up/ burn. trust me, Been there.
I use a Joshua Bardwell Signature bal. board (Fused). ISDT makes a decent one also.

Maybe others do it differently?? Most of my 6s packs are between 5500 and 6500Mah. They are fairly close in capacity anyway. Using a 24 400wat PSU D6 Duo. 2 of them to get many packs done faster.

Thanks SrC. Just purchased one of the boards, as my Chinesium one did burn but thankfully not the house.