Maximum charging amps for these ( RC Lipo ) cells

ebike11

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Hi guys..how are you?
Would you know how to calculate the max. charging amps that I can use to fully charge the pack as quick as possible without risk of cell damage etc.
When im at home I can slow charge but when Im on a long ride and have my charger, id like to be able to charge as fast as possible.
These are the cells

https://hobbyking.com/en_us/turnigy-high-capacity-battery-20000mah-6s-12c-drone-lipo-pack-xt90.html?queryID=27011e202542ed7e35469d8e5812ae7e&objectID=78412&indexName=hbk_live_magento_en_us_products

Constant discharge of 12C and Peak discharge for 10 seconds at 24C

Thanks!!
 
So it going to be 18s 20ah 74volt top charge. What were you thinking like a 1200 watt bulk charger ? Or 17amp charge as that might be a charger you can carry in your car or in your backpack maybe. And still plug in the most sockets that you find in the park in around. Will your charger need a trailer ?
I I was looking for a 84 volt charger and I keep looking at the kingpan 900 watt.. I had bought a 84 volt 5a 10 amp charger my blue app for first time I used it $99 free shipping I got my money back..
You could get a nuclear 24 fet controller and as what I read but don't understand you can take a power supply and charge to 2-phase wires to charge the battery ??? I don't know how that would work
 
999zip999 said:
So it going to be 18s 20ah 74volt top charge. What were you thinking like a 1200 watt bulk charger ? Or 17amp charge as that might be a charger you can carry in your car or in your backpack maybe. And still plug in the most sockets that you find in the park in around. Will your charger need a trailer ?
I I was looking for a 84 volt charger and I keep looking at the kingpan 900 watt.. I had bought a 84 volt 5a 10 amp charger my blue app for first time I used it $99 free shipping I got my money back..
You could get a nuclear 24 fet controller and as what I read but don't understand you can take a power supply and charge to 2-phase wires to charge the battery ??? I don't know how that would work

Hi there
Yes as the voltage of the pack increases then the charger size will also increase. Think at least 24s @ 20Ah. But no matter the amoint of cells I use, i still need to determine how many charging amps these cells can handle safely at high amps?
 
Oh I thought you were going to use as 18s my bad tell us more about the battery you're going to build.
what I meant is you'd have a hard time finding a charger that's going to max out those lipo packs.
 
ebike11 said:
i still need to determine how many charging amps these cells can handle safely at high amps?
Depends on how you define "safely" ... like before the chances of destroying the pack ?

https://www.amazon.com/Turnigy-High-Capacity-20000mAh-Multi-Rotor/product-reviews/B07DRDG7V8?reviewerType=all_reviews
https://www.amazon.com/Turnigy-High-Capacity-20000mAh-Multi-Rotor/product-reviews/B07DRDG7V8?reviewerType=all_reviews ... at $270 what's the minimum charge time you can live with Understanding that it decreases the cycle life of this Lipo ?

You should post your question on an RCGroups Quadcopter forum.
 
eMark said:
ebike11 said:
i still need to determine how many charging amps these cells can handle safely at high amps?
Depends on how you define "safely" ... like before the chances of destroying the pack ?

https://www.amazon.com/Turnigy-High-Capacity-20000mAh-Multi-Rotor/product-reviews/B07DRDG7V8?reviewerType=all_reviews
https://www.amazon.com/Turnigy-High-Capacity-20000mAh-Multi-Rotor/product-reviews/B07DRDG7V8?reviewerType=all_reviews ... at $270 what's the minimum charge time you can live with Understanding that it decreases the cycle life of this Lipo ?

You should post your question on an RCGroups Quadcopter forum.

Hmmm i guess i mean relatively fast...over 10A if possible.
Those links show a single bad review of these cells...there are more positive than negative that Ive read.
Plus who knows where and what condition he got the packs from. Direct from Hobbyking might be a better option
 
There used to be a 5-10% (15%?) dud rate for those hobbyking lipo's, not sure now since its been at least 5-8 years since the test was done. Test each of the six ziplock pouch of lipo in each of the 6S 20Ah bricks, to see if they are matched well.
 
markz said:
There used to be a 5-10% (15%?) dud rate for those hobbyking lipo's, not sure now since its been at least 5-8 years since the test was done. Test each of the six ziplock pouch of lipo in each of the 6S 20Ah bricks, to see if they are matched well.

Yes so far they are ok. I have a cell checker for that.
What do you think about charging them?
 
Testing is a little more involved. Not sure how icecube57 was testing them.
Looks like he's still got his website. http://lipoconnectionsolutions.com/
Looks like he actually logged in 5 months ago - https://endless-sphere.com/forums/memberlist.php?mode=viewprofile&u=6285

He's still got his Youtube channel maybe he shows how he tested the lipo batteries.
https://www.youtube.com/channel/UCjqEv4Zd9h_4RGtD8golnQA/videos

Check out this thread
Hobbyking Battery Testing
https://endless-sphere.com/forums/viewtopic.php?f=14&t=58210&hilit=hobbyking+test#p868273
 
100v 20ah of lipo can take 10a yes . You can charge them at 20 a. Now show me a 100v 20a charger for your ebike that you can carry without a trailer ?
meaning you can't find a charger that you're talking about and still carried on your bike the thing would look like a suitcase.
Plus what or where are you going to be able to plug it in on the go ? Yes where ?
 
Hobbyking states either 1C or 5C as an ideal charging rate for their lipos, depending on the model.

1C on a 30AH pack would translate to 30 amps. 5C would translate to 30A x 5C = 250 amps.
 
neptronix said:
Hobbyking states either 1C or 5C as an ideal charging rate for their lipos, depending on the model.

1C on a 30AH pack would translate to 30 amps. 5C would translate to 30A x 5C = 250 amps.

that is the ideal current.... for hobbyking..... to keep selling you new batteries.

you need to charge as slow as you can get away with in your use case. is a 5 hour charge fine for what you do with it? then take that as your benchmark. do you actually NEED fast charging you cn get a faster charger. but slow charging is always better. especially for uncompressed pouches.

fast charging uncompressed pouches like the hobbyking stuff is a perfect recepy to get some nice bulges in your pack. and some nice fiery pops if you really push it....
 
Damn. Half a kilowatt hour. 200$. Chinese cells.
 
DogDipstick said:
Damn. Half a kilowatt hour. 200$. Chinese cells.

there are cheaper ways to burn your house down... :roll:
 
ebike11 said:
Would you know how to calculate the max. charging amps that I can use to fully charge the pack as quick as possible without risk of cell damage etc.
Maximum charge is 1C. 20Ah @ 1C = 20A.
 
flippy said:
neptronix said:
Hobbyking states either 1C or 5C as an ideal charging rate for their lipos, depending on the model.

1C on a 30AH pack would translate to 30 amps. 5C would translate to 30A x 5C = 250 amps.

that is the ideal current.... for hobbyking..... to keep selling you new batteries.

I charged my 20C turnigy packs at 1C for a number of years and achieved around 500 cycles when hobbyking only promised 300.

A number of forum members have seen the same.

No conspiracy here.
 
neptronix said:
flippy said:
neptronix said:
Hobbyking states either 1C or 5C as an ideal charging rate for their lipos, depending on the model.

1C on a 30AH pack would translate to 30 amps. 5C would translate to 30A x 5C = 250 amps.
that is the ideal current.... for hobbyking..... to keep selling you new batteries.

I charged my 20C turnigy packs at 1C for a number of years and achieved around 500 cycles when hobbyking only promised 300.

A number of forum members have seen the same.

No conspiracy here.

flippy said:
fast charging uncompressed pouches like the hobbyking stuff is a perfect recepy to get some nice bulges in your pack. and some nice fiery pops if you really push it....

That's the least frequent reason for catastrophic failure of these batteries. But it is always a good idea to be as conservative as possible with charge and discharge rates on any battery.
 
Thx for the replies!
I wouldnt need FAST charging while at home...just on road trips where i cant wait 5 hours.
Of course charger size is also important
 
neptronix said:
I charged my 20C turnigy packs at 1C for a number of years and achieved around 500 cycles when hobbyking only promised 300.
A number of forum members have seen the same.
No conspiracy here.

with the spotty/less then stellar quality control of their batteries over the years i would be extremely conservative in bolting these batteries 10" from my nuts. especially if you start stacking them into high voltages....

ebike11 said:
Thx for the replies!
I wouldnt need FAST charging while at home...just on road trips where i cant wait 5 hours.
Of course charger size is also important

the most compact from a volume perspective would be the HRP mean wells series. you would need to put 2 in series considering the voltage.
 
I wrote the manual for assessing and doing second party quality control of RC Lipos but can't defend usage of them anymore because a majority of people haven't taken the memo.

I will say that number of cells in series is not inherently dangerous. Not minding the balance of the pack, not assessing for large discrepancies in amp hours and internal resistance with a proper RC charger, and not considering deformities in the cells is the most dangerous practice ever, but the second worst would be exceeding their C rating during charge or discharge. The third would be draining cells below their low rated voltage and then charging them.. which can be a consequence of the first problem.

Otherwise 18650's are just as dangerous when punctured or abused. But sometimes they have construction errors too; and 0 of those are spottable from the outside like they are with prismatic cels. This is likely the reason why extremely well engineered Tesla battery packs still randomly burst into flames from time to time.

I think Lipos are extremely unsafe to use without proper balance and frequent inspection. But construction errors plague pretty much every lithium battery cell and still result in catastrophic failure modes ranging from smokey to death metal show pyrotechnics.
 
considering they are making millions of 18650 cells a day and i have never seen a quality brand cell murder itself in a violent way that might pose a danger to other cells i am willing to say that 18650 is inherently safer then a metalized plastic bag filled with fire.
cheap chinese crap is a different story ofcourse. but that applies to any cell type.

the only tesla fire i ever seen up close was a model S that tried to mow down a tree at 130mph. (the tree won)

in the 8 years that i had access to the car manufacturers incident reports have never seen a offical report where an actual cell itself popped so hard that it took out the rest of a tesla pack. i have seen a couple in the A and B generation packs were a defect was in a specific series, but that was a pack issue, not a cell issue. but they silently recalled those after a couple cars went up.

ps: 18650 is safer simply because they hold less energy, is encased in a steel shell and any "exitement" is directed into 1 direction. with pouches the stored energy can be 10x or more so a simple needle against a pouch like that is a much larger issue then actually needing a hammer and a nail to puncture a 18650.

i think we can all agree that on a bike a taped up pouch pack in a bike bag is VASTLY more dangerous then a 18650 pack when pouches hold more energy and only 0.2mm of plastic separates the bags.....
 
flippy said:
ps: 18650 is safer simply because they hold less energy, is encased in a steel shell and any "exitement" is directed into 1 direction. with pouches the stored energy can be 10x or more so a simple needle against a pouch like that is a much larger issue then actually needing a hammer and a nail to puncture a 18650.

18650 packs fail just like RC Lipo packs fail. One cell develops a short and goes thermal, aggravates the others, they go off. An 18650 goes off like a Chinese firecracker show; tons of videos of it happening floating out there. We see the same thing happening in Tesla packs. It's what causes the car to stay ablaze for hours.

flippy said:
i think we can all agree that on a bike a taped up pouch pack in a bike bag is VASTLY more dangerous then a 18650 pack when pouches hold more energy and only 0.2mm of plastic separates the bags.....

We can't. I feel like you haven't watched many battery destruction and safety videos, otherwise you'd be siding with me. 18650s may be built to a higher standard generally and spontaneously explode less often as a result, but in the other ways a RC Lipo pack fails, they fail too, as the issue is not the size or shape of what you're putting these highly reactive chemicals into.

In the hands of an unskilled user, yes, RC Lipo is dangerous. With a skilled user who follows best practices, they're not far behind 18650 packs in terms of safety. Construction defects are your main risk factors with lithium batteries when the battery is cared for. The one upside of pouch cells is that they puff and will warn you before they go. They also occupy less space per watt hour.

If safety is concerning to you, a lifepo4 chemistry, whether it be a pouch cell or a cylindrical cell, is still a good choice.
 
neptronix said:
In the hands of an unskilled user, yes, RC Lipo is dangerous. With a skilled user who follows best practices, they're not far behind 18650 packs in terms of safety.

a dare you to tape a dozen pouches against your body and chew some asphalt at 35mph while i do that with 18650 cells. see who comes out on on top of that one. i dont think skill does much in that event....


the basic chemistry and its dangers are the same, that is totally not my point. and neiter is puncturing a 18650, wich is considerably harder then puncturing a pouch wich you can do with your fingernails.

my point is that a round steel case is inherently safer then a plastic bag, especially with the inherent "puffyness" behaviour pouches have.
and IF a 18650 does go off its only that one and its small as they harldy store more then 10Wh in a single cell. a pouch can store many times that and is not "restricted" in its exitement for direction so you are garuanteed to trigger other bags, wit 18650 that is a completly different story and it takes more time and is less violent by comparison and depending on the cause it is generally spread out over a larger area and more contained. have you ever compared a 18650 cell with a single pouch from a nissan leaf for example? now those pouches give a nice show.

nobody here is claiming that nothing happens, but if it does happen i rather have the lesser of 2 evils.... especially if 1 of those evils is on a hair trigger and is just waiting for a scratch.

would you rather transport gunpowder in a plastic bag or a steel container?

i rather make a pack with some samsung 25R's or HE4's then some pouches if i want serious currents.
 
Sure, 18650's are a bit more puncture resistant, but when pushed over the edge they react the same way as pouch cells.

I've dropped lipo packs on the floor a very short distance multiple times and after a 3 month cool off-period for those packs, continued to use them with no noticeable loss of capacity. So they are not as volatile as ou think.

Puffing is a good behavior for a cell with a slow internal short or other issue. 18650's don't give you that warning. They just pop faster than any venting mechanism could ever stop, because the force of the gases trying to exit the cell is extremely high. A pouch cell at least has 3x the expansion volume built into it.

Almost every battery fire i've seen with 18650's involved half or more of the cells exploding from thermal runaway. it's a problem that Tesla has thrown millions of dollars at and still hasn't figured out how to solve. The extreme temperatures a single cell is capable of producing alone is enough to set other cells into thermal runaway if they are close enough.. and with today's inadequate volumetric density of lithium cells, you will always find them packed together to conserve space.

To prevent contagious themal runaway on any lithium pack, you'd need some pretty serious measures, like liquid filling the pack, adding a heavy insulator, or spacing cells way far apart. having a series of very small cells do not help prevent contgious thermal runaway.
 
show me on this doll where the 18650 touched you. :roll:

thinking puffing is good is a simple fallacy. that is exactly the thing you dont want. that is why in cars and other industrial setups pouches all have compression bracing to keep that from happening, even lifepo blocks. you dont want gases to form and delaminate your delicate layers. that is why cells are round, to hold the layers in compression so any gas that is formed cant frock up the rest of the cell and cause it to pop. with pouches you are frocked as soon as that happens. round cells can simply absorb that so nothing will happen apart from prehaps a capacity loss. i have tried to frock up a couple dozen panasonic PFs and samsung 29E's and apart from actual physical dmage its impossble to get them to pop. even after shoving 30V into it at a dozen amps or so at a reversed polarity. something we both know you dont even have to try with a pouch to make them angry....

saying tesla has not solved the battery fire issue is just a flat out lie. they are litteraly the safest cars on the road today when it comes to EV's. please dont lie to try and "win" this argument. just because a burning tesla makes the news is not because it happens so often. en in my country the news is terribly clickbaty when they last reported on a tesla fire and the fire dept refused to touch the car. what they "forgot" to add to that is that the car hit a thin concrete pillar at well over 100mph and basically exploded into a million pieces. pretty sure a battery fire is secondary when you have to find the driver with a mop and bucket.

i still have a picture somewere of a tesla in germany that ended up sticking out the roof of a house. no fire....
 
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