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LiPo Battery True C Rate !!

LiPo Battery True C Rate !!

Old 01-30-2012, 03:01 PM
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Originally Posted by COBRARACING
The biggest battery factory for lipos and lifep04's is based in china and uses material imported from japan it is also Government funded with an unlimited budget and some of the best chemical engineers in Asia.

The highest they have reached is 6000mah for a 7.4v 5200mah for a 14.8v and 5500 for a 3.7v and that is from november of last year and a cont racting of 60c

No more comments id let you figure out the rest about others who claim these rediculous ratings we see today .

Have you personally tested a 3000mAh cell at 180amps ? If the info comes from the factory you should do your own tests as I got fooled by the factories claims. I think they understand that very few people have the equipment to test at these high rates so they will claim what they feel will sell more packs.
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Old 01-30-2012, 03:03 PM
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I totally agree with you.
Still would it not be useful for the end user to also know the C rating of the assembled pack?
While the C rating of the cells speak lots of the battery's capabilities the rest of the battery should be up to par with proper connectors, wires etc.
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Old 01-30-2012, 03:15 PM
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The meter we use can give the IR of the pack or the cells in the pack. We will rate the C rate on our own equipment pictured in this thread. C rate will be based on the cells used in the pack. Once we know the IR range of a given cell we can make sure every pack we sell will be withing the IR range. This is way better than just selling packs based on a factories rating and shipping them out as we get them.

The problem with doing C rate for the entire pack is the connector and wires can't handle enough amps without getting to hot.

I personally believe this can be a game changer as the customer will know exactly what he's paying for as each pack will come with the IR of each cell marked inside the packaging.

I'm also considering checking the match of the cells for mAh as I have seen this can also be a problem. Everyone claims there packs are matched but once again are they really matched ?
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Old 01-30-2012, 05:15 PM
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Originally Posted by Danny/SMC
Thought some of you might like to see my C rate tester. I'm able to pull over 200 amps with this setup. All tests are done on one single cell.
Nice. Had any good fires with that thing?

Originally Posted by Danny/SMC
I'm also considering checking the match of the cells for mAh as I have seen this can also be a problem. Everyone claims there packs are matched but once again are they really matched ?
I'm surprised it took this long for someone to look into it.
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Old 01-30-2012, 05:22 PM
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Originally Posted by martymiller
Besides the CE gfx, what meter can measure the IR of a cell. Just curious.

Thanks
http://www.progressiverc.com/esr-meter.html


EDIT: Also in example, the Thunder Power TP820CD charger does, as many other do. Not that new fangled Orion though..
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Old 01-30-2012, 07:32 PM
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No fires to report of yet. When you try a cell at to high of load it just cuts off right away.

I do believe our packs are well matched as I have tested some but with the new rating system I want to push it to another step and check every pack and most likely include a graph showing each cell within the pack.

I do have some graphs on our FB page.
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Old 01-30-2012, 08:39 PM
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Danny,

In my testing internal resistance changes depending on the battery temperature. Will you be providing specifications that include the temperature of the battery when tested ?

Thanks,
Jake D.
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Old 01-30-2012, 08:49 PM
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Yes the complete method that we use will be listed. Unlike the current C rate system that no one lists how they get there results. My goal is to have an accurate system to rate our packs which can be verified by anyone who uses the same meter we do and follows the method we list.
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Old 01-30-2012, 09:35 PM
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Originally Posted by COBRARACING
The biggest battery factory for lipos and lifep04's is based in china and uses material imported from japan it is also Government funded with an unlimited budget and some of the best chemical engineers in Asia.

The highest they have reached is 6000mah for a 7.4v 5200mah for a 14.8v and 5500 for a 3.7v and that is from november of last year and a cont racting of 60c.
What are you talking about? What you're saying doesn't make sense.
Nominal voltage for a lipo cell is 3.7V.
3.7V is one cell
7.4V is two cells in series
14.8V is four cells in series
They all can use the same cell, which would have the same capacity. If the highest single cell capacity available is 6000mAH, then putting them in a series would have the same pack capacity (1S, 2S, 4S). There's no distinction between 3.7V, 7.4V, 14.8V.

Last edited by Potato; 01-30-2012 at 11:32 PM. Reason: cell count math fail
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Old 01-30-2012, 10:02 PM
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14.8V is 4 cells in series not 3.

To sell any pack above 5000mAh they need to be built as 2P or higher. Shipping regulations require that no cells be higher than 5000mAh to be considered as a small LiPo and not be classified as class 9 Hazmat shipping.

In the case of a 6000/60C it needs to be 2S2P but you are right where you can use the 3000mAh cells and make a 4S2P to get 14.8V or 3S2P to get 11.1V.
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Old 01-30-2012, 11:25 PM
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Originally Posted by RC MARKET
unknow why they are mark up label C rate ?

in this moment battery factory in China , some material is from Japan ,
can made 60C , around 6500-6800 mah only !

But market had 65C 70C 75C & 90C Now !!
The server from your online store could use some more C...I'll bet loading with 90C will get you more customers instead of the 20C you've got now.....
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Old 01-30-2012, 11:34 PM
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Originally Posted by Danny/SMC
14.8V is 4 cells in series not 3.

To sell any pack above 5000mAh they need to be built as 2P or higher. Shipping regulations require that no cells be higher than 5000mAh to be considered as a small LiPo and not be classified as class 9 Hazmat shipping.

In the case of a 6000/60C it needs to be 2S2P but you are right where you can use the 3000mAh cells and make a 4S2P to get 14.8V or 3S2P to get 11.1V.
You're right, I fixed my post. I just didn't understand that post. There are two parts, one is an issue of cell chemistry (C-rate), the other is a matter of pack configuration.
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Old 01-31-2012, 12:15 AM
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Originally Posted by Matthijs
The server from your online store could use some more C...I'll bet loading with 90C will get you more customers instead of the 20C you've got now.....
lol !

Not to hijack the thread... but yeah, I believe that RC Market has the slowest web "server" in the world. I'm not even joking. They have a lot of stuff but glacial performance !

it probably runs on a 1200 baud modem !
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Old 01-31-2012, 01:05 AM
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Originally Posted by Magnet Top
lol !

Not to hijack the thread... but yeah, I believe that RC Market has the slowest web "server" in the world. I'm not even joking. They have a lot of stuff but glacial performance !

it probably runs on a 1200 baud modem !
Wo...rst we...b...si...te e...ver
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Old 01-31-2012, 01:34 AM
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Originally Posted by Matthijs
The server from your online store could use some more C...I'll bet loading with 90C will get you more customers instead of the 20C you've got now.....
We not have 90C battery to sale !
but saw why too many co. mark up C Rate to sale !
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