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Battery Questions?

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Grimjovv
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Battery Questions?
Roger Wolff
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At 20A, you're getting about 80W out of each battery. So with 60 of these, you have a maximum of 4.8kW of power available. Consider the VESC to do about 2kW max, you have some margin. On the other hand, my Hobbyking LIPO rated for 2kW, didn't like it much when I discharged it at around 1kW. So that factor-of-two safety margin is not a very big margin. With batteries, just like with mosfets they like to advertize the absolute maximum performance that you could extract for the component at absolutely perfect conditions. So the 20A they claim is going to leave a cell quite hot, even when well ventilated because that's the ideal conditions that they use to fill in the spec-sheet. In your actual setup you're going to have a bunch "middle cells" that are fully enclosed by other cells....

Grimjovv
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frank
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If you can, go for 12S 6P. Pneumatics on dirt consume mileage! There is no reason to lower the voltage. The best cell you can get is the Sony VTC 6 IMHO. I prefer cells being rated 15-20 A continuous discharge.

LG INR18650-HG2 3000mAh

Sony Konion US18650VTC6 3120mAh - 30A

Samsung INR18650-30Q 3000mAh - 15A

NKon is a good source if you ask me.

Frank

Pimousse
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VTC6 are good but quite exepensive and a 12S6P with those cells will cost a lot !!
I'd rather go with lipos for this kind of high-demanding setup.

Grimjovv
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Roger Wolff
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The Cell you suggested is 20A continuous, just like the ones that Frank is suggesting. So I would prefer a slightly larger pack over a more expensive pack with less cells.
Yes, NKON is a good shop. They stand behind their products. Won't they ship FEDEX, something that can ship LIPOs? Even if shipping comes to $100, on almost 1000 dollars that is not extreme....

Pimousse
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Don't focus on datasheets for amp ratings, sometimes manufacturers take some freedom with it.
Instead, you could use this website for having real measurements of celles capabilities :
http://lygte-info.dk/review/batteries2012/Common18650comparator.php

;)

frank
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Larger is better. If you go for 12S 6P and you have the 136KV motors, each set to 45A max, you are fine with 20A cells.

Truth is: You never drain the full amount of amps for a longer period of time. The Board is very strong and pushing the throttle hard is scary.

10 Seconds full throttle is mind blowing.

Frank

Grimjovv
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Grimjovv
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Roger Wolff
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That is exactly the policy that keeps batteries healthy.

Necromenz
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I have the Same Setup like you but i have the 118kv. I use 12s6p vtc 5 and the power of the Board ist very Great.

Grimjovv
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Necromenz
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Two singelpacks are more savty. One pack and one Amp for each Motor. One pack are Failed or so on, than you can you use the Second to come home. ? I have one pack, because the assambling of two packs and two Smart bms was to expensiv für me. And the Space in Box was a Limiting factor.

Grimjovv
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Pimousse
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This forum is related to VESC betas.
You'd better ask on electric.skateboard.builders for example, there are plenty of good threads about BMS with reviews and good sources. ;)

Grimjovv
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Roger Wolff
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Why did all of Grimjovv's posts become empty?

sl33py
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Kinda hard to follow with his posts deleted. Like listening to one side of a phone conversation... but creepier.