HK Battery Sale, and a 12s 5000 mAh pack for <$70

Heads up, HK is doing a sale on batteries, lots of options to build 12s, 4-5Ah packs for around $100. A few possibilities below

Link https://hobbyking.com/en_us/zippy-4000mah-2s1p-30c-hardcase-pack-1.html https://hobbyking.com/en_us/zippy-flightmax-4200mah-2s1p-30c-lifepo4-pack.html https://hobbyking.com/en_us/zippy-flightmax-5000mah-3s1p-30c.html https://hobbyking.com/en_us/zippy-flightmax-5000mah-3s1p-20c.html https://hobbyking.com/en_us/zippy-compact-5000mah-2s-25c-lipo-pack.html https://hobbyking.com/en_us/turnigy-nano-tech-4500mah-3s-45-90c-lipo-pack.html
Capacity (Ah) 4 4.2 5 5 5 4.5
Continuous © 30 30 30 20 25 45
Burst © 40 40 40 30 35 90
Charge © 3 2 2 2 5 10
Series © 2 2 3 3 2 3
Price © 15.05 16.72 23.43 16.72 15.96 29.99
Weight (g) 256 267 407 404 237 391
12s Continuous (A) 120 126 150 100 125 202.5
12s Price 90.3 100.32 93.72 66.88 95.76 119.96
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If you are in the UK you can do 12s 8AH for 100€. Shame they don’t ship to Portugal.

please keep in mind that the max Amps you can get out of the pack is not Imax=C*capacity

I just speak for myself, but I wouldn´t use a 30C pack with a capacity around 3-5Ah. As min not in 1P conifguration.

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is NOT Imax=C*capaciy? Isn’t that what the C means?

this formular is generally used. but the C-rating is no standard, so every company can define the C as they want. You can expact to get better packs with less voltage sag with higher C-rating, but it´s not directly related to the max Amps continues.

You can ask @PatRocks , he´s checking different packs with a wayne giles meter. I don´t know the exact values of the results but in general it is more or better lets say less than the half of the amps you calculate with your formular.

the multistar packs for example rated as 12C but real world measurements more like 3-4C after your formular.

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there already existing some threads about it. like this one: https://www.electric-skateboard.builders/t/multistar-6s-8000ah-10c-in-2p/44337/12?u=andy87

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So you are saying to get about 4400W out of a HK battery I should go for a 40C 8AH 12s minimum?

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You just got me lot to think about. Thanks for the heads up.~

To be fair HK even has a blog post about this: https://hobbyking.com/en_us/news/lipo-c-ratings

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As far as I can say, the hobbyking graphens with 65C are very good and have a long charge cycle live too. I drive E-MTB and use 60C const 120C peak packs and I´m happy with it. If you have a street board I think 40-45C and 5-8Ah packs are a good value if you go in 1P config. For sure you can take lower C-rated packs and put them in 2-5P what will add up in your max output amperage.

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I’m starting a emtb build and I was going for the Multistars I linked above. Not anymore I guess. I’m now considering in a 12s 2p configuration: https://hobbyking.com/en_us/turnigy-5000mah-6s-25c-battery.html

This should give me 5500W continuous and about 10000W instantaneous considering your half C rule.

The graphene ones a very expensive, basically double.

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I don’t even understand what’s so good of a deal here. A 12S2P with 30Q cells has 6Ah at 12S and costs ~86€ in cells.

Sure - 5500W continuous :scream: Can you please calculate how long the battery would last if this was actually true?

Edit: 12 * 3.7V * 5Ah / 5500W≈2min30s

have a look on the heavy duty ones from hobby king. they are 60C and you can get them for a good price.https://hobbyking.com/de_de/turnigy-battery-heavy-duty-5000mah-6s-60c-lipo-pack-xt-90.html I use them and I´m happy so far, but don´t have much charge cycles yet on them. So only time will tell how they hold up. that´s the thing with lipos. if pack double expensive but hold up 3 times as long in charge cycles, they in the long term more cheap.

out of a 12S1p pack of the above linked packs I get around 8-12km (depending on belt or chain and how hard i push them)

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I would need a 12s3p with 30Q (only 9AH), 1233.58 = 128€ plus work and the rest of the materials, so let’s say 150€. This is 172€ and it’s ready to go and has a higher C rating.

You do realize that rc airplanes and quads don’t usually fly for more than 10mins per battery. Lol My racing stuff barely lasts 2 minutes.

On an esk8, this is kinda stupid tho.

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I guess this calculations are more about what’s avaliable than what will be used for most of the ride.

sure - my comment was solely about him saying he will have 5500W continuous at his disposal with me assuming it was esk8 related. 5500W continuous for 2min: does that even count as continuous :smiley:

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RCs draw a lot more current than esk8. This is from an easy 3d flight with one of my RC helicopters

image

Now imagine what kind of amp draw this guy might have

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Holy fuck could you imagine doing that in a actual helicopter lmao

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Can’t be done in a full size helicopter due to various reasons (even remote controlled). The main reason is that there is no material with a young’s modulus high enough to withstand the forces on the rotor and not bend to the point of hitting the boom.