MEB Dirty Dervish | 12S Stealth Battery | Twin ESC | Hub Motor

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When I get my hubs I’m going to tap some treads right into the truck

@Bender That axle is tough!

Ahh I thought it was the thick part of the truck not the axle I guess a flat spot and lock-tite is the way to go

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Ha! I read this in Fry’s voice in my head.

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hey @oriol360 what brand of cells are you using in your production run?

They are a Chinese brand called Cham. They’ve been great for the 500 miles of stress testing I’ve been doing.

How many recharge cycles are they supposed to get? You’ve done about 40 cycles?

They’re rated for 1000+ cycles! I have around 34-36 cycles on this one. I’ve been testing for a month charging/discharging every day and some days twice a day! Going up and down parking garages as I do not have any hills in Miami :confused: and going full throttle with hubs. I have yet to go full throttle with a satellite motors as I have 250kv geared pretty low and it’s over 40mph which I’m too scared to hit.

So these are jacobs hubs ?

I’m sure most liion 18650s can do 1000+ but their capacity drops below 50%. Hopefully you can get to around 300 cycles and then test the battery capacity.

Pretty awesome using cells that are uncommon on esk8. Where did you buy them?

what makes you say that? Liion lasts for as long as you want if you treat the battery well. look at teslas 8year battery warranty …

problem might be that people always use very small batteries that live on their limit. if you have flat charge/discharge cycles, leave & store the battery around its nominal voltage whenever possible and make sure it doesnt heat up to much, it will last forever.

my first evolve battery 1 year ago probably saw 200 cycles and recently, the guy who bought the battery, sent me a gps log that showed that the battery basically had its first day capacity.

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It’s basically about how deeply u discharge the battery

Most 18650 Li-ion cells have about 70% capacity after 250 cycles. They may work to 1000 cycles, as you’ve said capacity would be severely reduced, probably more so than 50%. However, the test environment Samsung tests with discharges to 2.5v which is a lot lower than what most people normally discharge to, so you can probably make 18650’s last a very long time given proper care and treatment.

I wonder if there’s been any tests done to cells like these that discharge to a safer voltage like 3.0-3.2

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@appelton Might be clones. I got them from FreeRCHobby when I was looking for Hubs to test out. I have hubs from them, hobbytech and lofty.

@ArmandR Hmmm I’ll go there soon!

As for battery, BMS low voltage cut off occurs when a cell hits 2.9v However, on the optional LCD that comes with battery, 0% is displayed when cells are around 3.2v And moreover, I recommend if your ESC’s have a Low voltage cut-off to set it at 3.5v… That is the setting I ship all my ESC’s with and will keep both li-ion and lipos healthy for a long time. My MultiStar Lipos have over 200 Cycles and they still give me the same range as first day!

noone in their right mind would charge a battery to 4.2 and discharge to 2.5V. these cycles and capacity drops are NOT what you can expect in a hobby environment where you probably try to keep your batteries happy.

look at teslas 8year warranty is all Ill say here - they have a massive battery and use it within fairly flat charge % discharge states with low current per cell that keeps it nice and cool. and thats basically all there is to the “secret of eternal liion battery life”.

I know no one goes as far as 2.5v, I’m just saying that’s what these batteries are subjected to for quality control.

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what stirred me up is this:

and thats plain wrong in my eyes! I would argue that if your batterie isnt at least at 90%+ after 200 cycles, you probably didnt treat it very well.

always keep tesla in mind: […] the 85 kWh Model S, our most popular model by far, now has an 8 year, infinite mile warranty on both the battery pack and drive unit.

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That’s why I added the line right after that which explains that what I’ve said are factory test conditions for these cells. Datasheets are important and give an idea of bare minimum performance of quality cells!

I think people are getting very efficient in reading things nowadays - so much to read, so little time - so they go for the essentials and what “sticked” of your post was “200 cycles, 70%, 1000 cycles 50%”. Im pretty convinced that the yaddayadda about factory test cycles is something that wont reach many people when the skip through this thread, or, worst case, its stored as “200 cycles 70%, confirmed by manufacturer samsung”.

I just wanted to make sure that the “soak things up in 10seconds bottom line is not 200cycles 70%”, but that if you treat your battery well, it will last you a very long time! :sunglasses:

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Very interesting…did you already tried all three ? Out of all of them which one you think have the most torque and which one you like the most ?