u can get those rfid and nfc chip implants in any part of ur body, people usually have it in their hand, but u can choose other location 
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Could put one in your foot and have a reader in the deck
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Mmmm yeah that was definitely supposed to say skin tattoo… Guess there’s no going back now.
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probably doable to some degree, but i wouldn’t want a nfc implant that can only turn on my esk8 
tattoo is best for QR code if u dare enough, but i don’t know what u would use it for
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These 120a terminals:
Probably ridiculous. I’m ridiculous. I don’t like how long the male crimp ends are. That’s kind of a problem, but I prefer terminals over solder pads.
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I don’t think that connection would stand up to the vibration but they make other types that probably could.
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I’ll see if find anything about vibration, but any screw terminal that can meet the requirements is fine with me. Press fit PCB terminals seem to have the lowest resistance, they get cold welded to the copper when fit. I don’t think they work for surface mount pcb’s, though, but I think you’re working on a multilayer design, right?
edit: yes, not built for high shock environments.
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I have a pile of these terminals and they are solid, I will trusts them in fibration heavy environments. But indeed the male pins are very long. And they are expensive…
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Something I just thought of:
The main reason why people don’t trust discharge BMSes is because their over-current over-voltage protection can be overly sensitive at times, and usually they aren’t rated for enough current as our boards require (especially charge current)
I was thinking about how it might be useful to have a separate programmable device, whose sole function is to accurately monitor current, and cut the battery <-> ESC connection if it notices that the current is way above what the ESC max should be. For example, you set your ESC limits to ±200A, and this device only triggers if it notices current >300A, which probably indicates a short on the ESC side. (I’m not sure how often ESCs ever fail by short-circuiting, so if people could chime in to let me know, that would be greeeaaaaat)
And then I remembered “wait, we have an antispark switch between the ESC and battery anyway, maybe this functionality could just be integrated in the AS?”
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I’m wondering though if some would prefer the 300A of current, and the pack possibly surviving once the ESC blows up and stops the current flow, instead of the 300A being instantly cut off and them going flying? Even though that 300A would clearly indicate big, big problems are occurring.
Having said this, my design can still easily feature a “circuit breaker” type function.
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Most battery/power/BMS application use a biderectional mosfet switch of some kind. (to not have current going thru the body diode if current would change direction).
These are nice but bring twice the power dissipation since since current passes thru 2 FETs in series. They’re also not very space efficient compared to a one way switch.
I think it would be nice to have a real pre-charge circuit that actually pre-charges to around 90% of terminal voltage, in a good way, before the switch is fully open. This will prolong the liftime of the switch in general and also protect w/e is on the other side in a proper way. A big PTC/NTC is a easy way to implement it but might not always be suiteable.
Feel free to poke me in PMs if you want someone to bounce ideas of. Or we can do it here, w/e works.
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If press-fit they can work with SM boards but even soldered terminals can be used. You just need a second wave soldering step for the terminals. That adds cost though and, as you noted, these might not be a good fit for a high vibration environment.
Yes, my board will be at least 4 layers.
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Just rember small format is a must most people will want to jam as manny cells in as possible
22mm high 65mm long width ? is a good limit to keep in mined to sit near the battery. This needs to include any connectors or cable sticking out the side.
I do love how storm core connector sits inside its footprint when connected unlike trampa HD
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I agree, small is good and is always a design goal. But this is also what has led to less-than-reliable switches before. 
At a certain point we have to be willing to either replace it more often or accept a larger and more expensive product. I think our desires for low cost, small size, but still with good reliability have exceeded what’s actually possible with many products. We can’t have all three of those things at once and need to pick one, perhaps two of them.
So smaller is certainly possible but the cost goes up. Especially since this is not a high-volume China-manufactured product. But perhaps I am just cranky today. 
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Wow, thank you everyone for your thoughts!
You had some great ideas, ones I had never considered, that have considerably complicated things. In a good way though.
I’m thinking it all over and will be posting some questions here when I get a better grasp on the cost and development time for some of those requested features.
This could easily turn into a $150 switch. It would be an incredible piece of tech but if it’s not affordable then it’s pretty useless. But clever combining of some features, partial support for others, modular design for expansion to increase certain ratings, etc., can all be used to bring down the cost though.
I’d personally prefer if this just never happens. Ever. Even if I’m riding a fireball, I’d prefer it to have brakes as long as it’s physically able to.
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If the battery is being shorted I’m not sure if a still-working ESC will be able to brake anyway.
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What type of vehicle is this for? 200A continuous is a verrry high current rating.
What type of “burst” rating would you want?
For how long?
How often are the bursts?
How long before shutting down?
How fast would it need to start up?
Is half a second for the AS switch itself okay?
Perhaps a master/slave arrangement where the button and/or alternative startup method is connected to the Master and then a two or three conductor cable connects the Master to the Slave? Whatever the Master does the Slave does too.
If there is more than one slave there can be a cable from Slave 1 to Slave 2 and then from Slave 2 to Slave 3, etc.
Hmm…multiple AS under control of a single button would mean a shared ground between the AS’. I can use an isolated connection but that would add cost.
I guess a four terminal button (DPST) button could be used though. That would connect two completely independent sets of contacts. Each AS would run two wires to the button.
Using only bump/roll-to-start would allow for as many completely independent setups as needed as each would handle its own power up/down.
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Reliability = $$$.
That 200A continuous rating means a lot of $$$ and a big device too.
Is a true 200A continuous rating what you really need? Or do you just want a reliable device that can handle up to 200A bursts (esk8 acceleration)?
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Mutually exclusive (if not really expensive) but there can be a decent middle ground.
Love this idea!
There are some possibilities but it’s tough to find something that provides protection even if the turn-on method is known to everyone.
Needed with all the other battery voltage indicators typically available for the common setups? Or is this my esk8 noobness misguiding me?
An RGB LED can be used but jumpers would be needed to select the cell S count for the pack.
This one I don’t know enough about to say if feasible. IIRC the GPS modules draw a decent amount of current so it would probably have to be something like turning on for a minutes every few minutes and then doing that less and less often over time. We don’t need to board sending GPS data regularly when it’s sitting in a closet for the Winter.
Not sure how this one would be done. Yea, tapping into the ESC signals is probably the way.
If the remote is used for another board, and this board is put away, then we don’t want the alarm so it can get complicated quickly. I like the idea though.
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