Bottlenecks add up.
Your ESC’s connector/wiring is a bottleneck but any others you add will just drop more voltage, create more heat, and rob you of more power.
Whether you will notice the difference, or whether an all XT60/12AWG setup would create noticeably more heat, is unknown…it all depends on the little particulars of your setup and how you ride.
Using larger connectors and wiring wherever possible is just part of “best practices” for increasing performance. You’ll have to decide whether it’s worth it or not.
I do it where I can as performance is a priority for me. But at a certain point it’s just not worth it. If you have a decent length of battery wire and might be riding hard where you want to maximize battery performance then XT90/10AWG could be worth it.
Having that larger connector/wiring on the battery might be handy in the future too if you use it in a different board with a different ESC and/or larger wiring already inside.
If part of your answer to the question “Why are you building an electric skateboard?” isn’t “For the sake of doing it myself”, then you might want to rethink your decisions thusfar. Part of the point of the DIY building process (for me at least, and I think it’s similar for many others) is being able to do it “right”, or “better”. The ability to do it better than a commercially built one, or better than what someone else would do, whatever your definition of the word is, that is a core part of the DIY mindset. Building the battery pack to be the best it can be with the tools and skills you have, is a no-brainer in my opinion.
The battery pack is one of the most critical parts of any EV, and personal-sized EVs even more so due to the high stresses placed on it, both electrically and mechanically. The “magic chart” isn’t magic, it’s just a guideline that has been tested and found to be acceptably accurate. You don’t have to adhere to it strictly if you judge it not to be necessary.
Your current setup is using a single Xenith with 12AWG input, so you might indeed want to keep the continuous average current draw below ~40-50A to avoid excessive heating. That doesn’t mean it’ll immediately blow up if you exceed that, just that the harder you push it, the warmer things will get. You could set your battery current limit to 80A and probably be totally fine, because a 2WD street board even on super grippy tires won’t draw that maximum amount of current for more than a handful of seconds at a time anyway under most use cases.
However, since your battery cells are capable of more than that, it would make some sense to build the rest of the battery to match, even if it’s overkill for the rest of the board’s power system at the moment. You never know what that battery might end up powering next, you might need the extra headroom.
sure, and don’t get me wrong - I’m still building the battery to the best advice I received here.
however I cannot build an ESC, I have to buy one commercially available and there lies the bottleneck.
so I’m only raising a question in case I still missed something, because I’m building a battery capable of safely delivering 100A and then plugging it in to an ESC that’s limited to 40A.
whether this is acceptable practice, is really what I’m asking.
sure, I can swap the Xenith for Stormcore with XT90 connection and AWG10 wires from my battery terminals but that at 55A “optimal” limit would still be way off the capability of my battery.
as long as I’m told this is usual practice by other builders then I would know I’m not doing much wrong.
the previous eBoard I built (except the battery was done by an external builder) is running same Molicel but in 12S3P config and I’m limiting max battery current to 2x 37.5A and it has plenty of torque to climb some tasty offroad hills with the gearing I’m using.
the new board I’m building is also going to run with generous gearing 14T/76T and 160kv motors so I think limiting it again to 75A should be plenty.
and I have installed decent heatsink from @glyphiks
I will also mention that the current ratings for copper wires in that chart are based off of automotive chassis wiring standards if I recall correctly, and those are significantly more conservative than what many RC vehicle and PEV folks run. Especially with high-temp silicone insulated wire, which is rated up to 150 to 200 or even 250 degrees C, running double or even triple the “recommended” maximum current can be fine, as long as you know what you’re doing and accept the added drawbacks like increased voltage drop and heating.
Those solder joints look fine to me, there’s a good amount of flux and solder coverage. As long as the underlying surface was clean you should be fine. You could probably use a little less solder in your blobs if you want less heating of your batteries.
Load the custom FW onto it, the TS100 is pretty underwhelming with stock FW, at least if you’re going off what the reviews say vs how it performs out of the box.
