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Dispelling Battery Chemistry Myths - Link and Summary of Battery Chemistry Technical Insights from Luke Workman's Interview with Electrek.co


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1 hour ago, Vanturion said:

Potted batteries are the key to safe lithium ion battery packs

Great video, thanks for finding/sharing this. A lot of great insight. So basically the v13 battery is the only safe one and up here in the north east is a bad place to be riding EUC or any other electric device.

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10 hours ago, Punxatawneyjoe said:

So basically the v13 battery is the only safe one

Safer maybe, however, I don't think you could claim safe with 100% certainty especially in lieu of some of the information disclosed in the interview. From InMotion's website:


The battery pack is shielded with stainless steel plates and has an IP67 waterproof rating, making it safer for the riders to use their Challengers in wet conditions

IP67 is a test of water ingress in low-pressure immersion meaning the water surface tension property comes into effect (water tends to stick to itself) which makes it easier to pass this test. IP67 is no way an test of whether you will experience water vapor intrusion (spray coming off 50 mph wheel for example) in real world conditions as Luke pointed out.

The first digit 6 in the IP67 simply means that the Dust Tight: no ingress of dust; this is an airflow test. The second digit 7 is the water submersion test at 1 meter for 30 minutes.

It would be different matter if IP67 was testing a *insert max wheel speed* salt-water slurry spray over the device for 30 minutes and check of water ingress afterwards, but it's not. What the 7 in IP67 says is that you'll (probably) be OK if you pour water on the wheel or submerge it up to 1 meter depth for a while.

Without potting, the ever-present electrolyte leakage at the cell level can occupy the spaces that would otherwise be filled with resin in a safer pack design. This electrolyte bridge formation, if it occurs a high enough rate, over time, can create the hazard where a liquid ingress, salt spray especially, could cause a fire.

Another thing worth pointing out - I assume the stainless steel plates are to protect against mechanical intrusion; however, in the interview Luke highlighted that the electrolyte vapor leakage tends to condensate on metal surfaces, so it's possible that these plates could be a potential hazard by introducing more pathways/surface area for electrolyte bridging to occur. Although the risk would depend on where the plates are located relative to the cells, I'm just throwing that out there as a consideration that may not have been considered by the InMotion design team.

Notice InMotion wisely doesn't claim their packs are safe (perfect safety), simply that they make it safer to ride in wet conditions. It's not an objectively measurable statement beyond the IP67 rating. I'm spending a lot of time on this, but it seems like people, myself included, sometimes see a rating and make a lot of safety assumptions that aren't necessarily based in reality so I apologize for being long-winded here.

10 hours ago, Punxatawneyjoe said:

up here in the north east is a bad place to be riding EUC or any other electric device.

I think it's fair to say most riders prefer fair weather conditions so it's probably also reasonable to say the electrolyte leakage phenomenon probably won't cause problems for the full product (EUC) lifecycle. For those like yourself who may ride in winter conditions, especially in areas that salt, it would probably be wise to exercise increased caution with storing your wheels. At the very least, be aware that you're riding at elevated risk, especially over time.

Besides end-user safety, manufacturers should be producing a robust design that is safe in the full spectrum of riding conditions, including the most adverse. It just makes sense from a future liability point of view to pot all of their battery packs going forward.

Edited by Vanturion
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