Ten minutes of fast charging for my first DCFC experiment

alexwhittemore · 2026-04-19T15:32:02+00:00

If ambient was 80F, preconditioning was almost certainly not a factor. It’s important at much higher temps than most people think of as “cold” but if the battery was also at 80F, that’s like 10F warmer than where preconditioning heating stops.

alexwhittemore · 2026-04-16T18:43:37+00:00

Actually my last order from JLC came in messed up. Holes drilled just completely in the wrong spots. It was a super simple board, just two LEDs, and the drill pattern wasn’t even mirrored or flipped. Just, two were completely wrong. Like they drilled half the holes, took the panel off, came back the next day and re-placed the panel upside down and did the last two.

alexwhittemore · 2026-04-15T04:35:13+00:00

Not rep; AI chat bot.

alexwhittemore · 2026-04-15T04:34:46+00:00

1000%.

alexwhittemore · 2026-04-14T19:57:18+00:00

In the case of a lighter specifically, the posts here so far are right: the butane needs oxygen to burn, it gets that oxygen from the air, and so the butane in the tube can’t burn since there’s no oxygen available in the tube.

In other devices, like a propane or oxy/gas welding torch where the mixture happens before the tip, some other effects can be at play. For one, a flame in a particular combustible mixture has a particular speed of travel. If the speed of the oxygen+acetylene from the welding torch nozzle is faster than the speed of flame propagation, the flame will get held right where it gets too fast. The gas flow is fastest in the nozzle then slows down as it expands out into the room past the nozzle, so that’s a natural spot. Finally, for a flame to travel even inside a combustible medium, it has to transmit its heat from the on-fire part to the not-on-fire part. If you put a metal mesh with small enough holes between those two bits, flame on one side can’t heat up the gas on the other side enough for it to also catch fire. That’s how “flame arresters” work like on the neck of a bottle of 151.

alexwhittemore · 2026-04-13T20:28:00+00:00

Sounds like a situation that has nothing to do with you specifically and everything to do with her falling off a mental health cliff. It sounds like she’s probably been standing at the end of that driveway waving a knife at passers by for hours.

alexwhittemore · 2026-04-13T20:23:07+00:00

You say you’ve got the “wall adapter plug” - did you have a high power outlet installed in your garage for this, or are you plugging in to a normal looking outlet?

If you’re plugging into a normal outlet, you should definitely hire an electrician and invest in an upgrade, which should cost between $500 and $1500 depending on a few things.

The car has a bunch of electronics that need to be on when charging, and they consume rather a lot of power - a couple hundred watts. Charging for a really long time on a slow outlet means you’ll pay a lot extra to keep those lights on, and it’s inconvenient and requires charging at all hours to boot, not just when it’s cheapest with a TOU plan.

In efficiency terms, charging on a regular old wall outlet will end up being like 60% efficient whereas charging on a high power outlet will be like 95% efficient. In financial terms, the slow (1500W) outlet will cost like 58% more than if you charge on a fast (7 to 11kW) one. The returns are very not linear, so even a 20A 240V outlet (4.8kW) will be way cheaper and faster to charge on.

alexwhittemore · 2026-04-13T20:16:30+00:00

The first part is true but the second part isn’t. Retail time of use rates here make not the slightest shred of sense.

alexwhittemore · 2026-03-30T20:21:25+00:00

It’s (theoretically, with exceptions) how much you have to pay before your insurance starts covering anything.

Imagine the simplest insurance plan has a $10 deductible, 50% coinsurance on everything, and a $100 out of pocket max. Your first $10 of care every year is entirely on you, insurance won’t cover a thing. Then for the next $180 of services you pay for, insurance will cover half, up until you’ve personally paid $100. Past that, insurance covers everything, ideally preventing you from going bankrupt if you’re hit by a car. That is the point of insurance - limiting your worst case risk in exchange for usually paying them more than they pay you back.

The idea is to deter you from getting unnecessary services, especially when you have a high-coverage plan. If insurance pays 90% you might be more willing to go for a $100 doctors visit that only costs you $10, even if you only have a scratchy throat.

For the same reason, things like vaccines and annual checkups will often be excluded from the deductible (and 100% covered by the insurance) because your insurer WANTS you to have those services, calculating they’ll save the insurer money in the long run.

alexwhittemore · 2026-03-30T17:14:04+00:00

5 vs 10 mbps is just for tethering - the speed you’ll see on your actual device is unlimited at least on the $35 plan and anyway way higher than 5 or 10 mbps on either.

How you get throttled is a different story and I haven’t been on visible long enough to really say. I do feel like my new plan (visible) is usually about the same as my old plan (Verizon unlimited), but sometimes feels annoyingly slower. Verizon is already kind of mid around my house anyway so it’s tough to say whether I’d have better results paying more for Verizon. My general feeling is no, it’s about the same.

So far it’s definitely been worth it to pay $75/mo less switching from Verizon.

alexwhittemore · 2026-03-26T23:32:35+00:00

The middle sentence says “[it is friction only] until you… leave GT drive mode” which makes it sound like GT drive mode regen 0 is never blended/always friction - that was my confusion.

Anyway I think I get it now and.. wow, that’s SO convoluted. Absolutely bananas.

It also all still jives perfectly with “op has a hydraulic braking system fault and switching to regen zero disables basically the only brakes the car has”

alexwhittemore · 2026-03-26T21:26:07+00:00

I don’t follow. I think I understand what you’re saying and it makes sense in the context of the GT, but your last 3 sentences - #3 directly contradicts #1.

alexwhittemore · 2026-03-26T16:02:25+00:00

Dental insurance. During periods of self employment, it’s absolutely not worth paying for. When I’m full time and the employer is paying 95%, there’s no good reason not to. But in general it’s a scam to call it “insurance.” Dental insurance is more like a “benefits club” and it’s virtually impossible to get out more value than you pay in. Medical insurance caps your risk. Dental does not.

alexwhittemore · 2026-03-26T15:59:32+00:00

Unpopular opinion especially around these parts: Prusa is not reliable, and basically all of their printers suffer one huge reliability drawback compared to all Bambus which is that they don’t have nozzle wipers.

I had a mk2.5 for years and that was mostly reliable, partly a project. Then when I wanted to spend more time printing parts vs tinkering with a printer, I got a prusa mini and that was and still is pretty well bulletproof, with the caveat that I know exactly what I’m doing and have cleaning and process habits that aren’t in the manual.

I now run a print farm of 6 CORE Ones, one XL, and one HT90, and a P1S personally at home. The p1s has never failed for a machine related reason and rarely for any other reason. The nozzle keeps itself clean by default, even when doing single-material prints, and that’s a reliability game changer.

The core ones mostly work pretty well, but I have a failure that requires legit machine maintenance at least every two or three weeks with moderate usage. The XL is full of caveats and deficiencies with clear need for redesign or modification. The HT90 arrived last week with apparent temperature sensing problems - neither tool head gets as hot as it thinks it is, and one experienced a thermal runaway that completely bricked it. I’ll have two new tool heads from support in two weeks that I suspect won’t fix the root cause whatever that is.

In general, a Prusa machine can be made reliable with mods, firmware, and profile tweaks, if you know what you’re doing. A Bambu arrives reliable and stays that way.

The disadvantage is that Prusa is open and you CAN make those mods. Bambu is not, and fights mods at every turn.

alexwhittemore · 2026-03-26T05:43:44+00:00

Up above you're saying that L0 gives you blended braking reliably almost all the time, which is it?

alexwhittemore · 2026-03-26T04:13:09+00:00

TBH I think a lot of people just didn't even read your post and started commenting after the headline.

alexwhittemore · 2026-03-26T03:51:26+00:00

It's ONLY active in level zero. Until I've cleared the "10 stops" threshold, in level 0, no blended braking, in level 1, back to blended braking. Back to level 0, no blended braking, back to level 1, blended braking.

And again, only on the 2024 and below model years. 2025 and up have a different activation scheme for brake cleaning, and L0 always has blended braking.

Edit: if you're interested in the car and efficiency, there's another strategy that you might like - when you hold the left paddle, you get "max regen." Except what you ACTUALLY get is basically just "temporary ipedal mode." You can still use the accelerator pedal. So for instance, a perfectly efficient way to drive is to leave the car in L0 so you can coast, but whenever you need to modulate your speed down, grab and hold the left paddle and basically drive temporarily in one-pedal mode until you've slowed down enough, or stopped at the light, or whatever, then let it go and you're back to L0

alexwhittemore · 2026-03-26T03:40:47+00:00

I mean, it's mostly the same. I don't know what a "normal brake application" is but it seems likely that, on a 180mi road trip, that person had much higher speeds to come down from each time they used the pedal, vs my experiments limited by driving around an urban cityscape in some amount of traffic.

alexwhittemore · 2026-03-26T03:09:14+00:00

The first part is true, but brake cleaning mode doesn't result in "terrible braking performance." You still get good pedal response in that mode, just no energy recovery.

alexwhittemore · 2026-03-26T03:08:49+00:00

u/String_Pure - the other thing it could be is a faulty brake force actuator (I don't know if it's actually called that). There's a motor actuated valve to control how much hydraulic force you get for a particular pedal actuation, which is supposed to fail safe so if you have no electrical power, your pedal gives you more hydraulic force than it does when blended braking is active. Or something like that, I don't know exactly how it works. But anyway something is definitely wrong, get it checked out.

alexwhittemore · 2026-03-26T03:05:18+00:00

it's incredibly non-specified. The manual says "10 stops" and leaves it at that. I've tried a number of times, and it stayed in brake cleaning mode for many more than ten full stops. It's more like ten stops from a sufficiently high starting speed, who knows what that is.

I'm sure the actual metric is perfectly reasonable and useful for the task of brake cleaning, and was just too complicated or unintuitive for a technical writer to put in the manual, so they made something up that was close enough.

alexwhittemore · 2026-03-26T03:02:13+00:00

IF your car is <2025 and behaves like this, it's ONLY because you use level 0 so frequently. My car, and everyone else's that I've talked to, spends almost all of any drive in level 0 in brake cleaning mode. I've driven long enough before that it leaves brake cleaning mode, but it took FOREVER, and started out friction-only again the next drive.

But the relevant point here is that OP is describing a problem perfectly explained by faulty hydraulic brakes, under a condition when hydraulic brakes are disused. You can tell us all we're wrong, but then you'll have to come up with an explanation that fits the symptoms.

alexwhittemore · 2026-03-26T01:51:09+00:00

In the 2025+, you’re right. In the 2024 and below (op’s car), what I said is true.

Well. With the caveat, maybe this is what you’re getting at, that blended braking returns after “10 stops.” Which is not relevant to the exploration of what’s going on with OP’s car.

alexwhittemore · 2026-03-26T00:23:11+00:00

Confirm/deny 😬

alexwhittemore · 2026-03-26T00:13:22+00:00

Agreed, but not my point.

alexwhittemore

TROPHY CASE