I’m pretty terrible at soldiering and small electronics in general, but I’m kind of okay with how this turned out.

Back story:
That helmet is my sister-in-law’s, she drives a polaris slingshot. (It’s technically a motorcycle here in the US because it has three wheels.) and she hooked up some EL wire to her helmet and the larger black rectangle in the picture is what the battery pack looked like before. (It takes two AA batteries.) and doesn’t have anyway to recharge them natively.

I did some research and found a neat little charging board (TP4056) and got her a small single cell li-ion battery for it. Now it’s not only less than half the length of the original, but it has a rechargeable battery and a charging circuit built in. The battery is 500mAh and lasts about 65-70mins on a charge. Personally, I feel like that’s not a good enough battery life on a charge, but my sis-in-law says that her and her slingshot friends usually only run with the EL lights on for 30 minute stretches at time so they should be able to get two to three uses before needing a recharge. Which btw, only takes about 35-40 minutes from completely dead.

The box looks like shit cause I literally hacked away at the original casing with a pocket knife and then crammed all the pieces back in and hot-glued the casing together. But I took measurements of the final-ish design and will try to find a small electronics box that will be able to house everything internally. (L: 1-3/4” W: 1-1/4” H: 1-1/4”)

Electric cars are not better for the environment. All petrol cars combined are only responsible for 7.9% of CO2 emissions. If your electric car is charged from a grid that is powered by a coal-burning power station, it contributes nothing to dealing with climate change. It only provides you with the false sense of security, and you can look cool telling your friends that “you know, I drive a Tesla, I’m environmentally conscious, your gas car is bad”.

Electric cars are lame. When I’m out of fuel, I can refuel fully in minutes. With electric car, I’ll have to wait at least five hours. Let’s be realistic, superchargers aren’t common, and will never be.

Gasoline is 46.4 MJ/kg, or 34.2 MJ/l. Li-Ion is 0.36–0.875. Let’s be generous and say it’s 0.9. To match 1 kg of petrol, I would need 51 kilos of batteries.

Average gas tank is 18 gallons, or 68 litres. To match that, my battery must have a weight of 2.5 metric tonnes. Bear in mind, empty battery and full battery has the same weight. Also, bear in mind, batteries perform worse in the winter.

As per energy density and practicality, things don’t get much better than petrol. Liquid hydrogen has higher energy density, but to store it, gas tank has to have very, very thick walls, to withstand the pressure. And, hydrogen is a bitch. It’s extremely dangerous. You can’t smell it until it’s too late. Hydrogen-air mixture will explode if you look at it the wrong way.

All that “electric cars good for climate” hype is merely Elon maintaining his stock bubble.

TL;DR don't fiddle around with batteries if you aren't ABSOLUTELY sure what you are doing

For my arduino project I need to use 18650 Li-Ion batteries. They are pretty awesome but at the same time pretty dangerous if you don't use them the right way. You need protection boards etc. or they can/will go BOOM.

So I am looking around Amazon to find some good quality ones and reading some reviews made me wanna cry.

People were REMOVING protection circuits from the batteries and even removing the foil around the batteries. NEVER EVER FUCKING DO THAT!

I also found out that these are the batteries used in E-Cigarettes and now I really don't wonder anymore why they explode so often. People fuck around with the batteries just so they fit into their vapes, or reduce the resistance of the coil (the thing to heat up the liquid) to an absolute minimum so they can get more watts. A side effect of this is that a lot of current gets drawn from the batteries (>20A or something) which makes them go BOOM if no protection/fuses are used in the circuit.

The name of the inventor of the Li-Ion battery is John Goodenough and I think it’s beautiful. His name truly resembles the exact concept of what a lithium rechargeable battery really is.

Batteries don't like me anymore

Yesterday late evening I was out to bring a festive parcel to someone. I left home with 29% batt, went there and still had 27%. Made 3 short (~1min) calls and headed home. Opened Firefox and my phone crashed. WTF, how could FF crash Android? OS separation failure? I turn my phone back on and it says LOW BATTERY: 0%. wtf... With 27% I should have been good until the next morning with no problems! And now it went 27%→0% in a blink (literally).

Today I decided to stay on my lappy for the morning. YT videos to catch up to, dR posts to scroll through, etc. A few hours later laptop battery is drained down to 29%. I step away for a few minutes for a cup of coffee and when I come back - the battery indicator LED is glowing amber and OS says it's got 6% left

29%→6% in a few moments of idle. Riigghhhhttt.... And I thought I won't want anything for this Christmas.

I wonder what's the significance of 27/29% there...