Rolive

In a transformer, why are both coils apart from each other? Wouldn't make more sense to have the ferrite core (tube shape), wind the primary coil around that and then wind the secondary coil on top of the primary? So that the magnetic fields are as close to each other as possible?

Hi all

A higher nozzle diameter has the benefit of being able to print faster due to to bigger layer width. There is a tradeoff, you'll have to lower print speed and/or raise temperature to maintain proper layer adhesion. That means that there is an optimal nozzle size for a given print speed/temperature combination. You also don't want temperature too high because it will burn/degrade your filament.

In my experience layer adhesion is quite poor with a nozzle of 0.8mm and it also prevents you from printing finer details (gear teeth for example). The tradeoff versus a 0.4mm nozzle doesn't seem worth it especially if you print overnight.

What are your experiences?

Hi

I'm interested in building my own solar panels mostly for educational purposes. The idea is to use individual solar cells and solder 36 of them in series to get about 18V open circuit voltage. It's what commercial solar panels have as well so its easier to integrate later.

The cells are bonded to the substrate using optically clear silicone or EVA. Not sure which is better. Polyurethane is not good because the mere mention of humidity will cause tons of bubbles.

As for the substrate. Optically clear tempered glass is prohibitively expensive unless bought in bulk. Normal glass is significantly cheaper but could that be a safety hazard? I seriously doubt that thermal shocks are strong enough to break glass sheets unless cold rain falls on it.

Has anyone tried plexiglass/acrylic? It's UV resistant but could bend/warp at higher temperatures breaking the cells.

Perhaps using screen protectors for obsolete phones/tablets could work as well. It's really thin and strong but I don't know it holds up in a hailstorm.

Would love to hear from your experiences in DIY solar panels.

Hi all

I'm working on a DIY 18650 lithium ion home battery, built out of old laptop/ebike cells that have been tested for performance (capacity, internal resistance and temperature during cycle) and found to be good enough for use.

There are several safety precautions in my setup. Each cell has a 1A current fuse and a 60C thermal fuse attached to it(in series). Should a cell overheat or develop an internal short, the cell gets deactivated easily without fancy electronics. (protip, don't hotglue thermal fuses!) The BMS is a DALY BMS rated for 60A, although I'll probably never use it above 30. Additionally, an Arduino monitors the individual cell voltages as well as overall temperature (secondary BMS that can communicate over serial to a proper webserver.). This Arduino also watches a smoke detector and controls a solenoid killswitch should anything fishy happen, like overvoltage/temperature or the smoke sensor triggering.

This may or may not be a bit overengineered but I want to leave this system running pretty much autonomously with several layers of safety. A Chinese BMS on its own is not good enough and a professional one is outside my budget. Also the learning process is worth the effort.

Should, god forbid, a cell actually catch fire despite all safety measures I want to have the battery in a fire safe container as well. An iron cabinet like the IKEA Lixhult won't melt in case of battery fire but it will vent hot fumes that could set surrounding objects on fire. What would be a good way to engineer that? A metal cabinet with a metal chimney attached to it? So that the hot fumes get directed away from flammable objects? Perhaps something built out of stone where sand bags may be placed above the battery. Fire would cause the sand to drop on the batteries and smother it.

There isn't any way to crosspost on Lemmy right?

I'm interested in learning how to make a proper PCB rather than perf board with wires all over the place.