Honestly that charger doesn’t seem too expensive for what it is. I would like to see a higher current limit though than 8amps, it’s still not enough for spec charging a 12s6p 30q. But otherwise for something sold in Canada it’s only like $150 more than the meanwell and it has all the function you want built into a charger so can anyone here implement the same features for $150 in that bike charger without high jank levels?
If they made a 12A+ version of that charger for another $50 it would be a winner in my books
I have a 28x14x4cm adjustable charger laying (0-130V 0-25A)
I am in contact with + - 5 charger suppliers. The larger ones are usually cheaper. Also many companies use a bigger charger so the components need less air flow + they can use the charger for different wattage (voltage and current)
The easiest way I found to go “smaller” with chargers is to dual port charge with lower amps.
2 of those TB 4.5A chargers for 9ish amps and is way more portable and lighter than those chunky ass chargers. Not really sure how that would scale for higher voltages as I did this for my 12S board.
@kevingraehl has been doing that for 6 months now without issues (using 3 chargers), but there was a thread a while back explaining why with some chargers that might be a bad idea.
For the record, I sometimes use 2 chargers on the same BMS & battery and haven’t had any problems either.
It does make me nervous leaving them both plugged in when they’re green though. I typically only do that if I’m waiting for the charge to end, which also means it’s unlikely they’ll sit for a while on green.
As long as they’re charging and red, I don’t foresee any problems.
Here’s technical explanation, anyone correct me if I say something retarded .
Back in the day a standard AC-DC power supply was one transformer (output power was dependent on the size of the transformer and windings), a diode array, and a capacitor to smooth out output.
While they are decent, they have problem of being bulky, heavy, needing lot of copper for the coil alone:
having not so great stabilization and main disadvantage, not having variable voltage output and curren’t control.
Here’s and old arc welding coils with some chunky windings for high power use, there are variable power ones that have many times more windings
Nowdays most of the power supplies are switch mode power supplies. Why? Because they can be more compact and lightweight. Instead of using one large transformer at the start you can go straight to rectifier and use smaller coils, Voltage can be changed using one potentiometer, current can be controlled quite easly (good luck implementing that into reguler AC-DC power supply without solid state devices). Here’s couple of images of bare minimum and regular switch mode power supply:
The extra stuff you see at the start and at the end of schematic is mostly to make sure that the output is truly stable. Cheaper and smaller power supplies aren’t as stable due to lack of stabilization, bad capacitors etc. (I have lost so many hours on debug just because of some cheap shitty switch mode power supplies having really bad stabilization on output).
So yeah, good power supplies aren’t going to get smaller. However have tinkered with idea of making my own AC-DC power supply with specific current in mind, for esk8 use. As long as it stays specific it should be smaller in size Safety is huge concern however that I haven’t adressed.
Getting cost down for the chargers is the main prio. Most of them use double/single sided PCBs, which means the parts that you can actually make dense (which are a very small part since coils and caps are huge and already take up so much space, + w/e isolation they might need) is impossible.
Last post pokes best on why chargers look the way they do. If you were to feed your charger a DC voltage you could get rid of the rectifier stage making the design less bulky. But most of us have AC in our homes.
I’m not like most people. If I a see a g big charger. I’m less worried. Small chargers make no sense. unless you have a charger that has some crazy high efficiency, you can’t make em small to a low price point. You need the bulk to take care of the heat and put some sturdy components in there. If i see a laptopsized brick that is rated for kW, I dissmiss it as snakeoil. No way I’d feel safe letting that sit for hours.
Weight is a good tell as well, if it feels like lifting paper, snake oil.
Ridiculous power densities are achievable, but the main problem is price.
Price of high end components
Price of the engineering time required to make a really high performance design.
There are a bunch of tricks that can be used to improve the efficiency (and thus the power density) of a power supply.
One is to increase the operating frequency, something pretty much all switching PSUs do already compared to 50/60hz mains transformers. Most cheap power supplies run at a couple tens of khz usually.
By increasing the frequency further, up into the hundreds of khz, you can make the transformers and other magnetic components smaller for a given power throughput.
Increasing the frequency, however, means you need better control electronics, and better power semiconductors.
Another thing that can be improved is the topology itself. Instead of using diodes to rectify the high frequency AC back to DC, one can use mosfets for that role, thus eliminating the forward voltage drop of a diode, and the associated power dissipation.
All of that adds cost and extra design effort.
The other thing to consider is economy of scale. The reason those Huawei bricks are so cheap, is that they make a fuckload of them, so the design work and factory overhead gets spread out much more.
Higher frequencies = more heat from fets. So its still a tradeoff.
They do quite a bit when you have a bag pack with the charger on you. Smaller and lighter chargers would also open possibilities of integrating power supply in the board itself. Thus only power cable would be needed, and you could charge your board on the fly at friends house, etc.
It’s that or buying multiple 60$ chargers, placing them at each location you’re working at.
.
am I the weird one