The making of the BLF UC4 charger: the start of a new venture, INTEREST LIST, UPDATE 7 (Well, ramping stopped :/ )

Yeah, that’s one of the reasons why I want to stick with either using a 5,5*2,5mm DC input jack.

If we go with USB-C PD, then it would be best to make a model with an included power supply that would be more expensive, and one without.

Ok… I thought you were suggesting having one set geared at the lowest common denominator, for the beginner.

The only problems I see with having a set that will not power the charger to full capacity is confusion, misunderstandings, & ultimate headaches for the seller.

’To me’ one set that powers the charger to the fullest is the way to go. If it is an 80w charger (<- used as example only) a power supply of at least 80w should be included.

If there were an option without power supply, that would be OK too.

I do not think running/frightening off beginners/new people because of price should factor into this decision. There are plenty of very decent chargers out there already that meet their needs.

ymmv

I was thinking along of the lines of:

Option 1: Pimped charger. Full featured with a 60 watt power supply and 100 watt CPU cooler included.
Option 2: Basic charger. Same PCB and software, but only includes a 10 watt power supply and no CPU cooler.

I’d change a bit more.

Option 1: The Ultimate BLF charger. Aluminium body with a 100mm fan inside, and 60W discharging compatibility. The dream, but will take a LOT OF TIME AND ENGINEERING.

Option 2: A Miboxer C4-12 BLF edition or an XTAR BLF edition charger.

To clarify, I was suggesting these would both be in production at the end of the project. It would be the same guts, just sold in different ways.

Ideally we could work with a manufacturer to evolve a charger they currently produce.

Erm… I think there’s a reason we don’t use conductive materials for chargers, and I don’t think it’s cost savings. I’d steer clear of this particular idea.

@bmengineer
All the hobby chargers I have had used a aluminum casing to dissipate the heat. The casing is not electrically connected, it just a big heatsink containing all the electronic goody’s. Desktop Computers and the power supply’s in them are made the same way.

Option 2: The Ultimate BLF charger. Aluminium body with a 100mm fan inside, and 60W discharging compatibility.

Ditto for option 3. :wink:

Both USB PD and DC are standards.

I have a powerful universal DC PSU, so with a jack I don’t need a separate charger.
I don’t have a USB PD one but since it’s standard I don’t need one included. I’m likely to be buying one that is better than whatever gets included here anyway at some point.

I think that it would be nice to offer a variant without a PSU. Especially with USB PD.

Is this charger going to support 10180 size batteries or not? Just curious.

It looks to my semi untrained eye it would be pita to create slides & springs to accommodate battery sizes from 18mm to 78mm in length without sacrificing reliability somewhere along the way. :question:

If the fan is powerful enough it can have a built in hovering feature.

@teacher, never talked about 10180 support.
It would be nice to support, but something like a small charging module sold separately that can connect directly to the USB port would be better.

@Th558, would be nice, but the power supply would need to be upped to 160W.

@ BlueSwordM
Thank you for the verification. I had seen a few mention it like it was a done deal for 10180 support & was curious since I could not find where you had mentioned it.
Personally I saw no need for it at all.

remove that dangerous feature,
nobody really wants to make a potential thread for thermal runaway cell, recovering over discharged lithium batteries
such a cell has to go to the recycle bin

for NiMh it may be good, but definitely not on lithium

I agree with Lexel. I’ve read dendrite crystals can form inside a lithium battery that has been over-discharged and permanently short it out. Or short it out soon after.

How is that a dangerous feature?

Here’s how it’s usually done:

If between 2,0-2,5V, then charge at 100mA until the cell reaches 3,2V.

If between 1,0-2,0V, charge at 50mA until it reaches 3,2V.

If below 1,0V, charge at 25mA until it reaches 3,2V.

Most thermal runaway scenarios in relation to overdischarge happen because at such a low internal voltage, a lithium-ion cell has massive internal resistance, and the low voltage potential means parasitic reactions take place, robbing the cell of capacity.

However, when charging at normal current levels, the cell bounces back to normal voltages, but not before internal damage is sustained, and parasitic *chemical *reactions are pushed at a massive rate, resulting in elemental lithium plating, and a thermal runaway can occur.

In most cases, this doesn’t happen fortunately. What instead happens is that the massive voltage spike robs the cell of a lot of capacity.

That’s what I noticed back in late 2017: by charging cells back up at very low currents, my 18650/20700/21700 recovery cell yield had gone up tremendously. I did some research, my own testing, my own research, and came to the conclusion.

It not only improved the yield of used cells massively, especially powertool cells, but the percentage of higher capacity cells being recovered got up by a nice margin.

It’s also a very safe method of recovery. It does need an additional step in software to make the charger stop charging if the voltage stops rising after a predetermined period of time.

Some more stuff from other members: Processing Low V Cells | Second Life Storage & Solar

I wouldn’t want to implement a feature if I hadn’t tested it before myself, and a lot of other people for a long time.

It’s probably not an issue 99% of the time, but once you sell 1000 chargers, that’s 10 issues. It depends on your trust of a muggle, and opinion on the risk. I’d advise against taking the risk. It’s your choice though.

Ah, that’s where it comes in handy.

The main customers won’t be only us, and some muggles.

It’ll be a lot of people on other forums, like SecondLifeStorage, who already have tested that feature on hundreds of thousands of cells.

If you are going for it, can I at least convince you to add a prompt when the feature is activated that asks “Accept risks? Y/N”