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

Oooohhh…good point!

May someone explain me WTF with 7S li-ion battery pack owners? Pretty much sounds like a joke for me.

Yeah… I was thinking about that as well…
A charger doesn’t have a lot of volume available to make a large (92mm+) axial fan work.
But a single centrifugal fan would do just fine for what something like this needs. No need to complicate things with multiple fans…


I’m not sure what kind of form factor has been discussed but if it’s what 95% of chargers are out there then…
…with a centrifugal fan you could design a charger to be a teeny weeny bit taller such that a blower fits below the cells and it’s exhaust points towards the “top” where you have rest of the circuitry. That way the cells also get a bit of airflow because of the intake being below them.
And you don’t need to worry about ground clearance below the charger like you would do with an axial fan.

Looking at some blowers, 75mm x 15mm size is a thing. At that size the inlet is already about ~50mm wide so with a bit of clever design you can get that airflow to go past four bays.
Gdstime for example can do (almost) whatever you want. At 75x15 size they list 2500rpm all the way to 5000rpm, with starting voltage of 4V. A 2500rpm model is specified to move 10m3/h or push 9.1mmH2O.
They can make them with PWM as well, with that I guess it should be able to spin as slow as we realistically need.
Not sure if they can do hydraulic bearing blowers but at least ball bearing is an option. Not sure if I’d consider a sleeve. (Whether axial or centrifugal)

But regardless, a blower fan should be considered/should not be ruled out.
Let the designers choose what they think is the best option to achieve an efficient design.

@Barkuti, 7S battery packs are often used with 24V inverters since they do support a larger range of voltages vs 12V inverters, so, they are much more used than 12V inverters.

@Lag, just using an 120mm axial fan at 20% fan speed would do the trick, as we don’t need a lot of static pressure to push out the air.

Definitely not a joke for the DIY Powerwall community. :slight_smile:

+1, no autostart would be very nice.

Wellp, concerning the powerwall stuff I see.

With regards to centrifugal fans, one of the reasons I said what I said is due to fan's thickness (a 7575-15 fan is too small, imho, the slots' width is gonna be 100+mm). Taking (for example) a look at the Delta BFB range I don't see any big (100+mm) slim blowers. Using 4x 5050-10, 5151-15 or 6060-15 would do, though. Sort of the same goes for Adda. Of course others may know better.

Potentially interested.

Strong preference for USB Type-C personally.

Don’t really have many 5.5 * 2.5mm DC jacks lying around (especially not that aren’t already in active use somewhere), but I’ve got a ton of USB PD bricks, and the number is just going to grow as it sees more adoption.

If it’s DC, the charger that it has would effectively become a dedicated charger for it. With USB PD, I can plug it in all over the place.

I can buy standard 5.5 × 2.5mm DC power connectors cheap as chips and turn powerful unused laptop bricks into valid power supplies for this application.

All of that USB PD @#$% is an unnecessary evil here, imho. How is it going to save money? How is adding USB PD electronics plus type-C connectors gonna make this cheaper? It's quite the opposite. And not everyone has a PD supply, much less a really powerful one.

As everyone else I also am somewhat biased. But you can see the points.

With the long list of features this device is already a challenge for the price. I prefer to keep things simple.

Can you use old laptop bricks? Absolutely. It’s a fantastic use for them if you still have them lying around (although, obviously they will be larger and heavier than the chargers we’re seeing hit the market now, unless you’re planning on going out and buying a new one).

Can you use new laptop bricks? Not as much. Many of them are switching to USB PD.

I didn’t claim it would save money.

I said that it would make it possible to use it with USB Type-C chargers (which are relatively common at this point, and are quickly increasing in popularity, particularly in the ~60 W range with laptops moving to USB PD and new technologies like GaN chargers hitting the market).

I said that if it’s 5.5 * 2.5mm DC, for me personally it would end up being stuck on one dedicated charger (as the 5.5 * 2.5mm DC chargers that I have are in use with their devices that they came with), instead of being able to be plugged in around the house (as I have a plethora of USB PD chargers, and the number is increasing).

I also didn’t directly mention this, but USB PD is also a positive if I take it with me somewhere, as then I can just bring one USB PD charger for everything or plug in to one locally, instead of having to bring a USB PD charger and a charger for this as well.

Don’t get me wrong, I see why people would want 5.5 * 2.5mm DC. I just personally have a strong preference for USB PD (especially from a convenience standpoint).

Well I have no usb pd here and lots of 5.5 * 2.5. But I am on board with usb PD. It sounds like PD is looking forward, and 5.5 is looking to the past. I always vote with moving forward toward good new tech.

Even if you go with USB PD, couldn’t there be a 5.5 * 2.5mm barrel connector wired in parallel? Write “Do Not Connect Both At Once” on the back :slight_smile: or switch them with MOSFETs for automatic power source selection.

Is this charger going to balance charge packs? Like an iMax B6 can?

I also don’t have a powerful PD PSU.
But I am sure I will buy one at some point anyway because I believe it’s the future power socket for many devices.
I’d strongly prefer the BLF charger to be a part of this future as otherwise it will force me to lug around a dedicated PSU which is simply inconvenient.
Also, USB input would allow me to charge cells from a car outlet.
Or a bus. Or a bench. There are way more USB outlets scattered around the public places than AC ones, let alone barrel DC.

Preparing for the future seems reasonable to me, especially since it’s been stated that a wider market other than solely BLF is being planned for.

@Phlogiston - “Even if you go with USB PD, couldn’t there be a 5.5 * 2.5mm barrel connector wired in parallel? Write “Do Not Connect Both At Once” on the back Smile or switch them with MOSFETs for automatic power source selection.”
Again, to me two connectors is also reasonable and a good idea, although I feel the addition of automatic power source selection is not necessary.
OG

Did I miss the chance to request this in time? :frowning:

Charger is only for individual cells (1S), nothing assembled in series.
Just the beginning still. Blue is finalizing specs and discussing with mfgs soon.

I do not mean to be disheartening but, fellows, please keep a look at the already long list of features and capabilities for the target price. Maybe some of you would prefer a “deluxe” version, don't you?

At this point BlueSwordM may want to start asking some really budget manufacturer like LiitoKala. I could also do it, @#$%.

Joshk, balance charging? That feature requires quite a different design than the usual for independent slot devices. It would require to set any contiguous slot “in series compatible” with the previous one, or else stuff would blow up. Someone already did that with a Lii-500 and… magical smoke.

I don't mean to be impolite but I still have no answer. Please can someone confirm if this feature will be part of the specifications or not? Thank you.

+1 !