POLL: Your favorite Chinese knife?

You can see the archived poll results on the Wayback Machine:

https://web.archive.org/web/20221220093741/https://budgetlightforum.com/t/-/72637

POLL5 is live.

Note:

this recycled thread can be reached by surfing to http://bit.ly/dreamcharger

alternatively, you can reach BLF polls by surfing to http://budgetlightforum.com/poll


Dear reader,

the (changing) poll questions refer to the **** dream charger (for round batteries) project and its parameters and specifications. If you have voted already in a previous poll, e.g. in POLL1, then you could cancel your old vote and re-submit your new selection with respect to the new poll question (POLL2). Otherwise, never mind since it cannot be expected that *everybody* from the preceding polls follows the suggested procedure and updates his/her selection with regard to the updated poll question. At the end of the day the questions (POLL1, POLL2, POLL3, ..) and their poll options are more of an incentive for discussion and for leaving your opinion on the current topic.

Please share your thoughts, thanks.

Cheers, dino.


POLL4: You Dream these days?

(POLL4 RESULT: Something better, e.g. dreamcharger.)

We surely are looking into universal chargers that is multi chemistry with both LiIon and NiMH support, aren't we? Well, Thrunit has come up with such a charger, Soshine probably has such a thing too, we all have the Nitcore and there are tons of i4 imitations, XTAR recently released several new models of interest, and let's not let hobby chargers out of sight. Do you know any other relevant universal charger? And don't even mention Efest ****! :P

Oh, you're not happy with the above current selection of universal chargers, they are not what you've been really dreaming about, are they? Then don't be shy and vote for waiting for something else, a future dream charger to be released. That's what this entire thread is about.

Maybe you don't want to wait, maybe it's urgent and you're impatient, maybe you don't believe in the existence of such a thing as a dream charger, maybe you don't trust promises made by a green dino girl, etc., so you're buying one off the current market selection.

Well, i am tellin ya. Your bad! If you don't trust dino, then you should at least give the squirrel a chance ;)


POLL3: You Dream what else?

(POLL3 RESULT: charger should feature Capacity reading w/ discharge.)

Assuming that your charger is very fast, very accurate, otherwise flawless, well-built, not cheap, and long-lasting, then it has the most important basic qualities but is still far from being called a 'dream charger'. So the third question is the discussion and inclusion of a realistic set of fancy features which most other chargers don't have and which would make the product more advanced, innovative or special than the competition.

The poll options have been collected from the XTAR thread. Since the poll does not allow for multiple choices, feel free to vote for 1 single coolest feature or post what else you've been dreaming about. Just keep in mind that having more fancy features will also increase the production cost; in other words, if you wish to have so many fancy features, then you must also be willing to pay a premium for them.


POLL2: You Dream Charger most important basic quality?

(POLL2 RESULT: charger should be Very accurate.)

Second question to proceed with in the product design is the prioritization of the charger's essence. One needs an ordered list of essential basic key qualities which serves as strict guideline during the design process at the drawing board since sometimes certain compromises need to be accepted in favor of the more important properties. Sometimes all criteria cannot be fulfilled at the very same time.

Assuming that the dream charger is officially announced and on the ad paper the specs, looks and price are intriguing given that the product lives up to your, in this moment generated, expectations, then which 2 or 3 basic qualities are the very very most important to you, after having paid the asking price? Maybe you could even single out the most important character which your newly purchased product should feature.

To me, i don't care much about max charge rate or that it performs super-duper accurately like a FLUKE dmm. Warranty/Guarantee is imho nothing intrinsic to a product itself and sometimes even superseded by national regulations; Zebralight grants 1.0yr warranty and it does not deter folks from buying it at insane EUR-prices. So my personal top expectations are (in order of descending priority): 1. charger must be very very well-constructed and well-built with top quality components and parts, nothing cheap nor sub-standard (this will also ensure a long-lasting life, just without guaranteed warranty on paper!), 2. it should be a mature product from the initial release (hardware revision v1.0 RTM) with a long track record of testing, and thus operate absolutely flawlessly with no bugs, shortcomings, nor nothing, 3. since we call it a dream charger, it must have a set of special functions already, e.g. digital display with capacity measurement, etc. Beyond these special functions, any additional unexpected extra fancy functions are welcome as long as they don't compromise 1. and 2.


POLL1: You Dream Charger max current (per channel)?

(POLL1 RESULT: charger should have 2.0-3.0A max per channel.)

First question to start a design with is the specification of the max current per channel. It's a key parameter afaik.

The new XTAR XP4 charger delivers a max of 4x1.0A and accepts 4x 26650 afaik. I am thinking that a universal charger which accepts up to 4x 26650 should have 2000mA per channel. That's 8.0A total. Is that realistic?

Please cast your vote so that XTAR's next release is nearer to our idea of a dream universal charger, thanks!

Rated to 3a, that way components will be oversized and understressed most of the time. 2a per channel minimum if it accepts 26650 but 3a deffo better.

Why does the XP4 look so Jetbeamy?

Maybe the single LED changes colour depending on status?

40 amps per channel or 70 amps slaved together… can charge 20 lithium cells at one time.

Dream charger also needs to be the usual 12vdc (off-grid use), fed from a wall wart. 4chs at 4v and 3a = 48w wall wart, that’s pretty big, double what I’ve seen on most budget chinese chargers.

Hmm, four colours, flash or no flash. Strobing all colours = fully charged!

An OLED display wouldn’t be too expensive and could show lots of detailed info.

3 steps
200-300mA for 16350 (500-800mA)
700-800mA for 18650 (2200-3400mA)
1500-2000mA for 26650 (3500-4500mA)

4 steps
250mA
750mA
1500mA
2000mA

Close, but I was thinking more like this.

How about 0.1A or 50mA?
Once you buy hobby charger you are not limited by amps.
Problem with normal chargers is that I can’t use them for small batteries because of high current.

+1

:stuck_out_tongue:

I’m surprised 1.5a seems quite common on a 26650 or even 32650 charger. Votes seem to dictate at least 26650.

I haven’t read up on Li-ion charging but is it similar to some other chemistries in that a middle current can be a bad choice as termination is hard to identify for the charger and thus overcharge is very possible?

A really low that is safe long term works I guess but at levels that low you are looking at 12hr+ charging time (and who wants to sleep with the charger on!)

A relatively high charge rate that the manufactures say a cell will safely accept is best to aid termination and keep times realistic.
.

Edit;

Infact DigiKey specify a 1c charge rate, so a 26650 ideally around 4A!

Source: http://www.digikey.com/us/en/techzone/power/resources/articles/a-designer-guide-lithium-battery-charging.html

I'm with Texaspyro, none of the choices have high enough numbers

i am not the only one who masters the art of stealth deletion, thanks ezarc :p

i haven't voted yet. still undecided. i think the hardcore charging people incl HKJ prefer 3.0A?

No, 2A for a slot is enough. With 18650 I nearly always uses 1A. With 26650 the 2A current is fine for standard charge, many of the 26650 batteries could accept 3A or 4A for a quick charger (i.e. with slight damage to the battery), but I have not seen a need for that.

Making higher charge current in a charger will also make it more expensive, especially if you need PFC correction (Required at higher power levels).

Are you required to have PFC over a certain power in Denmark? I’d be surprised if even a 4a, 4 channel charger required one. Would be nice tho.

I agree 2a is enough but more would be nice, who knows what’s around the corner and the ability to rapid charge if really needed would be nice.

Yes, it is above a certain power level, the rules are common for EU.

I do not know exactly at what power, probably somewhere between 60 watt and 100 watt. A 4A 4 channel charger might be around the limit.

What is around the corner, might required other voltages. I prefer to charge at safe current levels and then more batteries at the time.

That’s how I thought about it too, plus I know the 2A ~ .5C is better for the battery but 3A is under 1C and should be able to accept that charge …shouldnt really damage a 4200mAh 26650 battery until 4.3A should it?