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

Thanks for PRO knowledge Lexel, much appreciated.

In terms of above pieces of information - does it apply also to cells so called “protected”? Can the PCB mounted inside prevent catching on fire?

No, protection circuits won’t do anything to prevent internal shorts from causing a cell to fail spectacularly. However, they do prevent over-discharge, which is one way those internal shorts can develop. Though, I suspect manufacturing defects to be a bigger issue for most users, and the protection circuit won’t help with that.

Attention should be given to the durability of the slider mechanism. Reading reviews on Amazon for the Opus BT-C3100, I came across a complaint that the sliders were connected with glue. A reviewer of another popular charger (I forget which) said the slider springs were breaking after about a year. If I’m buying a new charger I want it to be long-lived.

Good point. Wonder if it’s feasible to have a sliding rail that isn’t spring loaded. Instead, make the contacts be magnetic? That way there won’t be undue stress against the battery or sliders.

This brings to mind how a file-cabinet drawer’s back plate works. There’s a back plate that slides forward and back manually, with a lock. There is no spring. It keeps your files snug, no matter how loaded the drawer is.

IMO, some tweaks to the MC3000 would do the trick, so SkyRC could be the company to work with.

BTW: I guess you all know the story behind the MC3000? SkyRC built this charger to specifications of a flashlight enthusiast. Sounds like history repeating, somehow.

Great start. I’d also like to see a 2-cell version for greater portability.

I worked out the probability that you’ll see anything from this project, and it turns out it’s only 2.718%.

Still, it’s fun to speculate what could be. IMO, the only thing that stands a chance of getting anywhere close to the requirements is a modified MC3000. Though, that would never get done on the budget requirement of $39-$49.

Group buys (like the recent one for the Xtar Li500S) make a lot more practical sense for a “budget” charger.

The only way a BLF charger would get done is to ask a company like Xtar to make some very minor modifications to an existing charger, and do a group buy. But that will never come close to the requirements for this project.

Finally a realistic view.

That’s a very precise number. Show your math please.

You sound a lot like my elementary school math teachers…

In HS and college science they teach that only the last digit is non-precise. So if I say I have 2.5 gal of gas, it’s understood it could be 2.48 or 2.54. But if you say you have 2.500 gallons of gas, then it’s a fact that it was measured to at least the hundredth of a gallon.

So when you say “I worked out the probability” and the answer is 2.718%… that is fascinating to me.

Perhaps he simply asked Spock to calculate it. :wink:

BlueSwordM, is there news on this project?

Yeah, something like a modified RC3000 is out of the picture.

@WalkIntoTheLight, as I’ve said before, if the additional features don’t work out, then the basic adaptable voltage charging(3,60-4,20) and very low current voltage recovery will be the only features implemented.

@JoshK, not until Wednesday next week.

Why is that?

Cost…

Perhaps he tallied all the options, say 32 of them, and gave ‘a not probable’ value of 1; to a ’probable’ value of 100; thus creating 3200 total points of which he subjectively added up some 87. This gives a ratio of 87/3200 = 0.027188 or 2.718 % chance of fruition.

Not defending WalkIntoTheLight, just pointing out what he could have done…

Guys, it was a joke. The number I picked is just e (Euler’s number), expressed as a percent. I thought pi would be too obvious.