USB Charger Stand (Making My Own) ?

[MEXICOWANDERER]

Cellulars, Kindle, Nook, Yadda. Too many gizmos to count, it seems like. And the ebooks much prefer gentle charge rates (current limiters). Then there is Mexican electricity. In a fit of optimism, I purchased a Meanwell 12-amp power supply ($8.00). 5.0 volts + - 10% adjustment.

Yet another project.

If and only if I can get my hands on the necessary goodies to complete the project.

I want six outlets, but the USB outlets will have permanent 16" long USB cords and they will be designed to be changeable when their tips wear out. Where to buy shorter really great quality charge cords is a question, here. I like braided cords but they are usually 5' in length.

Four of the charging cords will be direct connect while two will have current limiting to 500ma for the ereaders. NOOK is especially mad-dog about insisting on gentle charging currents. It's OK - I have all night to recharge the devices.

Now some more questions...

Obviously 3.7 volt lithium batteries cannot tolerate 5.0 volts. So a device must have an onboard circuit to manage the disparity. A charge controller. What I do not know is if it is "best" to limit current with stuff other than the ereaders. If the answer is "yes" then all 6 outlets will get current limiters.

Do the batteries "suffer" with continuous charging? A laptop's circuit stops charging altogether. Laptop charging circuits cost more than the entire cost of a USB charged gizmo. They can stay plugged in. Putting individual charge time limiters on the new charger will be child's play. And look, it's ridiculous to think precise charging limits are mandatory. I can install 6-hour limiters. Some of the USB gizmos may stay connected for days and days and -that- is what I am concerned about.

Ho ho ho, you say?

Have a friend connect a Scope Meter to the output of YOUR USB charger. Check the RIPPLE developed by your USB charger. Then read up on lithium batteries and their vulnerability to being exposed to a charging current that has ripple. Surprise! It's pure cyanide for the battery. OF course the degree of ripple has everything to do with how good or bad the charging current is for the lithium battery.

With the Meanwell I can build an AC power inlet filter to make its life easier, then add capacitors to keep output ripple to under one millivolt. If you feel like arguing the ripple/battery life issue please do it with the battery manufacturer not me.

Why is this necessary?

It is necessary when one lives so far from the United States that buying (for example) a replacement NOOK means incurring a hundred fifty dollar DHL shipping charge once transfer from the seller's shipper to DHL is made (a hassle and a half). Then, arranging a 300-mile round trip to get to the DHL office. Wanna wait two weeks for a three hundred eighty dollar NOOK? I don't. And NO the battery is not field replaceable, period. I wish they were.

If I can manage to learn what I do not know about small device lithium battery onboard chargers, and secure great quality charging cords, I will build a bedroom shelf device charger that will last. And yes, the Meanwell is built to go the distance 24/7 for many years.

Thanks in advance for tips, and help. And yes, I am close to the border at present and yes the Nook and Kindle are sparkling brand new. After surgeries, I move 2,550 miles further south.

[pianotuna]

Hi Mex,

I tend to be a buy and hold person for many things including cell phones. Twice I've been in a position where I could not purchase a replacement battery, even from a 3rd party source. Maddening to say the least.

I am currently using an S4 and I have a back up unit. I also use a Samsung J7 and it is a considerable upgrade. Battery life is at least double the S4 and voice quality is better.

MEXICOWANDERER wrote:
If the S4 battery lasts three years - great. A snap to change. Tiny and inexpensive. Eat one now save one for later.

[MEXICOWANDERER]

If the S4 battery lasts three years - great. A snap to change. Tiny and inexpensive. Eat one now save one for later.

BTW the techs I talked to at NOOK and Kindle were techs not glorified salesmen nor hoodoo online forum ESP analyzers who attempt to miracle "fact" by sarcastic lowbrow witticism critical of a poster not facts. The techs knew the board electronics and expressed cumulative years of experience.

I agree with you Landy, it is better to cycle the eReaders to perhaps 15% then fully recharge time limited with a low ma rate. Some of the unwashed may laugh at going to these extremes but then they do not own eReaders and their perceptions and opinions clearly reflect this.

[landyacht318]

I only own one USB source that is powered by AC, the rest are directly from 12vdc. Seems a DC battery as a buffer would be better than trusting mexican hertz and voltage. You mad e the borg tolerant of Mex electricity surges correct?

Keeping lithium batteries full always is not so great for them, best to keep in the 20 to 80% range if what I read on them can be believed.

My favorite USB source is a Blueseas 12vdc direct charger. That and a short quality cable.

But All I really charge via USB is my S4 mini. Its first battery spent a lot of time being treated like lead acid. Topped up constantly. it did not fare so well. Have a 'duracell' replacement. I don't often leave it at or near 100%.

[full_mosey]

pianotuna wrote:
Hi Mex,

There are lots of posts about batteries swelling up from continuous charging for MIFI (hot spot) devices.

...

I have a MIFI that had a swollen battery. It runs fine 24/7 without the battery while drawing power from a 12V to USB adapter .

HTH;
John

[mike-s]

MEXICOWANDERER wrote:
Techs at both Nook and Kindle said battery life of their units is compromised by high USB charge rates. Are the techs stupid? Are they unaware of the unit's onboard charge management? Or are they savvy to reality?

They not techs, they're just call center agents trying to get the strange nutcase off the phone.

[MEXICOWANDERER]

Fascinating...

[MrWizard]

OFF Topic

LOL momment

"I am a tired and retired electrical engineer. When I smell a skunk it means black and white fur."

we have the black with white stripe kind around here, quite a few of them
but most of the time, IF i smell 'skunk' it does not have Fur

[MEXICOWANDERER]

OK 🙂 I'd better recap this...

I do not care about the Samsung S4 battery. They are a snap to change.
I am not concerned with gizmo device USB battery charging or power. Not critical.

BUT BUT BUT BUT

I am concerned with expensive device non replaceable batteries.
Kindle
Nook
I intend to do all I can to increase the battery lifespan of these two devices.
Because when the batteries go bad the devices become near junk.
And because some people think getting ESTAFETA shipping across Mexico is cheap.
Try $380 pesos and then an eighty mile drive to retrieve packages. $25.00 USD plus $12.00 in gasoline, and a day wasted. Forget about the week wait I can stare at my navel.

Techs at both Nook and Kindle said battery life of their units is compromised by high USB charge rates. Are the techs stupid? Are they unaware of the unit's onboard charge management? Or are they savvy to reality?

Mr Wizard has a great recollection. Yes there are hot flashes down here that DESTROY even premium direct plug-in USB chargers. The last device was reputedly "Blow Up Proof" by testimonial after testimonial. A TWENTY FIVE DOLLAR USB charger purchased on Amazon. Two ports - one regular the second current limited for Apple devices Nook and kindle.

That and three other USB chargers have failed in the last two weeks. I'm you know, sort of disgusted...

Does the power down here get so wacky that it tampers with those IC regulators and you know like destroys them? Is an average of 26 months on an eReader battery normal before it plays possum? Keep your eye on the bouncing ball $25.00 charger. None of the failed chargers cost less than ten dollars. This is not pass the collection plate grade USB chargers.

Oooooooo what other symptoms? multiple laptop's bricks that get a hell of a lot hotter down here DELTA T than they do in the USA. We are talking 10 to 15 degrees hotter. "****! Ouch!" hot.

The laptop bricks get hot but they do not fail. Ooooooooo a clue.

No, and I mean ZERO wall wort is going to have the protection circuitry of a power brick. And no power brick has the survivability of a Meanwell power supply. We are getting closer.

The less work the eBook power management circuit has to do, the longer it will survive, right? Why shovel funnel feed a poor battery to charge in 2 hours when it has ALL NIGHT to do so? Cram-jamming only is appropriate when continued charging cost more than it's worth - like generator battery charging in an RV. And cram-jam charging an RV battery does not significantly lessen the lifespan of the RV battery.

Something is KILLING my USB chargers and Five hundred dollars worth of eReaders gives me a suggestion something is afoot. Forget about the FOUR HUNDRED dollars it cost me to go get the replacement eReaders. And months doing without...

So do I spend yet more money on another wall wort miracle gizmo? A Jim Varney moment.

I am a tired and retired electrical engineer. When I smell a skunk it means black and white fur.

CONCLUSION

There is enough greatly appreciated useful information above for me to proceed. Yes I am going to build a Meanwell powered USB charger. It's going to have two ports with 300ma limited 5.1 volt output. WITH 0.001 max vdc ripple. And latching 12 hour timers on all charging leads.

And it will not provoke a DON'T MESS WITH TEXAS grade handshake with the eReader circuitry.

Thank You

[GordonThree]

mike-s wrote:
If you want to build a 5 volt USB charger which supports multiple devices, you want to look into something like the TI TPS2511, which does the appropriate handshake for different devices.

Better yet is something like the Active Semi ACT4533C, because that covers multi-voltage standards like Qualcomm Quickcharge, but that requires a programmable power supply (per port).

It's up to the device to limit the charging current, not the charger. The charger just tells the device how much power is available.

The simplest charger is just 5.2 volts on the power pins, and the data pins shorted together. That meets the USB charging spec and will cover most devices other than Apple at up to 1.5 amps. 5.2 volts because the spec is 5 +-5%, and many devices will start limiting their charging current as the voltage drops below 5 V, the extra accommodates voltage drop in the cable, is within spec, but still leaves some leeway.

X2 on all of this... Or buy a premade smart charger and Frankenstein it 😉

[Bend]

Run 2 or more in parallel if needed:

https://www.amazon.com/dp/B0141Y4IRG/_encoding=UTF8?coliid=I3FYDZ0NMM45HG&colid=2ZBKPJ1MXQ6H5

Color: 6 Port Car Charger

• 1. THE MOST POWERFUL CAR CHARGER EVER - 65W 13A rapid charging supports up to 6 of your power-hungry devices with their maximum charging speed while driving.
• 2. EXCLUSIVE SI TECHNOLOGY – The exclusive Jelly Comb smart identification technology recognizes your device and distribute the maximum charging current possible.
• 3. GUARANTEED SAFETY & BUILT TO LAST QUALITY - Industry grade materials and premium circuitry give you superior performance and reliability. 12 / 24 volt input compatible with all standard cigarette-lighter sockets. Premium solid ABS material endures wear and tear from long-term usage.

[mike-s]

If you want to build a 5 volt USB charger which supports multiple devices, you want to look into something like the TI TPS2511, which does the appropriate handshake for different devices.

Better yet is something like the Active Semi ACT4533C, because that covers multi-voltage standards like Qualcomm Quickcharge, but that requires a programmable power supply (per port).

It's up to the device to limit the charging current, not the charger. The charger just tells the device how much power is available.

The simplest charger is just 5.2 volts on the power pins, and the data pins shorted together. That meets the USB charging spec and will cover most devices other than Apple at up to 1.5 amps. 5.2 volts because the spec is 5 +-5%, and many devices will start limiting their charging current as the voltage drops below 5 V, the extra accommodates voltage drop in the cable, is within spec, but still leaves some leeway.

[MEXICOWANDERER]

The Meanwell laughs at 167 volts and I have a fist full of 232 volt MOVs and 214 volt TVs. I've even got a 1500 watt computer line conditioner that could sort things out for the finals. I timed the Kindle charge time at 300ma to be 9. hours 18 minutes. Those adjustable eBay timers are hard to beat for the money. I've got the buttkicker SOLA at home for line filtering. Now to baby those batteries. Yes I intend to battery this Sumsang before I leave. To know there are so-called "experts" who have not a clue about chemical thermodynamics of any battery. Glorified salesmen.

[MrWizard]

Mex
was it you that once posted,
it was common to see 167v on the 120v inside house down in your neighborhood,
(not talking about where you are now)
isn't that a bit high for your 145v protection
and are you planning on a timer for each charge circuit
or one timer for everything ?
one wind up timer, for a line conditioner with/on power strip, does the whole thing
i know you will go heavy on the over build
will what you are designing be anymore light weight or compact, than a line conditioner and power strip with a timer ?

i don't have any info on Li-Ion charge management

but since you asked: i bought a "powerbear" replacement battery for my S4

https://www.amazon.com/PowerBear-Samsung-Battery-Verizon-Warranty/dp/B01JHYW84K/ref=sr_1_1?ie=UTF8&q...

[MEXICOWANDERER]

Well the Meanwell is ideally suited to take a scad of 20mm MOV's and 190 volt ptp TVS bi directional diodes. Line to Neutral and Line to earth ground. The internals laugh at 80 volts and 150 volts. So that aspect may be covered pretty well. USB charging duty for a power supply that big is a real shovel-leaner.

Press a button start a timed charge. So little wattage a wire-wound resistor will last forever for current limiting. Remember whatever I charge has it's own version of "what's for dinner" control. The timer is nothing more than an automatic "Unplug Now" disconnect.

And I, not some idiot sets the charging limit voltage.

______________________________________________________________________________

Both Eduardo and Orlando have identical Craftsman 12-volt lithium drills. Eduardo lost his charger when he moved. He asked me to recharge his battery with my lab power supply. So I did. Gently. The battery charge hit a brick wall just like an AGM battery. Only at 12.17 volts. I gave the battery back. a few days later came the feedback...

My drill has NEVER been this powerful when I charged with the Craftsman charger.

Orlando charged his battery then gave it to me. Charged? According to whose Hookah? "Now it will almost break my wrist" reported Orlando after a ramped gentle charge.

Milliamps, time, temperature were all carefully controlled.

Why do I get the feeling I am running into the same idiocy as I see with new lead acid battery chargers? Show me HOW or where to find clear statements of Li-Ion management that spells out dangers of "The ease in which small Li-Ion are overcharged to the point of endangering lifespan".