car usb charger not durable

I have gone through several car usb chargers that plugs into cigarette lighter plug.

They usually die in a few months.

I just opened one up and it has a 34063a IC in it. The circuit is probably 
similar to this:
http://www.ifixit.com/Teardown/Generic+1A+USB+Car+Charger+Teardown/10108

When I plug this in it draws 3mA but the built-in LED doesn't light up. I assume 
the IC has fried.

Any idea why these chargers don't last long?
Where can I buy one that last longer, and how is it made differently to make it 
last longer?

On Fri, 28 Mar 2014 15:56:41 -0700, bob <nospam@hotmail.com> wrote:

>I have gone through several car usb chargers that plugs into cigarette lighter plug.
>
>They usually die in a few months.
>
>I just opened one up and it has a 34063a IC in it. The circuit is probably 
>similar to this:
>http://www.ifixit.com/Teardown/Generic+1A+USB+Car+Charger+Teardown/10108
>
>When I plug this in it draws 3mA but the built-in LED doesn't light up. I assume 
>the IC has fried.
>
>Any idea why these chargers don't last long?

Because they're junk?

>Where can I buy one that last longer, and how is it made differently to make it 
>last longer?

What are you charging?  I see some that are rated for 2A but I've
fried a few of those, too.  Some have two USB ports.  Don't do it!

On Fri, 28 Mar 2014 15:56:41 -0700, bob wrote:

> I have gone through several car usb chargers that plugs into cigarette lighter plug.
> 
> They usually die in a few months.
> 
> I just opened one up and it has a 34063a IC in it. The circuit is probably 
> similar to this:
> http://www.ifixit.com/Teardown/Generic+1A+USB+Car+Charger+Teardown/10108
> 
> When I plug this in it draws 3mA but the built-in LED doesn't light up. I assume 
> the IC has fried.
> 
> Any idea why these chargers don't last long?
> Where can I buy one that last longer, and how is it made differently to make it 
> last longer?

Didn't think too deeply about it, but it's a different circuit topology than the
one shown on the first 34063 datasheet that I pulled up.  I hope that the ifixit
web site is wrong, because the inductor location seems wrong!

On Fri, 28 Mar 2014 15:56:41 -0700, bob <nospam@hotmail.com> wrote:

>I have gone through several car usb chargers that plugs into cigarette lighter plug.
>They usually die in a few months.

I passed out about 15 of those to various friends and customers last
Christmas as "stocking stuffers".  None have failed so far.  Most are
being used to charge phones.  Unlike yours, these have two USB
sockets.  One wired for Apple, and one for the rest of the planet.
Something like this one:
<http://www.ebay.com/itm/111192401361>
I'll tear one apart today, if I can find where I put them.

>I just opened one up and it has a 34063a IC in it. The circuit is probably 
>similar to this:
>http://www.ifixit.com/Teardown/Generic+1A+USB+Car+Charger+Teardown/10108

The schematic looks odd.  There's also no spike or reverse polarity
protection on the 12V line.  The automobile electrical system is a
hostile environment, which is quite capable of delivering high voltage
spikes to connected electronics from starter back-EMF and such.  Extra
credit for alternators that don't know what to do with a dead
battery[1].  Since I can't seem to find a plague of similar problems,
my guess(tm) is that your situation is unique.  I suggest you plug an
oscilloscope and DVM into your cigarette lighter jack and see what's
coming out, especially when you toggle loads (lights, heater fan,
radio, etc) and start/stop the engine.

>When I plug this in it draws 3mA but the built-in LED doesn't light up. I assume 
>the IC has fried.

Doing a post mortem might help, but you're probably correct.  There's
not much else to blow up except the IC.

>Any idea why these chargers don't last long?

Your vehicle might be killing them.

>Where can I buy one that last longer, and how is it made differently to make it 
>last longer?

I bought some of these.
<http://www.ebay.com/itm/390759035788>
on a recommendation by a friend.
<http://tips.navas.us/2014/01/best-usb-car-charger.html>
It seems to charge my Samsung tablet at the rated 2A, but I haven't
bothered to measure it.  No failures so far.


[1] I lost 3 alternators, several 2way radios, and the glow plug timer
in my 1983 Dodge D50 before I figured out what was happening. Charging
a good battery is fairly simple.  What to do with a half-dead battery
is not so simple.



-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

On 3/29/2014 12:05 PM, Jeff Liebermann wrote:
> On Fri, 28 Mar 2014 15:56:41 -0700, bob <nospam@hotmail.com> wrote:
>
>> I have gone through several car usb chargers that plugs into cigarette lighter plug.
>> They usually die in a few months.
>
> I passed out about 15 of those to various friends and customers last
> Christmas as "stocking stuffers".  None have failed so far.  Most are
> being used to charge phones.  Unlike yours, these have two USB
> sockets.  One wired for Apple, and one for the rest of the planet.
> Something like this one:
> <http://www.ebay.com/itm/111192401361>
> I'll tear one apart today, if I can find where I put them.
>
>> I just opened one up and it has a 34063a IC in it. The circuit is probably
>> similar to this:
>> http://www.ifixit.com/Teardown/Generic+1A+USB+Car+Charger+Teardown/10108
>
> The schematic looks odd.  There's also no spike or reverse polarity
> protection on the 12V line.  The automobile electrical system is a
> hostile environment, which is quite capable of delivering high voltage
> spikes to connected electronics from starter back-EMF and such.  Extra
> credit for alternators that don't know what to do with a dead
> battery[1].  Since I can't seem to find a plague of similar problems,
> my guess(tm) is that your situation is unique.  I suggest you plug an
> oscilloscope and DVM into your cigarette lighter jack and see what's
> coming out, especially when you toggle loads (lights, heater fan,
> radio, etc) and start/stop the engine.
>
>> When I plug this in it draws 3mA but the built-in LED doesn't light up. I assume
>> the IC has fried.
>
> Doing a post mortem might help, but you're probably correct.  There's
> not much else to blow up except the IC.
>
>> Any idea why these chargers don't last long?
>
> Your vehicle might be killing them.
>
>> Where can I buy one that last longer, and how is it made differently to make it
>> last longer?
>
> I bought some of these.
> <http://www.ebay.com/itm/390759035788>
> on a recommendation by a friend.
> <http://tips.navas.us/2014/01/best-usb-car-charger.html>
> It seems to charge my Samsung tablet at the rated 2A, but I haven't
> bothered to measure it.  No failures so far.
>
>
> [1] I lost 3 alternators, several 2way radios, and the glow plug timer
> in my 1983 Dodge D50 before I figured out what was happening. Charging
> a good battery is fairly simple.  What to do with a half-dead battery
> is not so simple.
>
>
>
Another approach would be to bodge in a PolyZen.  They're brilliant.

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

On Friday, March 28, 2014 6:56:41 PM UTC-4, bob wrote:
> I have gone through several car usb chargers that plugs into cigarette li=
ghter plug.
>=20
>=20
>=20
> They usually die in a few months.
>=20
>=20
>=20
> I just opened one up and it has a 34063a IC in it. The circuit is probabl=
y=20
>=20
> similar to this:
>=20
> http://www.ifixit.com/Teardown/Generic+1A+USB+Car+Charger+Teardown/10108

That website is the usual internet electronics site: junk. The schematics a=
re both obviously wrong in that the feedback to IN(-) requires a DC input a=
nd therefore should be connected to the output node and not the diode node.=
 Other comments there are similarly smug and probably wrong.


>=20
>=20
>=20
> When I plug this in it draws 3mA but the built-in LED doesn't light up. I=
 assume=20
>=20
> the IC has fried.
>=20
>=20
>=20
> Any idea why these chargers don't last long?

The thermal impedance of that IC package is rather high at about 90oC/W, wh=
ich means it's going to run hot, the Darlington output drive is the least e=
fficient way to use the 34063.

>=20
> Where can I buy one that last longer, and how is it made differently to m=
ake it=20
>=20
> last longer?

snip!
> 
> Jeff Liebermann     
> 
> 150 Felker St #D    http://www.LearnByDestroying.com
> 
> Santa Cruz CA 95060 http://802.11junk.com
> 

OT: Say Jeff, do they still have that big nude hot tub place in Santa Cruz? 

I thought that was rather unique, when I was there...
jb

On Sat, 29 Mar 2014 13:06:48 -0400, Phil Hobbs
<hobbs@electrooptical.net> wrote:

>On 3/29/2014 12:05 PM, Jeff Liebermann wrote:
>> On Fri, 28 Mar 2014 15:56:41 -0700, bob <nospam@hotmail.com> wrote:
>>
>>> I have gone through several car usb chargers that plugs into cigarette lighter plug.
>>> They usually die in a few months.
>>
>> I passed out about 15 of those to various friends and customers last
>> Christmas as "stocking stuffers".  None have failed so far.  Most are
>> being used to charge phones.  Unlike yours, these have two USB
>> sockets.  One wired for Apple, and one for the rest of the planet.
>> Something like this one:
>> <http://www.ebay.com/itm/111192401361>
>> I'll tear one apart today, if I can find where I put them.
>>
>>> I just opened one up and it has a 34063a IC in it. The circuit is probably
>>> similar to this:
>>> http://www.ifixit.com/Teardown/Generic+1A+USB+Car+Charger+Teardown/10108
>>
>> The schematic looks odd.  There's also no spike or reverse polarity
>> protection on the 12V line.  The automobile electrical system is a
>> hostile environment, which is quite capable of delivering high voltage
>> spikes to connected electronics from starter back-EMF and such.  Extra
>> credit for alternators that don't know what to do with a dead
>> battery[1].  Since I can't seem to find a plague of similar problems,
>> my guess(tm) is that your situation is unique.  I suggest you plug an
>> oscilloscope and DVM into your cigarette lighter jack and see what's
>> coming out, especially when you toggle loads (lights, heater fan,
>> radio, etc) and start/stop the engine.
>>
>>> When I plug this in it draws 3mA but the built-in LED doesn't light up. I assume
>>> the IC has fried.
>>
>> Doing a post mortem might help, but you're probably correct.  There's
>> not much else to blow up except the IC.
>>
>>> Any idea why these chargers don't last long?
>>
>> Your vehicle might be killing them.
>>
>>> Where can I buy one that last longer, and how is it made differently to make it
>>> last longer?
>>
>> I bought some of these.
>> <http://www.ebay.com/itm/390759035788>
>> on a recommendation by a friend.
>> <http://tips.navas.us/2014/01/best-usb-car-charger.html>
>> It seems to charge my Samsung tablet at the rated 2A, but I haven't
>> bothered to measure it.  No failures so far.
>>
>>
>> [1] I lost 3 alternators, several 2way radios, and the glow plug timer
>> in my 1983 Dodge D50 before I figured out what was happening. Charging
>> a good battery is fairly simple.  What to do with a half-dead battery
>> is not so simple.
>>
>>
>>
>Another approach would be to bodge in a PolyZen.  They're brilliant.
>
Yeah.  They're really slick.  I'd use a bunch, except that they won't
reset themselves when the fault is removed.  I'm looking for a
replacement for expensive TVS diodes.  Thinking about a couple of
nose-to-nose pass-fets with appropriate controls but they're not so
good (or cheap) at high currents, either.  

Jeff Liebermann <jeffl@cruzio.com> wrote:
> [1] I lost 3 alternators, several 2way radios, and the glow plug timer
> in my 1983 Dodge D50 before I figured out what was happening. Charging
> a good battery is fairly simple.  What to do with a half-dead battery
> is not so simple.

What I have done in the past, if I had a car battery that only wanted to
sip a few mA from the 6 A or 10 A charger, was to stick the dumb 1 A
charger on it and let it cook for a few hours.  After that, I could put
the "big" charger on it and it would actually charge at a decent rate
(5 A to 10 A) and then taper off as normal.  Maybe some alternators
don't know to back off if the brute force approach isn't working?

By the time I had to do that trick to get it to charge, the battery was
kinda beat, but doing that would get it to work as good as it could for
a while - days to weeks, depending on the usage of the car.

If the battery still wouldn't take a good charge (more than a couple of
amps) after cooking on the 1 A charger overnight, it was usually toast.

Matt Roberds

On Saturday, March 29, 2014 2:22:50 PM UTC-4, mrob...@att.net wrote:
> Jeff Liebermann <jeffl@cruzio.com> wrote:
>=20
> > [1] I lost 3 alternators, several 2way radios, and the glow plug timer
>=20
> > in my 1983 Dodge D50 before I figured out what was happening. Charging
>=20
> > a good battery is fairly simple.  What to do with a half-dead battery
>=20
> > is not so simple.
>=20
>=20
>=20
> What I have done in the past, if I had a car battery that only wanted to
>=20
> sip a few mA from the 6 A or 10 A charger, was to stick the dumb 1 A
>=20
> charger on it and let it cook for a few hours.  After that, I could put
>=20
> the "big" charger on it and it would actually charge at a decent rate
>=20
> (5 A to 10 A) and then taper off as normal.  Maybe some alternators
>=20
> don't know to back off if the brute force approach isn't working?
>=20
>=20
>=20
> By the time I had to do that trick to get it to charge, the battery was
>=20
> kinda beat, but doing that would get it to work as good as it could for
>=20
> a while - days to weeks, depending on the usage of the car.
>=20
>=20
>=20
> If the battery still wouldn't take a good charge (more than a couple of
>=20
> amps) after cooking on the 1 A charger overnight, it was usually toast.
>=20
>=20
>=20
> Matt Roberds

Did you have a meter on that 1A charger? Was it delivering 1A or just a few=
 hundred miliamperes too? I suspect the big charger was using a 3-stage alg=
orithm and was knocked right into stage 3 float charge by the high terminal=
 voltage, whereas the 1A charger was some simple 1-stage taper charge.