Electronics and charger go bang, poof and smoked!

[Jordi]

Luckily not in my Zuk.

I drive a 12 plate wagon. So its reasonably new. It has NO usb sockets and only one 12v socket which is a hella plug, not a cig lighter plug.

Bought a 12/24v usb plug adaptor and it lights up but doesn't actually give any power out. Bought another one. It worked, but got warm. Used it to charge my mobile wifi and tablet.

Earlier it decided to get hot, make a loud pop noise and fill the cab with smoke as its internals moulded into one piece of wire reinforced plastic.

All i ask in this modern world is all truck manufacturers get a grip!

All cars have usb and auxillary sockets for chargers and phones and mp3 players. They are driven for a few hours. We "truck drivers" live in these things and can't even plug a normal 12v charger in without an array of adaptors, half a mile of cable and a multi meter!

Its starting to piss me off a bit.

I said "truck drivers" as i drove to Port Glasgow on wednesday, sat there for 48hrs, tipped and drove back to peterlee.

Needless to say his weekend i need to acquire another set of usb chargers/adaptors and check if it also blew my wifi up that was charging at the time.

[ianedwards]

Oh, that sucks. hope you have luck figuring out what's up. I've bought cheap car chargers off eBay before now and one of them done something similar charging my iPad. I ended up buying a griffin one, and that's lasted well over a year now being used in my ranger all day charging my phone and iPad. It cost more but it's lasted.

Don't know if that's any help.

Ian

[kiwizook]

just get the boss to get some proper ones installed in the truck, at the garage

[turbo-tom]

My granddad actually made a a bank of four 12v sockets and the all went through there own blade fuses. But as they say nothing is made like it use to be! which is a big shame as is never lasts!

[Jordi]

The useless one was a universal adaptor from a phone shop and the one that went poof was a motorway service special, one of those e-lite cigerette chargers. The stickers all said the same input and output values. It was working a charm till it smouldered and died.

The griffin stuff is spot on i have the itrip for my phone.

I need to see if i can get a 12v hella plug'd multi usb charger. So i don't have to fart on with any wiring and can charge my wifi and tablet at the same time.

The newer the gadget the worse the battery life. Everything goes flat within a few hours. I forgot to mention sat nav and blue tooth headset also require plugging in at some point to charge.

[Anton]

Most of these cheap chargers are nothing more than a dc-dc voltage regulator which deliberately wastes 7v as heat (19v on a 24v truck supply), leaving you with a 5v supply. So they're actually designed to get hot.

It's stupid, but it's cheap. Stupid because they can often get so hot, they either break, or they start to melt, short out and then you've got a small plasma cutter in a plastic box. They're really designed to be used for 10 minutes in an emergency, not for continual use - although no-one says that when you're buying one...

Sounds to me like what he really needs (if he's using these things a lot) is a high efficiency inverter. "Switch mode" inverters, I think they call 'em - they switch on an off rapidly (thousands of times per second) to reduce voltage, then use capacitors/bridge rectifiers or whatever to "smooth" out the supply into a constant voltage.

Get him to get something that is rated to handle way more amps than he's going to be drawing. That way it won't produce too much heat, even if it's not a high efficiency design.

[Rhinoman]

The ones that I've had apart use a very simple switched-mode power supply which keeps power dissipation down but they have very little protection against the noise and voltage surges that you get in an automotive environment. They get away with that because they aren't designed to be permanently connected to the vehicle supply so they only need to meet a much lower type approval standard.
I don't think that you'd be able to use a linear regulator without a sizeable heat sink which would be way too expensive, a 12V system actually runs at around 13.7V or thereabouts so you would be looking at over 4W of power dissipation at 500mA.

[Anton]

I've had two of them get *really* hot and fail on me, and both of them had a 7805 linear regulator inside when I pulled 'em apart.

Ebay cheapo nasty rubbish.

4w of heat isn't actually all that much (well, it *is* for the inside of something so small, but on the other hand it's not hellish levels of heat).

Having said that, I now have one that cost me a fiver and that doesn't get nearly so hot, so I assume it's got a switch mode supply inside. I've just bought a 3.5A regulated switch mode supply off ebay (from china) - just to experiment with!

I know, I know, more ebay cheapo rubbish. Sue me.

[Rhinoman]

I've had two of them get *really* hot and fail on me, and both of them had a 7805 linear regulator inside when I pulled 'em apart.
Ebay cheapo nasty rubbish.
4w of heat isn't actually all that much (well, it *is* for the inside of something so small, but on the other hand it's not hellish levels of heat).
Having said that, I now have one that cost me a fiver and that doesn't get nearly so hot, so I assume it's got a switch mode supply inside. I've just bought a 3.5A regulated switch mode supply off ebay (from china) - just to experiment with!
I know, I know, more ebay cheapo rubbish. Sue me.

4W is a lot for a 7805 without a heatsink, that would be a junction temperature of around 290C - except it would smoke in less than a second. Did they have a current rating on them?
Cheap Chinese stuff isn't necessarily bad, a lot of good stuff comes from there too. Whats inside the 3.5A jobbie?

[timwilks13]

I had this problem with my old hyundai, kept blowing chargers both cheap and dearer, and my mobile in one case, so i just cracked open a cheap 12v usb adapter and soldered a resettable fuse on the + wire before the little adapter circuit, did the job for me. Sometimes my phone wouldnt be charging as the fuse was cooling down after a little surge, but never for more than a few minutes.