We're looking for a power inverter to recharge our Compaq notebook in the car. Is it better to buy one with a larger rating (400W) rather than a smaller one? Black & Decker has a 100W model ($13) and it gets decent reviews:
formatting link
But the notebook uses ~90W, so we'll be very close to this inverter's capacity. The alternative is something larger, e.g.
formatting link
This one's 400W, but we're wondering if the extra cost is worth it.
Not a good idea. There can be spikes of up to 400 volts in an automotive electrical system. Then there is the possibility of a 'load dump' which happens when the voltage regulator fails, or a loose battery cable.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.
Fat wires directly to the battery has always served me well in a number of instrumented cars. Only one accident with a blown regulator in a generator, suddenly about 100 volt instead of 12 volt. That was over a period of 40 years. The battery works like a rather big capacitor. :)
To get 100 volts you'd need not only a faulty regulator but a faulty or disconnected battery. Turning the average alternator hard on only usually results in the high teens volts wise. Although I've no idea what happens with some of these modern ultra high powered water cooled types. ;-)
--
*Arkansas State Motto: Don\'t Ask, Don\'t Tell, Don\'t Laugh.
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
At those heavy overloads the battery will form a gas layer between electrolyte and electrode. That gas layer will act as high resistance(for a short time), long enough to explode the caps in a number of convertors. After servicing about 12 supplies and an assorted 10 opamps, we were back in bizness. The generator survived. The battery as well. The regulator needed two transistors and a new zener diode. But spikes as mentioned? Never a problem.
No wondering, at all. They are designed to meet the specifications. Believe whatever you want, but there are detailed specifications for automotive electronics, and the required protection. G0 to the design newsgroup and tell some of the engineers that there are no spikes, or load dumps.
The early Delco transistor car radios had a 'Spark plate', that arced over to damp the spikes, along with a large series inductor.
ignorance may be bliss, but it damages lots of equipment.
--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
I'd guess the Delco designers knew how crap their car electrics were. Early Blaupunkt seemed to work just fine without.
Sure it might if you're stupid enough to disconnect the battery with the engine running.
It's a bit like memory effect on Ni-Cads - it can happen but is very very rare. Doesn't stop some 'engineers' saying it happens all the time. And others believing them.
--
*TEAMWORK...means never having to take all the blame yourself *
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
Every crappy solid state Blaupunkt I worked on had similar protection. They were the lowest grade construction of any automotive electronics that I ever had the misfortune to repair. I repaired over
1000 car radios when I was a teenager. Delco was one of the best, as far as durability & ease of repair. They were durable, because they were better designed. Philco was the worst US design, followed by the Japanese radios, then the European designs. I never saw anything from Russia, but I've heard that they were even worse.
So, you claim that batteries never fail, or battery lugs come loose? You've never seen an open fusible link? You are just a parts changer who doesn't understand the intimate details of a design.
Results 1 - 10 of about 177,000 for automotive electrical load dump. (0.30 seconds)
Its nothing like Ni-Cad 'Memory effect' which was reported in some spacecraft that had the exact same charging cycle, over and over due to their constant orbit. The effect was proven in the lab by duplicating the charging cycles. By varying the charge cycles that doesn't occur.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.
There are universal 12v adapters just as there are universal AC adapters.
Some of the Dell laptops can positively identify a genuine Dell PSU and won't charge if it isn't genuine. Dell put a silicon serial number IC inside the PSU which the laptop can read.
It's fairly simple to add the serial number if you can find a defunct PSU (although a major reason for Dell adapters being faulty is that the serial number chip dies!) but genuine AC adaptors are pretty cheap on eBay.
It's just a boost converter, there's no separate 'step up' stage followed by a regulator. Can be done with a single IC but most of the ones I've seen have been based on the MC34063 controlling a high current MOSFET switch driving a toroid.
I did it for a living, in a large city. That 1000+ radios was all brands. The Delcos usually took less time to repair than it took to write the service ticket. The Philco, Motorola & Bendix took a half hour to one and a half hours, while the Blaupunkt repairs averaged nine months, because they were so damn slow to ship parts to their US distributor. No part we needed was EVER in stock.
Are you really that ignorant? A lot of failures occur while on the road. A worn battery cable can arc to the frame, cusing a large splie. The fusible link can open, a battery cable can come off. It has all happened, more than once. I can see you aren't smart enough to uderstand the ramiofications, so this will be my last reply to your ignoerant comments.
They were crap. At least whatever they exported to the US was. We were the only shop for 100 miles who would even repair them in the '70s. The parts were crammed in tightly, the wiring harnesses were brittle, and broke quite easily. I still have some manuals, showing what crap they were. Some had clusters of cheap Japanese style resistors standing on end, that vibrated & cracked the leads. Just trying to locate the bad one would break several that were already weak from metal fatigue.
Hung up? Fad? 177,000 hits isn't a fad, idiot. It has been well known by electrical engineers who designin automotive electronics since the early '60s. One of the first hits was from the IEEE, but I doubt you have any idea who or what they are.
Go to news:sci.electronics.design and let some of the older engineers tell you of the damaged equipment and explosions from load dumps in the labs.
Plenty of idiots who failed science class and who believe in old wives tales and don't understand the chemietry involved.
Have you ever done any real design work, or ar you just another ignorant parts changer? My design work is in space. Some is aboard the International Space Station, comprising one of the main audio, video & data communications systems. Definitely a place where you have to be damn sure that your designs will not take out the main DC power buss, or be affected by transients.
--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
The reason this was such a great deal was that I already 'had' a genuine supply for it. I once had a surplus of Dell bricks, but I've gone through a few, since. I could use another 90 watt supply for my D400 docking bay. If you boot it with the original 70 watt unit, the laptop knows. You get a message in POST that tells you it knows...and it won't boot the docking bay.
Right. So your opinion of a design is clouded by spares availability?
Strange. I've owned - and had experience of - hundreds of cars. And never had this happen. Despite the majority having Lucas electrics.
My first one was a Frankfurt bought in the '60s when it was one of the few available with FM - as well as LW, MW and SW. The only thing that went wrong with that in a long life was the on/off switch which was part of the volume control. A new part was in stock. And it appeared to be very well made. I've no experience of their OEM stuff - I've no doubt it was made down to a price same as all other OEM radios. It was transferred from car to car - for a long time. I didn't junk it after buying a cars with reasonable factory fit stuff - and sold it on Ebay not that long ago for more than it cost new.
You don't know much about search engines, do you?
In the labs. Says it all.
My point exactly.
Lucas called themselves Lucas Aerospace...
--
*I feel like I\'m diagonally parked in a parallel universe*
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you\'re crazy.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.