[ltp] Thinkpad power adapters and less than 100V mains

[Richard Neill]

 > Does it damage a Thinkpad power adapter to use the laptop plugged in
 > when the electricity supply is potentially less than 100V?

Personally, I think you're unlikely to damage the supply, but may force 
it into thermal shutdown; you may wish to try to reduce your laptop's 
current draw at this point.

IBM used to make AC/DC supplies that could run off either a 110/240V AC
line or off a 12 cigarette-lighter socket. You can still get these on 
eBay; I'd imagine that internal electronics of these is rather more 
over-specced.

Best wishes,

Richard


BTW, I wouldn't necessarily blame the manufacturers for shipping 
lower-wattage supplies: as the machines get more energy-efficient, they 
just need less power, and a lower-wattage supply weighs less.




On 17/10/11 03:25, Jason Brooks wrote:
> Since the power coming out of the supply will be regulated it
> shouldn't hurt the laptop.
> You could cause problems for the power supply because it will be
> working harder. The constant charge and surge that the capacitors will
> go through in a low power situation would shorten the life of them.
> Normally this wouldn't be a issue since they charge and stay charged
> in a full power situation.  Is this why your power supply is acting
> flaky? Maybe but more than likely it is from every day use. All
> manufactures are cutting back and bundling the lowest wattage power
> supply they can. They don't last. I had a HP power supply that was 90W
> for about a year... then it was 70 watt...  Replaced it with a APC
> power supply and have not had a problem since. I would suggest the
> same to you.
>
> On Sun, Oct 16, 2011 at 6:54 PM, Damon Lynch<damonlynch@gmail.com>  wrote:
>> Hi everyone,
>>
>> Does it damage a Thinkpad power adapter to use the laptop plugged in when
>> the electricity supply is potentially less than 100V?
>>
>> This past summer I used my T400s in such a situation. The laptop was
>> sometimes doing computationally intensive work. The power supply became
>> quite a bit hotter than it normally does. In fact sometimes it was very hot
>> indeed. I don't know if this damaged it or not. All I do know is that when I
>> now use my T400s for computationally intensive work for extended periods, if
>> I use that same power supply, the laptop can shut down without warning. If I
>> use another power adapter (which I did not use in that kind of low voltage
>> situation), it never shuts down.
>>
>> Perhaps the answer is "Why yes of course, you have damaged the power supply.
>> Never run on less than 100V." However I believe the power adapter simply
>> might be a bit dodgy, as the laptop would occasionally shut down without
>> warning even before I used it when the mains was less than 100V . It didn't
>> do it a lot, but it did sometimes. The only difference is that it does it
>> far more regularly now.
>>
>> A related question: if I am in a situation where the mains supply is less
>> than 100V and I'm running the laptop off it with the battery present (which
>> might be charging), does it make any difference if I am using lower power
>> Thinkpad like a T400s as compared to say a W520? Furthermore, if using the
>> laptop when the laptop is powered on actually is bad, is it still perfectly
>> ok to charge the laptop battery from a low-voltage mains when the laptop is
>> off?
>>
>> As you might guess, I'm far from expert in these matters so if the answers
>> to my questions are blindingly obvious then I apologize :)
>>
>> Thanks,
>> Damon
>> --
>> http://www.damonlynch.net
>>
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