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From: nick on 11 Jan 2010 08:39
Hi Bill

I put a desktop PC supply 12v (@13A) in series with the bench
supply set to 7v with a 4A max capability. Measured the total output as
19.0v on a DVM.

Fitted the discharged battery into the laptop, Plugged in the power
supply and turned it on.

No change.

After about 12 seconds the charge light comes on amber but <100mA
is supplied to the laptop.

Laptop will not power up. Power light blinks green once. That's all.

Would have thought the lash up supply would at least be capable of
charging the battery with the laptop switched off.

Removed battery.

Laptop still will not power up. Power light blinks green once. That's
all.

Strange thing is that when I charge the battery externally and then
boot the machine with the power supply plugged in, it then takes ~3.5A
once the computer has started, presumably from the battery. Although
the battery discharges eventually, all that current must be going
somewhere. The load fluctuates as the CD is accessed, so I guess it's
powering the computer.

Do you still think it's worth buying a 19v 4.74A adapter (only 0.74A
more capability than my lash up)?

Or perhaps the circuitry between the power jack and the battery is up
the creek?

Nick



From: BillW50 on 11 Jan 2010 11:09
In news:hif9m7$mdr$1(a)news.eternal-september.org,
nick typed on Mon, 11 Jan 2010 13:39:19 +0000 (UTC):
> Hi Bill

Hi Nick! Ill be in and out today. And my email is good except you need
to change the KOM part to COM. Chat at you later.

--
Bill
Asus EEE PC 702G8 ~ 2GB RAM ~ 16GB-SDHC
Windows XP SP2


From: ~misfit~ on 14 Jan 2010 07:07
Somewhere on teh intarwebs nick wrote:
> BillW50 wrote:
>
> Hi Bill,
>
> thank you for another great post.
>
> today I am lashing up a 19V supply from 3 desktop supplies to see what
> gives. Anyway please see comments below.
>
> Nick
>
> PS: Is your email attached to this post good? If so I'll take this
> thread off the group, if that's OK with you.
>
>>> Do you think an adapter with the right ratings will help, or that
>>> there's something wrong with the charging circuit inside?
>>
>> Hi Nick! Laptops if the supply voltage is too low or if it figures
>> out that the supply just doesn't have enough current. They will
>> often refuse to charge the battery, but work fine otherwise. So that
>> could be what is going on here. Charging the battery is often half
>> of the total draw while the laptop is on.
> The adapter rating for this laptop is 19V at 4.74A i.e. 90W.
> Presumably the adapter would be capable of running the laptop
> and charging a completely discharged battery. So the current
> split is probably 2.5A for the laptop, and 2A for the battery. It's a
> 4Ah battery so the initial charge current would be C/2 which makes
> sense.
>
>>
>> Why the charge light only comes on for about 10 seconds and a draw of
>> 100ma is interesting. It could be the laptop is unhappy about the
>> voltage and waits 10 seconds before giving up. Although it could
>> decide something is wrong with the battery too. So I would keep this
>> in mind as well.
> Not quite. When you plug in the adapter the charge light is initially
> off. After about 10-12 seconds it come on (amber) and stays on for as
> long as the adapter is plugged in.
>
>>
>> Otherwise you are on the right track. I am assuming the 3.5 amp draw
>> was at 15v, eh? I don't know what the original one put out, but 19v
>> at 3.5 amps is very common. My docking station has a supply of 19v
>> at 6.3 amps. Overkill for what I use it for. Although it supports
>> much beefier laptops than mine.
>>
> Yes 3.5A at 15V. Been looking at adapters on ebay. Thought I might
> invest in a 19V 6.3A one so there's a bit of spare capacity.
>
>> And you say you are charging the battery on the bench. Have you
>> charged lithiums before? As if you overcharge them or charge them
>> too fast, they will explode. It is usually recommended if you charge
>> them without safety circuits, to place them in some sort of metal
>> container. Thus if it does burst into flames, it shouldn't catch
>> anything else on fire. Plus don't throw water on it if it does. As I
>> believe that only makes it worse.
>>
> Yes I have done this before. Thanks for the warnings though.

Clevo isn't a brand that I'm aware of, they're probably not imported into
this country. However a cursory Google tells me that model is a fairly new
one? Core2Duo CPU? All I can say is that some laptops are very smart. I have
two different size power adapters that fit this ThinkPad T60, a 65W and a
90W, both 20V.

The Lenovo Power Manager utility recognises which adapter is attached and,
if the battery is charging, adjusts the projected time to completeion
accordingly. Perhaps your machine is querying the power supply for a signal
and isn't getting one? I've heard that some newer laptops won't accept a
multi-voltage, multi-tip adapter such as I have as it doesn't 'identify
itself' as being genuine. (I'm sure I read that somewhere...)
--
Shaun.

"Give a man a fire and he's warm for the day. But set fire to him and he's
warm for the rest of his life." Terry Pratchet, 'Jingo'.


From: nick on 14 Jan 2010 15:52
~misfit~ wrote:

G'day!

>
> Clevo isn't a brand that I'm aware of, they're probably not imported into
> this country. However a cursory Google tells me that model is a fairly new
> one? Core2Duo CPU? All I can say is that some laptops are very smart. I have
> two different size power adapters that fit this ThinkPad T60, a 65W and a
> 90W, both 20V.

Made in Taiwan

http://www.clevo.com.tw/en/index.asp

Rebadged and marketed in the US and EU under various names.

Yep, it's a Core2Duo, 2GB DDR2, 17" screen. I though it was worth
salvaging.

Interesting that the ThinkPad knows which adapter is connected. Dell
use an extra wire in the cable between the adapter and the laptop.
Perhaps the ThinkPad does something similar.

http://www.laptop-junction.com/toast/content/inside-dell-ac-power-adapter-mystery-revealed

>
> The Lenovo Power Manager utility recognises which adapter is attached and,
> if the battery is charging, adjusts the projected time to completeion
> accordingly. Perhaps your machine is querying the power supply for a signal
> and isn't getting one? I've heard that some newer laptops won't accept a
> multi-voltage, multi-tip adapter such as I have as it doesn't 'identify
> itself' as being genuine. (I'm sure I read that somewhere...)

I've had a close look at the power connector on the back of the laptop,
and there's only the plain old tip and sleeve, so no third wire there.

Hard to see how the laptop can know much about the adapter over 2 wires
except the voltage.

The battery is a different matter though. Quite prepared to believe
that the battery is part of the problem.

But the laptop doesn't power up off the adapter with the battery
removed, so either the adapter isn't man enough or there's a fault in
the laptop.

The battery won't charge in the laptop, so I'm inclined to think the
charging circuit in the laptop is hosed.

Nick

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