W520 Brick

The W520 comes with a huge 170W brick.

I have 3 or 4 65W bricks with my T61.

Can they be used with the W520? Not to power the laptop but to recharge the battery at night.

With the new battery life, let's say you head out for appts or school during the day and want to recharge at night. In my case that is quite often in a hotel.

I would rather fly with a 65W brick than a 170W.

Thoughts? Not being an EE this is a bit beyond me but I would think the smaller power supply would charge the battery just over a 3 x longer period of charging.

Perry

 

It won't work. The only other one you can use is the 135W.

 

it won't even recharge the battery with the computer shut off?

 

Lenovo ThinkPad W520 - mini review - Keith Combs' Blahg - Site Home - TechNet Blogs

The 90W ones don't work. What's the chance for 65W?

 

I'm a bit perplexed about the W520 brick. Dell has long had to use various sized bricks for their computers. If you connected a 60W brick to a 15" M70 it would warn you that the 60W supply was under powered and performance would be limited. Presumably it would cut back on CPU and graphic speed and would limit charge current to the battery. The low power brick could be used but with restrictions.

So Lenovo comes out with a computer that is thirsty at times and includes a big power supply. The W520 brick is keyed so the new brick can't plug into the old computers... why? I mean it appears you can use the old bricks with the new computer since the computer plug is backwards compatible. Presumably like Dell the computer knows to keep power usage down when using the low power brick.

All right, so going back to the W520, why would Lenovo design the large brick to not plug into an older, lower power computer? I mean, these are smart systems and the wattage numbers are simply upper bounds. If the computer only needs 15W that's all it will draw. Since the computers do talk to the power supplies and do know when they are using an undersized power supply, why make the new one physically incompatible with say the T410 in your office?

 

Thank you. Apparently a different connector.

Which brings us back to the electrical engineering question. Will a 90 or 65w brick charge the 9 cell battery if a little corrective surgery is done on the connector cord.

I would think yes. But than you need to buy a 135 or 170W brick to get the donor connector. Not likely worth it but you would be saving about half the 1.7 lb wt of the brick.

Perry

 

A 90 watt SHOULD be able to. I use a 90 Watt with my M4400 all the time. It came with a 130W but I have several 90s and never had an issue. Even 60 watts is more than enough to charge the battery. With lithium you can rather easily trade charge current for charge time. The charge voltage of the Lenovo battery is likely 12.6V (4.2V/cell * 3 cells in series). That gives a charge voltage of 12.6. You are probably looking at a charge current into the battery of no more than 4 amps. That would be 50 watts into the battery. With losses you would need the full 60 watts out of the lower power brick for charging. However, you could easily cut the charge current in half. At that point you should have enough power to both charge the battery SLOWLY and run the computer in a low power mode. I can see that potentially making some customers unhappy (hey a power cord is a power cord right?) but there is no reason why it couldn't work electrically. My computer will charge off a Dell 60 watt supply but slowly and any CPU load will result in the battery not charging.

However, it is clear that Lenovo doesn't want it to work. Why a simple software warning isn't enough I don't know. Why they would make the computer so it CAN receive a connector from a 60 watt supply but the 170 can't plug into a T410 I don't know.

 

AFAIK, the W520 uses a 170 watt adapter that is not compatible with other Thinkpads.

 

That is my understanding. The question is why make it incompatible.

 

I am not an expert at electronics but my guess is the W520 requires more power to run than previous thinkpads, as to why they have beefed up the adapter to 170w. If you plug it into a laptop..battery? that is designed to run on a 90/65w adapter..you might just blow it up. No idea if it's true, but it makes sense. Unless someone designed a way for the adapter to downgrade the power outage..but that's not something lenovo would do cause they wouldn't be selling as much.

 

The thing is it doesn't work that way. First, the computers can detect the maximum power the supply can deliver. That way the power management circuits can tell the computer don't draw more than X. That's why a 17" Dell Precision laptop will warn of reduced performance when plugged into a 60 watt supply vs a 120 watt supply.

The other thing is the supplies try to proved 20V (or 18V or what ever they are rated for). To get the 170W number you take voltage x current. So 170/20=8.5 Amps. The supply doesn't always have to provide 8.5 amps. It's OK if it provides less. In fact much of the time it will provide less. So long as the voltage is held at 20V the wattage number doesn't mater so long as it's more than the system needs. Just like you can replace a 200 watt desktop supply with a 500 watt unit but you can't replace a 500 watt unit with a 200 watt unit.

Of course what I talked about above is based on the assumption that the computer sees these as simple power supplies. It is quite possible that Lenovo does something crazy with their power supplies but I'm not sure what or why since others generally don't and the safe rule of thumb is that a it's OK to use a supply that's rated for more than needed but not less than needed.

 

Looks like the blog post was updated an hour or two ago. It appears the 90W power adapter will in fact charge the W520 if the machine is off.

See the update at the bottom of the blog post (just above the bricks pic).

The Lenovo ThinkPad W520 i7 Quad Core has seven hours of battery life? Really? - Keith Combs' Blahg - Site Home - TechNet Blogs

 

my 65W brick from my T61 charges my w520 when it's off.

 

Why did Lenovo engineers make such a blunder for W520 by desiging such a "master piece"? They should all resign and take up jobs as sweepers as part of janitorial work force.

Kennsington - you saved us last time with 120 W slim power supply. When will you make 170W to replace this monster?

 

More power hungry components necessitate a larger power brick that supplies a higher wattage. No way around that, really, and if it's really a dealbreaker, the W520 probably isn't the right machine for you in the first place.

 

Given that the battery life of the W520 is around 8hrs if you use it to surf the web (no Flash), I highly doubt that you really need to carry the brick with you unless you are going to play games or something. And I've carried it around, sure it is a bit heavier than the 30W brick for a netbook, but it fit nicely in my backpack, and it wasn't that heavy, even with the W520 in there too. So, no complaints for me.

 

I have successfully used a 90W IBM charger (bought v. cheaply on ebay) to charge my W520 while off/sleeping.

 

IBM charger or Lenovo charger?

 

That is one of the primary reason I opted for the T520. Even though you get a better spec on the W520 for slightly more, I just can't live with the 170W "brick" that the W520 shipped with.

 

Which also means you are chalking up a battery cycle, or more, per day. Considering the W520 battery won't last all day and evening, using a 90W charger is a bad strategy for most people.

The best solution is a 135W charger if you don't have the extreme quad core processor and raid.

 

That assumes the battery was used during the day. More likely the 90W supply has enough power to run the computer but not run and charge the battery at the same time. Remember that charging takes up a lot of power (probably about 30-45 watts at its peak). The power pack is sized to be able to charge and run the computer at full tilt. So a 135W supply has about 90 watts above and beyond what is needed to charge the computer. If the computer doesn't need to be charged you can probably run the system on the 90 watt supply alone.

 

Nope, you cannot.

 

OK, in that case it's a software (hardware) limit. I assume you mean the system refuses to operate on a lower power supply. I used a 60W supply with a Dell 17" computer a few times. The computer warned of reduced performance but it still ran.

As I said earlier in this thread, I can't understand why they designed the power supply to not work with the computers that don't need as much power but not the other way around. The largest of the current Dell supplies is something like 130 or 160 watts yet it will still act as a stand in for a 60 watt supply. Why make the things physically incompatible.

 

Maybe Lenovo doesn't want to start a fire from the power brick burning out in case the laptop starts drawing too much power. Again, I don't see what's so bad about the power brick. It is not that heavy, and with the battery life of the W520, it is not like you need to bring it anywhere unless you are going to play games or something.

 

Not sure about the 65W adapter, but I can confirm that the 90W adapter does charge the battery when the W520 is put to sleep or power off. The 90W adapter, however, does not have enough "oomph" to power the W520 when it is on.

 

If fire was even remotely a possibility that brick needs to be recalled. The supply MUST be able to supply full rated power continuously under the sort of conditions the computer would be able to operate under. Furthermore, these are smart bricks plugging into smart computers. The power control systems of the computer knows how much power the brick can supply and how much the computer needs at the moment. The computer certainly can be smart enough to refuse to over demand from the brick based on the smart connector alone. I mean if I plug my x120e' 30W brick into a T420 the larger computer will, through software, make sure it doesn't draw more than the brick can supply.

The part I really don't understand is why they made the high power brick not work with the lower power systems. I've charged my x120e using the higher power brick that comes with the T420. No issues of course. If nothing else, I would expect Lenovo to make it the other way, so the smaller brick can't plug into the high power machine. Not to avoid the safety issue you mentioned but to avoid the customer frustration that occurs when the software says, "no".

Don't get me wrong, I don't disagree that the large brick is the price you pay for this type of system. I just think it's crappy that they made it so an x120e owner such as me (well maybe not me but odds are decent that a W520 owner might have a second Thinkpad) can't share one supply with more than one computer. I did do that a lot when I had two Dells.

Does it run in a lower power state (my Dell M20 for instance would reduce the abilities of the graphics card when running on batteries) or does it just not run?

 

if you really want to travel with one brick and two systems, you can share the W510's 130W adapter between your W520 and X120e.   just don't expect full power from the W520 using the 130W at 100% load.

 

I guess, but the software can be somewhat inaccurate at times, or at least I'd think it would be. But, I think that the keying of the power plug on the 170W brick may be just to keep the plug in place so optimal contact is maintained. Thinking about how much electricity has to pass through that little connector boggles my head somewhat.

 

Well since my bigger computer is a Dell I can't exactly share supplies but it still seems odd that Dell was able to make it work but Lenovo decided to handle it a different way.

BTW, I did assume the W520 was sized for a 130W supply. I did forget it was a larger than 130W brick.

The software would have no issue. It's very easy to monitor the power draw in hardware (thus in software). You however, may be correct about the connection. It's possible the higher current load requires a more robust mechanical connector.

 

I recommend not messing with the power brick setup on your computer.

Using a smaller brick may drain your batteries even when the computer is in use, as the power consumption will be greater than the AC supply, and it has to come from somewhere.

If your batteries are always being discharged heavily, they will not have a long life. For the sake of argument, a battery pack might have say 600 full-depth discharges, but 1800 half-depth discharges. Li-I packs tend to die after 3-4 years, but at $170, you want it to last that long, don't you?

I think that a quad-core and a Quadra 2000 take 45 watts each by themselves; that's 90 watts with no chipset, not hard drives, no display backlight, no networking, and no USB ports.

The W520 is a powerful machine, and it wants power.

 

I think may drain depends on the computer. Speaking from Dell and older HP systems (5-7 years old), the Dell will operating the system in a power saving mode and won't charge the battery while the computer is on. The older HP I had would simply switch over to batteries when the load exceeded the rating of the power supply. However, most of the time this wasn't a problem. Only when the computer was dealing with a demanding process like a video game would it over work the brick. My current Dell came with a 110W supply but I've been running a 90W with no issues (not that it's a huge reduction in juice).

 

Checking again, the Quadro 2000 takes up 45 watts; sorry for the misquote.

 

This is my best guess as to what's going on with the 170 watt power supply. This is all speculation however as I'm not affiliated with Lenovo, just thinking it out from an engineering perspective.

If I had to guess, I'm going to guess that when Lenovo started using this form factor of power supply on the thinkpad lineup, they created 65, 90 and 130 watt supplies as standards. Hence, all their laptops could recognize 65, 90, and 130 watt supplies. Laptops, I believe, identify the supply using the third pin (the one in the middle) on the supply. I'm not sure if it's a communication protocol or voltage level identification system, but the bios is programmed (I believe) to recognize something on this pin that tells it, this is a 65/90/130 watt supply.

So heres my big guess. I'm guessing that Lenovo never originally planned on having a 170 watt supply being needed in this formfactor. So when they released the W520 with a 170 watt, they keyed it, so that if you plug it into an older system (say a T510) it won't give you the "I don't recognize this power supply" message and throttle the machine down to all heck (or maybe not even power on at all). The only other way to avoid this issue, would have been a BIOS update to ALL thinkpads that use this form factor/pin layout for their power supplies to add a new power supply id code.

Again..... this is ALL one big guess....... take it or leave it.

 

I thought the Quadro 2000M took up to 55W?

 

No idea if you are right but that does sound like a logical and would explain why they would make the larger supply incompatible with older systems.