power laptop with ac adapter through battery port

[waterhouse]

I have a laptop (inspiron 600m) that will only run on battery even though the ac adapter is fine. Can I take the adapter (with if necessary some voltage modification) , and connect it directly into the battery input. Looking and reading up on laptop batteries though I see they are extremely complex with communication back and forth with computer to sense energy level and so forth. Can this be overriden allowing me to just feed a constant dc voltage in.

 

[Mikebits]

Sounds like a bad idea.
What makes you so sure the adapter is working properly? Have you verified the adapter under load conditions, have you looked at its ripple output with a scope?

 

[waterhouse]

I tried another adapter of the same model and the laptop wouldn't power with it either.

 

[Mikebits]

Hmm, sounds like a good test. Your adapter did work with other Laptop I assume. Shoot I am not sure what the answer is, but your proposal is not it. Sounds like the charger has failed, but you say the batts work ok right? Maybe look for an external batt charging circuit... I dunno

 

[sPuDd]

That fault is common to Dell laptops. It can be either a damaged PCB near
the power socket, or the 1-wire reader that checks the PSU is faulty, or
one of many other problems. The only fix is to send it to Dell for repair.

This post written on a Dell D530 - however it will be followed by a Panasonic CF-30 ToughBook.

sPuDd..

 

[waterhouse]

The laptop is old and out of warranty. A repair shop would be too expensive for such a computer. The battery is also on its last leg. So its either repair or throw out.

 

[98formulaLS1]

This is a typical problem. The answer ends up being that the AC power connector on the motherboard is somehow damaged. If you disassemble the laptop, you will probably find the connector broken, or not connected properly anymore. just a note.

 

[HexKrak]

I'd pop it open and check the connections from the adaptor socket to the pcb and see if it just needs some re soldering. That could easily be a much simpler fix than chopping up your cable.

If you can replicate the output of your battery with your adapter then it's possible that you could just wire it up, but chances are that the output of the adaptor differs from the battery.

 

[waterhouse]

I tried taking it apart in hopes of resoldering the power jack or whatever I might find that was loose. Unfortunately I've got a stuck screw that won't allow me total access. Also from what I see the manufacturer has made the connection inaccessible so you have to buy an entire motherboard if it is broke. It sould seem there should be some way to just supply dc power to the computer through the battery input. After all if this where say a toy with an alkaline battery of 9V you could just build a DC power supply of 9V and feed it to the + and - inputs, fundamentally if I could just bypass all the sensing and charging apparatus that is all the laptop battery is doing as well.

 

[Diver300]

Dell have the stupid idea that they will not work unless they recognise the power supply is of the right type.

Then they use the worst possible connector so that the connection to the 1-wire identifier fails, so you get this warning that you are using the wrong power supply, when it is their fault in the first place.

You only need to make the connection briefly and the Dell will work until you unplug it. You could try wiggling the connection until the screen brightens, which shows that the power supply is recognised.

The motherboard connectors for Dells are now available on Ebay. You do have to get the whole thing apart.

 

[jerald]

Hi Waterhouse,
Were you able to power the laptop with ac adapter through battery port?
I also have the same problem and I was searching google to find any answer.
Please let me know about it.

Thanks

 

[zapatista]

jerald and waterhouse yeah i connected my ac adapter directly into well soldered it directly into the battery port and runs well. i had to solder a rechargable battery first into the battery area then re wire the battery to have an ac/dc connected straight to it when its low. took some trial and error but warranty was out repair too much it was just a door stopper with a screen so what the heck and well it works well----------------------------------

 

[mc42002]

I have a HP notebook and the same problem. Also I want to connect AC power directly to the battery port. But supplay exit from power is 19 V on a batery about 11.1. Is that a problem?

 

[boltstop]

AC jack directly on a battery pac bypass motherboard

Can you put a female ac jack into the battery pac and bypass the one mounted on the motherboard? ive been thinking about this for some time and dont know where to begin

 

[Hero999]

Can you put a female ac jack into the battery pac and bypass the one mounted on the motherboard? ive been thinking about this for some time and dont know where to begin

Sounds like another bad idea to me.

 

[tcmtech]

I rebuilt the battery pack for my laptop a while back and once you remove the cells its not all that hard to work with.

If its a 11.1 volt battery three should be three sets of cells.
One end is the positive and the other end is the negative of course but there are two tap leads for balancing the three cell sets that would need to be attached to a simple three resistor voltage divider circuit so that the original battery monitor system should think that the cells are intact when the external power is active.

In theory if the internal battery monitor system sees the correct range of voltages at the right lines it should also think that the battery is working and supplying power.
But its just an educated guess overall.

 

[gdesilva]

jerald and waterhouse yeah i connected my ac adapter directly into well soldered it directly into the battery port and runs well. i had to solder a rechargable battery first into the battery area then re wire the battery to have an ac/dc connected straight to it when its low. took some trial and error but warranty was out repair too much it was just a door stopper with a screen so what the heck and well it works well----------------------------------

Hi, can you please post a schematic (with pinouts) on how the soldering was done?

Many thanks

 

[jailhousews]

Hi, can you please post a schematic (with pinouts) on how the soldering was done?

Many thanks

Let's just say that in the course of trying to replace my laptop's dc power jack I messed it up probably beyond repair. I have been planning on doing this same workaround but don't know exactly how....

I would also very much like to know exactly how you did this, zapatista as I've been without the use of my laptop for a few weeks now.

 

[Blueteeth]

Probably a little late on this one, and perhaps not helpful but...

Asd many have stated, most likely the connector for the external PSU to the laptop is damaged. Connectors often fail, since you're constantly plugging things in and out of it. If anyone in this thread has this problem, I would strongly advise to NOT route power via the battery connections. As the OP stated (quite rightly) there are several connections, including data, between the battery pack unit (which also has some intelligence) and the laptop.

Often laptops will check the part number of the battery, and refuse to charge it if it doesn't recognise it, or if its not deisgned to work with it. This not only ensures that the thing won't explode when using a dodgy copied battery (by over charging) but also, so companies can make more money, forcing the consumer to use one specific battery, and charging (punn intended) what they like for it.

Replacing the DC/AC jack on a laptop isn't always easy, but it can be done, with basic tools. The only really hard part is getting to it. Laptops have many tinys screws which are easily lost (my laptop has lost 13 so far lol). When desoldering parts, remember, you usually have to sacrifice something. That is either the PCB, or the component.

In this case, the DC jack is screwed and so you must sacrifice that, as you obviously want the PCB to be fine. Instead of trying to desolder it as-is (difficult on a double sided/multilayer PCB, with non-lead solder), cut it off. destroy it with wire cutters, leaving only the pins stuck in the board. These can then be easily removed with a soldering iron, just don't 'pull' or 'push' them, melt the solder, and tap them until they come out. Any force could lift/break the copper pads on the PCB (which are held on with glue which melts at a lower temp than solder), and make your life a lot more difficult. Clean it up with soldering wick and flux, leaving pristine tinned pads, and solder on a new one - which you can usually get form ebay

Done this 4 times with my laptop, and 5 times with its singe USB socket. It's still going, although I should probably stop dropping it on its side at work.

Its not an interesting 'hack', but its less likely to destroy your laptops ability to communicate/power from batteries. - which defeats the point of a 'portable computer', as well as leave you wil NO way to power the thing.

 

[jailhousews]

I have already taken apart my laptop to replace the DC jack as you said. The pins on the thing were so darn small it was very difficult to work with. I couldn't get the solder to melt at first, until I switched to a fatter tip. Even then, when it did melt, the solder wick and pump both wouldn't get it all up. So I lost my patience and took my pliers out.... twisting the jack side to side until the pins snapped. Unfortunately I STILL couln't get the pins out.

Basically I'm stuck with only battery power, and I don't have an external battery charger. I never use my laptop portably, and on the rare occasion I do, it's only at college with plenty of outlets available, or at a friends house. I don't need to be able to run on battery. I could get a professional to put a new jack in for me, and pay a butt-load of money, but I'd rather not. Also I broke off two tiny square metallic things that look like part of the dc power circuit in my frustration and carelessness so it may be broken for good anyway.

Anyone, help please?

Edit: another reason for the battery pack hack is purely for the fun of it. If worse comes to worst I'm not afraid to buy another battery pack if I ruin my current one, and I can still always find a way to fix the dc power jack.