Acer 5315 fried charger circuit 'hotwiring' solution?

  johnrambo 10:54 07 Sep 2011

Please help if you can. I've got a 2008 Acer 5315, the 'universal' charger got unplugged and the was polarity reversed doh! now the charging circuit is stuffed and I'm told it is uneconomic to repair. I'm too poor to buy right soI want a solution that will allow me to continue using the pc using the charger.

Using a voltmeter, the battery has 7 pins, this is what I got:
live live ? neg neg neg neg

Using male spade terminals on the charger I can charge the old battery, that lasts about 10 mins, I'm currently writing on this pc now, so I assume the damage is limited to the charging circuit.

Here's my questions:

1)what voltage does this pc run on? the charger is 19 volts, if I were to use some female spade connectors on the pc internal battery terminals (with the battery permanently removed) and power direct from the charger, would this be ok, or do I need a resistor to reduce the voltage? If so, any idea what value in ohms or what sort of voltage I need? Does it need any sort of surge protection when the charger is plugged in?

2)could I open up the(old and useless) battery and wire 19 volts from the charger straight to the modified battery, or maybe just keep the battery 7 pin block connector and power to those live and neg terminals? the battery says do not dismantle, if i avoid shorting it what are the dangers?

3)Could I power just to two of the seven pins, I'm guessing one pair of pins is OUT to pc, the other pair is charging current IN to battery.

An odd question I know, but if the rest of the computer is working, and I can 'hotwire' direct to the battery or battery terminals then it is a workable solution rather than selling the pc for spares.

Finally, I'm told there might be a blow fuse or charger reverse polarity protection diodes somewhere, anyone got a picture and is it cheap and do-able on this pc?

thanks for your help

  robin_x 12:44 07 Sep 2011

Hey! You're 3rd result on a search!

Wade through this lot.

Acer 5315 circuit diagram

Good luck. You may get lucky and find a fuse or a blown component.

  robin_x 12:52 07 Sep 2011

By the way, if you mess with DC power sources when modifying/maintaining stuff, put your own protection diode in the power lead.

+ve line supply o- - -[>1- - -o load

Allow 4.5A (95W,19.5V laptop), 0.6V drop across diode =2W or 5W diode should do it.

(only for test, continuous use and the diode may get very hot)

  johnrambo 11:44 08 Sep 2011

Thanks Robin, Really I'm looking to power the battery direct from the charger, rather than going from the dc input through the damaged circuit board to the battery. I rarely ever use it on battery power alone so using it continuosly with the charger seems a possible solution.

As it is working fine on the battery I asssume the problem is confined to the charging circuit.

Using a 5W diode, would that be purely as a reverse polarity protection? I was looking to solder direct to either the battery terminals or dismantle the battery and connect internally.

Really just looking for a cheap and easy fix.

  robin_x 12:13 08 Sep 2011

My suggestion was just to protect WHATEVER you connect to the supply.

Since I don't know what current the diode needs to handle, I assumed worst case 4.5A ish.

Silicon diodes always drop 0.6V across them.

So I x V = W gives the power rating needed for the diode.

If you solely want to charge batteries from the source then they will be taking 10's of mA.

Therefore you wouldn't need anything like a 5W diode.

BUT NOTE that Li-ion batteries get hot and can be a fire risk. I would research a decent charging circuit/set-up carefully before just sussing out the pins and hooking it up.

ie you need to reproduce a circuit that does the same as what you blew up on the motherboard.

Do NOT connect the laptop charger directly to the battery.

  johnrambo 10:24 09 Sep 2011

Thanks, I've stripped the pc down now, and found a what i think might be a diode pack on the dc input jack socket, which is removable form th MB. I'm going to try replacing that, hopefully that will sort it. thanks

  johnrambo 14:00 10 Sep 2011

Do NOT connect the laptop charger directly to the battery

The mb micro fuse and dc input protection diodes on the dc input are ok, unless anyone has any idea where else to look then I need to wire straight from the charger to the battery. What sort of circuit would this be?

I'm guessing 'protection' diodes, a voltage stabiliser circuit, a ripple smoothing capacitor and maybe some battery charge and temp sensor that stops the battery from overcharging. I need to put the same voltage at the relevant battery pins from the charger that the battery is producing...

Any ideas?

  locater007 00:24 06 Oct 2011

Hi I have exactly the same problem for 5315 acer. Google ACER 5315 WORKS WITH BATTERY BUT NOT WITH CHARGER I also took the laptop apart so had a good look around i.e. connections on MB. I found damaged pins on screen connector straighten them out and thought had cracked it but unfortunately not. What I will say is that before no life at charge light but did get it to stay on for about 5 seconds so getting close. I think maybe a dry joint so will check soon with a magnifying glass. Check all your connections if you've taken it apart. Hope it helps

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