Just rebuilt my laptop battery!!!

[BenziT]

I used back Lit-ion. Wire the same way, in series and did not reverse the polarity

 

[Cyrix_2k]

Hi,

I have just rebuilt my Compaq M2013 battery.

However, the charging lights stays on for about 5 mins. Thereafter, it starts to blink.

Any idea what is wrong ? There is no charge to the battery at all. Do i have to do anything eles? ie to reset the battery etc ?

I have left it to charge overnight. No charge to the battery at all.

Did you have to rest the PCB ?

If so , how to do it. < 3 volt per battery ?


Many thanks

under 3volts per cell? I think you probably activated the protection built into the cell. Depending on how the cell is built (or the controller), you may be able to manually charge the cells for a bit to get them above the protection threshold. However, I believe that most protection circuits use fuses so that once it's activated, the cell cannot be revived.

 

[imposter]

How would i manually charge a cell? i have an 8 cell battery i took it apart and they are all reading 3.9 volts how can i tell which is bad? i know it needs to be under a load to test it properly any ideaS? i am going to order a new battery anyway but for fun i wanna get this one to work.

 

[Cyrix_2k]

Wait - each cell measures 3.9 volts!?!? Fully charged is 3.7 volts. If that's the case, then you should have enough working cells to get the battery pack to work. Since you said it is an 8 cell pack, I'm guessing it's wired as two parallel circuits each containing 4 cells in series. Either that or it's one series circuit with every cell in parallel with another. In both cases, final output should be ~14.8 volts charged.

Now, the blinking light on my armada indicates the battery pack is bad and won't charge so your pack probably has a bad cell. What you need to do is remove and test each cell individually until you find the one that doesn't measure the same as the others. In my case, the bad cells measured .4 volts instead of 3.x volts. There's probably no point in putting 7 cells into the pack, so revise it to be one series circuit of 4 good cells only. If you need help with what I'm talking about, I can try and post pics of what to do later.

 

[The_Jizzler]

youd have to be able to cycle the cells individually to find the bad one. basically a charge/discharge. youd need a charger that can do 1 cell (a cell phone charger possibly) and a way to discharge/load (light bulb maybe). sometimes a bad battery will pass the volt test, but under load the voltage will plummet if the cell is bad.

 

[imposter]

Wait - each cell measures 3.9 volts!?!? Fully charged is 3.7 volts. If that's the case, then you should have enough working cells to get the battery pack to work. Since you said it is an 8 cell pack, I'm guessing it's wired as two parallel circuits each containing 4 cells in series. Either that or it's one series circuit with every cell in parallel with another. In both cases, final output should be ~14.8 volts charged.

Now, the blinking light on my armada indicates the battery pack is bad and won't charge so your pack probably has a bad cell. What you need to do is remove and test each cell individually until you find the one that doesn't measure the same as the others. In my case, the bad cells measured .4 volts instead of 3.x volts. There's probably no point in putting 7 cells into the pack, so revise it to be one series circuit of 4 good cells only. If you need help with what I'm talking about, I can try and post pics of what to do later.

i have the same problem as "armada", though 3.9 should be fine becuase its not on a load, i am sure once its on a load it wouldl read 3.7. I tested each battery like you said to do for armada but they all read the same voltage... any ideas? PCB is bad?

AH: edit i didnt read the jizzler thanks ill get to work.

 

[BenziT]

OIC. Cause I was reading thru the forum. There was a comment to drain each cell to below 3 V as to reset the PCB .. Thus, I was wondering if this is true.

 

[BenziT]

The battery packs from Compaq states 10.8V. Mine is a 6 cell. Thus, it should be in 3 x cell to form a series and each cell // to one..

I noticed that my laptop DISCHARGES the battery, instead of Charging it. Now, each cell is only 2.4V

Did I reverse the polarity ?????

 

[imposter]

How do you reset the pcb?

 

[Cyrix_2k]

OIC. Cause I was reading thru the forum. There was a comment to drain each cell to below 3 V as to reset the PCB .. Thus, I was wondering if this is true.

haven't heard that before. Usually you reset the PCB through software, but I don't know exactly how that's done. Mine worked without being reset.

The battery packs from Compaq states 10.8V. Mine is a 6 cell. Thus, it should be in 3 x cell to form a series and each cell // to one..

I noticed that my laptop DISCHARGES the battery, instead of Charging it. Now, each cell is only 2.4V

Did I reverse the polarity ?????

umm, I really hope you didn't... the negative side of the cell has metal to the plastic insulation, the positive side has an insulator between the metal center & plastic insulation.

 

[BenziT]

Looks like I did not reverse the battery

But why is it DISCHARGING .. ??

 

[Cyrix_2k]

maybe it's calibrating itself?

 

[BenziT]

f they use Lithium Ion (Li-Ion) batteries, my guess is that the internal circuit board, which is there to control charging etc. has failed, or has switched off the power due to battery voltage going too low, in order to protect the cells. Each Lithium Ion cell has a nominal voltage of 3.6v as opposed to NiCad and Nickel Metal Hydride (NiMH) cells whose nominal voltage is 1.2v. The Li-Ion cells should not be discharged lower than 3.0v, and the circuit will switch off the pack at that voltage. The irony is that if the pack is switched off, the cells continue to self-discharge, and go below 3.0 volts anyhow.

I have a Battery repacking business in Queensland, Australia. Our experience has been that in about 5 out of 10 cases, the cells are OK, but the circuit board is faulty.
If you have a regulated power supply, and can correctly identify the positive and negative contacts on the battery (usually the first and last in the row of contacts) apply a small charging current no greater than 1/10 the capacity of the battery, (if the pack says for example, 10.8 volts 2600mAh, the charging current should be no more than 260 milliamps)for 30 to 60 minutes. The circuit board will sometimes switch back on as the voltage increases above the minimum. Sometimes it is necessary to open the pack and apply the current directly to the cells, bypassing the circuit board altogether.

 

[BenziT]

Dun think it is self calibrating. Cause after a while, the low battery light will appear. And the Battery is not accepting any charge.

And I dun have an external charger to bring it to above 3 V

 

[Cyrix_2k]

failed charging circuit maybe? I think your problem may go beyond the battery. As for a charger, if you feel ambitious, you could probably make one out of an old plug-in type transformer from an answering machine or something.

still, I would leave it plugged in for 24 hours or so and hope that it's calibrating itself. The low battery light might appear in that scenario since calibration usually discharges the battery all the way and then charges it again, sometimes for several cycles.

 

[BenziT]

I will try leaving it overnight for today. If all fails, I might use a DC/AC 13.2 600Ma. charger ( Used to charge my portable battery pack Ni-CD ).

Will this charger be ok ? I was thinking of connecting the "charger" directly to the battery pack. bypassing the circuit board altogether.

 

[Cyrix_2k]

sounds ok to me since you said you have a 6 cell battery. The charging current is a bit high, but I think my laptop actually charges the battery at about 2 amps (2000ma), so I really don't think 600ma will be a problem at all. . Just monitor the batteries very carefully and make sure they don't heat up or overcharge. If anything doesn't seem right, stop immediately. If you have one, I recommend keeping a class D fire extinguisher near by.

 

[BenziT]

both method did not work

 

[Cyrix_2k]

guess the circuit board's bad then Did it charge at all before you replaced the cells?

 

[BenziT]

I did charge befroe I changed the battery. The old battery went dead on me as they were giving me only 6 mins with a full charge.