How to check battery voltage with a multimeter?

Hello, I have a M6600 laptop that I bought used recently. The battery seems to be not up to capacity. I'm guessing 50% runtime it should have. I come from the RC world and we use smart chargers to charge all of our batteries; which can balance the packs cells and tell how many mAH and what voltage is going into the pack. Long story short I can't get any voltage readings from the Dell battery. I've been probing the pins with small wires and yes they are connecting. There are 9 pins and i have looked online at the pinout. I tried probing 1 & 9, 2 & 8, and other combinations and i get nothing! I would like to wire up the battery and cycle it and see what condition it is in, if I need to replace the 18650 cells or not.

DELL D500 D600 battery - AllPinouts

Does anyone know what pins I need to have to check the voltage? Or do i need to probe more then 2 connections at a time?
Does the M6600 balance the cells in the pack while charging?

 

Yes, cells are balanced (there's connections from the PCB to every cell). I don't think you can read individual cell voltages from the external connector, but you can view the pack voltage with an app like HWMonitor.

If capacity isn't very good, try conditioning the cell. Run it down completely (if the system goes to standby, continue waking it up until it no longer powers up at all), then freeze it in a sealed plastic bag for 2-3 days and make sure it thaws completely before recharging. Otherwise, consider purchasing a replacement cell. I wouldn't recommend replacing cells not only for safety reasons, but you might not be able to work around the wear counter, making it all wasted effort.

You can find a new standard 9-cell battery for ~$50, or a 3-year 9-cell battery for ~$75:

Genuine Dell Precison M4600 M6600 97Wh Laptop Battery FV993 BRAND NEW | eBay

9Cell Genuine FV993 PG6RC R7PND DELL Precision M4600 M6600 87Wh original battery | eBay

 

Thank you for all the info! Good to know the batteries are balanced internally. I downloaded a couple different monitors and they are showing 8.3% and 9% for battery wear. That isn't too bad I guess. I've had it on balanced mode for the last 20 min and it has lost 10% of the capacity, and I've only ran a few programs. Just mostly idling. I don't know how accurate the numbers are on here, or if I need to do like you said and drain the battery completely down to the shutoff voltage, then charge it up, and maybe windows battery meter would read the battery better? The highest I have ever seen it say just over 4 hours remaining, with the battery fully charged and on extended battery life mode. That seems crappy compared to all the reviews I have seen where they are getting 10 or 11 hours idling, even 5 hours playing a DVD!

Yeah I have those batteries marked on my ebay! haha, one has a few bids I looked into replacing the cells, but the cost of 9 cells would be $50 to 75 depending on the quality/brand of cell, and the few hours labor replacing them almost isnt worth the trouble. I've replaced cells before in plenty of things, I have a nice weller station. If you are telling me there is a wear counter inbedded in the battery that can't be reset then there is no point in replacing the cells?

I will run it completely down tomorrow and charge it, and report back. It came with a 210W charger though, shouldnt matter. I have a 240W on order. I would like to charge the battery with my RC charger and see really whats going in.... :/

 

8-9% wear should be almost unnoticeable, but if the battery hasn't been conditioned for a while, it won't be accurate.

It's just intuition, since it's a counter that only increases. After all, there's no reason why the wear counter should ever decrease...

 

I drained it completely down to where it wouldn't turn on, and then charged it up. It's showing 11% wear now. After doing some research I think I figured out why i'm not getting as much battery life as the reviewers. 1. I have the 8900 card and there is no Optimus, and 2. I still have a 7200rpm hard drive. I ordered a 128GB Sanforce controled SSD yesterday, that should give a little more life. I found the other guys on here with the 8900 cards are getting the same battery life as me or less. I did read somewhere that some guys were working on getting optimus working with the ATI cards, but I don't think it happened.

 

That would make sense. 11% wear isn't too bad, I wouldn't worry about replacing the battery yet.