Dell XPS M140 battery

Be prepared to be seriously annoyed.

Dell chargers have a third wire (the central one). This connects DIRECTLY to the data pin of a memory chip in the charger. The memory chip stores an identification code that identifies Dell XPS M140 battery the charger as made by Dell.

The BIOS in your Dell computer checks for the presence of this code. If it doesn't see it, it disables the ability to recharge your battery. You can have a perfectly good charger delivering perfect DC current, but if the laptop doesn't see the secret `made by DELL' code on the data wire, it punishes you for not using a Dell charger by refusing to charge your laptop battery.

To make matters worse, the inside of a charger is not a very hospitable place for a memory chip. They tend not to live long in such hot places. And connecting the data pin of a memory chip Dell XPS M1530 battery directly to an external wire is just lousy design. All you need is a single static spark to hit the data wire and zap - you've fried the memory chip with the Dell secret code. If the memory chip dies, your laptop won't recognise that the charger is made by Dell any more and will refuse to charge your laptop.

If you complain to Dell about this, they won't tell you the true nature of the problem. They'll just try to sell you a new charger.
I have Dell 6400 which had the same thing happen after 2 years. I purchased one off eBay which was supposably an OEM battery, but while it looked similar, it was slightly different in a few ways - which makes me think it was just a regular non OEM battery.

Anyway, it seemed to last about 4hours each charge, which was the same as my OEM battery. Except I only got 1 year out of it before it rapidly lost it's ability to hold Dell XPS M1730 battery charge. It cost me AU$80 which seemed like a good price, but when you only get a year out of it, it makes you wonder if it is worth it..

So I guess to sum up, they are cheap and easy replacements but don't expect any more than 12 months out of them. Sourcing one from Dell will cost more but you should get a longer life and better quality product.

By the way, if your battery is toast, take it out or your laptop will literally try and charge it 24/7! 

I gambled with a much cheaper battery off of some site (I don't remember which offhand) for my m1330. It's worked fine and has actually lasted longer than the original. I got it for like $50, which was a lot cheaper than the $90+ Dell wanted for it.

My AC adapter stopped charging like a week after I got the new battery. At first I thought it was the Dell XPS M2010 battery fault, but I think it was just a coincidence, since the new AC adapter has worked like a champ.  The 3rd party batteries are a crap shoot, in terms of whether they work well.

If you buy the dell (from dell), you at least know the quality you are getting.

My brother bought one of the third party batteries because they were much cheaper. Then he wound up buying the dell battery a month or two later after the third party one turned out to be junk.