Thinkpad T420 and W530 battery compatibility?

I just noticed something peculiar.

My T420 came with 6-cell 55+ battery. My W530 (on order) will come with 9-cell 70++ battery.

Per official documents I found on the Lenovo website, my 6-cell battery is NOT compatible with

my W530. However, 9-cell (70++) battery from W530 is compatible with T420.

What gives? Does anybody know why W530 battery is compatible with T420 but not the other way

around?

I plan to test it out once I receive W530 but I'm afraid I might blow out something.

 

The --30 batteries (and the newer laptops) have a chip in them, whereas the older batteries don't. I tried booting a W530 with a W520 battery, and it would give you a BIOS warning and not boot to the OS with that battery.

I guess Lenovo wants to discourage 3rd-party batteries and older Lenovo batteries?

 

You won't blow anything up.

As to why Lenovo did this, who knows. I guess it's the same reason Apple does it.

 

I can tell you at least why Lenovo claims they do it:

One of the features of the --30 series notebooks is rapid charging up to 80% of battery capacity in 30 minutes. Older batteries are not designed for this and would be damaged by charging in a --30 series notebook. Also, 3rd-party batteries are not verified (by Lenovo) to confirm they can handle being rapidly charged, so they're out too. The chip mentioned earlier is to ensure only batteries that can officially handle being quickly charged are used with the system.

 

Very interesting discussion.

I am also thinking about buying a new battery for my X220. Does it make more sense to purchase a X230 battery than a X220 battery?

 

Not in my opinion unless you get a better deal on it.

Your X220 won't know the difference...

 

Buying x230 battery for x220 makes sense. I've checked ebay and find that "original" x220 batteries are much cheaper than x230's, which makes me to believe that all cheap "genuine" *20 batteries are fake. While x230 batteries are more expensive you also get a better chance to get a genuine Lenovo one.

 

if you can get the X230 battery, this means that you sell the X220 in the future and get the X230, you can still use the new battery.