Aftermarket Delkin batteries
 

For anyone tired of waiting for Canon batteries, I just preordered from Delkin, available mid May. ( Replacement for Canon LPE6 Battery :: Batteries :: Delkin USA )

This is what they say:
"The Delkin LPE6 battery operates just like the Canon original, enabling fluid communication between the battery and camera to communicate current battery capacity as well as the number of shots remaining in each battery. Unlike some of the other aftermarket LPE6 batteries available, the Delkin LPE6 battery is fully compatible with the original Canon battery charger (LC-E6) and does not require a dedicated aftermarket charger. Delkin batteries have a 100% compatibility guarantee and are protected by a 2 year replacement promise.

• 1650mAh, 7.4V
• Compatible with Canon 5D Mark II
• Compatible with Canon LC-E6 charger
• 2 year warranty

Intended Use:
For use with the Canon 5D Mark II camera and Canon LC-E6 battery charger.

Thanks for the heads up, Mike.

I've been waiting for after-market batteries that are compatible with the camera communications and battery charger, and I'm even willing to pay double for the privilege ($20 instead of $10). But at $80 these Delkin batteries are no cheaper than the Canons.

I'll keep waiting until I either:

1. Start lugging around my 10-pound car battery and Hutech adapter.
2. Order the Chinese knock-offs and live with no battery communication.
3. Someone comes out with communicative batteries at 20 bucks or less.

:)

Digitalrev also carry batteries that are supposed to be fully compatible for $63.84 shipped. I haven't tried it myself.

I bought a couple of genuine Canon LP-E6 batteries from Hong Kong for $117.80 each including shipping. GENUINE CANON LP-E6 Battary for EOS 5D MK 2 LPE6 MKII on eBay, also Batteries, Digital Camera Accessories, Camera Accessories, Cameras Photo (end time 20-Apr-09 13:49:17 BST) I have also bought four cheap knock-offs each with charger as they won't charge in the Canon charger or communicate their state of charge with the the camera. They did however cost less than a single Canon battery for all four of them delivered so they are handy to keep in reserve.

I bought 4 of the non communicating versions, and they operate fine. It seems that when they are running down, you know becasue any button you push will not work, even though live view is still up. When that happens, I switch camera off, and simply pop it out, and replace it with a new one, and we are off.

I bought them with charger unit, so I can have them charging simultaneously with the Canon one.

If you get the battery grip you can use AA batteries even rechargeable ones, and it raises the cam so matt boxes fit better.

Battery life with AAs are extremely poor.