Yikes! Postponed picking up a second battery until I had a better handle on how long the NP-FV70 would last. The FV70 unit came with my X70. B&H had the NP-FV100 previously listed at USD 99, but now it's up to USD 159. For that price, I'm tempted to just get two more NP-FV70s plus a travel charger.

The only thing I'm nervous about though is recoring a live performance approaching one hour in length. I'm using an Audio-Technica phantom-powered mic, will be using the LCD screen and recording in XAVC-L 50 Mbps (HD). So power consumption tends to be high.

What have other's experiences been with a FV70 vs. FV100 in real-world continuous record times?

Thanks.

Edit: I'm picking up the Sony brand of batteries (just saw another thread regarding file corruption). Personally I always stick to name-brand chargers, and batteries.

I ran a test a while back on the Sony battery which might be helpful -- with the included Sony NP-FV70 battery, running a straight flat-out record in XAVC mode (24 FPS), I got 2 hours 46 minutes. Not too bad, and just a little less than it would take to fill my card -- the resultant video file was around 62 GB. That was WITH the LCD open, but WITHOUT a phantom mic.

Of course it would be easy enough for you to run this test yourself, and have the mic attached. Point it at a TV if you want it to have some motion to keep the codec busy.

Not so good is the battery gauge; most of the way down it read 10% above the actual time left. It read 10% with 5% of the time remaining, and the camera died as the display showed 5%. Worth keeping in mind!

Having said that, I hear you on off-brand batteries; and the gauges on them are usually even worse.

I record plays too, with a phantom mic. No real tests, but the supplied FV70 seems to die in a little over 1 hour with a Rode NGT1 phantom mic attached. I have a non Sony FV100 equivalent that lasts for well over 2 hours. I don't use the FV70 for plays as acts can be well over 1 hour.
Look up DealeXtreme - Cool Gadgets at the Right Price - DX Free Shipping Worldwide (http://www.dealextreme.com), they sell authentic Sony FV100 batteries at really good prices, they may take a while to get to you tho'! I've just got my first Sony FV100 from Dealextreme so I can't say how well that lasts.

Thanks guys!

Good tip Atticus on recording a TV screen. Will do that shortly.

Update: Continuous recording of my TV (live action with medium to high-speed motion), I got 1 hour of footage with just 41% battery usage. This was 1080p at 29.97. AT-BP4025 mic (phantom powered), manual audio levels. Dual slot recording.

Later today will update this post with another hour-long continuous shot, but with me panning, zooming, and making exposure adjustments.

But so far, things look good for the NP-FV70.

Update: Got rained out, but got about 12 minutes of footage at 59.94 over three recordings. Each involves lots of pans, zooms and gain adjustments. Only used 5% of the power. Though I know things are not necessarily linear.

Wondering if the 2.0 firmware made some improvements? So far, this is really good. I'll most likely just order a 2nd NP-FV70 as a backup.