KastarNP-F570 Battery (4-Pack) for Sony L Series InfoLithium Battery NP-F570, NP-F550, NP-F530, NP-F330 and Sony DCRVX2100, HDRFX1, HD1000U, HVRZ1U, HXR-NX5U, NEX-FS100 Cameras

Till today i dont have any complaiments about them. They work as expected. Good Price for Good Quality

fully recommended. very good quality

This is a 4 pack of NP-F570 Li-Ion batteries, 7.4v with 2900 mAh.These batteries fits the form of a NP-F550 or similar series battery and effectively increases the run time of your devices due to the increased mAh rating. During my initial testing, I found that my batteries came almost fully charged. From my understanding, Li-Ion batteries should be stored at around 50% charge, but this is not a big issue nonetheless. The listing boasts its use of Japanese cells, supposedly eliminating memory effect. I have yet to confirm this, but it is widely accepted that Li-Ion based cells have little to no memory effect anyways, so I believe it holds true.Fitment is great, I've had zero issues with any NP-F550 powered devices so far. The battery itself is well made, comparable to bigger brands at a higher price point. I have had no issues with the contacts bending pins on my devices, it seems to always align perfectly and insert smoothly. The grooves are identical to most batteries in this form factor, and lock in with security just the same as my Sony batteries and any other quality aftermarket batteries.Each battery is sealed individually in slightly inflated plastic film, and then individually boxed, and packed into a small master carton. Packaging is done well to protect the batteries during shipping.With the nature of these devices, It is hard to speak for the durability, as well as reliability after sustained use and re-charging, at the time of writing this review. For initial impressions, these batteries have the build quality and performance similar to the better aftermarket batteries I've tried, and run longer than NP-F550 batteries in all applications I've tried them in. At this price point, this is good value (~$10 a battery, taxed and shipped to California at the time of writing)Recommended for anyone who needs to quickly stock these batteries, who already has a charger, or anyone looking to make an upgrade from NP-550 batteries that does not need the extra mAH that the higher numbered models such as NP-750 have to offer. This is also great for those who cannot use the bigger batteries such as NP-750, or would prefer not to use them to keep their devices lighter.So far so good, I will update this review should my opinions change, or a battery begins to show failure.

It's a 4 pack of Sony NP batteries, which is useful for many lights and field monitors.This is NP-550 model, which is the smallest/least capacity.You will get shorter battery life, but if you need more portability/less weight, it's a nicer option.

My other Kastars, after being promised "now" they have addressed their issues -- still fail quickly. I hope these don't.

If you make videos, you can never have enough of these NP-F style batteries. As a general rule, I will only use Sony brand batteries in my camera (and FX3 and an A7iv), but for other gear, I have no problem using off-brand replacement batteries. Given their capacity, I don't use them in lights (although, I've tried them, and they work fine), but I mainly use them for field monitors (a Ninja V and a Desview p5ii). I get almost exactly the same amount of runtime as I get from other, similar capacity, off-brand batteries. I've had these batteries in rotation for only two months, so it's impossible to know how hey will hold up over time. At $9 per battery, they are priced similar to other off-brand batteries, but are a fraction of the cost of name brand batteries (for instance a single Atomos brand 570 is $75, and a single Blackmagic brand 570 is $55). I am very happy with them so far.

Batteries won't charge. It appears that the female ports are too wide so they do not stay connected to the male tips. Even when you push them in, they just slide back out. Bad design.

I got these to work in a set of LED studio lights, as my old lights were bulky and far from being remotely portable. I used 2 per light and ran them for 3 hours. It was fantastic!I don’t know much about the standard of these NP batteries, but it seems the line of them scales up the mAh as the number goes up. I used a low wattage off brand USB charger to charge them and really have no complaints. They are doing exactly what I needed them to do.