NP-F video battery charger performance tests
Comparison of the the various NP-F battery chargers I use and which one is the best.
I use lots of generic Sony NP-F 970 batteries to power my video cameras, lights and external monitors. Initially I brought 2 of the EXpro chargers bellow but quickly found they were so slow at charging I was running into trouble if I had back to back shoots and needed to recharge a lot of batteries. This would often mean setting an alarm to get up in the middle of the night to swap batteries over. Another problem with the EXpro chargers was the inconsistent performance, my cameras and light generally run for about 3hrs on these batteries but would occasionally run for much less. I would mark the batteries at the time just in case they were defective but on other jobs they would work fine, I put this down to the charging. These issues encouraged me to buy other chargers and test their performance to find better alternatives. This list now comprises in purchase order, EXpro dual charger, Sony AC-VQ1050 and the SWIT S-3602F.
The quality of the NP-F batteries I use appears a bit inconsistent so I used the same 2 Duracell DRS F970 7800mAh batteries for each test running them flat on the same video light and then allowing them to cool to room temperature before charging. Room temperature was around 20 C for all the tests. The Duracells have probably been charged about 20 times prior to the test.
Duracell generic NP-F batteries used in the tests
EXpro dual NP-F Charger
EXpro dual charger
This is a generic charger branded as EXpro there are many other versions of this charger on Amazon UK and the current price is £22.99. It comes with a mains lead and a lead to allow it to be powered from the 12v socket in a car. It shows the status of charge in 10% increments. It charges both slots simultaneously. The display is backlit and it shuts off when both batteries get to 100%.
It has 2 slots with swappable battery plates and 2 charge levels L&H. The low output for 2 batteries is 500mA/slot and the high output is 800mA/slot I always use it on the high setting.
Charging 2 Duracell DRSF970 7800mAh batteries took 17hrs 28mins. After removing the batteries from the charger for 1 hour the voltage of the 2 batteries was 8.4v and 8.41v.
Pros
Low Price.
You can swap the battery plates to accommodate different batteries.
Cons
The batteries take a long time to charge.
The readings during charging are not consistent. If you swap the batteries mid charge it will provide completely different charge levels. If you insert 2 flat batteries the right hand slot always reads between 20 - 50% higher.
The right hand slot often fails to make a connection and the battery may need to be reinserted several times before it starts charging.
The charger will say the batteries are 100% charged but they can then fail under load after an unexpectedly short run time.
The charging terminals are constantly exposed, making them liable to damage.
The battery plates fall off when removing some batteries.
Summary
If you only want to charge the occasional large NP-F battery or want the flexibility of charging different types of batteries at the same time then it may be OK for the money. It was the inconsistent charging and extremely long charge time that lead me to look for another charger.
Sony AC-VQ1050
Sony AC-VQ1050
After the slow charging performance of the EXpro charger I purchased the Sony charger used on ebay for £85. It has the facility to be powered from the 12v socket in a car. It charges both slots sequentially. It has an 8.4v output for powering a camera via a 3 pin plug.
This has 2 slots and has an output of 2.0A Sony claim a charge time of 5hrs 10mins for a NP-F 970. If you are using genuine Sony batteries the charger is able to provide lots of information like capacity, run time, how many times the battery has been charged etc. unfortunately none of these are available with non Sony batteries.
I was hoping for much faster charging performance from the Sony charger but you really need to be using genuine batteries to get the best from it. It is designed to fast charge the batteries to 85% which it calls a Normal Charge you can then leave the batteries in place and it will add the remaining 15% at slower rate. If you don't replace the Normally Charged battery it will continue to fully charge the battery before swapping the other uncharged battery. Unfortunately with generic batteries it does not offer the fast charge facility and charges at a much lower rate. This means that charging actually takes longer than the EXpro charger despite the 2.0A available output.
Charging 2 Duracell DRSF970 7800mAh batteries took 14hrs 43mins. After 1 hour the voltage of the 2 batteries was 8.37v and 8.33v
Pros
It potentialy provides a high level of charge.
The terminals are covered when not in use.
The build quality feels better than the EXpro.
Cons
The batteries take a long time to charge.
The price is very high for the performance on generic batteries.
Summary
If you are using genuine Sony batteries this charger will potentially give you a good charge performance and useful information on the state of your batteries. Unfortunately it would cost me around £1,500 to replace my existing batteries with genuine Sony batteries. If you are using generic batteries I would not recommend this charger.
SWIT S-3602F
SWIT S-3602F
Following the disappointing performance of the Sony I purchased the SWIT charger these are available from about £100 - £120 from various retailers. It is mains power only. It charges both slots simultaneously. It has an 2, 8.4v outputs and will operate the charge slot or the 8.4v output for each bay.
This has 2 slots have a combined output of 1.8A.
Charging 2 Duracell DRSF970 7800mAh batteries took 4hrs 51mins.
After 1 hour the voltage of the 2 batteries was 8.36v and 8.34v.
Pros
It provides the best rate of charge by far.
The terminals are covered when not in use.
The build quality is better than the EXpro but doesn't feel quite as good as the Sony.
Cons
I can't really find anything negative to say about the SWIT.
Summary
I was worried that the fast charging SWIT over heat the batteries so measured the surface temp while charging. With a room temperature of 20 C the battery top surface temp increased to a 25.9 C at the highest and so this wasn't really a concern. This is by far the best performer and well worth the price, I will be buying another one. This is the only unit I have used that will charge batteries faster than the Blackmagic Pocket 4k making on location charging viable.
Disclaimer
Batteries and charger were purchased by me and I have no affiliation with the battery or charger makers.