It’s Alive! Keeping Your Batteries from Dying

Camera Assisting 18 Comments

Electrical Power Plug for Cinema Battery and BatteriesCreative Commons License photo credit: _maddin_

Imagine you’re on a shoot with only enough battery power to last you the standard 12 hour day. You’re diligent about charging the batteries, you don’t use any excessive power, and you haven’t had any issues the past couple of days when you’ve wrapped early.

But one scene is taking forever to shoot and soon you’re an hour behind schedule. Another scene goes by and another hour. Before you know it, you’re looking at a 15 – 16 hour day of shooting.

You’re also looking at the battery power you have left and the situation is grim — at this point, you’re close to running on empty. What do you do?

The Gatekeeper of Batteries

One of the overlooked responsibilities of a camera assistant is to keep all batteries for the camera and its accessories charged. This includes batteries for:

  • Cameras
  • On-board monitors
  • Video village
  • On-camera accessories (i.e. syncboxes)
  • And more…

Maintaining and keeping all equipment within the camera department operational includes keeping batteries charged and ready to go.

This is usually a team effort between all players in the camera department: the 1st assistant camera (1st AC) will keep an eye on the batteries on the camera while the 2nd AC keeps an eye on those charging and helps swap fresh batteries in/out. You don’t always get as many batteries as you would like, or possibly even need, but you have to work with what is handed to you.

If all goes well, there should never be a delay in shooting because of a lack of battery power.

Staying Ahead of the Curve

Have you ever noticed when you plug your iPhone in to charge it takes almost no time for it to get some juice, but to get a full charge, you have to leave it plugged in for awhile?

The battery is designed to get maximum charge at first for when you need it most.

It’s the way that most rechargeable batteries work — including the kind you strap onto an Arri Alexa. They charge very fast right when you plug them in and then charge slower the closer they get to 100% capacity.

Knowing all of this about batteries isn’t just knowledge to have, but to use to your advantage.

Let’s go back to the scenario mentioned at the beginning of this article: you’re encroaching on long day with limited battery power left. The director can’t figure out what they want, the actors are flubbing lines because they’re tired, and you’re sweating knowing your batteries lose more power with each delay in shooting.

Fortunately, if you understand battery technology sufficiently enough, you can stay ahead of the curve for just a little bit longer.

So you take a moment to go check your batteries charging, are they at about 75%?

If they are, take them off and put on completely dead ones. Dead batteries charge much faster to a limited charge than the one battery would take to charge to 100%.

By doing this, you stretch the potential power of your batteries for a much longer period of time. The trade-off will be more frequent battery changes, but that price is small compared to the alternative of finding yourself without any way to power the camera.

When worried about having enough battery power, be diligent about having somewhat charged batteries over fully charged batteries. It will take less time, you’ll have more power in the long run, and you just might make it through that long day.

Understanding Battery Charging Technology

So why don’t they just design batteries to charge that fast the entire time? Well, because it would shorten the lifespan of the battery substantially.

To quote from Anton Bauer’s Video Battery Handbook:

As a cell nears full charge, the voltage of the cell, its temperature and pressure all will rise. The art in charging a cell is to obtain the most charge without the increase in these parameters exceeding safe limits specified by the design of the cell.

Exceeding the limits of any of these factors, depending on the chemistry, can lead to unreliability, shortened service life or in some cases catastrophic failure of the cell, including explosion and/or fire.

As you can see, for reasons of safety and expanded battery life, manufacturers must be careful as a battery approaches a full charge.

And at a couple hundred dollars a pop, you want to have batteries that work for awhile.

Battery Case Study: Anton Bauer DIONIC 90 and RED Brick

To illustrate this fast-to-slow charge concept, let’s take a look at a chart from the manual of Anton Bauer’s DIONIC 90 battery — a battery that is typical for use with high end video and digital cinema cameras.

Anton Bauer DIONIC 90 Battery Charge Chart

On the left side of the chart are the various types of chargers that are compatible with the DIONIC 90. On the right side is the charging times for the batteries up to 90% and 100%.

It is worth noting that in every instance, no matter which charger, it takes a few hours to get up to 90% charge and then another hour to crest all the way to 100%.

To give you a comparison, RED’s batteries charge in a similar fashion by front-loading the charge and leveling it off at the end.

RED One Camera Battery and Batteries Brick Charge Graph

Even though it takes 210 minutes to fully charge one of the RED Brick batteries, the initial 80% of the charge comes in the first 120 minutes.

RED knows this and it’s why, when two batteries are charging simultaneously, they bring both up to 80% then work on charging them fully.

It takes substantially less time to give a battery an initial jolt of power than it does to fill it up completely.

It Keeps Going and Going…

Being acutely aware of your battery situation and the power you have left is an understated part of camera assisting, but that doesn’t mean it isn’t important. Without the power to the camera, you don’t have any way to keep on shooting.

You may find yourself in situations where your power is dwindling and you fall back on your knowledge of how batteries work to stay ahead of the curve — at least for a little bit longer.

Of course, this tactic will only last for so long before it catches up to you. Having more batteries is always the best option to keep shooting because who doesn’t want to work for 17 hours at a time?

About the author:

About the author: Evan Luzi is the editor and founder of The Black and Blue as well as a freelance camera assistant.

You can learn more about him or follow him on Twitter and Google+.

The digital cinema pocket guides are available now.
  • FB

    “funny” thing is, sometimes you don’t have battery chargers with charge indicators, you don’t have power to recharge batteries on the camera truck, or both situations. That’s pretty much what we’ve lived with for the first five weeks of the shoot I’m on. Sometimes (let’s say 2-3 days a week) our truck is not connected to the generator because our production dpt. geniuses put the genny near costumes, make-up and actors trailers (so they can power the coffee machine, I guess), 2 miles away from where the set and camera truck are. So one of the first things we do in the morning is scout the location to find a plug to charge our 24V batteries, and we get to bring our on-board batteries home to charge them every night (which I don’t like at all, for a number of reasons, but it’s still better than not having fresh batteries the following day). 

  • http://www.theblackandblue.com/ Evan

    Hey FB! Been awhile, good to see you here again…

    Yeah, I’ve been on shoots like that where you have to fight for an outlet or fight for use of the genny. I am also accustomed to bringing batteries home with me every night just to make sure all of them can be charged. It’s not ideal, in case you forget them, but sometimes it’s necessary.

    Have you run into any issues with running out of power?

  • FB

    Always great to be around here, Evan! Quite busy, and shooting nights 3 days a week recently, with call times changing every day, I feel I’m on a different time zone all the time, but it’s a great crew, great department, great dp, great director, so I can’t really complain. Tough, but really good.
    No problem with batteries so far, we always have a back-up plan, we don’t use on-board batteries if it’s not strictly necessary (i.e. handheld), so we have those to cover our back 99% of the time. Plus, we carry a custom-made power supply “block”, but we’ve never used it, we just have to keep our eyes open and make sure we have charged batteries all the time. (8 weeks to go, though…fingers crossed) :-)
    I’d really love batteries and chargers with charge indicators, though, for a change…

  • http://twitter.com/stingers_cam Neil Irwin

    Well more batteries is not always necessarily the best option – more like reliable batteries and the best batteries for the job! Here’s my little story:
    I was working as a dailies 2nd AC on a small indie horror feature and coming on board as a dailies knowing little about the cast and the crew. Understanding what equipment you do and don’t have is always essential when first coming on to set so you know what you’ve got to work with. In this case – I was told we have about 8-12 batteries to use on a RED (can’t remember the exact number but it was a somewhat stupid amount of batteries) and from what I remember they were IDX V-locks. However, it seems to be that we had the standard battery used on a Sony DSR for instance with nowhere near enough juice to keep a RED powered for a decent enough period of time. Each battery on set lasted approximately 45 mins (with some barely reaching 30!). At the beginning of the day – it wasn’t too much of an issue, but by lunch time it was soon becoming apparent that we were running out of batteries! An hour break however helped boost the amount of decently charged batteries, but it was not the full amount that we had at the beginning of the day. By the end of the day, it soon got to a stage where we had used practically every battery and could only use one for about 20 minutes before we had to change!
    So, the moral of the story – use the right batteries! Either that or a high capacity battery for the job as using the wrong type could be quite detrimental to the film.

  • http://www.theblackandblue.com/ Evan

    Does sound very tough. Is this the 16mm shoot you were talking about awhile back? 8 weeks is a nice chunk of a gig! Congrats.

    Per the batteries, I wouldn’t put it past you to have a Plan A and then a backup plan. And it’s rare that we always get what we want as AC’s haha

  • http://www.theblackandblue.com/ Evan

    Amen, Neil. I ran into a similar issue — using some third-party batteries on RED — and they did not hold up for very long at all. It gets frustrating and hard to keep track of when you’re swapping out that fast.

    Did you guys ever run into a problem of completely running out?

  • FB

    Luckily a new steadicam operator has just joined the show, and he mounts anton/bauer batteries on his steadicam, so at least those have charge indicators and they’re super-quick to charge.

    Totally agree on backup plans…actually, I think it’s at the core of this job to consider plan b to be part of plan a, and then have plan c and d as backups ;-)
    (Yeah, it’s a really nice gig, Super16, we’re shooting on 7213 and 7219, 13 weeks on a Tv series 2nd Unit. Who knows for how much longer it will be shot on film…)

  • Anonymous

    A simple but effective way to backup yourself  power wise is to get a AC power supply. This is pretty ideal for most shooting situations, unless you are doing day exteriors gorilla style with no electricity whats so ever. Totally helps in a pinch. Sometimes when shooting on a stage with camera on a dolly, its pretty easy to plug the camera into the house power and not have to worry about batteries. Just make sure you get a long enough stinger!

  • http://www.facebook.com/people/Daniel-Mimura/1390278635 Daniel Mimura

    Battery maintenance has improved so much in the past few years!  NiCad batteries used to have cell memory, so if you only charged to 75%, the next time you charged, the charger would think that 75% was the max and shut down. 

    On one particular show where I was video assist, we we going through batteries like mad (lots of slow mo…2-3 35mm cameras running all the time)…  No one listened to me about cell memory (I thought more people knew about this, b/c everyone had more experience than me)…and by the end of the show, about a 1/3 or more of the batteries weren’t even taking a charge at all and we were having major problems.  

    I keep a power inverter in my glove box at all times, so I have my own power solution independent of G & E.

    They use batteries too now (litepanels)… I’ve lent v-mounts to them a couple times, knowing that in a bind it may work the other way some day…  Plus, it’s just funny to give a juicer power.

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  • Ailtorres

    I wish I had found this website a month ago when I worked on a set. Could you add a section explaining the different terms they have for lights and stands and gels? For example, what is a blonde? 2K, baby? Other types of stands like Mombos and grip heads?

    Thanks. Very helpful website!

  • http://www.theblackandblue.com/ Evan

    Hi there, I have done something like it before: http://www.theblackandblue.com/2010/12/09/film-set-lingo-general-production-slang-part-1/

    As for some of the G&E terms, I’m no grip nor electrician so I’m afraid I couldn’t be much help there! Sorry!

    Best,
    Evan

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