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Context

So I'll be shooting out in the sun for the next few weeks. My camera was overheating in the sun a few days ago and switched bodies for safety reasons. The flash at the end of the shoot was warm and the AA Ni-CD batteries were burning but the temperature warning never showed up on the flash.

I was carrying extra batteries on my backpack (AA and camera ones) and they were warm, as with everything else.

Question

I'll be out carrying my gear in the heat (during the hottest parts of the day). Is there any advice on carrying extra batteries in the sun or in use during the day? I don't have a backup flash but I have a backup body so that will help the shoot there.

Am I being paranoid about my Eneloops exploding under use in a flash and my camera batteries going bad?

Related

  • 2
    Are we talking San Diego sun or Sahara desert sun? – mattdm Jun 1 '16 at 20:16
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NiMH (which is what eneloop are, not NiCd) won't explode in heat you can survive in, but may suffer. The most likely effect is a significant reduction in capacity, most of which will recover on cooling and recharging. Reducing the drain on the flash batteries will help (e.g. by swapping between sets frequently, or only using the flash as much as strictly necessary.

The Li-ion camera batteries shouldn't get too hot and (unless they're very cheap no-brand replacements) will have a thermal cutout. They are much more dangerous if they do fail.

Keeping your spare batteries in an insulated container (or just wrapped in a fleece jacket) will limit their temperature rise before you use them. I wouldn't cool them below room temperature before doing this, but they could be wrapped in with something fridge cold. If you do this, be sure to wrap the batteries tightly in plastic (small resealable bags work well) to make sure that no condensation can reach the contacts.

Try to hold the camera and flash out of the sun as much as possible. If you're doing a walk-shoot-walk type of activity, I suggest taking the batteries out of the camera before packing it away and caring them separately. The padding of your bag is a decent insulator and will keep the heat in, allowing it to spread to the camera electronics.

  • I would highly advise against actively cooling the batteries in any way - this will invite condensation (unless you are in a very dry environment but even then you'll have some). - However keeping them an in insulated container e.g. fleece wrap to prevent them from heating up is fine. Otherwise this is a good answer. – DetlevCM Jun 8 '16 at 13:11
  • @DetlevCM, Good point. I'll put a note in to keep the contacts protected. – Chris H Jun 8 '16 at 13:13
  • The contacts are one aspect - but is the battery case really sealed? It has two halves. Unless it's for long term storage, not cooling the batteries is better. Plus, if it is humid, the cold battery will invariably attract moisture in the camera too. – DetlevCM Jun 8 '16 at 13:17
  • @DetlevCM having cut one open (for a 350D), yes they are sealed including the protection circuit. Given that I said don't precool the batteries, just wrap them in with something fridge-cold at most, it would have to be very humid to get any condensation by the time you unwrap them. – Chris H Jun 8 '16 at 13:20
  • Good to hear there is a seal. – DetlevCM Jun 8 '16 at 13:24
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Only Lithium batteries may explode if they are used while overheating.

For NiMH, overheating may damage them permanently in a way that will shorten their lifespan, but nothing more.

As for NiCd, I think nobody sells this crap anymore because it's really bad for the planet.

For precautions of use, hide your gear from the sunlight as much as possible. It's not recommended to cool it before because thermal shocks are even worse than simple overheat.

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My practical aproach.

  • Try to get a white camera bag instead of a black one.

  • Or put a white cover, like a raincoat on your bag.

  • Put your bateries (on the plastic casing) inside a methalic mylar bag.

This material https://en.wikipedia.org/wiki/Space_blanket is used to reflect thermal energy, in spaceships it reflects the sunlight keeping the equipment cold. You can buy them online as "emergency blankets".

  • Make a white (or metalic mylar) "raincoat" for your camera when it is not in use, for example, while you are walking to the location, or when you are preparing the next shoot. Probably you can use it while shooting too if it fits well on the camera.

  • You can also carry some stuff on a thermal bag for food. https://www.google.com/search?q=thermal+bag+for+food There are some that are designed to keep food warm, you need one to keep food fresh.

All this tips are to reduce the infrared rays and sunlight that are absorved a lot more by dark objects than white or reflective ones.

  • Rafeal: By 'methalic', do you mean 'metallic'? – JS. Jun 8 '16 at 20:47
  • Like the bags used to store hard drives. Mylar with a reflective surface. It can be with a white plastic too. The bateries inside a plastic case and that case inside the bag. – Rafael Jun 9 '16 at 0:36
  • Those are anti-static (i.e. 'conductive') bags. The risk is rather low, but would hesitate to recommend storing batteries in conductive bags. – JS. Jun 9 '16 at 0:45
  • Inside a plastic case, after that the reflective bag. Reflective material bounce infrared light. – Rafael Jun 9 '16 at 2:23
  • en.wikipedia.org/wiki/Space_blanket The metalic layer is on one side, the other side is plastic. – Rafael Jun 9 '16 at 2:26
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Sorry, not an expert, just my two cents:

1) Warm/burning/overheating: this is a feeling, not something real. If you touch something and it feels warm, it's just well below your body temperature; if it feels like burning but you can keep touching it, it's at about the same temperature of your body.

NiMH pessimistic limit is 60 °C, Li-ion limit is 40 °C In both cases, unless your body temperature is way over 40 °C (but in that case you are already dead, so no need to worry for the batteries, really), you have nothing to be concerned of.

2) I shoot two days in Dubai with my K50 and temperatures between 50 and 60 °C. Still here, and the camera had no problem at all, nor the batteries. (and, honestly...it's been much better than shooting in December in a storm during a weather red alert in Asterdam, believe me ;-D )

3) When you expect temperatures to be somehow higher or lower than room temperature range (15 °C - 25 °C), keep in mind your batteries will discharge a little quickier. Nothing too extreme (unless you are going extreme with temperatures too) and more noticeable on spare batteries than those you are using, but still something worth to consider.

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