$25 DIY battery pack for flash

Discussion in 'Lighting Equipment' started by eslincol, Feb 19, 2010.

  1. Lacking the funds to purchase one of Quantum's $500 battery packs for my Nikon Speedlight flashes, and faced with an upcoming 3-day assignment requiring power that's more dependable than half-dead sets of rechargeable AA batteries, I looked into building my own rechargeable, 6-volt battery pack.
    I found after some online research that it can be done, and has been done by others successfully, for very low cost. There's the possibility of frying your flashgun, but I took the chance and was rewarded.
    The DIY tutorials I looked at all required some sort of soldering action. I didn't have to do that. I made it as simple as possible. It took about two hours. I hope you can see the pics I posted here because otherwise it might seem more complex than it is. You can get all the parts at Radio Shack and/or Home Depot, and it won’t cost more than about $25.
    The idea is to create two fake batteries which will transfer the current from a 6-volt battery to your flash and allow you to fire away for five hours at a wedding or event, all while patting yourself on the back for being such a scrupulous, electrical genius.
    The reason you have to create the fake batteries is because otherwise you will have to shell out $40 for a cable from Nikon, which will still require further hacking.
    So, here's the list:
    Small pair of pliers | Wire cutter | hacksaw | tweezers | electrical tape | 15-ft roll of color-coded, 18-gauge speaker wire | small machine screws | 6-volt, 4-a/h rechargeable, sealed battery (in the emergency lighting section at Home Depot, costs about $12) | old CD-spindle | 6-volt lantern bulb (optional, for testing) | female wire connectors (I used "AMP female disconnects" from the electrical section at Home Depot) | about 7-ft of Split Flex Tubing (same electrical section at Home Depot) | foam (leftover from a Pelican case works)
    With the parts laid out, this will begin to look like you are working on a bomb. Just sayin'.
    Okay, the old CD spindle -- you probably have one lying around, if not, get one from Best Buy, or just go buy a pack of CDs, or find something hollow that you can cut that will fit like an AA battery into your flash. Other people have used wooden dowels or PVC pipe. I found that the CD spindle center post is exactly the same size as a AA, and you can cut it and put a screw in the middle, which is what you'll be doing.
    So cut two pieces of the spindle, one that’s the same length as a AA battery, one a little shorter – the reason is, one will go in the negative terminal, and the other will go on the positive terminal but you will need to leave some space for the cords to pass over it and out of the flash. You can see what I mean in the photos. If you screw this up, no big deal, CD spindles are cheap and you can do it over.
    You may want to use a knife or file to smooth out the ends that you just cut.
    Cut a length of wire however long you think you might want it to reach from the battery to the flash. I cut mine 7-ft long. It just needs to go from your hip to the flash, anything longer is probably overkill, but it’s just wire and you can stuff the other 4-ft into the bag in case you need it.
    Strip the wire ends and wrap one each around a machine screw. Secure this with electrical tape. That’s important – you don’t want these things shorting out inside your flash.
    Wrap a small piece of foam tightly around the screw/wire/tape, and twist this into one of the little CD-spindle/battery tubes, so that the head of the screw is just sticking out from the bottom (like a battery).
    Now, using the tweezers, cram a few more pieces of foam into the top of the battery tube so the screw stays in place.
    At this point, make sure you don’t open the door if anyone knocks, because what you have on the table will look very suspicious.
    Do the same thing with the other battery tube.
    Now strip the other ends of the speaker wire, take two female disconnects and secure them on the ends, and crimp them with the pliers. These should already be insulated if you bought them in the electrical section.
    Next, cut a small notch in the bottom of your flash battery cover to allow the speaker wire to come out.
    To test the current, plug the female wire connectors onto the battery, then touch the screw on the red battery tube to the bottom of the 6-volt lantern bulb (this is the little one that goes into a regular lantern flashlight), and touch the screw on the black battery tube to the side of the bulb. It should light up.
    Now, assuming the light went on and all is well, put the battery tubes into the flash, but make sure you put the black wired one into the upper negative terminal, and the red positive one into the lower positive terminal. Screws bottom first, facing into the flash, of course. See the photos.
    If you do this wrong and then plug in the 6-volt battery, your flash will get fried.
    Arrange the wire as needed and close the flash battery cover. If it doesn’t close, you may need to cut the battery tubes a little shorter. Then put the wire through the notch on the flash battery cover and close it.
    Take your split flex tubing and wrap it around the 7-ft of wire. This protects it and makes it look more professional.
    Plug in the ends of the wire to the battery – red wire to red terminal, black wire to black terminal. Don’t get this wrong, ever, or you will hear a *zap* and that will be the end of your flash.
    That’s it. Turn your flash on and test it. You just saved yourself $500 that you can go spend on some other piece of photo equipment that you can’t hack, like a lens. Remember not to fire too frequently and melt the flash, either. Give it a cool-down period now and then, or switch it out for another flash.
    You can stuff this all into a little $10 camera bag that hangs off your shoulder.
    Ah, you say, but what about charging this thing? Just go to Walmart, get a 6-volt electrical adapter, cut off the plug, strip the end of the wires, attach two more of the female disconnects, and voila, use this to plug in your battery before the next event. I think it takes about 4-6 hrs to charge.
    You may want to get two of the batteries to have on hand at gigs. They’re cheap and small, and it’s worth it.
    I hope this helps. I've also built my own Sound Blimp and saved about $1,200, but that's for another post.
  2. How much better is the performance vs. rechargeable AA's? How many times more shots? Faster recycle time?
  3. Eric,
    I'm impressed! I'm a DIY kinda person and have built some of my own continuous lighting. I've never monkeyed around with my strobes, but I know that something like this would be very useful. Thanks for thinking of this and showing us how it's done. I use a different brand of flash & camera, but wasn't too thrilled with the idea of spending ~$200 for the "compatible" battery pack, which is little more than what you've created...
  4. I don't know the specifics, and I haven't pushed it yet to see how many shots it will give out. But the recycle time is much faster, especially on less than full-power. I was only getting about ten full pops on my flash with the AA's before it started slowing down, but with this I can shoot for hours with no decrease in power. Also from what I've read, the 6-volt battery will push it's maximum power out until the end, which is different from AA's since they give steadily decreasing performance as they get used up, meaning your flash gets slower and weaker as you shoot. That was something that caused me problems in the past during fast-paced events, because I would expect a full pop, even after waiting for the flash to recycle, and still just get half. I doubt I'll ever use AA's again. This thing was so easy to make.
    There are some other links here I looked at before building this. It might help if you want to research or see options:
  5. Here's another good link:
  6. Thanks Tim! It's great to get some feedback. I figured there had to be some other people out there who could use this. It works really well, I was kind of surprised it actually fired when I finished it. Having the pack maintain steady power to the flashes will get me through weddings and media events with a lot more confidence. And knowing I saved half-a-grand doesn't hurt, either.
  7. And here's one more link with some photos similar to my setup and a discussion: http://www.flickr.com/groups/strobist/discuss/72157600346653826/
  8. Instead of using the CD spindle for the fake batteries, you can use H/C Pex Plumbing Tube, 3/8" x 1/2". It's in the plumbing section at Home Depot. You get 5-ft of it for about $2. You may have to look for it in two or three isles. It looks like PVC pipe, but wasn't next to the other PVC pipes when I found it.
  9. woah, thats talent.
  10. Thank you for this post! Your suggestions helped me come up with my own external pack. Here is my version for a Nikon Speedlight.
    I thought I would share what I have done and maybe you can take this into consideration when making your own. This solution is more expensive but I think it is nice to have the ability to clip the 5th battery holder on the flash and disconnect the cable when needed. It may be a little overkill on the solution but it shouldn't have any problems.
    I have a friend that has good equipment such as a lathe and I told him what I wanted to do and he had some aluminum handy and this is what we came up with. We also bought a charger from Walmart to be a connector. We made a cable with 16 gauge speaker wire.
    Supplies used:
    16 gauge speaker wire - $10
    Walmart charger for male connector - $2
    Female connector for the 5th battery holder - $1
    Werker SAL Battery - ? I can't remember. I think it was around $18
    Terminal connectors - $2
    Aluminum to make dummy battery cells - spare aluminum (I don't know what it costs)
    Nikon 5th Battery Holder - Came with the flash
    My friend made some dummy AA cell batteries out of aluminum.

    We installed the connector from the Walmart charger in the 5th battery holder.

  11. Thanks for the additions and photos, Mark. Being able to disconnect the side of the flash and the cables is a good tweak. I've found that in heavy use, with my version, the plastic hinge pops off of the flash sometimes -- it isn't built to handle the constant pulling and tugging from the cables. So this might solve that. Great idea, and I'm glad you got some use out of the post!
  12. Eric,
    Thanks so much for this tutorial..I made one and love it! I was wondering if you could tell me how to determine which chambers to use on other flashes. I tried to use it on a YN-560 and fried it. I've since bought another but don't really want to try again unless there's a way to figure out the right chambers.
  13. I originally built it for the SB 28 which it works great with but i also have a sb600, a YN560, and a LP 160 that I'd like to be able to use the battery pack with.
  14. If there are any Nikon SB Flash owners that would like the same solution that I have for the external battery and the aluminum dummy AA batteries I can have the same solution made for you. Drop me an email if you are interested.
  15. I was looking for a suitable high voltage pack for my hand held flashgun, after my Quantum Turbo died of old age (circuit inside got corroded) . I love turbos but they are frightfully expensive in India. Actually, by adding 25% more to its price, one can buy a 1200ws power pack with 2 heads.

    After reading many a discussion threads here on Flickr and other sites, I decided to do my own bit of tinkering.

    So, here it is...

    Yongnuo SF-18 (8 cells) pack for Nikon SB-800 modified to accept 8v 3.2AmpHr SLA battery.

    This can be done to similar type battery packs from Nikon / Canon and/or other suppliers.

    As for the battery, do not go more than 9.6v for safe cruising, or else you might end up with a burned pack.

    Flash set to Manual full power - this set up recycles as fast as the Qunatum Turbo I had.
    In other modes its blazing.

    Follow the images for instructions.

    Have fun.
  16. I realize this is old thread.... But I have started undertaking this project so I don't have to rent a battery pack for some charity events I shoot and wanted to share a case I found for the the battery at my local tiger direct/compu-usa store for $5. It is actually a Canon case for the FS series video cameras, but the battery slides perfectly into the case with room at the top for the wiring connections and I am actually thinking of building removable connection point on the case itself. That said, looking around the 'net, I find that most places report these as unavailable or out of stock or a $30 price tag.
    Question for the group, is what charger is available at a reasonable cost to provide a three hour full charge? I am guessing that's about a 6v 1.5a charger based on the battery being a 4a model.
  17. Gel cells don't like rapid chargers, if you don't want the battery to overheat and leak, recharge them at 10% of their AH capacity, so on a 4AH battery, you want a 400ma charger on it for approx 12-14 hours.

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