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.