Pulled from someone else site:
How to build an External Rechargeable battery pack.
I have built several packs using this method for me and some of my friends. If you don't have an understanding of how electricity works, or how to soldier; I suggest you purchase a pack from eco-charge, oade, et al. If you want to learn, I have found the employees at my local electronic store (NOT RADIO SHACK) helpful, a lot of this is hard to explain with out having 'hands on' experience.
I have built packs for the following devices, Sony D-8/D-7, SBM-1, M-1(remember due to its construction you can use a 6v battery to run the m-1), Tascam DA-P1; Sound Devices MP-2; Grace Designs Lunatec V2, V3; Apogee AD1000, Mini Me; Benchmark/Sonic AD2K+, GP ADC-20/DMIC. I have used these packs in the field at many shows. The packs I have built have been to hundreds of shows and seen over 200,000 airplane miles. I have never had a problem with the packs.
This page shows some basic ideas of how to build the battery packs. I tried my best to link you directly the products, to save you searching for part numbers. After you finish reading this you will probably guess that I like Mouser Electronics. They seem to have most of everything you will need, and the offer online ordering and a variety of shipping methods. Mouser will not have everything though, you will have to take a quick trip to your local hardware store and Radio Shack (RS).
You will have to know how to soldier to build one of these packs. You can buy a soldiering iron at R.S. or any electronic store, buy one with a fine tip. You can also order one from Mouser, mouser has online ordering as well. You will also need solider too. Use solider with a 60/40 (63/37) rosin core solder and use a thin diameter solider, Mouser sells it, but its a rather big roll. RS will have it cheaper.
You will also need a heat gun to melt the shrink wrap, a good blow dryer MIGHT work, if not a lighter if your really careful works, or the soldiering iron will work. Heat guns are usually expensive, so you might go with an alternative.
Charger: First off you need a charger, I am very happy with the Xenotronix brand of chargers. I have only had 1 charger fail, and it was promptly replaced. They now have online ordering. Xenotronix are always helpful. They always ship promptly and will call you if there is any problems. The charger is great, it has a multi color led, with auto fast charge and float charge. The cost is approximately $40. The charger is portable, with dimensions of 2.8" W x 3.8" H x 2.8" D and Weighs less than 1.5 lbs. This is the same charger that eco-charge originally used. Dat header Jonathan Pressman suggests the power sonic charger which can be found at Mouser (which is a rebranded Xenotronix charger)
Batteries: Next you will need a battery, For 6v devices (Sony D-8/D-7, SBM-1, M-1; Tascam DA-P1; Sound Devices MP-2; Grace Designs Lunatec V2, V3; Apogee Mini Me) I use Power Sonic 6v 7ah (amp hour) JK Electronics and at Mouser. For the Apogee AD1000 and Sonic AD2K+, You have to use a 12v battery. Again I use the Power Sonic batteries. I fine the 12v 7ah to be plenty for the Sonic AD2K+, available from Mouser. For the Apogee AD1000 I would suggest you either carry 2 12v 7ah batteries or 1 12v 10ah battery, again available from Mouser. Eco Charge uses Panasonic batteries, they are available through Allied Electronics (800) 433-5700.
Note: The Apogee Mini Me, and Grace Design V2 and V3 will all run on either 12v or 6v. For the Apogee Mini Me and Grace Design V3, you will need to make sure your power cable to the device is wired to the correct XLR pins (explained below). If you have a 6v version of the V2 you can run 12v or 6v, If you choose to run a 12v battery pack your low power indicator light will not work, and vice a versa.
Wire: I use a vacuum cord or lamp cord for the battery to XLR, and XLR to device (except for Sony, where I use attached wire). Eco charge uses lamp cord. Both are available at a local hardware store (home depot, lowes, etc) or RS. Mouser and most other online stores only sells this in 50 or 100 foot spools.
Connectors: Next you need 4pin XLR connectors. The industry standard is 4pin XLR connectors. They are a bit pricey, but I do suggest using them. Radio Shack has a variety of other, cheaper connectors, just remember 4 pin is the industry standard connector, and that is what I suggest you use. I suggest you use Neutrik XLR connectors. There are a variety of companies (Switchcraft, Deltron) that manufacture XLR connectors, but I suggest Neutrix due to their design. All assembly instructions below are for nutrik connectors. You will need a female (NC4FX) for the charger and a female for as many different power connectors your going to run. You will need 1 male connector (NC4MX), this connector is off the battery.
Mouser: 4 pin male ($4.58), 4 pin Female.($5.59), on line ordering. Camel Traders also has them. Full Compass is a bit cheaper, but charge a lot for shipping.
Parts for Sony Products: If you are using Sony products you will need a 4mm (O.D.) X 1.7mm (I.D.) standard Sony connector. I have found that my local electronic store has the said connector with a wire attached to the connector already (one less solider I have to do) and all you have to do is clip the wire to the desired length and solder to the XLR. Mouser stocks the connector with pre wired cord as well. The only drawback of the mouser connector is the head of the connector is rather large. You can also cut the connector off your wall wart that was supplied with your Sony product. If RS is the only thing around, the following link should help. http://www.peteheilig.com/images/d8batpak.gif
. Thanks to Pete Heilig, I used link with out his knowledge, but I want to make sure he receives the credit for the page. When placing Sony connectors to an XLR I usually just solider 2 Sony connectors to one XLR. You can use the extra for a extra dat or something like a SBM-1 and DAT combo. On Sony products the striped wire is positive.
PTC Resettable Fuses: For circuit shorting protection you might want to try a PTC (Positive Temperature Coefficient) Resettable Fuse. Its your option. There are positives and negatives about using circuit protection. Mouser stocks them and they are rather cheap, I suggest ordering a few, they are rather delicate.
Other: You will also need some Heat Shrink tubing, Zip ties, and Zip tie holders with a sticky back. Electronics store or RS. RS links: Heat Shrink, Zip Ties. Mouser Links: Zip Tie Holder. I would suggest the heat shrink packet from RS, as there are a few diameters. The zip ties are also inexpensive. I could not find a part number for Zip Tie Holders from radio shack. You can also check your local hardware store for all of these products, if that's where you choose to purchase your lamp or vacuum cord.
Note: If you live in a large city you should be able to get every thing local for about the same prices. Although sometimes it may be difficult to track down 4pin XLRs. With Mouser now having online ordering, I highly suggest that route.
1. The charger comes with wire that connects easily to the charger but has alligator clips on the other end. remove the alligator clips, strip and prime the wires.
Note: (prime the wires means to me: clean them, twist ends, and place solider on them.)
2. Once again I use a vacuum cord or lamp cord. from the battery to XLR and etc, except for Sony connections. Cut the wire to desired length, remove insulation, strip and prime wires.
3. Slide the black plastic cover of XLR onto wire, DON'T forget to do this. The cover does not go on last, trust me on this
4. Cut shrink rap, and place into position. (over ends of primed wire) (careful, as the heat from the solder will melt the shrink wrap)
5. Now your ready to solder the connections. Start with the Charger cord first. The charger cord is lamp wire. The side of the lamp wire that has ridges on it is your POSITIVE(+) end.
ON ALL XLR CONNECTIONS POSITIVE = PIN 3 (6volt) and PIN 4 (12volt) ON All XLR CONNECTIONS NEGATIVE = PIN 2 (6volt) and PIN 1 (12volt)
Solder the positive end of the charger to either Pin 3 (6v) or Pin 4 (12v). For pin numbering on the XLR look at the back side of the connector, you will see tiny numbers on it. On the front of the female xlr if you look close you can see numbers on it.
6. Next is your XLR for your battery. If you are using vacuum cord the white wire is positive Pin 3 (6v), Pin 4 (12v) black wire is negative. After you have soldered on the XLR, connect the other end to the battery. The battery terminal is clearly marked + and - or is identified by color. Red equals positive (+). Black equals negative (-). NOTE: When connecting always remember negative is always last, just like a car battery. When Disconnecting its opposite, negative is always first. THINK BEFORE YOU DO. Place shrink rap into position on wire and solder to the correct terminal.
6a. For circuit protection you can add a PTC Resettable Fuse. Simply soldier one leg to the positive connection of the battery and the other leg to the positive side of the connecting wire. I insulated mine with some shrink wrap.
7. Make your connectors for the applicable device you are using. For Sony connectors, if you purchased the connector with the wire attached the white and black striped wire is usually positive, this gets soldered to Pin 3 of your XLR. You can double check with a continuity checker. Place one lead of the continuity checker on the tip (see picture below), place the other lead of the continuity checker on the striped end of the wire. Your continuity checker should reflect that this is a continuous connection. All Sony products Tip is positive, Ring is Negative. This theory might prove useful for you with other products as well.
8. Heat all your shrink wrap, so they fit tightly. Your done. Charge Battery.
9. Secure wires to battery, using the above parts . I place shrink rap on the end of the vacuum cord where the inside wires are exposed to connect to the battery, its not necessary, it just looks pretty. I also hold the wire in place with zip ties and sticky back zip holders. This seems to work well for field work.
General Notes: For using the battery pack with DA-P1's, Mini Me's or other devices that have and expensive/non standard connectors to the device, I find it cheapest to simply cut the connector from the ac wall power supply and make a connection with an xlr plug on the ac power supply and the cut end of the power adapter (or plug). This way you can use the connector for your battery pack and ac power supply.
DAP1 notes: I would not charge the internal battery of the dap1 off an external battery, such as a sealed lead acid. It would lessen your run time off an external battery. You should already have a fully charged internal battery before you use it in the field anyways.
DAP1 plug is wired in this way:
The red wire is positive, the white wire is your deck negative, the black is your dap1 internal battery charge ground (negative).
For a connection to a 6v external battery:
You should connect the XLR dap1 plug, and XLR for the dap1 AC adaptor like this: Pin 3 = Red; Pin 2 = White; Pin 1 = Black.
This set up enables you to charge the internal battery for your dap1 off the dap1 ac adapter. (just like before you cut the plug)
You should have NOTHING connected to pin 1 on the EXTERNAL battery XLR.
Your positive terminal from your battery should be connected to Pin 3 of the XLR and your negative wire from the external battery should be connected to Pin 2. This is an industry standard. There is no need to connect anything to pin 1 (unless you want to charge the internal dap1 battery off an external battery)
Apogee Notes: Apogee AD1000 power connectors are as follows: you need a 15 pin shielded metal d-sub hood and HiDen 15pin MALE straight PCB mount (and a s/pdif for your digi out) Pin 1 to center of coax, Pin 6 to shield of coax. For power: Pin 14 is ground, and Pin 15 is positive or hot (12v)
Other Connectors: If your using an Sound Devices MP-2 or G.P. ADC-20/DMIC, your best bet is to get a pre made plug with xlr from a US dealer of the product, i.e. sonic sense, oade, ac masterpiece, et al. I find them to be pretty reasonable on the price. You can also try eco-charge, though they are outrageously expensive.
Legal disclaimer: This is just a guide, Build the battery packs at your own risk. If you fuck it up and blow your self up, or melt all your batteries, you did something wrong. I will except no responsibility. In fact I will laugh at you and take your taping gear away from you
Good Luck, Craig.