Hacklet 39: Battery Power

3296371398740598106[robin] has a Red Camera (lucky!), an absurdly expensive digital video camera. As you would expect the batteries are also absurdly expensive. What’s the solution? Battery packs from cordless drills.

Cordless drills are interesting pieces of tech that can be easily repurposed; there are huge battery packs in them, big, beefy motors, and enough hardware to build an Automatic Cat Feeder or a motorized bicycle.

What if those old Makita batteries don’t charge? That usually means only one or two cells are dead, not the whole pack. Free LiIon cells, but you need to charge them. Here’s a single cell charger/boost converter that will do the trick.


A problem faced by amateur radio operators around the world is the lack of commercial power. Plugging a portable shack into a wall will work, but for uninterrupted power car batteries are everywhere. How do you combine wall power and car batteries for the best of both worlds? With an In-line battery backup module.

9k=All of the projects above rely on charging a battery through wall power, and sometimes even that is impossible. Solar is where we’re headed, with solar LiPo chargers, and solar LiFe chargers. That’s more than enough to keep a smartphone charged, but if you want to go completely off the grid, you’re going to need something bigger.

[Michel] has been off the power grid 80% of the time since he installed his home PV system a few years ago. How’s he doing it? A literal ton of batteries, huge chargers, and a 5kW inverter.


Replacing Dead Battery Pack Cells Saves You Some Coin

No one will deny that cordless drills can be super convenient. Sure, they need to be charged once in a while but that’s not a big deal. The big deal is when the batteries no longer hold a charge. Buying a new battery pack from the drill OEM is not cheap. If you need several, it’s almost cheaper to buy a new drill/battery combo.

It is not uncommon for only one cell is bad in the battery pack. Getting a replacement cell makes economic sense. And at about $1 per cell, even replacing all of the cells in the pack is way cheaper than the alternatives. [ksickafus] had a battery pack that did not work and not only did he replace all the cells, he wrote a great instructable about it.

The process started by removing the cells from the plastic container. Since they were soldered together they came out in one unit. The cluster of cells was then laid down on a piece of paper and the perimeter of each cell was marked to document the cell orientation. Next, the leads connecting each cell to its neighbor were noted on the same sketch.

The new cells were then laid out on the template to make sure they were in the same orientation as the originals. [ksickafus] uses braided shielding as his new tabs to connect the cells together and learned from experience that flux is necessary for this type of repair. Once everything is soldered up, it’s time to re-assemble the cells in the plastic case and give it a charge. If you do this at home, make sure you keep an eye on it the first time so nothing goes wrong!

If replacing NiCd’s with NiCd’s isn’t cool enough for you, maybe popping some LiPo’s in your drill would be up your alley.

Fix a Broken DS by Removing a Screen

There are apparently a lot of broken Nintendo DS Lites out and about on eBay, and [Fede] has gotten his hands on one. His idea was to essentially turn one of these DS Lites into a SS (single screen?) (.es, Google translate) by modding the case, and he’s done it with pretty spectacular results.

If you’re going to do a case mod, you should go all out. To that end, [Fede] started by taking everything out of the DS and tossing the original 1000 mAh battery in favor of a 4000 mAh battery. From there he is able to shoehorn the two PCBs into the case with the speaker in between, which he notes doesn’t sound as nice as the original but works well enough.

After reshaping the plastic case in a few subtle ways and putting a few layers of paint on it, [Fede] now has a single-screen Nintendo DS for €2 plus parts and paint. While we’ve seen similar mods before, we’d be interested to see this one in action; some DS games don’t utilize the second screen as much as others, so perhaps this wouldn’t play every DS game perfectly, but for the price it can’t be beat.

MacGyver, Jedi Knights, Ammo Stockpiles, and Candy Crush

Everyone’s favorite machinist, tinkerer, YouTube celebrity, deadpan comedian, and Canadian is back with a tale of popping a few benzos, stumbling around Mexico, and wondering why everyone else on the planet is so stupid.

The hero of our story considered the feasibility of one hundred and eighty-sixth trimester abortions as he stood outside a Mexican airport watching a stockbroker complain about the battery in his cellphone. Meanwhile, cars drove by.

Here’s how you charge a phone with a car battery and an ‘ol Dixon Ticonderoga.

To charge a battery, all you really need to do is connect the terminals to a power source with the right voltage. A cell phone battery needs about three volts, and a car battery has twelve. You need a voltage divider. You can get that with a pencil. Take out a knife, get to the carbon and clay wrapped in wood, and wire the battery up. Make a cut a quarter of the way down this rather long resistor, and there you will find something around three volts.

Does it work? Yeah. It works even better if you have some tape to hold wires onto the cell phone battery when charging. Is it smart? It is if there is no other conceivable way of charging your cell phone. Should you do it? Nah. Video below. Thanks [Morris] for the link.

Continue reading “MacGyver, Jedi Knights, Ammo Stockpiles, and Candy Crush”

Fixing a Toyota Camry Hybrid Battery for Under Ten Dollars

[scoodidabop] is the happy new owner of a pre-owned Toyota Camry hybrid. Well at least he was up until his dashboard lit up like a Christmas tree. He did some Google research to figure out what all of the warning lights meant, but all roads pointed to taking his car into the dealer. After some diagnostics, the Toyota dealer hit [scoodidabop] with some bad news. He needed a new battery for his car, and he was going to have to pay almost $4,500 for it. Unfortunately the car had passed the manufacturer’s mileage warranty, so he was going to have to pay for it out-of-pocket.

[scoodidabop] is an electrician, so he’s obviously no stranger to electrical circuits. He had previously read about faulty Prius batteries, and how a single cell could cause a problem with the whole battery. [scoodidabop] figured it was worth testing this theory on his own battery since replacing a single cell would be much less expensive than buying an entire battery.

He removed the battery from his car, taking extra care not to electrocute himself. The cells were connected together using copper strips, so these were first removed. Then [scoodidabop] tested each cell individually with a volt meter. Every cell read a voltage within the normal range. Next he hooked up each cell to a coil of copper magnet wire. This placed a temporary load on the cell and [scoodidabop] could check the voltage drop to ensure the cells were not bad. Still, every cell tested just fine. So what was the problem?

[scoodidabop] noticed that the copper strips connecting the cells together were very corroded. He thought that perhaps this could be causing the issue. Having nothing to lose, he soaked each and every strip in vinegar. He then wiped down each strip with some steel wool and placed them into a baking soda bath to neutralize the vinegar. After an hour of this, he reassembled the battery and re-installed it into his car.

It was the moment of truth. [scoodidabop] started up his car and waited for the barrage of warning lights. They never came. The car was running perfectly. It turned out that the corroded connectors were preventing the car from being able to draw enough current. Simply cleaning them off with under $10 worth of supplies fixed the whole problem. Hopefully others can learn from this and save some of their own hard-earned money.

Emergency Power Based on Cordless Drill Batteries

[Don Eduardo] took matters into his own hands after experiencing a days-long power outage at his house. And like most of us have done at least one, he managed to burn his fingers on a regulator in the process. That’s because he prototyped a way to use power tool batteries as an emergency source — basing his circuit on a 7812 linear regulator which got piping hot in no time flat.

His next autodidactic undertaking carried him into the realm of switch-mode buck converters (learn a bit about these if unfamiliar). The device steps down the ~18V output to 12V regulated for devices meant for automotive or marine. We really like see the different solutions he came up with for interfacing with the batteries which have a U-shaped prong with contacts on opposite sides.

The final iteration, which is pictured above, builds a house of cards on top of the buck converter. After regulating down to 12V he feeds the output into a “cigarette-lighter” style inverter to boost back to 110V AC. The hardware is housed inside of a scrapped charger for the batteries, with the appropriate 3-prong socket hanging out the back. We think it’s a nice touch to include LED feedback for the battery level.

We would like to hear your thoughts on this technique. Is there a better way that’s as easy and adaptive (you don’t have to alter the devices you’re powering) as this one?

Continue reading “Emergency Power Based on Cordless Drill Batteries”

3D Printed Camera Battery Emulator

There are certainly battery hungry devices out there on the market and, unless you do some serious research before the purchase of said device, you really don’t know how it will perform. Needless to say, some of us get stuck with power hog device, and it seriously sucks because changing out batteries often is expensive and just plain annoying.

If you couldn’t tell, I am speaking from experience, my old Sony DSC-H5 camera works great with the exception of needing new batteries every hour. And if you get cheap batteries, the camera won’t even turn on! There’s a USB connector on the camera but it is only for transferring data and there is also no DC input jack. The entire situation is a totally bummer.

I’m happy (or disappointed) that I am not alone in the world. [Phil] wrote into the HaD tip line to tell us about his solution to this very problem. He has a Canon SD1000 camera and although the battery works fine he needs it to work at an altitude of 15km in order to take some sunrise photos. Cold weather testing (in the fridge freezer) showed that the battery isn’t going to cut the mustard for the hour-long flight. The rest of the balloon-lifted unit already has a battery pack and the plan would be to tap into that to power the camera. Unfortunately his camera, like mine, doesn’t have a DC input jack and can not be powered off the USB port.

[Phil] decided to make a 3D printed battery emulator. It sits in place of the stock battery and holds bare wire where the batteries terminals normally are. The other end of the wires are run out of the camera to a voltage regulator that converts the battery pack’s 6 volts down to the 3.9 that the camera needs.

Continue reading “3D Printed Camera Battery Emulator”