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?

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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.

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What is the Matrix…Clock?

We’re surprised we haven’t seen this kind of clock before, or maybe we have, but forgot about it in the dark filing cabinets of our minds. The above picture of [danjhamer’s] Matrix Clock doesn’t quite do it justice, because this is a clock that doesn’t just tick away and idly update the minutes/hours.

matrix clock

Instead, a familiar Matrix-esque rain animation swoops in from above, exchanging old numbers for new. For the most part, the build is what you would expect: a 16×8 LED Matrix display driven by a TLC5920 LED driver, with an Arduino that uses a DS1307 RTC (real-time clock) with a coin cell battery to keep track of time when not powered through USB. [danjhamer] has also created a 3D-printed enclosure as well as added a piezo speaker to allow the clock to chime off customizable musical alarms.

You can find schematics and other details on his project page, but first, swing down below the jump to see more of the clock’s simple but awesome animations.

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A Year Long Time Lapse Camera

All [val3tra] wanted was an RF-accessible camera. A camera that would take pictures, save them to an SD card, and occasionally send them over an RF link to a computer. This project has grown out of control, and now it has become an open-source camera that’s able to take year-long time-lapse movies.

The build started as a low power camera using an eBay JPEG camera modified for 3.3V. That’s only 640×480, but each frame averages only 48kb – small enough to store a few thousand pictures on a FAT16 formatted SD card. A $4 RF module, an ATMega, and an RTC make up the rest of the build that has a power draw of about 100 Joules per hour. A D-cell has about 60,000 Joules, and a pessimistic estimate of a battery of four in series, two in parallel gives a run time of 200 days.

This build was then improved, bringing the total battery consumption down to about 3.5-4 Joules per frame, or at one frame every 10 minutes, about 24 Joules an hour. That’s impressive, and getting this camera to run longer than a dozen or so months raises some interesting challenges. The self-discharge of the battery must be taken into account, and environmental concerns – especially when leaving this camera to run in a Moscow winter, seen in the video below – are significant.

If you don’t want to go equipment-lite you could seal your DSLR, Pi, and some serious batteries in a weatherproof enclosure.

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Battery Basics – Choosing a Battery for Your Project

If choosing a rechargeable battery for your project intimidates you, [Afroman] has prepared a primer video that should put you at ease. In this tutorial for battery basics he not only walks you through a choice of 5 rechargeable chemistries and their respective tradeoffs, but gives a procedure that will allow you to navigate through the specs of real-world batteries for sale – something that can be the most intimidating part of the process.

You cannot learn everything about batteries in 9 minutes, but watching this should get you from zero to the important 80% of the way there. Even if your project does not give you the specs you need to begin buying, [Afroman] tells you what to measure and how to shop for it. In particular, the information he gives is framed in the context you care about, hopefully ensuring you are not waylaid by all the details that were safe to ignore. If this is not enough, [Afroman]’s prequel video on battery terminology has more detail.

Much like your high school English teacher told you, you need to know the rules before you can choose to break them. Many of battery absolute Dos or Don’ts are written for the manufacturer, who provides for the consumer, not the hacker. Hackaday has published hundreds of battery articles over the years; search our archives when you are ready for more.

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[Amazing Science’s] Simple Electric Train

Making an electromagnet is as simple as wrapping some wire around a nail and taping the wire to both ends of a battery. When you’re done, you can pick up some paper clips – it demonstrates the concept well, but it could use some more oomph. [Amazing Science] has done just that, making an “electric train” (YouTube link). All that’s needed is some coiled copper wire, a battery and magnets thin enough to fit through the coils. The magnets snap onto both ends of the battery. Put the battery inside the coil and watch the fun! The electromagnetic force generated by the current moving through the coil pushes against the magnets attached to the battery, pushing the battery along the way.

[Amazing Science] plays with the setup a bit. Connect both ends of the coil together and the battery will travel in a loop until it’s drained. Add a small hill, or even another battery/magnet set to the mix, and watch them go! We may even make a version of this ourselves to take with us to family gatherings this holiday season – it’s simple, fun, and can teach the young ‘uns about science while we swig some egg nog.

[via Reddit]

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