Save A Couple Thousand Dollars With A DIY Remote Lighting System

April 4, 2016 by Gerrit Coetzee 20 Comments

When you don’t need the durability of a professional system, this DIY remote lighting system will do.

Pelican makes a great remote lighting system. Unfortunately, it’s the kind of great that comes with a “Request Quote” button instead of “Add to Cart”. It’s designed to be thrown in the back of a tank and guaranteed to work at the end of the day. [mep1811]’s system is not that system. It’s the store-in-a-Rubbermaid-tote and throw in the back of the family Honda kind of great, but it’s made from stuff you can buy anywhere.

The build is contained by a water resistant plastic box. Two sealed lead acids and a battery charger sit inside. The system is hooked together with simple car outlets — also known as the worst accidental electrical connector standard of all time. For the lights, [mep1811] simply made mounts for chinese LED spots and bought some inexpensive camera tripods. With a full charge, he says it runs for forty hours.

In the end it’s not a complicated hack, but its simplicity adds a certain amount of ruggedness, and it will definitely do the trick in a power outage.

Hacklet 39: Battery Power

March 27, 2015 by Brian Benchoff 8 Comments

[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.

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.

An Interview With Tesla Battery Hacker [wk057]

November 11, 2014 by Adam Fabio 63 Comments

We covered [wk057] and his Tesla Model S battery teardown back in September. Since then we had some time to catch up with him, and ask a few questions.

You’ve mentioned that you have a (non hacked) Tesla Model S. What do you think of the car?

It’s the best car I’ve ever driven or owned, period. Not to get too into it, but, I love it. I’ve put almost 20,000 miles on it already in under a year and I have no real complaints. Software feature requests… but no complaints. After almost a year, multiple 1700-miles-in-a-weekend trips, and an overall great experience… I can never go back to a gas vehicle after this. It would be like going back to horses and buggies.

A salvage Tesla Lithium battery had to be expensive compared to a Lead Acid setup. What made you go with the Tesla?

Actually, if you consider that the Model S battery is already pre-setup as a high-capacity pack, contains the wiring to do so, and the modules are much more energy and power dense than any lead acid battery bank, it’s actually almost cheaper than a comparable lead acid bank and all the trimmings.

I haven’t officially weighed them, but the modules from the Model S battery are roughly 80 lbs. 80 lbs for a 5.3 kWh battery is around 15 lbs per kWh, which is impressive. For comparison, a decent lead acid battery will have a little over 1 kWh (of low-rate discharge capacity) and weigh almost the same.

Also, the Tesla pack is much more powerful than a lead acid bank of the same capacity.
Generally a lead acid battery bank would have a capacity that would only be realized with slow discharges, so, 1/20C. Much over that and you sacrifice capacity for power. 1/20C for an 85kWh pack is only 4.25kW, barely enough for a central air unit and some lights without losing capacity.

Now the Tesla pack can be discharged (based on how it does so in the vehicle) at up to 3.75C for short periods, and at 1/2C continuously without really affecting the overall capacity of the pack. That means I can run 10x more power than lead acid without a loss in overall charge capacity. Leads to a much more flexible battery solution since the loads will, in reality, always be so low that this will not even come into play with the Tesla pack, but would almost always be a factor with lead acid.

Charging is also somewhat better with the Tesla battery. Charge a lead acid battery at a 1/2C and it will boil. Charge the Tesla pack at 1/2C (42kW) and it might warm up a few degrees. Oh, and the charging losses at high rates are much less than lead acid also.
Overall, without continuing to yack about the technical aspects, it’s just a much better battery, takes up less space, weighs less, and has more power available.

There are likely decent arguments for other solutions, but the rest aside, this one won out because it was definitely more interesting.

Click past the break to read the rest of our interview with [wk057]!

Continue reading “An Interview With Tesla Battery Hacker [wk057]” →

Electric BMX Has Pedals That Can’t Be Pedalled

September 25, 2013 by Mike Szczys 30 Comments

electric-bmx

We don’t mind it that there’s no chain connected to these pedals. At least there’s still somewhere to put your feet and our legs are too long to comfortably pedal this size of bike anyway. As you can tell, the added hardware takes care of locomotion using an electric motor.

The first step in this project was to find a steel bike frame to make welding a bit easier than it would be for aluminum. From there the paint was sanded at the attachment points and mounting brackets were fabricated from some angle iron. The rear mount houses a 500W 30A AC motor which uses a chain to drive the rear wheel. A specialty hub was found which allows the added sprocket to be installed on the left side of the rear wheel. Some threading issues prompted [Michael Monaghan] to come up with a method of adding a slot to lock the part in place.

Near the front fork the second mounting bracket holds the batteries; a pair of sealed lead-acid units. The speed control mounts on the top where the rider has easy access to it. The finished bike can get up to thirty miles per hour with a range of up to twenty miles between charges.

If you want your own electric bike on the cheap you can try building one from a salvaged washing machine motor.

555-timer Charges Lead Acid Batteries

February 14, 2013 by Mike Szczys 16 Comments

555-timer-charges-lead-acid-batteries

[Kenneth Finnegan] took the focus of a great design and redirected it to solve his own problem. What results is this lead acid battery charger based on the 555 timer. It’s not a top-of-the-line, all the bells and whistles type of charger. But it gets the job done with a readily available IC and no need to code for a microcontroller.

The original idea came from a solar battery charger entered in the 555 timer contest. The main difference in application between that and [Kenneth’s] application is the source. A solar array or wind turbine is limited on how much juice it can produce. But mains power can push a shocking (har-har) amount of current if you’re not paying attention. Herein lies the alterations to the circuit design. To control this he’s using a Laptop power supply as an intermediary and only implementing the constant current portion of the tradition 3-stage lead acid charging profile (those stages are explained in his write up).

He did a talk on the charger at his local radio club. You can see the 90-minute video after the break.

Continue reading “555-timer Charges Lead Acid Batteries” →

Convert A Speaker To A Battery-powered Amplifying Party Box

August 13, 2012 by Mike Szczys 19 Comments

[Matt the Gamer] loved his pair of Minimus 7 bookshelf speakers. That is until a tragic hacking accident burned out the driver and left him with a speaker-shaped paper weight. But the defunct audio hardware has been given new life as a single portable powered speaker. Now he can grab it and go, knowing that it contains everything he needs to play back audio from a phone or iPod.

The most surprising part of the build is the battery. [Matt] went with a sealed lead-acid battery. It just barely fits through the hole for the larger speaker, and provides 12V with 1.2 mAh of capacity. He uses an 18V laptop power supply when charging the battery. The PSU is just the source, his own circuit board handles the charging via an LM317 voltage regulator. Also on the board is an amplifier built around a TDA2003A chip. He added a back panel which hosts connections for the charger and the audio input. Two switches allow the speaker to be turned on and off, and select between battery mode and charging mode. As a final touch he added a power indicator LED to the front, and a drawer pull as a carrying handle.

Motorized Skateboard Just Begging To Be Your Next Project

May 27, 2012 by Mike Szczys 21 Comments

You’re not going to be doing any flip-tricks with this board, but it’ll let you get around without getting sweaty. The ZBoard is a motorized skateboard which is in the pre-order stages thanks to a successful Kickstarter campaign. It’ll set you back $500 now or $600 later. With that kind of budget wouldn’t it be fun to build your own?

This base model can go about five miles or five hours between charges. It carries a seal lead-acid battery (really?) but if you upgrade to the pro model for just $250 more you get a LiFePo that doubles the range (but curiously not the run time). To make it go there are pressure sensitive foot pads on the front and rear of the deck. This allows you to go slow with just a bit of pressure, or put the pedal to the metal to get up to the 15 mph speed limit. It’s even got regenerative breaking to slow things down while giving a boost to the battery.

The idea is nothing new. But the cleanliness that this product brings to market is something to be respected. We’re hoping this sparks some inspiration for a rash of DIY clones, kind of like we’ve seen with the Segway.

Continue reading “Motorized Skateboard Just Begging To Be Your Next Project” →