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[sigplus] Critical error: Image gallery folder photos/2011-marlinespikes is expected to be a path relative to the image base folder specified in the back-end.

Update: We went with Custom Arduino-based LVD solution for this project.

The LVD Project is great, but relatively complex -- overkill for some applications. A more static circuit could be made with a zener diode, a signalling LED, and possibly a relay (for actual switching)

This is a zener-based circuit. An interesting reference is at http://pubpages.unh.edu/~aperkins/pdf/Misc-devices/unijunction.pdf --- highly recommended, but a bit technical.

A subset of an LVD (or a starting point) is just the "detection" (signalling) portion:

A prototype is about the area of a dime, with only 6 components:

This working model lights up right at 10.7v, indicating sufficient voltage for a specific application (SLA batteries with 15w fluorescent load).

Parts

P/NDescription
743550 10v zener diode, 5240
38359 3904 NPN transistor
333201 small LED (t1)
691340 100k Ohm resistor
691104 10k Ohm resistor
690865 1k Ohm resistor

Wire the LED-side of the transistor over to an appropriately-sized relay and you get the actual protection circuit. For better usability, green and red LEDs can be added on the open/closed size of the relay as well, to indicate low/high voltage conditions.

For lower-power applications I found a Bestar BS-102B relay -- 12V SPDT, switches 2A, and draws less than 200mW.

This email address is being protected from spambots. You need JavaScript enabled to view it. (or comment in G+) if you're interested in this as a kit or working unit. The PCB is annoying to source, but the rest of the parts are $18 for qty 100 via Jameco

This is a robust low-voltage detection setup, managed with a PICAXE 08M2 microcontroller (and some supporting hardware) to manage the accessories on my motorcycle. Schematics, parts, and source code are at the end. I've also made a Custom Arduino-based LVD with the 8-pin ATtiny45, and A Simpler LVD with no microcontroller and static detection.

This project has also been set up as a "kit" at clubjameco.com. This email address is being protected from spambots. You need JavaScript enabled to view it. if you have any questions.

Background

The problem: motorcycle batteries are barely strong enough to start a bike on the first/2nd try. The lowest-possible load on my battery is about 80-100W. High-beams are another 65W, auxiliary lighting is another 70-100W, heaters are 18-36W, plus a few watts here and there for things like brake lights, iPhone chargers, etc.

On my Bandit, this extra load can drain the battery in under 30 seconds, low enough that it can't be started. On a related note, I'm getting pretty good at push-starting this bike.

[sigplus] Critical error: Image gallery folder photos/2011-marlinespikes is expected to be a path relative to the image base folder specified in the back-end.

Dad stole my rigging knife w/ marlinespike. After turning over my house looking for it, I asked him about it when we met in the FL Keys. He said it was back at his house in Neptune Beach, so I decided to try and make one.

We went to Marathon Marina & Boatyard and found one piece of recycled "teak" -- basically a 2x4 about 8' long, weathered on one face and with holds drilled at regular intervals. We had it cut down to a few smaller pieces and I brought some home with me.

{gallery}photos/2011-marlinespikes{/gallery}

View the album on Flickr