I’ve always wanted to have a battery powered BBQ fan. The plan was to make it small/portable, but it all went wrong:
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Category: @nioko Labs
I prefer having a cold beer when I’m on our boat, but since this is usually on the sunny days, the performance of our fridge (Waeco CF-18) was too weak to cool one down in a short time (temperature in the cabin goes up to ~35° C if the sun is burning down).
I’ve been thinking about some kind of a GSM-based remote control, and actually found a nice product called microguard. The product seemed perfect, relatively cheap, easy to implement, available, but there was no time-out that could be set. Even if I have a separate starter-battery, it was key to find a solution that turns off the fridge after a given time without user interaction. Luckily, the guy who runs microguard was very cooperative, and added a timeout feature for me (and everyone else of course).
The module now turns on a relay for two hours after it’s been called from my or one of 4 other predefined phones. this is a bit on the short side, but I can live with calling twice.
This is how my installation looks:
From left to right:
Charge split diode / Rear side of main switches / Fridge fuse / Microguard module with relays, cables, mounted on an a plastic case / RedBull cup as holder for a Siemens S45.
The Cat5 network cabling goes directly to the voltmeters on the dash, this was made to show the exact voltage without loss due to load on the cabling.
As mentioned before, I have two separate batteries the starter is a traditional lead/acid battery, and the domestic is an AGM type, which allows deep cycles.
This is how the battery compartment looks:
The switches on the left are starter / jumper / domestic. This allows maximum flexibility. The domestic main switch actually doesn’t kill the microguard / fridge, so it can be off, and I can still call the fridge.
There are many reports about unbalanced Li-Ion cells in Magicshine Bike lights. This can lead into overcharged cells, which is dangerous, or at least will damage the cells. The charger which comes with the light does not have any balancing capabilities, the battery itself only has some very limited under/over voltage protection.
To solve this problem, you’ll need to modify the battery (add a balancing connector), and use a different charger, or external balancer. I’ll use my hobby charger, which has an integrated balancer.
This is no complete guide, it needs common sense, and some knowledge about electronics. You should also know, that working with Li-XX cells is dangerous.
If you don’t know how Li-XX balancing works, please read:
http://scriptasylum.com/rc_speed/lipo.html
http://www.rcgroups.com/forums/showthread.php?t=599316
before starting to modify your battery pack.
Adding the balancing connector:
Open up the pack:
The interesting part is the four 18650 cells, remove the top of the pack (shown on the left):
Add a new wire which will end as your balancing connector, this is connected to the “middle” of the pack, the pack is 2S2P.
Your Magicshine Pack should now look like that:
The next Step is to put back the isolation, and bring the balancer wire out of the case. this can be done through the original cable exit:
I’ve added a 2mm banana connector, some heat shrink tube, and a cable tie:
Finished Pack, charging:
As you can see, the connections were made as follows:
– from the battery goes to – of the charger, and pin1 of the balancer.
newly made balancing wire goes to pin2 of the charger
+ goes to + of the charger, and pin3 of the balancer.
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Trisa Elektrozahnbürste AA Mod
This article is about a swiss product, which I don’t think is very common outside Switzerland, so I’m writing in German.
Als ich mir die Elektrische Zahnbürste von Trisa gekauft hatte viel meine Wahl auf dieses Modell, weil ich weder Platz noch Lust auf eine Ladestation hatte. Das Konzept aufladen und leerbrauchen hat mir da einiges mehr zugesagt. Am liebsten hätte ich jedoch eine Zahnbürste gekauft, die mit einer herkömlichen AA Batterie / Akku betrieben wird.
Letzte Woche ist mir die Trisa aus unerklärlichen Gründen ausgestiegen. Ich habe dann am Ladeanschluss mit einer Zange die Platine inkl. Akku rausgerissen. Eigentlich mit der Idee das Teil zu reparieren, doch der AA gedanke war schnell wieder da. Kurz eine Batterie reingesteckt, passt perfekt, nur findet auf der Vorderseite kein Kontakt statt. Es fehlten einige Milimeter beim Minus-Pol, welcher in der Bürste sitzt. Ein Quadratischer Neodym Magnet mit 7mm Seitenlänge war schnell zur Hand, und stellt nun den kontakt her.
Die Zahnbürste läuft nun perfekt mit einem AA Akku.
Some of you might have noticed that i like playing with magnets, so i did again. I’ve used neodym magnets which have hole in the middle, and used a screw, which I soldered the wires to. This makes very practical charging leads which can be attached to just about everything.
This wasn’t my idea, someone on the candlepower forums posted some similar charging leads a while ago.
It’s been a long time since I wanted to mod my 3c Maglite, which to be honest wasn’t exactly bright. Costs always held me back, but then I’ve found this:
http://www.dealextreme.com/details.dx/sku.9358
This module is very bright, but too much of a thrower for my use, but i didn’t know that, and probably cannot change it (any suggestions are welcome). It has an included circuit to drive the led’s from 3.6 v- 9v. It also has 3 Output modes, strobe, low, full, they are very annoying, because they change every time you disconnect the power source. The Mag switch actually connects, disconnects for a short time, and then connects again, if you pusch it once. This makes it even worse. So i would not recommend this module, or at least not if you’re planning to use the original switch.
Now to the mod itself:
I’ve had to cut down the mag’s head, and sand out quiet a lot of alloy to get the thing in:
I guess this is much easier on the D mag, but i always preferred the C over the D.
Connecting the module to the switch is easy, the important thing is how to disassemble the mag, but i won’t describe this here, it can be easily found on the internet. The whole thing should look more or less like this (module installed in Mag-head, switch disassembled, wires soldered to switch contacts):
After reassembling it looked like that, the parts next to it are the leftovers from the mag minus the reflector:
Note: Three rechargeable NiCd or NiMh cells provide the absolute minimal current to run this thing, it gets brighter when running on higher voltage. Which is something I’ll maybe do i future, using 2 18650 Li-Ion or maybe LiFePo (much saver than Li-Ion) cells.