Reddit mentions of DROK DC-DC Buck Voltage Converter 4.5-40V 12V to 5V/2A Step-down Volt Transformer Stabilizer Voltage Regulator Module Power Supply Switch Inverter Board with LED Voltmeter 5V USB Charger

Of course I couldn't waste all that energy from the exercise bike... so I thought I'd build a generator to capture some of it.

I have a working prototype using a NEMA 17 motor and a simple two bridge rectifier. I'm getting ~20-35v normal riding, but the problem is, at peaks I'm getting upwards of 45v. I was using a 2596-SDC (4-40V buck converter) but I let out the magic smoke when I rode on the bike at a fast pace.

My intent is to use this to charge a USB battery bank. I purchased a DC-DC buck converter (4.5-40V to 5V/2A), but I'm worried it will suffer the same fate.

Looking for advice on how to handle the overvoltage. Some sort of zener diode circuit?

https://www.amazon.com/gp/product/B00IWOPS8K

You'll need a 5v regulator to charge your phone. If you've got a extra battery tray lying around this buck convertor will do the trick. But it would probably be easier to hit up walmart and pick up a small portable battery bank. I've got a few that are about the size of a 26650 cell and say there 2400mah. You might even be able to find them at a dollar store but there quality may be a bit more dubious.

When looking for 26650's these are the only ones you should concern yourself with. All mooch's recommended 26650s and hes the best person to trust when it comes to batteries. Canvape usually has the best price on batteries in Canada. Otherwise if your cool ordering from the US hit up illumn or lightningvapes

AWT Yellow 75A 4500mAh
Basen Black 4500mAh
Brillipower Green 80A 4500mAh
Efest Green 20A 4200mAh
MXJO Yellow 35A 3500mAh

I'm using one of these to power my pi. It's hooked up to the power supply 12V. I wanted the entire printer and octopi setup to be switched through the main power supply switch.

http://www.amazon.com/gp/product/B00IWOPS8K?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00

It should have plenty of juice to power the pi and peripherals. If you cut one of the traces on it, you don't have to press the button to turn it on every time. Read the amazon reviews.

USB has a pretty strict voltage requirement. You'll probably want to start with locating a voltage regulator that will limit the voltage that reaches the charger to 5 volts. Then, I assume the dynamo has a positive and a negative terminal of some sort, simply hook those up to the appropriate inputs on the voltage regulator.

Something like this should do the trick, and provides a USB output.

http://www.amazon.com/DROK-Converter-Step-down-Transformer-Stabilizer/dp/B00IWOPS8K/

http://imgur.com/a/24BVq

The actual installation could have been better, I was in a hurry but it works lol

It's a wireless charger, so I just plop my phone in the dock and I get a nice little trickle charge. I took the dash cam out the other day, but it basically just went up the A-pillar trim and tucked nicely beneath the top of the windshield frame thing.

I used these guys to step down the 12v from the car to an acceptable 5v

Here is one that goes up to 40 volts

http://www.amazon.com/gp/product/B00IWOPS8K?psc=1&redirect=true&ref_=ox_sc_act_title_1&smid=AFHAE9RJVUMB

> adding an LCD volt meter directly to the battery so i can see the voltage,

Why? It's gonna read 12V. It would be a lot easier to write "12V" on a sticker and slap it on there, and it would do the same job.

But if you really want to it would be pretty easy to do. You can buy LCD voltmeter panels; they are really common in process engineering. Most will measure up to 600 V or so.


> where a guy used a car charger adapter thing to accomplish this

There's a 12V to 5V converter built into that. They are pretty small, so they fit in there. That's what I meant when I said you can buy one in the grocery store. You can also get the naked chip. In fact I bought this last month and it's worked great. Turns any voltage from 8 to 22 volts into a USB charging port. The same guy also sells this which seems to be tailor made for you.

> I also need to determine the best AWG size that will easily handle any potential loads

AWG refers to the size of the conductor (the copper). The AWG size is dependent on the current you need to handle, not the voltage. A wire will also have a voltage rating, which refers to the size of the insulator around the copper. For reading a voltage (any voltage) you will have next to no current, so the smallest AWG you can find will work, as long as the insulation is sufficient.

24 V is a tiny amount of voltage; I think any wire you find will be able to handle that. Standard wires are generally rated to 400V at least, often 600.

> I think for current I would need to get into series between the battery and the UPS circuits?

Yes, that's right.

Thanks, yeh that was the plan - to use the battery as a sort of regulator? as it has a consistent output so a phone connected to it would be fine. Sorry for any ignorance - new to electronics, but whats the inverter?

Is something like this what I need? http://www.amazon.com/DROK-Converter-Step-down-Transformer-Stabilizer/dp/B00IWOPS8K/

Before my electric bill came today I was thinking of the following semi-off grid setup:


-----[solar system]-----

solar panel(s)

charge controller

battery(s)


-----[mining rig]-----

Raspberry Pi

Zeusminer Blizzard


-----[electrical stuff]-----

Samlex power supply


PowerSwitch Tail II relay


Raspberry Pi lamp timer circuit


buck converter



-----[The Plan]-----

Plug the Samlex into the PowerSwitch-Tail and PowerSwitch-Tail into wall. Hook the solar system battery up to the Samlex's battery backup terminals. Hook the Blizzard and Raspberry Pi up to the Samlex's 12v output (use buck converter to step the 12v down to 5v for the Pi). Finally, use a cron job on the Raspberry Pi to control the PowerSwitch-Tail. In the morning the Pi would use the 'lamp timer' circuit to open the PowerSwitch-Tail causing the Samlex to draw power from the solar system battery. During the night the Pi would close the PowerSwitch-Tail causing the Samlex to draw power from the grid. The Pi would also restart cgminer to mine to different addresses depending on which power source was being used. I would setup the cron job based on the capacity of the solar system. More panels and batteries would mean the system would run longer off of the solar system before switching back over to grid power. I think it would have worked, but not sure. I'm pretty new at this stuff.

edit: formatting