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Step 1 Parts List

Tim O'Brien edited this page Jan 28, 2021 · 8 revisions
Home 1:Parts 2:Hardware 3:Software 4:Data 5:Wiring About

New: Now supports multiple power supplies

There are now two options for DC-DC conversion now and more to come in the future.

The beast: Drok BKP6012 Simple & Sexy: DPS5005
Drok in action DPS in action
The Drok is the more powerful option. 720W theoretical max power, 12A max current. Beast! The DPS5005 is less powerful and more expensive but can be assembled without soldering a thing!* It maxes out at 50V input and 5A output so it's suitable for most installations and it's what I now recommend to people because of its super easy setup.
Cons:
  • Requires a voltage divider in order to measure the solar panel voltage that needs resistors and soldering. See the hardware build page.
  • Needs an additional active cooling fan (in most cases)
Cons:
  • *You'll need a simple adapter cable. See the hardware build page. It can be soldered, crimped, or, if you ask nicely on discord, mailed to you in a paper envelope.
  • It's less than half as powerful so I'd super recommend (at least 24V) batteries

More DC-DC power supplies are in the works too. If you've already got one and are curious if it will/could work ping me (tim) on the discord channel with a link/specs and let's talk.

Microcontroller Parts List

Thing ~Price Links Notes
ESP32 $8-$10 amazon ali search The brain of it all. Measures the solar panel voltage and controls the DROK over serial. Right now I'm targeting the nodemcu esp32s. Anything else and you'll have to change the pinInvolt_ in the code.

The project should work with almost any ESP32. Potentially even an ESP8266 (DPS5005 only-- the ADC is even worse than the ESP32). I've even got a development branch with display support for the insane $10 M5Stick-C.. let's chat on discord if you're interested in testing.

DPS5005 Parts List

Thing ~Price Links Notes
Power Supply $27-40 amazon search or ali search Make sure you get one with Bluetooth or USB! The firmware is different on devices that don't include either option and won't work sadly.
Alternative option: $40-50 amazon search or ali search Alternatively this same supply is available in a 20A max version. I haven’t tested one yet but as long as it’s one with Bluetooth or USB it should work fine in larger or lower voltage systems
that's it! $2-$8 amazon 5pack ali search Your DROK is amazing but fails at cooling. The fan only turns on at 5A or above, and it can easily get toasty after hours at 2A. My solution is power the fan with a super cheap LM2596. It's a 3.0-40V to 1.5-35V voltage regulator that can also be used to power your ESP32. If your battery is > 40V (mine is) you'll want the LM2596-HV instead. See the

Drok BKP6012 Parts List

Thing ~Price Links Notes
Power Supply $22-30 amazon or direct from drok The Drok DKP6012 is the powerhouse of the system, converting 10V-75V (I've gone up to 83V without issue) down to to 0-60V at 12A/720W. Referred-to as DROK/Power Supply/PSU (power supply unit)
LM2596 or LM2596-HV $2-$8 amazon 5pack ali search Your DROK is amazing but fails at cooling. The fan only turns on at 5A or above, and it can easily get toasty after hours at 2A. My solution is power the fan with a super cheap LM2596. It's a 3.0-40V to 1.5-35V voltage regulator that can also be used to power your ESP32. If your battery is > 40V (mine is) you'll want the LM2596-HV instead.
80mm CPU Fan $2-$8 amazon example Any cheap thing you've got will do, 5V/12V whatever (since you're powering it with the LM2596 above). Make sure to test the LM2596 output first before plugging in the fan.
Misc small parts ~$0.10 You'll need a 3.3kΩ and 100kΩ resistor, about 5 'female-to-female 0.1" jumper wires', a couple male 0.1" header pins, access to a soldering+iron and a volt meter, and some heat shrink. Any local hackerspace/makerspace will have these.

Optional / Useful things

Thing ~Price Links Notes
Power meter ~$12 amazon Having a volt/amp/power/capacity meter is super helpful. I have this HiLetgo DC 6.5-100V 0-20A meter because it goes up to 100V.
Low voltage disconnect ~$8 ali search If you're charging a battery bank like I am-- you'll probably want some extra protection for your battery to keep from discharging it too far. Make sure to get one that works with your battery voltage, this XY-CD60 works up to 60V
Caps & resistors $0.02-$8 You may want a couple of 1.0 µF (or so) Capacitors and common 1-100k resistors (depending on your input voltage). Use them to smooth out the incoming voltage otherwise it's unmeasurable. If you don't have any get a variety pack from amazon or aliexpress.
Replacement transistors ~$5 amazon If your fan dies and your Drok fails– 99% chance it just needs a replacement power transistor.

Solar install

  • Go to the wiring page for more info on how I'm not an expert on the outdoor part of a solar power system! These are some general things you'll need, not an exhaustive list.
Thing ~Price Notes
Solar panel(s) $50-200 Check your local craigslist, set up an email alert for the price range you want. Ideally you'll want to check for hot spots
Outdoor Wire ~$30 You need UV resistant solar cabling, look for solar cabling at your favorite store. this looks about right. 12AWG is okay for 10A max.
Zip Ties ~5 You'll want zip ties to strain-relief everything so the connectors don't fail over time, especially outdoors.
Connectors $5-20 Connecting to your panel outdoors will usually use IP67 MC4 solar connectors like these.
panel on my roof
example of a simple install on my roof

Battery install

Thing ~Price Links Notes
Batteries depends You can directly charge your ebike battery.. or, like I do, charge a stationary battery during the day and then run & charge everything from that any time you'd like. Search craigslist for LiFePO4, there's often lots of used batteries if you do some research. jehugarcia on youtube has lots of tutorials, hook-ups, and tips.
DC Breaker ~$23 amazon example or example Wire this between your battery and everything else. You NEED fuses on your battery. My LiFePO4 batteries will put several thousand amps through any short-circuit for example. Any crushed wire or inadvertent connection should set you back a $0.50 fuse– not your life.
Fuse block $10-30 amazon search Fuse blocks give you per-device fusing and a nice way to distribute power without soldering some sort of wiring harness (bad idea). May want some extra fuses: amazon search (or just ask for a few at a car repair shop)
Indoor wiring $10-30 Indoor wiring is up to you. Since you've installed fuses/breakers (so you won't short circuit your battery when when your cable breaks) you can use the appropriate gauge speaker wire to wire your gadgets.
Indoor connectors For your indoor connectors use whatever you'd like. I use XT-60, there's also Anderson powerpulls, nylon marine connectors, Deans, etc.

Next step, build the hardware