CHT solar (photovoltaic) system
< DRAFT+ >

Solar-related information and open questions CHT collected while starting out in DIY systems.

    xxx stub
    2015-10-11 couture
    2016-03-06 quick sketch of cht4c situation, should prep doc for release
    2017-08-17 restyle
    2017-09-22 update to cht5a state
    2020-08-17 moving over + overviewing ...

Ties to:
    * 🔗stuff - under "Energetics"
    * parts of 🔗ordering for currently provisioned gear
    * parts of 🔗tech-tree (and other infrastructures)


DESIGN (2020)

Within 🔗hackbase-type4.

Panels are tied (!) to top of 🔗trucko.

    2x 50W nomadic foldable solar panels
    1x 50W glass/alu panel
    500W MSV Inverter
    DC-DC 20V (direct charging Lenovos)
    AGM battery
    independent IBM battery charger hold
    li-ion power banks

DESIGN (2017)

Within 🔗hackbase-type2.
a 50W portable solar panel

{{1}}->LED lights {{1}}->DC regulator, ~18-20V out DC regulator, ~18-20V out->AC inverter (220V) DC regulator, ~18-20V out->laptops (Lenovo-type, macbooks, etc) DC regulator, ~18-20V out->sound systems built-in USB 5V out->Lithium 5V battery packs built-in USB 5V out->Mobile phones built-in USB 5V out->tiny WLAN built-in USB 5V out->tiny sound Lithium 5V battery packs->Guitar effect pedals (via 5V->9V regulator) Lithium 5V battery packs->Raspberry Pi built-in 18V semi-regulated output->charge controller charge controller->load 12V out charge controller->AGM battery (12V) 50W solar panel->charge controller 50W portable solar panel->built-in USB 5V out 50W portable solar panel->built-in 18V semi-regulated output AC inverter (220V)->(any 220V load) load 12V out->DC regulator, ~18-20V out load 12V out->WLAN router load 12V out->3.5" external HDD AGM battery (12V)->{{1}} to ignore controller's load disconnect, when battery is not really completely empty AGM battery (12V)->charge controller SUN->50W solar panel SUN->50W portable solar panel SUN->SUN SUN->SUN SUN->SUN LED lights LED lights DC regulator, ~18-20V out DC regulator, ~18-20V out built-in USB 5V out built-in USB 5V out Lithium 5V battery packs Lithium 5V battery packs Mobile phones Mobile phones tiny WLAN tiny WLAN tiny sound tiny sound built-in 18V semi-regulated output built-in 18V semi-regulated output charge controller charge controller 50W solar panel 50W solar panel 50W portable solar panel 50W portable solar panel AC inverter (220V) AC inverter (220V) (any 220V load) (any 220V load) load 12V out load 12V out WLAN router WLAN router 3.5" external HDD 3.5" external HDD AGM battery (12V) AGM battery (12V) Guitar effect pedals (via 5V->9V regulator) Guitar effect pedals (via 5V->9V regulator) Raspberry Pi Raspberry Pi laptops (Lenovo-type, macbooks, etc) laptops (Lenovo-type, macbooks, etc) sound systems sound systems SUN SUN

Parts specifics: 🔗stuff and 🔗ordering

^ not the CHT system ;-)

Related projects

    * AltPwr:
        * [...]

    * +chrono:
        designing own solar charge controller @

    * check "open hardware charge controller":
        * [...]

    * [...]

Solar panel materials (mono/poly/?)

Read this first:

For prices, I took a random look through
Not sure if they deliver to Canarias and what the price would be!!!

poly 145Wp 18V 240€ (1.5€/W)
mono 45Wp 21V 150€ (3€/W)
thin film 50Wp 21V 100€ (2€/W)
mono 50Wp 12V 60€
mono 160W 200€ (folding portable 2x80W halves zip together)

For more prices etc, see 🔗ordering!

this is prob for @@ordering

Charge controllers

Looks like they're 30€. Example:

    * "up to 40% improvement"
    * can charge higher-voltage panels (?):
        (case with big Sharp panels @Fuerteventura)

Problem of fake MPPT chargers:
    A giveaway ~6:00min:
        Should be ~100V.

Branded gear "for nomads" is expensive

(List not updated in a while.)

    * Voltaic systems
        * $400 for 10W + 72Wh batt
        * $400 for 18W 18V + 72Wh batt
        * $170 for 20W , 18V
    * Goal Zero :
        * expensive ~ $10/W
        * Nomad series:
    * [...]

Motorised sun trackers

+Tila has built one in @arreita.
I think mostly because they look cool.
It's not a giant improvement in efficiency, I've heard "20%".
But it feels like you could get more.


DIY solar recipes

    * :
        going to waste, asking for used "garden lights"
    * :
        lots of awesome links
    * [...]

Charge-up in public inconspicuously


    * put chargers, devices and possibly extra batteries in a bag + 220v splitter, to be inconspicuous
    * just plug that one cable from the bag while #squatworking

    * problem: heat? maybe
    * what's the fastest (W) one can expect to charge?
    * how not to destroy ports?

### not really solar

Powering RPi from batteries

#rpi #solar #energetics

(this is for rpi1/rpi2? ###)

    Max: 2.5A @ 5V, Expected: ~500mA -> 2.5W
    Didn't work from an 550mA Alcatel USB charger, but exits on powerbanks are usually 1A, 2.1A
    Frequent unexpected poweroffs can corrupt SD card
    Roughly (made up :)): hours ~= cap / ( draw - charge/2or3{night} * 0.8or0.9{losses}) >> what's your experience?
    Solar 7W + 5000mAh(=~10h) battery min could work
    Could get a few days on the 3W+10000mAh below maybe (survives ~2nights + 0.5Wcharging)

Less power:
        Have a 5min circuit breaker + OS that takes one measurement, then shuts down (but security won't work that way, just sensors)
        RPi 1 or 2, or zero (zero is hard to get)
        Arduino? base is ~50mA, but at more than 5V... can it easily work with sense hat?

Batteries: AGM? Gel? Lithium?

2020 update:
    it seems lithium is now price-viable, even if you don't build it yourself.
    ... accounting you can only use 50% of AGMs rated capacity ...
    ... but, what about cycles? 

Lithium batteries

    * ###
    * [..]

    * do not charge to 100%
    * consider lifepo4
    * you can build your own BNC
    * [..]

Mixing random solar panels ("punk solar systems")

Though mixing different solar panels is not recommended, it’s not forbidden and things would be ok as long as each panel’s electrical parameters (voltage, wattage, amps) are carefully considered.

    ? max input voltage
    * [...]


PWM could be better than MPPT !
In systems with multiple solar panels of different voltages (e.g. 32 cell panels mixed with 36 cell or 40 cell panels), PWM charge controllers are preferable to MPPT controllers because their operation algorithms are less finicky. 



    * in SERIES:
        * VOLTAGES add up
        * CURRENT is limited to minimum panel
        * TOTAL is multiplication !
        """if you connect in series solar panels with different voltage and current ratings, the total output power is determined mostly by the solar panel of the lowest rating!"""

    * in PARALLEL:
        "For this reason, parallel connection is more typical for off-grid systems."

    * [...]


    How to evauate clearly if you have gained (or lost) by adding a random panel?
    How to measure amp outs with a multimeter?


Laptops and dirty power (input voltage tolerance)

    * What happens with a Lenovo X220 if you provide it with wrong voltage / current if it's turned off?
    * ... and if it's turned on?
    * why do laptops actually physically "whir" with the wrong voltage?

Better than off-the-shelf

Looking at Voltaic etc (below) it seems that we could get by with much less?
maybe a 20W panel + 100Wh (~8.33Ah @12V) battery system (per laptop)?

Using truck battery to charge laptops

Deep-cycle batteries
= lead battery designed for repeated discharges + recharges

Cost ~0.5€/W ?
Inverter per panel

Concentrated water heating -> hot water (heating, bathing, power)


Solar ovens !!!


Calculate our price per watt


General guides
(DE) nice guide about solar on vehicles

<------------------------- (new) QUALITY RANDOM INFO  ↑↑↑

*** PAD

[!] ask corps for sponsorship (Voltaic, etc)

asked so far:
    * giga turbines (insta)
    * germans (that gave 50% off ot influencers)
    * [...]

[!] document types, prices and availability of batteries

update 2020: we have a direct source on @lanzarote

update 2020:
    (see above, about batteries)

Solar in Canaria

    * Sol-Lar (Canarsol - Lar):
        * at Puerto in Arrecife, Lanzarote
        * pics: [img:IMG_20150416_140426974.jpg]
        * 12V 85W 155€ poly (~1.5€/W)
        * 629 16 12 09 (Open Mon-Friday 9-13h)
    * Sun-Telco @Lanzarote:
    * people suggest buying from Gran Canaria and shipping in!
    * guy we've met that has a direct link:
        50% off prices!
        see XXX🔗contacts
    * [...]

ARCHIVE: Historic primitive, and imagined designs

    Main coordinates (2015)

We are moving along with our project, and have some funds available for dive into solar.

Need info around the following basic coordinates:
    * start small and cheap.
    * Looking for:
        * 200W out
        * 5h (1kWh) of battery
        * size & weight optimisation not a must, but would be nice
        * optimizing around price
    * Devices to power are all DC:
        * 2 laptops ~20V 50-90W <-- data via what chargers are rated at 220V ac charger label, not consumption
        * 3 smartphones ~5V 10W
    * That would make it maybe 250Wp (?), but could live with half of that too (?)

Main idea currently:
    * Do it without DC->AC inversion
    * Just pure DC system, with a voltage regulator
    * can build it ourselves

    System 0 (CHT4b):
        -> solar panel
        -> directly to an old Samsung 19V / 40W laptop with broken screen

It turned on and worked as a regulator to charge USB devices.
Can't verify the laptop worked stable, because broken screen.

    * what could possibly go wrong?

    System 1 (imagined):
        -> solar panel with higher wattage
        -> DC conversion, no battery
        -> directly to laptop

        * CONTRA: You'd need a big panel, probably 100W size (X220 takes 65W)

    System 2 ("DC straight to battery"):
        -> solar panel
        -> DC convert to 11.1V (X220 battery voltage)
        -> charge batteries directly with some contraption to connect them like
        -> switch batteries in laptop

        * is possibly higher / fluctuating current a problem?

        * PRO: awesome because using standard and Li-Pol batteries
        * PRO: can bring with you away, split weight, etc

    System 3a ("DC straight to laptop"):
        -> solar panel
        -> DC convert to standard battery voltage (12V / 24V)
        -> AGM battery ~50€
        -> DC convert to 20V / even better, manual dial-in any DC voltage
        -> plug in laptop

        * CONTRA: two DC converters needed

    System 3b
        -> solar panel
        -> charge controller (12V / 24V)
        -> AGM battery ~50€
        -> notebook power adapter (cigar lighter) ~30€
        -> plug in laptop
        -> all stuff stored in an IKEA box (samla)
        -> battery protector 12€ like]

        * PRO: could be extended by an USB cigar lighter adapter like
            * what happens if the battery becomes almost empty? Is it better to use a constant current source?

    System 4 ("standard solar"):
        -> solar panel
        -> DC convert to battery
        -> AGM 12V battery / series of batteries
        -> inverter to AC 220V
        -> laptop adapter to 20V DC

        * inverters to AC 220V are / seem expensive (~150€ for 300W):
            UPDATE: not really. see 🔗ordering
        * Q: how much do you lose with DC -> AC -> DC conversion?:
            Probably least 20-30%.
        * but you can plug in anything which is handy!

    Cht4b Status (June 2015)
    * Bought:
        * 50W SolarWorld panel (for 90€):
            (classic poly-crystal panel)
            outputs ~18-21V
            ~1x1m, ~5-6kg
        * DC-only, to charge laptop (Lenovo X220)
        * laptop accepts 20V 3.25A / 4.5A. Unsure about tolerances / dangers?
        * Battery in laptop 11.1V
        * can charge devices on 5V USBs via laptop

    Cht4c Status (March 2016)
    * Bought:
        * Battery
        * Charge controller
        * Step-Up voltage regulator
    * Powering with up-regulator:
        * (Cinch-based connector setup (temporary hack))
        * Lenovo X220 ~20.5V
        * sound system ~15V, takes 20V
        * Apple Macbook cable (16V, still works ~18V)
    * Powering direct from battery:
        * LAN + WLAN direct from battery (12V)
        * 3.5" disk drive (unstable!)

    Test setup Germany (Gerrit)

Instance of 3b (above).

        * 12V x 12Ah = 144Wh AGM battery (for 28€):
        * 20Wp mono solar panel (for 32€):
        * 12V cigar ligher (for 8€):
        * charge controller (for 26€):
        * notebook power adapter (cigar lighter) ~30€:
        * battery protector 12€:
   included in this charge controller      

PROJECT "hyperbattery": own battery system based on 18650s 


nice solar BMS for LiFePO4:

BMS = Solar Battery Management System

        * Shipping, Ready to buy
        * LiFePO4 is cheaper long term:
            ~2000 (even "up to 8000" cycles, compared to ~500 for Lipo for 2-3x price (or lead acid "250 to 1200")
            however perhaps easier to damage if you're experimenting, and a bigger upfront investment
        * Copyleft hardware designs & firmware !:
            ### looks like @@real-hacks

<-------------------------- ((new))

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