Power Supply (Ghana)

Power is intermittent in Ghana, so we need to obtain our own independent power supply for the office there. After setting one up for our Ghana office, 🙂 we can use it as a springboard for installations elsewhere in Ghana via fundraisers, as we will know the exact prices to display as the target amount. Recipients should show in the blurb how they intend to use it to fund the maintenance and parts replacements into the future, thus not becoming dependent on our system.

Solar Panels
Inverter (maybe all DC instead?)
Batteries.

The above would solve the power supply problems, but normal equipment is supplied with mains plugs and meant to use AC power. The conversion of the battery power to 240 or 120 V AC and then by each device back to DC again is really wasteful. The solution may be to use the cards shown in this video. All that we need is provided by the methods below.

Laptop on 12V DC

Why avoid the inverter

  • Laptops ultimately run on DC power (typically 12–20 V depending on brand/model).
  • Standard setup in a solar system:
    Battery (DC) → inverter (DC→AC) → laptop charger (AC→DC) → laptop.
  • Each conversion loses ~5–15%.
  • Total efficiency may be only 70–80%, wasting precious stored solar energy.

The Laptop Power Brick

  • Converts AC mains (110/230 V) into DC (commonly 19 V, sometimes 16 V or 12 V).
  • Inside the laptop, this is stepped down further to ~5 V, 3.3 V, 1 V, etc.
  • Goal: replace the AC→DC “brick” with a direct DC-DC solution.

1: Use a 12V DC-DC Laptop Adapter

  • Safest and easiest method.
  • These are often sold as car laptop chargers or “universal DC-DC adapters.”
  • Input: 12 V (from battery or car socket).
  • Output: regulated laptop voltage (15–20 V).
  • Includes interchangeable tips for different laptop brands.
  • Efficiency: 90–94%, much better than inverter + brick.

2: DIY Direct Connection

(Not Recommended)

  • In theory, you could open the laptop’s AC charger and inject DC directly on the low-voltage side.
  • Risks:
  • Wrong voltage = instant damage.
  • Ripple or noise can harm sensitive laptop electronics.
  • Only viable if you’re very experienced with electronics.

Notes on 12V Variability

  • A “12 V” battery ranges from 10.5 V (discharged) to 14.6 V (charging).
  • Direct wiring is unsafe—voltage must be regulated.
  • Car laptop adapters are designed to handle this variability.

Efficiency Comparison

  • Standard setup:
    Battery (DC) → inverter (85–90%) → laptop brick (85–90%)
    → Net efficiency ≈ 70–80%
  • DC-DC adapter:
    Battery (DC) → DC-DC adapter (90–94%)
    → Net efficiency ≈ 90–94%

Result: 20–30% longer runtime from the same solar battery.

Best option for laptops: Use a good-quality 12V DC-DC adapter designed for laptops. This avoids the inverter, saves energy, and is plug-and-play.

Desktop PC on 12V/24V DC

Why avoid the inverter

  • A normal desktop power supply (ATX PSU) expects 110/230 V AC and converts it to the low-voltage DC rails your PC actually uses (12 V, 5 V, 3.3 V, etc.).
  • In a solar setup, you usually have a DC battery → inverter (AC) → ATX PSU (DC again).
  • This means two big conversions (DC→AC, AC→DC) with ~20–30% total energy loss.
  • For an off-grid system, that wasted energy can be significant.

1: Use a DC-DC ATX Power Supply

There are specialized DC-DC ATX PSUs that take 12 V (or sometimes 19–24 V) directly from your solar battery and provide the standard ATX connectors.

Examples:

  • PicoPSU (tiny, efficient, up to ~160 W)
  • Mini-box / HDPLEX DC-ATX units (higher power, up to 400–500 W)

How it works:

  • Input: 12 V (some models also accept 19–24 V)
  • Output: standard ATX connectors (24-pin, 4/8-pin CPU, SATA, etc.)
  • Efficiency: 90–94% (much better than inverter + standard PSU)

Use case: Small desktops, home servers, low-to-mid-power PCs.

2: Buy a Native DC PSU

Some industrial and “car PC” PSUs are built for wide DC input ranges (e.g., 6–24 V or 12–48 V). These often slot directly into an ATX case and replace the normal PSU.

Pros:

  • Cleaner install (looks like a regular PSU).
  • Higher power capacity than PicoPSU-type modules.

Cons:

  • Harder to find, more expensive.

3: DIY or Hack an ATX PSU

Advanced option only—you can gut an ATX power supply and bypass the AC rectifier stage to feed it DC directly.

  • Most ATX PSUs rectify AC mains into ~325 V DC (for 230 V regions).
  • You’d need a high-voltage DC source to feed this, not a 12 V solar battery.
  • Not practical for a 12 V system unless you build a dangerous boost converter.

Not recommended unless you’re very experienced with power electronics.

Efficiency Comparison

  • Standard setup:
    Battery (DC) → Inverter (DC→AC, ~85–90%) → ATX PSU (AC→DC, ~85–90%)
    → Net efficiency ≈ 70–80%
  • DC-DC ATX PSU:
    Battery (DC) → DC-DC ATX (~90–94%)
    → Net efficiency ≈ 90–94%

So you save 15–25% power and avoid running an inverter full-time.

Notes

  • Voltage range matters: a “12 V” lead-acid battery actually varies from 10.5 to 14.6 V depending on charge. DC-DC ATX units handle this; don’t connect a motherboard directly to the battery!
  • Power budget:
  • Small servers (Intel NUC, Mini-ITX, Raspberry Pi) → PicoPSU fine.
  • Mid-tower gaming PC with GPU → needs higher power DC-ATX or stick with inverter.
  • Laptops are easier: just use a DC-DC car adapter as we discussed.

Best option for desktops: A PicoPSU or DC-ATX power supply matched to the system’s wattage, fed directly from the solar battery or via a regulated DC bus.

or…

in case google deletes it, it’s the ZY12PDN PD Trigger Board