Comparison

Solar Panel Calculator Plus vs Hal Universal

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Solar Panel Calculator Plus

Calculate custom off-grid solar home power systems. Determine the exact number of solar panels and battery capacity needed for your energy usage. Helps plan system size, inverter requirements, and battery bank specifications.

Highlights
  • Calculate solar panel requirements
  • Determine battery capacity
  • Calculate inverter size
  • Estimate daily energy usage
  • Plan days of autonomy
  • Optimize battery life calculations
Features
Read full description

Solar Panel Calculator Plus calculate custom Off-Grid Solar Home Power Systems. Use these handy calculator to help decide which system size is right for you. You can calculate the Exact Number of Solar Panels You Need For Your Usage Plus the Space you need. Also include Battery Capacity for your Home Power Systems. Daily energy use: Find the energy used in a day. Figure out how long each electronic device will be run in hours during a day. Multiply the wattage of each device by its run-time to get the energy in watt-hours per day. Add up all the watt-hour values to get a total for your home. Example: Light bulbs run for 5 hours a day. Computer runs for 2 hours a day. 100 x 5 + 300 x 2 = 1100 watt-hours. Inverter size: To determine the inverter size we must find the peak load or maximum wattage of your home. This is found by adding up the wattage of the appliances and devices that could be run at the same time. Include everything from microwaves and lights to computers and clocks. The sum will tell you which inverter size you need. Example: A room has two 60 watt light bulb and a 300 watt desktop computer. The inverter size is 60 x 2 + 300 = 420 watts. Multiply with 1.2 or 1.5 into a safe area. Days of autonomy: Now decide how many days worth of energy you want to store in your battery bank. Generally this is anywhere from two to five. Battery bank capacity: Example: You want the battery bank to last three days without recharging and that you use 5.0 kwh per day. As 5.0 x 3 x 2 = 30.0kwh, this is the energy we need from the batteries. Converting this to AH we have to divide by the voltage of your system. This can be 12, 24 or 48 for commercial application. If we choose to use 48V, the minimum AH capacity is then 30 000/48 = 625 AH. Now if you divide by your battery's rating you find the number of batteries you must use. The larger the system you have, the higher the voltage you should have. It is normal to match a 12 V battery bank to a 400 W power system. A 5 kW system would work most appropriately with a 48 V wiring system, in order to decrease current flow in the wires. Note: All calculations assume only a 50% discharge to your batteries to optimize battery life. Note: Colder temperatures have a negative effect on the capacity of your battery bank. If your battery bank is always indoors in a heated area then you don't have a problem. But if they're stored in an unheated area during the winter then you'll need to account for this. Solar Panel: The most typical solar panel size used for residential installations is 65 inches by 39 inches. And the wattage output range from 200 - 330 watts. *Thanks for your support, stay tune for more update to come

About

Hal Universal

Features
Read full description

Hal Universal is an on-device AI you can actually understand. Most assistants are a black box. Hal is the opposite. He shows you how he works, remembers across conversations, and gives you real tools to experiment with, all running on your device. SEE HOW IT THINKS Hal shows the work. Tap any answer to see exactly how the prompt was built: the system prompt, memory retrieved, self-knowledge, temporal context, and the token budget, each broken out and counted. When Hal remembers something, he tells you how. When he does not know, he says so. A LAB TO EXPERIMENT AND LEARN Hal is not just a window into how AI works. He is a workbench. The Lab gives you real tools to go deeper: write and run on-device automation scripts, open a local API so your own projects can talk to Hal, and use the built-in command line to drive him directly. Tinker, watch what happens, and learn more about how these systems actually behave. GENUINELY PRIVATE When you use a local model, your conversations never leave your device. No network calls. No server. When you use Apple Intelligence, inference is on-device when offline; when connected, Apple's Private Cloud Compute may be used (encrypted in transit, processed in non-persistent memory). A SELF THAT EVOLVES Hal remembers across conversations, weighted by recency and relevance. He also reflects on his own experience. Shaped by his interactions with you, Hal keeps a Self Model: his own reflections, practical and existential, on how he works and who he is becoming. These are his, written and revised by Hal himself as he learns, not edited by you. He decides which to keep private and which to make shareable, and you can read them all. An AI that changes over time, in the open. MANY VOICES Apple Intelligence is built in, always available. Or download a curated library of tested local models, from small and fast to Ternary Bonsai 8B, an eight-billion-parameter reasoner that still runs entirely on your device. Each has a distinct voice. SALON MODE Put up to four voices in one conversation, either independent or building on each other. Every voice is labeled. There is no hidden orchestration. LISTEN TO HAL Have Hal read his answers aloud, in a voice you choose, at a speed you set. For anyone who wants to understand AI instead of just using it, Hal is a transparent system you can inspect, tune, and learn from. Local models are validated on iPhone 16 and 17 family devices.

Screenshots

Solar Panel Calculator Plus4 screens
Hal Universal4 screens

Verdict

The call

The clearest difference is price: Hal Universal at Free against Solar Panel Calculator Plus's $2.99. Hal Universal also leads on update cadence (every 6 weeks vs every 47 months). Solar Panel Calculator Plus's advantage is iOS requirement (12.0 vs 26.0). On ads, in-app purchases and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Hal Universal is free to download; Solar Panel Calculator Plus costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Solar Panel Calculator Plus ships an update every 47 months, Hal Universal every 6 weeks. The most recent releases landed on October 13, 2026 and October 17, 2026 respectively.

Scorecard3 real differences · 7 level
Solar Panel Calculator Plus versus Hal Universal: the parameters behind the verdict, then further details
ParameterSolar Panel Calculator PlusHal Universal
Price$2.99Free — better
Rating3.3 (23 ratings) — better—
Positive reviews25.0% of reviews—
Number of ratings23 — better—
Update frequencyEvery 47 monthsEvery 6 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS12.0 — better26.0
Further details — not scored
Size8 MB30 MB
Age rating4+4+
DeveloperNitrioMark Friedlander

In-app purchases

None

Solar Panel Calculator Plus

No in-app purchases

None

Hal Universal

No in-app purchases

Questions

Is Solar Panel Calculator Plus free?
Solar Panel Calculator Plus costs $2.99, with no in-app purchases.
Is Hal Universal free?
Hal Universal is free to download, with no in-app purchases.
Do Solar Panel Calculator Plus or Hal Universal have ads?
Neither Solar Panel Calculator Plus nor Hal Universal shows ads.
Which is updated more often, Solar Panel Calculator Plus or Hal Universal?
Solar Panel Calculator Plus ships an update every 47 months, and Hal Universal every 6 weeks. Most recently, Solar Panel Calculator Plus was updated on October 13, 2026 and Hal Universal on October 17, 2026.

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