Introduction
Let’s be honest—picking the right battery size for a solar lighting project isn’t glamorous. But it’s the part that makes everything else work. Mess it up, and suddenly your client’s lights cut out halfway through the night, and you’re fielding angry calls at 6 a.m. Get it right, and nobody even notices… because everything just works. That’s the sweet spot.
If you’ve ever stared at a spec sheet wondering whether a 60Ah or 24v 100Ah lithium battery is overkill—or not enough—you’re not alone. This guide is built from field experience, real headaches, and the lessons learned the hard way.
24v 100ah lithium battery
Understanding Battery Capacity and Its Importance in Solar Lighting
Battery capacity is the total amount of electric charge a battery can store and deliver, usually measured in ampere-hours (Ah), indicating how long it can power a device before needing recharge.Battery capacity sounds technical—and it is—but here’s the real-world version: it’s like the size of your gas tank. Bigger means more runtime. But also more cost, more weight, more space.
You’ll see capacity listed in amp-hours (Ah). That tells you how many amps a battery can deliver over an hour. So a 100Ah battery at 25.6V stores about 2,560 watt-hours (Wh). That’s your energy reserve.
But here’s the kicker: a perfectly sized battery gives you just enough juice to handle your load with a little breathing room—no more, no less. Too small? Lights go dark on cloudy days. Too big? Your client overpays for performance they’ll never need.
Common Battery Capacities Used in Commercial Solar Lighting
In commercial solar lighting, battery capacity decisions often follow a pattern based on light wattage, runtime, and backup needs. For 24V LiFePO₄ battery systems—which offer high efficiency and deeper usable capacity (up to 90% depth of discharge)—here’s a realistic guide to typical battery sizes:
| Battery Capacity (Ah) | Stored Energy (Wh) | Common Applications | Notes |
|---|
| 60Ah / 24V | 1,440 Wh | Low-power fixtures (10–20W), garden paths, park trails | Covers ~2–3 days at 10W, 12hr/night use |
| 100Ah / 24V | 2,400 Wh | Medium LED lights (30–40W), commercial walkways, lots | Sweet spot for most mid-size installations |
| 150Ah / 24V | 3,600 Wh | Multi-head poles, wide roadways, small industrial sites | Ideal for long runtimes or low-sun regions |
| 200Ah+ / 24V | ≥4,800 Wh | Large industrial areas, ports, or remote zone lighting | Adds autonomy in high-risk or backup-critical zones |
Let’s say you’re installing a 40W LED light that runs 10 hours per night and needs 3 days of autonomy.
- Energy needed = 40W × 10h × 3 = 1,200 Wh
- Required battery capacity = 1,200 ÷ (24V × 0.9 DoD) ≈ 55.6Ah
A 60Ah LiFePO₄ battery at 24V gives you breathing room while covering cloudy days and system inefficiencies. Oversizing slightly adds reliability without unnecessary cost.
Assessing Your Solar Lighting Load and Energy Consumption
This is where installers sometimes cut corners—and it backfires. Don’t guess. Measure. If you’re not sure what the load is, run a quick audit:
- What’s the fixture wattage? (Let’s say 40W)
- How long is it on per night? (Maybe 10 hours?)
- How many fixtures run per battery?
A 40W light running 10 hours burns through 400Wh daily. Your 100Ah 25.6V battery holds 2,560Wh. Divide the two and you’re looking at roughly 6.4 days of operation.
Sounds great, right? Except… what if you get two straight days of rain and the panels can’t charge? Or what if the controller isn’t running efficiently? Always build in a buffer. Batteries don’t live in spreadsheets.
Considering Environmental and Operational Factors
Let’s talk weather. It’s not just a conversation filler—it wrecks batteries when you ignore it.
- Cold? Cuts down usable capacity.
- Heat? Speeds up degradation.
- Shade or low-sun zones? Less charge time.
- Rain and high humidity? Increases corrosion risk.
Smart installers don’t design for ideal conditions—they design for bad days. Most build in 2–3 days of autonomy to survive cloudy stretches. It’s like packing an umbrella when there’s only a 20% chance of rain. Because you just know it’ll pour the day you don’t.
Comparing Lead-Acid and Lithium Battery Capacities for Solar Lighting
Yes, lead-acid is cheaper—upfront. But you get what you pay for.
Let’s stack them up:
| Feature | Lead-Acid | Lithium (LiFePO4) |
|---|
| Usable Capacity | ~50% | Up to 90% |
| Lifespan | 300–500 cycles | 2,000–5,000+ cycles |
| Maintenance | Regular water/top-off checks | Practically none |
| Weight | Heavy | Light |
| Efficiency | ~75% | 95%+ |
Think of lithium like that dependable coworker who shows up early, stays late, and never calls in sick. Lead-acid? The guy who might show up on time… if the weather’s nice.
Calculating the Right Battery Capacity for Your Project
Let’s break the math down without making your eyes glaze over. Here’s the formula:
Battery Capacity (Ah) = (Watts × Hours × Backup Days) ÷ (Voltage × Depth of Discharge)
Quick Math:
Say you’re running a 60W light for 10 hours a night and want 2 days of autonomy.
- 60 × 10 × 2 = 1,200 watt-hours
- 25.6V battery × 0.9 (90% DoD for lithium) = 23.04
1,200 ÷ 23.04 = ~52.1Ah
Boom. A 60Ah battery covers you with room to breathe. (And sleep at night.)
You don’t want to overspend. But cutting corners here? That gets expensive in callbacks.
- Size to the actual need—not the wish list.
- If conditions are tough (low sun, harsh winters), build in margin.
- Modular setups can help. Two 60Ah batteries might offer better flexibility than one 120Ah.
- Think total cost of ownership. Lithium lasts longer, works better, and saves you headaches.
- Have a weird system or layout? Custom battery solutions can fit the space and load better.
We’ve seen projects tank over a \$30 difference in battery cost. Don’t be that story.
When to Seek Professional Help for Battery Sizing and System Design
Look, some jobs are simple. Others… not so much. When you’ve got:
- A mix of light types
- Odd install locations
- Tight enclosures or mounting constraints
- Clients who change specs mid-project
…it might be time to bring in backup.
Experienced battery pros can help with:
- Load profiling
- BMS tuning
- System balancing
- Integration with controllers and charge units
And let’s face it, showing up with the right answers builds trust. Fast.
Need a second set of eyes? We’ve helped commercial teams, cities, and solar integrators size things right—before the first pole goes in the ground.
Conclusion
Battery sizing isn’t sexy. But when the lights stay on, and you don’t get that late-night panic call? That’s the win.You don’t need a PhD in battery chemistry—just solid math, common sense, and a partner who done this before.Don’t leave it to chance. Nail your battery size, and your system becomes one less thing to worry about.
Contact Kamada Power Our battery experts to get a tailored solution built around your specific power needs.