LiFePO4 vs Lead Acid Battery: Which Is Better for Off-Grid?

TL;DR:

LiFePO4 wins for daily use - it lasts 10x longer, weighs half as much, and costs less per cycle over its lifetime. Lead-acid still makes sense for backup-only systems where upfront cost matters and cycling is rare. For any application with regular discharge cycles, LiFePO4 pays for itself. Use our Battery Bank Sizing Calculator to find your needs.

The Quick Answer

If you're using your batteries regularly - daily or even weekly - LiFePO4 is the clear winner despite higher upfront cost. Here's why:

2x usable capacity from the same Ah rating (100% vs 50% depth of discharge)
10x more cycles (4,000-6,000 vs 300-500)
Half the weight (25-30 lbs vs 60-70 lbs for 100Ah)
3-5x faster charging (2-4 hours vs 8-10 hours)
No maintenance (no water topping, no equalization)

Lead-acid only makes sense when upfront cost is the primary concern and you won't cycle the batteries frequently.

Head-to-Head Comparison

Specification	LiFePO4	Lead Acid (AGM)	Winner
Cycle Life	4,000-6,000 cycles	300-500 cycles	LiFePO4
Depth of Discharge	80-100%	50%	LiFePO4
Round-Trip Efficiency	92-98%	70-85%	LiFePO4
Weight (100Ah)	25-30 lbs	60-70 lbs	LiFePO4
Charge Time (Full)	2-4 hours	8-10 hours	LiFePO4
Lifespan	10-15 years	3-5 years	LiFePO4
Maintenance	None	Water checks, equalization	LiFePO4
Upfront Cost (100Ah)	$300-500	$150-250	Lead Acid
Cold Weather Charging	Not below 32°F*	Yes (slow)	Lead Acid

*Many LiFePO4 batteries include built-in heaters for cold weather charging

Lifespan and Cycle Life

This is where LiFePO4 dominates. A quality LiFePO4 battery delivers 4,000-6,000 charge cycles before dropping to 80% capacity. Lead-acid typically lasts 300-500 cycles.

What This Means in Practice

Daily cycling (RV, van life, off-grid): LiFePO4 lasts 10-15 years. Lead-acid needs replacement every 1-2 years.
Weekend use: LiFePO4 lasts 30+ years (you'll upgrade before it dies). Lead-acid lasts 5-8 years.
Backup only (once/month): Lead-acid can work for 5-10 years. LiFePO4 is overkill unless you want the other benefits.

Key Insight

Lead-acid cycle life drops dramatically with deep discharges. Discharge to 80% depth regularly, and you might only get 200 cycles. LiFePO4 doesn't have this limitation.

Usable Capacity (The Real Story)

A 100Ah battery label doesn't mean 100Ah usable. This is where the comparison gets interesting.

Lead-Acid: 50% Usable

Discharging lead-acid below 50% dramatically shortens its lifespan. That 100Ah battery? You can only use 50Ah before recharging.

LiFePO4: 80-100% Usable

LiFePO4 can safely discharge to 80% depth (some to 100%) without damage. A 100Ah LiFePO4 gives you 80-100Ah of actual power.

Real-World Equivalence:

1 x 100Ah LiFePO4 = 2 x 100Ah Lead-Acid (in usable capacity)

This means a single 100Ah LiFePO4 battery replaces two 100Ah lead-acid batteries - and weighs less than one of them.

Use our Battery Runtime Calculator to see the actual runtime difference.

True Cost Analysis

Lead-acid looks cheaper until you do the math over the battery's lifetime.

10-Year Cost Comparison (100Ah System)

Cost Factor	LiFePO4	Lead-Acid (AGM)
Initial battery cost	$400	$200
Batteries needed (equal capacity)	1	2 (for same usable Ah)
Upfront cost	$400	$400
Replacements (10 years, daily use)	0	4-6 sets
10-Year Total Cost	$400	$1,600-2,400

Cost Per Cycle

LiFePO4 ($400, 4,000 cycles): $0.10 per cycle
Lead-Acid ($200, 400 cycles): $0.50 per cycle

LiFePO4 is 5x cheaper per cycle - the relevant metric for regular use.

When to Choose Each Type

Choose LiFePO4 When:

You cycle batteries daily or regularly (RV, van life, boats)
Weight matters (mobile applications, portable power)
Fast charging is valuable (short sun windows, driving breaks)
You want set-it-and-forget-it reliability
Space is limited (same capacity in smaller footprint)
You're building a long-term off-grid system

Lead-Acid May Still Work When:

Budget is extremely tight and cycles will be rare
The system is backup-only (once/month or less)
Cold weather charging without heating is required
You already have charging infrastructure for lead-acid
It's a temporary or experimental setup

Our Recommendation:

For most off-grid and solar applications, LiFePO4 is the better investment. The upfront cost difference disappears quickly when you factor in lifespan, usable capacity, and replacement costs.

Already have batteries? Check their charge state with our LiFePO4 Voltage Chart.

Frequently Asked Questions

Is LiFePO4 worth the extra cost?

For daily use, yes. LiFePO4 costs 2-3x more upfront but lasts 10x longer (4,000-6,000 cycles vs 300-500). Over 10 years, LiFePO4 is 3-5x cheaper per cycle. For occasional backup power, lead-acid may still make sense.

Can I replace my lead acid battery with LiFePO4?

Usually yes, but check your charge controller settings. LiFePO4 requires different charging voltages (14.4-14.6V vs 14.4-14.8V for lead-acid). Most MPPT controllers have a lithium setting. You may need a DC-DC charger for vehicle charging.

How long do LiFePO4 batteries actually last?

Quality LiFePO4 batteries last 10-15 years with 4,000-6,000 cycles. At one cycle per day, thats 10-15 years. Lead-acid lasts 3-5 years with 300-500 cycles. Even cheap LiFePO4 outlasts premium lead-acid.

Can LiFePO4 batteries charge in cold weather?

LiFePO4 batteries should not be charged below 32°F (0°C) as it can damage the cells. Many LiFePO4 batteries have built-in heating systems for cold weather. Lead-acid can charge in cold (slowly), which is an advantage for unheated installations.

Which battery type is safer?

LiFePO4 is safer. It doesnt contain toxic lead, doesnt produce hydrogen gas when charging, and has excellent thermal stability (no thermal runaway like other lithium types). Lead-acid can leak acid and produces explosive hydrogen if overcharged.

Size Your Battery Bank

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