Lithium vs. NiMH D Size Rechargeable Batteries: Which One Should You Choose?

By Ufine, Updated on April 2, 2025

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Part 1. What are D-size rechargeable batteries?
Part 2. What are NiMH D-size rechargeable batteries?
Part 3. What are lithium D-size rechargeable batteries?
Part 4. What are the key differences between lithium and NiMH D-size rechargeable batteries?
Part 5. Which D-size rechargeable battery lasts longer?
Part 6. Are lithium D-size rechargeable batteries safe?
Part 7. Which D-size rechargeable battery is better for high-drain devices?
Part 8. How do D-size rechargeable batteries perform in cold temperatures?
Part 9. What's the cost comparison over time?
Part 10. Which D-size rechargeable battery should you choose?
Part 11. FAQs about D-size rechargeable batteries

D-size rechargeable batteries are essential for anyone who uses high-drain devices like flashlights, radios, toys, or medical equipment. But when you’re trying to decide between Lithium and NiMH (Nickel-Metal Hydride) batteries, the choice isn’t always obvious.

You may be asking yourself:
Which battery type lasts longer? Which is safer, more efficient, and better for my specific device?

This comprehensive guide explores the differences, advantages, and use cases of Lithium vs. NiMH D-size rechargeable batteries. We’ll also help you make the best choice based on performance, cost, safety, and more.

Let’s dive in.

Part 1. What are D-size rechargeable batteries?

D-size rechargeable batteries are large cylindrical batteries typically measuring 33.2 mm in diameter and 61.5 mm in height. These batteries are designed for high-capacity use and are commonly found in:

Flashlights
Portable radios
Boom boxes
Camping gear
Emergency kits
Medical instruments
High-drain children’s toys

Unlike disposable alkaline batteries, D-size rechargeables are environmentally friendly and cost-saving in the long run.

Part 2. What are NiMH D-size rechargeable batteries?

NiMH (Nickel-Metal Hydride) D-size batteries are among the most common rechargeable options. They typically deliver 1.2 volts per cell and offer a capacity ranging from 2500 mAh to 10,000+ mAh.

Key characteristics of NiMH D batteries:

Safe and stable chemistry
Low internal resistance, meaning consistent voltage output
Cost-effective
Widely available

NiMH batteries are ideal for household devices that are used regularly but don’t require extremely high power.

Quick Tip: NiMH batteries work well in devices designed for 1.5V alkaline batteries, even though they only deliver 1.2V. That’s because they maintain their voltage better under load.

Part 3. What are lithium D-size rechargeable batteries?

Lithium D-size rechargeable batteries are more advanced and powerful. They typically use Lithium-ion or LiFePO4 chemistry and deliver 3.6V to 3.7V per cell.

Key characteristics of lithium D batteries:

High energy density (more power in a smaller size)
Lightweight compared to NiMH
Very low self-discharge (can hold charge for months)
Longer lifespan (up to 2000 cycles)
Performs better in extreme temperatures

These batteries are ideal for high-drain or critical-use devices, such as emergency flashlights, tactical gear, and scientific instruments.

Part 4. What are the key differences between lithium and NiMH D-size rechargeable batteries?

Before we look at the table, let’s briefly explain the significant differences:

Voltage Output
NiMH batteries provide 1.2V, which suits most household electronics.
Lithium batteries provide 3.6V or 3.7V, which can overpower devices not designed for them.

Capacity
Lithium batteries tend to have higher capacity (up to 14,000 mAh).
NiMH batteries are lower but more stable under load.

Cycle Life
Lithium batteries can last up to 2000 charges.
NiMH typically lasts 500-1000 cycles.

Weight and Size
Lithium is lighter.
NiMH is heavier but sometimes more robust.

Cost
NiMH is cheaper upfront.
Lithium offers better long-term value.

Detailed Comparison Table

Feature	NiMH D Battery	Lithium D Battery
Nominal Voltage	1.2V	3.6V – 3.7V
Typical Capacity (mAh)	2500 – 10,000	5000 – 14,000
Weight per cell	~160-180 grams	~100-120 grams
Cycle Life	500 – 1000	1000 – 2000
Self-discharge rate	High (20-30%/month)	Low (1-2%/month)
Operating Temp Range	0°C to 45°C	-20°C to 60°C
Initial Cost	$6-$12 per cell	$15-$25 per cell
Charger Compatibility	Standard NiMH charger	Requires Li-ion charger
Device Compatibility	Broad (1.5V-compatible)	Limited (voltage-sensitive)
Safety	Very safe	Needs protection circuits

Part 5. Which D-size rechargeable battery lasts longer?

Lithium D size rechargeable batteries last longer than NiMH batteries both in:

Single-use runtime (due to higher capacity and voltage)
Lifetime use (more recharge cycles)

Example:
A 10,000 mAh NiMH battery in a radio might last 10 hours
A 14,000 mAh lithium battery in the same broadcast may last 14+ hours

If longevity is your top concern, lithium is the winner.

Part 6. Are lithium D-size rechargeable batteries safe?

Yes, but with a few precautions.

Lithium batteries have a higher energy density, which can lead to overheating or fire if misused.
Always use protection circuits (built into quality batteries).
Only use chargers designed for lithium-ion cells.

NiMH batteries are inherently safer, making them a better choice for beginners or casual users.

Part 7. Which D-size rechargeable battery is better for high-drain devices?

When it comes to high-drain devices like:

Tactical flashlights
Emergency radios
Power tools

Lithium batteries perform better due to:

Higher voltage
Better performance under load
Superior efficiency at high discharge rates

NiMH batteries may be suitable for moderate-drain devices such as toys or clocks.

Part 8. How do D-size rechargeable batteries perform in cold temperatures?

Lithium batteries outperform NiMH in cold environments.

NiMH batteries lose capacity quickly below 0°C
Lithium batteries work well even at -20°C

Lithium is the better choice if you’re camping, hiking, or preparing for emergencies in winter.

Part 9. What’s the cost comparison over time?

At first glance, NiMH batteries are cheaper but wear out faster and don’t hold charge as long.

Let’s compare:

Type	Initial Cost	Lifespan	Cost per Charge
NiMH	~$10	~700 cycles	~$0.014
Lithium	~$20	~1500 cycles	~$0.013

Lithium batteries may seem expensive upfront, but they last longer and provide better value over time.

Part 10. Which D-size rechargeable battery should you choose?

Here’s a quick breakdown:

Need	Best Battery Type
Budget-friendly replacement	NiMH
Long runtime & fewer recharges	Lithium
Use in extreme cold or hot environments	Lithium
Safer option for children’s toys	NiMH
High-drain equipment (tools, flashlights)	Lithium
Infrequent use (occasional backup power)	Lithium

Choose NiMH if:

You’re on a budget
You use your devices daily
You value safety over performance

Choose Lithium if:

You need maximum power and runtime
You use devices outdoor or in emergencies
You want long-term savings

Part 11. FAQs about D-size rechargeable batteries

Can I use lithium D batteries in devices made for NiMH?

No, lithium batteries output 3.6V, while NiMH outputs 1.2V. Using lithium in a 1.2V device can cause damage or overheating. Always check voltage compatibility.