One of the most confusing questions for electric vehicle (EV) owners is: "If I have Class 1 insurance and my battery is destroyed in an accident, will the insurer pay 100% of the cost?" The answer is "not always." That is because of a condition called "battery depreciation," which determines how much the insurer will pay you — and how much you have to cover out of your own pocket.
In this article, PrakanEV — electric vehicle insurance specialists — will explain battery depreciation in the simplest possible terms, from "what it is → how it's calculated → how to claim → who pays the difference," with a real calculation example using round numbers you can apply right away.
- Battery depreciation is the rule that determines what percentage of a new battery's cost the insurer will reimburse you.
- Depreciation in a policy is not the same as your battery actually degrading — it is the coverage ratio set by each policy's terms.
- Insurance only covers accident-related damage; it does not cover natural battery degradation.
- Full battery replacement has a special Battery Replacement condition, separate from depreciation.
What Is Battery Depreciation in EV Insurance?
What does battery depreciation mean?
Put simply, "battery depreciation" is the rule insurers use to decide what percentage of a brand-new battery's value they will reimburse when your battery is damaged and needs repair or replacement. This ratio gradually decreases as the vehicle or battery ages.
For example, if a new battery costs 300,000 THB and your policy sets battery coverage at 80%, the insurer will pay up to 240,000 THB, and you are responsible for the remaining 60,000 THB.
Why does EV insurance apply battery depreciation?
Because the battery is the most valuable component of an electric vehicle — on some models it accounts for 40–60% of the car's entire price. If insurers had to pay full replacement cost every time regardless of vehicle age, they could not sustain the risk, and premiums would become prohibitively expensive. Depreciation is the mechanism that keeps premiums affordable while still providing fair battery coverage based on the vehicle's age.
Depreciation in a policy is NOT the same as "your battery actually degrading"
This is where most people get confused. The "depreciation" in an insurance policy does not mean your battery has actually degraded by that percentage. It is simply an accounting rule used to set the reimbursement ratio under the policy's terms.
Here is an example to make it clear. Your car may be only 2 years old with a very healthy battery (State of Health, or SoH, as high as 95%). But the policy may state that "battery coverage in year 2 = 80%." That 80% is the payment ceiling, not a statement that your battery has degraded 20%. The two things are completely separate.
Why Does EV Insurance Apply Battery Depreciation?
The battery is a high-value component
EV battery prices today average around 250,000 – 700,000 THB depending on brand and capacity, and some large models approach nearly one million baht. This is why insurance has special conditions specifically for the battery, rather than paying in full as it would for ordinary parts.
Batteries degrade with age and use
Every lithium-ion battery has a lifespan. Over time its capacity gradually declines naturally (known as Battery Degradation). So the battery's real value decreases over time. Depreciation in the policy reflects this principle — an older battery is worth less than a new one.
Battery cost affects the claim payout
In an accident, the claim amount is calculated as actual damage value × the coverage ratio based on depreciation. The older the car, the lower the coverage ratio, and therefore the lower the amount the insurer pays — keeping the balance between collected premiums and assumed risk.
Why is EV depreciation different from a conventional car?
Because a gasoline car has no single component worth half the vehicle's price the way an EV battery is. When a component holds such enormous value, the regulator — Thailand's Office of Insurance Commission (OIC) — issues specific rules and endorsements for EV battery claims, including endorsement ร.ย.ฟ.06 covering reimbursement by replacing the battery with a new one (Battery Replacement), which is handled separately.
How Is EV Battery Depreciation Calculated?
What is battery depreciation based on?
In principle, battery depreciation is based primarily on the vehicle's age (in years), because age reflects the usage the battery has been through. As the vehicle ages, the battery coverage ratio decreases according to the schedule set out in each insurer's policy.
Does vehicle age affect battery depreciation?
It has a direct effect. The older the car, the lower the battery coverage ratio. For example, in the first year coverage may be near 100%, but by year 5–6 the ratio may drop to just 50% of the new battery's cost. However, under the OIC framework, battery coverage generally does not fall below 50% over the life of the policy — meaning even a 10-year-old car still receives battery coverage.
How is battery depreciation expressed as a percentage?
Below is an example table to illustrate how the coverage ratio declines with vehicle age. Please note that these figures are not a single standard used by every insurer. Each product may start at 100% or 90% and decrease at a different rate. Always check the coverage table in the policy of the insurer you are considering.
| Vehicle / Battery Age | Example Coverage Ratio | Policyholder's Potential Share |
|---|---|---|
| Year 1 | 100% (or 90% per terms) | 0% (or 10%) |
| Year 2 | 90% | 10% |
| Year 3 | 80% | 20% |
| Year 4 | 70% | 30% |
| Year 5 | 60% | 40% |
| Year 6 and above | 50% (OIC minimum floor) | 50% |
*Note: This table is only an example to illustrate the principle. Each insurer has its own coverage table — some start at 100% in year one and decrease in steps to 50%. Always check each company's policy endorsement before deciding.
How is battery depreciation different from the "coverage ratio"?
These two terms are often used interchangeably, but they differ slightly. "Depreciation" is the concept that the battery's value declines with age, while "coverage ratio" is the actual percentage written in the policy stating how much the insurer will pay — a figure derived from applying depreciation. Simply put, depreciation is the reason; the coverage ratio is the result you see in the document.
Example: Calculating EV Battery Depreciation
To make it as clear as possible, let's walk through a real calculation with round numbers.
Example with a 300,000 THB battery
Suppose your car is in an accident that damages the entire battery, requiring a full replacement, and the cost of a new battery (including labor) is 300,000 THB.
🧮 Example: Battery Depreciation Calculation
- Cost of a new battery300,000 THB
- Battery coverage set by the policy80%
- Insurer reimburses (80% × 300,000)240,000 THB
- Difference paid by the policyholder60,000 THB
If insurance covers 80% of the battery, how much do you pay?
From the example above, if your policy sets battery coverage at 80%, you will receive 240,000 THB from the insurer and must pay the remaining 60,000 THB yourself.
If the entire battery is destroyed, how much does insurance pay?
When the entire battery is destroyed and must be replaced, the insurer pays according to the coverage ratio stated in the policy — not necessarily the full 100%. For example, at 80% coverage, it pays 240,000 THB of the 300,000 THB cost.
How much does the policyholder have to pay?
The difference is the cost of a new battery minus the insurer's reimbursement. In this example, 300,000 − 240,000 = 60,000 THB. This is why choosing a policy with a high battery coverage ratio and a Battery Replacement condition is so important — it can dramatically reduce the amount you pay out of pocket.
If My EV Battery Is Damaged, Does Insurance Pay 100%?
The answer is it depends on the type of damage and your policy's terms. Let's look at each case.
- Partial damage (repairable): If only certain modules are damaged and repairable, the insurer pays the actual repair cost according to the coverage ratio. A full replacement is usually not required.
- Complete damage (replacement required): The insurer reimburses according to the coverage ratio based on vehicle age — e.g. 80% of the new battery cost — not the full 100%, unless a Battery Replacement condition applies.
- Full battery replacement required: If your policy includes the Battery Replacement endorsement (ร.ย.ฟ.06), you may receive a new battery without age-based depreciation deducted — coverage superior to ordinary depreciation.
- Repairable battery: The insurer may choose to repair rather than replace, if the repair restores safe operation to the service center's standard.
- Natural degradation from normal use: Insurance does not cover this. Car insurance only covers "accidents." For natural degradation, claim under the manufacturer's warranty instead, typically 8 years or 160,000 km.
The key point to remember is to distinguish between "accident-related damage" and "natural degradation." This is the clearest dividing line between what insurance will and will not pay.
Battery Depreciation vs. Battery Replacement: What's the Difference?
Reimbursement based on the depreciation ratio
Standard reimbursement pays new battery price × the age-based coverage ratio. For example, a 300,000 THB battery at 80% coverage pays 240,000 THB, and you cover the difference.
What is Battery Replacement?
Battery Replacement is special coverage set out in the OIC's endorsement ร.ย.ฟ.06 on reimbursing EV battery claims by replacing the battery with a brand-new one, instead of paying cash based on the depreciation ratio. This means that in a severe accident, you may receive a new battery without bearing the full depreciation-based shortfall (depending on the terms and period each insurer specifies).
Can I buy additional battery coverage?
Yes. Many insurers let you buy additional battery coverage or choose a plan that includes Battery Replacement, in exchange for a slightly higher premium — but with the peace of mind that you will not have to pay a six-figure shortfall yourself if the battery fails in an accident.
Is Battery Replacement worth it?
If you drive a high-value EV or one with an expensive battery, Battery Replacement is very worthwhile, because the depreciation shortfall you would otherwise pay can reach six figures, while the premium increase is only in the thousands to tens of thousands of baht per year. Compare the premium against the potential shortfall before deciding.
How Is Battery Depreciation Different from Car Depreciation?
What is car depreciation?
Vehicle depreciation is the decline in the value of the whole car with age and use — a broad concept applied to valuing the car, both in second-hand sales and in setting the sum insured.
What is EV battery depreciation?
Battery depreciation, by contrast, focuses on the battery component alone, because it is the highest-value part with its own reimbursement rules, separate from the car body.
Why is the battery such an important issue in EV insurance?
Because the battery is the most expensive component and one of the most vulnerable to accident damage (especially underbody impacts or flooding). Battery depreciation therefore has a massive impact on the claim amount, and is something every buyer must read carefully before signing.
How does battery depreciation affect the claim?
When you claim for a battery, the payout is calculated directly from the age-based coverage ratio. The higher the depreciation, the lower the payout and the larger your out-of-pocket share. This is why you should choose a policy with a high battery coverage ratio and a Battery Replacement condition.
Does an EV Battery Actually Degrade?
What makes an EV battery degrade?
An EV battery degrades with age, number of charge cycles, and the operating environment — for example, extreme heat or frequent DC fast charging both accelerate degradation.
How does battery age matter?
Over time, battery capacity gradually declines, so the car travels less distance per charge. However, modern EV batteries last a very long time — most manufacturers warrant the battery for 8 years or 160,000 km (whichever comes first).
Do charge cycles matter?
Yes. Lithium-ion batteries have a limited number of charge cycles. Charging to 100% and draining to empty counts as one cycle; the more cycles, the lower the capacity. But for typical users, cycle-based degradation is so slow it is rarely a concern in the first 5–8 years.
What is State of Health (SoH)?
SoH, or State of Health, is the percentage indicating the battery's actual health compared to when it was new. For example, SoH 95% means the battery still holds 95% of its original capacity — which is different from policy depreciation, which is only a rule for setting the reimbursement ratio.
Is insurance depreciation the same as SoH?
No, they are not the same. SoH is the battery's real, technically measurable health, while policy depreciation is the rule that sets the payout based on vehicle age. Your battery may have SoH as high as 95%, yet the policy still uses the age-based coverage ratio to calculate the payment. The two should not be confused.
When Does EV Insurance Cover the Battery?
To make it clear, here is a summary table of which cases are covered and which are not.
| Case | Covered? | Notes |
|---|---|---|
| Accident damages the battery | ✓ Covered | Per the battery coverage ratio in the policy |
| Flood / natural disaster | ✓ Covered | Only if natural disaster coverage is specified |
| Fire | ✓ Covered | Per the fire coverage terms in the policy |
| Accident-related damage | ✓ Covered | The primary case insurance covers |
| Battery degrades from use | ✕ Not covered | Claim under the manufacturer's warranty instead |
| Battery fails without an accident | ✕ Not covered | Insurance only covers accidents |
*Note: Actual coverage depends on each insurer's policy terms. Always check the endorsement before deciding.
Do Different Insurers Apply Different Battery Depreciation?
Does every insurer calculate depreciation the same way?
No. Although all insurers operate under the OIC's regulatory framework, the details of the battery coverage table — the starting percentage, the annual rate of decline, and the minimum floor — can differ between products.
How do battery coverage tables differ?
As seen in the market, some insurers start year-one coverage at 100% and decrease in steps to 50% after the vehicle exceeds 5 years, while others start at 90% and decrease 10% per year. The coverage percentage is therefore something you must compare policy by policy.
What else should you look at besides the coverage percentage?
Beyond the percentage, check whether a Battery Replacement condition is included and how many years it covers new-battery replacement, plus the supported repair centers (high-voltage repair requires qualified facilities) and a sum insured sufficient to cover the battery's value.
Is buying insurance with 100% battery coverage better?
In principle, higher battery coverage is better because it reduces your out-of-pocket share — but it also comes with a higher premium. So you should weigh premium against coverage, not look at the percentage alone. A plan with 100% year-one coverage plus Battery Replacement is often the best value for a high-priced EV.
How to Choose EV Insurance That Covers the Battery
Before buying EV insurance, go through this checklist.
- Check the battery coverage percentage: See where it starts in year one and how it declines each year.
- Check battery depreciation: Read the depreciation table in the endorsement carefully.
- Check the Battery Replacement condition: Is it included, and how long does it cover new-battery replacement?
- Check the sum insured: It must not be lower than the battery's value, to avoid insufficient coverage.
- Check the deductible (excess): See how much you must pay for a battery claim.
- Check repair centers and EV garages: Choose a dealer-repair plan for high-voltage safety.
- Check partial-battery-damage terms: Some plans only cover full replacement, not partial repair.
- Compare premium against coverage: Do not look only at a cheap premium; compare what you actually get covered.
Summary: Battery Depreciation in EV Insurance
- Battery depreciation directly affects how much the insurer reimburses on a battery claim.
- The coverage percentage depends on each policy's terms, not a single market-wide standard.
- Battery degradation from use is not the same as accident damage — insurance only pays for the latter.
- Always check Battery Replacement and depreciation terms carefully before buying insurance.
Battery depreciation can leave you paying a shortfall in the hundreds of thousands of baht after an accident. You can reduce this burden by choosing Class 1 EV insurance with a high battery coverage ratio and a full Battery Replacement condition. Get a free EV premium quote online from PrakanEV today!
FAQ: Battery Depreciation
What is battery depreciation in EV insurance?
It is the rule insurers use to decide what percentage of a new battery's cost they will reimburse when the battery is damaged in an accident, with the ratio decreasing as the vehicle ages.
Does EV insurance deduct battery depreciation?
Yes. EV insurance reimburses the battery according to a coverage ratio that decreases with vehicle age — it does not always pay the full 100%, unless a Battery Replacement condition is specified in the policy.
What percentage of the battery does EV insurance cover?
It depends on the policy. Generally it starts at 90–100% in year one, then decreases about 10% per year down to a 50% floor under the OIC framework. Check the coverage table of the insurer you are considering.
If the battery is damaged, do I have to pay the difference?
Yes. If the policy sets battery coverage below 100%, the difference between the new battery cost and the payout is your responsibility. For example, at 80% coverage of a 300,000 THB battery, you pay 60,000 THB.
Does EV insurance cover battery degradation?
No. Car insurance only covers accident-related damage. Natural degradation must be claimed under the manufacturer's warranty, typically 8 years or 160,000 km.
What is Battery Replacement?
It is special coverage under the OIC's endorsement ร.ย.ฟ.06 that reimburses the claim by replacing the battery with a brand-new one, instead of paying cash based on the depreciation ratio — greatly reducing your out-of-pocket share.
Can I buy additional battery coverage?
Yes. Many insurers let you buy additional battery coverage or choose a plan that includes Battery Replacement, for a slightly higher premium, while reducing the risk of a six-figure shortfall.
What is battery depreciation based on?
Primarily the vehicle's age in years. As the vehicle ages, the battery coverage ratio decreases according to each insurer's schedule in the policy.
Are battery depreciation and SoH the same?
No. SoH is the battery's real, technically measured health percentage, while policy depreciation is the rule that sets the payout based on vehicle age. The two are completely separate.
Which insurer has the best EV battery coverage?
There is no single answer. It depends on the coverage table, the Battery Replacement condition, and the premium. Compare several plans together, or let PrakanEV help you compare for free.
📚 Related Articles:
Don't want to pay a six-figure battery shortfall? Let PrakanEV take care of your car!
📸 Chat with us — send a photo of your car for a free quote! (Click here)Not sure what your premium would be? Use our homepage to check EV insurance premium estimates for your model in under 3 minutes.