diff --git a/README.md b/README.md
index 98c5e48..39369b6 100644
--- a/README.md
+++ b/README.md
@@ -149,6 +149,7 @@ Architecture and research notes:
 - Fixed re-authentication having no effect until a manual instance restart: after completing the admin OAuth login the running poll loop kept using the previous (often expired) token, leaving `info.connection` false with no telemetry. The poll loop is now rebuilt with the new token immediately after re-auth (#175).
 - Fixed a single transient token refresh failure (network error, timeout, 5xx) blocking telemetry for up to 75 minutes: the refresh retry backoff is now classified per error. Rejected credentials (invalid_grant / other 4xx) still back off for an hour, but a transient failure only skips roughly the next poll (#178).
 - The underlying reason of a failed token refresh is now logged once as a warning, so it is visible even though `status.lastError` is later overwritten by the throttle message (#178).
+- Fixed the token being refreshed on every poll: BLUETTI delivers the numeric OAuth fields (notably `expires_in`) as strings, which the token normalizer dropped, so no expiry could be derived and `isNearExpiry()` stayed true. Numeric strings are now coerced, restoring the #46 behaviour of refreshing only near real expiry (#178).
 
 <!-- markdownlint-disable-next-line MD024 -->
 ### 1.0.1 (2026-09-25)
diff --git a/src/lib/bluetti-stored-token-provider.test.ts b/src/lib/bluetti-stored-token-provider.test.ts
index 2cad0f8..fb3d8ed 100644
--- a/src/lib/bluetti-stored-token-provider.test.ts
+++ b/src/lib/bluetti-stored-token-provider.test.ts
@@ -4,6 +4,7 @@ import { expect } from 'chai';
 // suffix is needed at runtime, while the main tsc config does not enable it.
 // @ts-expect-error Runtime import resolved by ts-node.
 import * as tokenProviderModule from './bluetti-stored-token-provider.ts';
+import type { BluettiOAuthToken } from './bluetti-stored-token-provider.ts';
 
 const {
 	BluettiStoredTokenProvider,
@@ -165,6 +166,57 @@ describe('BluettiStoredTokenProvider', () => {
 		expect(refreshCalls).to.equal(1);
 	});
 
+	it('accepts expires_in delivered as a numeric string and does not refresh on every poll (#178)', async () => {
+		let now = 1_000_000; // created_at stamped at load as floor(now / 1000) = 1000 s
+		let refreshCalls = 0;
+		const provider = new BluettiStoredTokenProvider({
+			// Real BLUETTI shape: every numeric OAuth field arrives as a string.
+			oauthTokenJson: JSON.stringify({
+				access_token: 'string-expires-access-token-secret',
+				refresh_token: 'string-expires-refresh-token-secret',
+				token_type: 'bearer',
+				expires_in: '3600',
+			}),
+			now: () => now,
+			refreshToken: () => {
+				refreshCalls++;
+				// Cast: the live wire response carries expires_in as a string, which the
+				// BluettiOAuthToken type intentionally does not model.
+				return Promise.resolve({
+					access_token: 'refreshed-access-token-secret',
+					refresh_token: 'refreshed-refresh-token-secret',
+					token_type: 'bearer',
+					expires_in: '3600',
+				} as unknown as BluettiOAuthToken);
+			},
+			persistToken: () => Promise.resolve(),
+		});
+
+		// The string lifetime is coerced, so an expiry is computable and no refresh is forced.
+		expect(provider.isTokenNearExpiry()).to.equal(false);
+		for (let poll = 0; poll < 5; poll++) {
+			now += 60_000;
+			expect(await provider.getAccessToken()).to.equal('string-expires-access-token-secret');
+		}
+		expect(refreshCalls).to.equal(0);
+	});
+
+	it('drops a non-numeric expires_in instead of leaking the raw string through serialization', () => {
+		const parsed = parseStoredToken(
+			JSON.stringify({
+				access_token: 'bogus-lifetime-access-token-secret',
+				refresh_token: 'bogus-lifetime-refresh-token-secret',
+				expires_in: 'not-a-number',
+			}),
+			() => 1_000_000,
+		);
+		expect(parsed).to.not.equal(undefined);
+		const roundTripped = JSON.parse(stringifyToken(parsed as BluettiOAuthToken));
+		expect(roundTripped).to.not.have.property('expires_in');
+		// With no derivable lifetime, created_at is not stamped either.
+		expect(roundTripped).to.not.have.property('created_at');
+	});
+
 	it('refreshes after the cloud provider marks the token expired', async () => {
 		let refreshCalls = 0;
 		const provider = new BluettiStoredTokenProvider({
diff --git a/src/lib/bluetti-stored-token-provider.ts b/src/lib/bluetti-stored-token-provider.ts
index 50d657d..9c1c7a2 100644
--- a/src/lib/bluetti-stored-token-provider.ts
+++ b/src/lib/bluetti-stored-token-provider.ts
@@ -220,17 +220,12 @@ function normalizeToken(value: unknown, now?: () => number): BluettiOAuthToken {
 		token.refresh_token = value.refresh_token;
 	}
 
-	if (typeof value.expires_at === 'number') {
-		token.expires_at = value.expires_at;
-	}
-
-	if (typeof value.expires_in === 'number') {
-		token.expires_in = value.expires_in;
-	}
-
-	if (typeof value.created_at === 'number') {
-		token.created_at = value.created_at;
-	}
+	// BLUETTI returns the numeric OAuth fields as strings ("3600"), so coerce numeric
+	// strings here — otherwise the raw string leaks through the spread above, no expiry
+	// can be derived and isNearExpiry() forces a refresh on every poll (#178).
+	setFiniteNumber(token, 'expires_at', value.expires_at);
+	setFiniteNumber(token, 'expires_in', value.expires_in);
+	setFiniteNumber(token, 'created_at', value.created_at);
 
 	// BLUETTI's /oauth2/token response carries only a relative lifetime (expires_in),
 	// with no created_at/expires_at. Without an issue timestamp getExpiresAtMs() cannot
@@ -293,6 +288,23 @@ function isObject(value: unknown): value is Record<string, unknown> {
 	return typeof value === 'object' && value !== null;
 }
 
+// Assigns a numeric OAuth field, accepting both numbers and numeric strings ("3600").
+// Anything non-finite (missing, empty, non-numeric) clears the key so the raw string
+// value copied by the spread in normalizeToken() cannot survive.
+function setFiniteNumber(
+	token: BluettiOAuthToken,
+	key: 'expires_at' | 'expires_in' | 'created_at',
+	value: unknown,
+): void {
+	const num =
+		typeof value === 'number' ? value : typeof value === 'string' && value.trim() !== '' ? Number(value) : NaN;
+	if (Number.isFinite(num)) {
+		token[key] = num;
+	} else {
+		delete token[key];
+	}
+}
+
 function extractSafeErrorMessage(error: unknown): string {
 	if (error instanceof Error) {
 		return redactSensitiveText(error.message);