Berap ya harga untuk tukar bateri iphone 11 pro max?

In your country, the service provider will set their own price for the battery replacement, check this article:

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Apple Authorized Service Providers can set their own fees, so ask them for an estimate.

Choose a service provider

We’ll inspect your product when we receive it and confirm the service charges. If your iPhone has any damage that impairs the replacement of the battery, such as a cracked screen, that issue will need to be resolved prior to the battery replacement. In some cases, there may be a cost associated with the repair.

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copied from: iPhone Battery Repair & Replacement - Apple Support (MY)