The short answer: it stays in force.
Impact Power Technologies (IPT) land mobile battery customers tell us that OEM sales reps have sometimes advised them that using a non-OEM replacement battery like IPT’s “voids the land mobile radio warranty.” Such a claim is absolutely NOT true. In fact, tying a radio or other warranty to a battery is, quite simply, against the law.
In US antitrust law – the Sherman Act, for example – some arrangements or restrictions have been ruled by the courts to be “per se” or automatically illegal. This is one of those restrictions. Forcing you to buy an OEM battery by tying a radio warranty to a battery purchase is one of the few practices determined by the US Supreme Court to be illegal “per se” under the Sherman Antitrust Act.