New problem! 
Added my BEV, set the Bridge to the active bridge, added the VIN, pressed Save, opened the BEV Thing, and:
Cannot invoke “String.startsWith(String)” because “pattern” is null
Stacktrace:
2023-10-17 22:02:36.473 [ERROR] [nal.common.AbstractInvocationHandler] - An error occurred while calling method 'ThingHandler.initialize()' on 'org.openhab.binding.mercedesme.internal.handler.VehicleHandler@6b6bcf19': Cannot invoke "String.startsWith(String)" because "pattern" is null
java.lang.NullPointerException: Cannot invoke "String.startsWith(String)" because "pattern" is null
at org.openhab.binding.mercedesme.internal.handler.VehicleHandler.updateChannel(VehicleHandler.java:937) ~[?:?]
at org.openhab.binding.mercedesme.internal.handler.VehicleHandler.lambda$4(VehicleHandler.java:877) ~[?:?]
at java.util.Map.forEach(Map.java:713) ~[?:?]
at java.util.Collections$UnmodifiableMap.forEach(Collections.java:1553) ~[?:?]
at org.openhab.binding.mercedesme.internal.handler.VehicleHandler.distributeContent(VehicleHandler.java:766) ~[?:?]
at org.openhab.binding.mercedesme.internal.handler.AccountHandler.registerVin(AccountHandler.java:249) ~[?:?]
at org.openhab.binding.mercedesme.internal.handler.VehicleHandler.initialize(VehicleHandler.java:151) ~[?:?]
at jdk.internal.reflect.GeneratedMethodAccessor37.invoke(Unknown Source) ~[?:?]
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?]
at org.openhab.core.internal.common.AbstractInvocationHandler.invokeDirect(AbstractInvocationHandler.java:147) ~[?:?]
at org.openhab.core.internal.common.Invocation.call(Invocation.java:52) ~[?:?]
at java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[?:?]
at java.lang.Thread.run(Thread.java:833) ~[?:?]
(this seems to happen when I save a change to the Thing, and is preceded by " [INFO ] [ercedesme.internal.utils.UOMObserver] - No mapping found for KM_PER_LITER" in at least two cases)