What will make it charge for a little while and then just quit charging

You didnt post the model of the IMOGEN and the battery that you are charging or the charger information. Additionally what fuse is blowing? The car fuse, the cord fuse the charger fuse? Imogen is not forthroming with any specifications about the current draw that the units need. You probably should contact imogen directly

It's quite possible that bike has a built in alternator Made to charge the battery as the motor is running.

Did you have the old alternator tested at parts store?

Did you have the battery fully charged & tested?

Now you need to work off wiring diagrams, to learn the
charging system, so you can do your testing,or pay
a shop to do what is required

It could be a couple of problems. My gut tells me your building high pressure either due to a plugged condenser or over charging. If you haven't charged recently try washing out the A/C condenser which looks like a radiator in front of your coolant radiator. Do this with the air shut off. If you have recharged recently try letting a little pressure out of the a harder valve where you filled the system with freon.

If the used alternator quit working then it\'s broke! Make sure your battery is not shorted internally as this could make an alternator work much harder than it needs to. Try getting the alternator repaired at a shop. Buying electrical parts at a junk yard is always a crap shoot...Chris

If the batt light is on, the alternator is not charging the battery.
If the battery won't hold a charge, it could be failing.
If you are having a specific problem with your PT Cruiser or Mustang, let us know what it is.

battery losing charge or a little more serious your alternator is about to pack up simple test charge your car battery and try again alternator thats a job for a mechanic or it could be a dirty carburettor is it ticking over or just miss fireing if its miss fireing its your carb if its not ticking on key turn its your alternator and quite possibly your battery to

This sounds like you might have a bad alternator. If you can get the car to an auto parts store, some will test the charging system and battery for no charge (call ahead before you go).

A car's engine can run for a little while with battery supplying the spark, etc. After that drains down, it will sputter out or just quit.

Best wishes!

--JK

Providing the battery cables are in good condition,it would be the alternator again as the rest of the system is all internal in the alternator.

Check battery connections with a meter.