HiThe Deltran tender is a good choice, you can get single or multiple units depending on how many bikes you want to hook up and what your budget is, and its suitable for glass matt batteries as well.Be careful though - all 2004 (and some of the late 2003) models, with the exception of the F650, require a generation II Gel Battery Charger if you are using the onboard power socket to plug into - the use of any other charger will overcharge and damage the battery.Bikes with CAN BUS technology, i.e. R1200GS-RT-ST---K1200S/R, come equipped with either an AGM or GEL battery, depending on the model, and to charge these through the accessory socket requires a special charger, like the BMW Maintenance Charger, and these come with specific instructions on how to use it. You can charge the battery directly on the battery terminals if your charger is suitable for charging a AGM(glass matt) battery, and the Deltran is fine for this.DO NOT try and charge the battery thought the charge point/aux socket unless you have a specific charger, it will blow the main computer on the bike - many $$$$.If you have the right charger and you’re using the charge point/aux socket then:1: Turn the ignition of the motorcycle to the "ON" Position. 2: Connect the battery charger to the ON BOARD SOCKET first, THEN connect the power plug to a 110 volt outlet. 3: NOW Turn the ignition key to the "OFF" position. Note - if a battery fails due to improper maintenance or if any damage is incurred on a CAN Bus equipped bike due to the wrong charger, these items are not covered under BMW Warranty.Hope that helps
