Yes there is depending on your requirements you can buy a cheap one and connect Battries in parrell if they are roughly the same capacity also you can charge 2 12 volt Battries in series with a 24 volt charger. Just follow the manufactures guidelines on capacity dont charge a 5 amp battery with a 20 amp charger. You can get a high end charger that will do 6, 12, 24 volt battery's almost at the same time and you can alter the load as you see fit but you have to know what you are doing and you will be spending a lot of money.
If I can take a guess and you want to charge 2 bikes at the same time just connect in parrell to a 5 amp charger for a few hours. JJH