Looking to buy a 2nd Battery to use with a diode

[Talon]

I have a 1,000 watt motor ebike with a 35 amp Controller. I have a 52v 18ah battery. I want to increase my range by maybe adding a 2nd battery 52v in the 13 to 14ah range with a Diode to run them together. I want to keep battery lag down to a minimum. No batteries are available from known sources like Em2ev or Luna at this time. Building my own battery is not gonna happen. Any suggestions are appreciated at this time

 

[calab]

Do not bother trying to connect the 2 different sized batteries together, just unplug the one battery and plug in the fresh battery.
Takes a whole whopping 4.5 seconds out of your riding time.
Unless your late, of course, but then you should have left earlier.

 

[dogman dan]

Just parallel connect them to discharge, then no diode is needed if you disconnect them to charge individually. Connect them only when both are full.