This has been done many times, it's often called "buddy pairs." That's putting pairs of batteries together in parallel, and then putting these buddy pairs in series. Some racers have even done triplets.
I bought a 72 volt system with six deep cycle batteries. At 30 miles per day per day round trip it looks like I will need more amp hours to use this vehicle.
I was planning to add to the system. Six batteries in series and six in parallel to extend the range. Would this be ok, or will I need to change the motor and controller?
If you know a link where this issue has been addressed, please let me know.
What vehicle are you using this system on, what motor/controller ?I bought a 72 volt system with six deep cycle batteries. At 30 miles per day per day round trip it looks like I will need more amp hours to use this vehicle.
I was planning to add to the system. Six batteries in series and six in parallel to extend the range. Would this be ok, or will I need to change the motor and controller?
If you know a link where this issue has been addressed, please let me know.
No, if you hook them in "buddy pairs" (2 parallel x 6 series), as you suggested, your charger will work fine and your controller will work fine. Your string will still be 72 volts but your Ah rating will double. A 72 volt system with that truck will dictate some pretty high current requirements (if your controller can handle it... I don't know it's rating) which means you need to verify your battery conductor cable. What size cable do you plan to use?I have a 72 volt charger. You think I will need a different controller?
My motor was made for 36-48 volts. My battery pack is 192 volts. I limit the voltage to 160. You may run your motor to a higher voltage than 72. You need to determine if the brushes are advanced or not. My brushes are advanced 13 degrees. This helps to prevent brush arcing. Look at the alignment of the each brush as compared to the field winding centre lines. (mount screws) Other members including "Major" can help you with identifying your motor capabilities with more detail. Post specific questions in the Motor section of this site.The motor is only 72 volt.
I am using Size 2, 600 Volt welding cable.