I have a 48 volt system on my motorcycle conversion. Four 12 volt 55 AH 22NF-AGM Lead Acid UB12550 Batteries in series. An Alltrax AXE4834 300 AMP controller. A MARS ME0709 18 HP / 300 AMP peak motor (8 HP / 125 AMP continuous).

[B]My current (no pun intended) top speed is 45 MPH.[/B]

To go faster I plan on adding 2 more batteries which will give me a 72 volt system. Of course I will have to upgrade my controller to either the AXE7234 200 AMP or the AXE7245 450 AMP.

To increase the range I need to up the AH, and that’s where I am confused. I know in the parallel configuration the Amp Hours are added up, but where do the extra Amp Hours go when I add the additional two batteries like I am planning to do? I realize I will be carrying the additional weight.

[B]If I limit myself to 45 MPH top speed Is my range going to increase at all?

[/B]

I guess the key thing I just learned on another forum is something called AMP Hours which is the true determination of range. It is Volts times Amp Hours, so…

4 x 12V 55Ah setup, I have 48V x 55Ah = 2,640Wh of energy divided by 10 miles (rounded down for easy math) that’s 264Wh per mile

6 x 12V 55Ah setup, I will have 72V x 55Ah = 3,960Wh divided by 264Wh will take me 15 miles.

So if my current 48 volt system takes me 10 miles (rounded down for easy math) than the new 72 volt system will take me 15 miles. That is goodness and is inline with the 50% increase in my battery pack for both volts and Watt Hours.

[QUOTE=Gregski;9475]I guess the key thing I just learned on another forum is something called AMP Hours which is the true determination of range. It is Volts times Amp Hours, so…

4 x 12V 55Ah setup, I have 48V x 55Ah = 2,640Wh of energy divided by 10 miles (rounded down for easy math) that’s 264Wh per mile

6 x 12V 55Ah setup, I will have 72V x 55Ah = 3,960Wh divided by 264Wh will take me 15 miles.

So if my current 48 volt system takes me 10 miles (rounded down for easy math) than the new 72 volt system will take me 15 miles. That is goodness and is inline with the 50% increase in my battery pack for both volts and Watt Hours.[/QUOTE]

That sounds right. Keep in mind that you may not get quite 15 miles because of the added weight from the extra batteries. Accelerating slowly will help too.

Very knowledgeable post,especially for those who have started using electric vehicles.