Assuming that the top speed is limited by the voltage available to the motor, that is correct.

Oh... so close. Yes, if top speed is limited by voltage available to the motor then doubling battery voltage will increase top speed. But you have twice the energy available, so your range will be doubled. Driven the same way *motor* current will be the same, but with this configuration *battery* current will be cut in half.

Why would you assume that lower current means greater efficiency? 8 kW is still 8 kW regardless of the battery configuration. That power will be half as much in proportion to battery capacity by doubling the battery capacity (which is good), whether the battery modules are in series or parallel.

The motor speed won't be changed by the battery voltage. Are you considering changing gearing?

So to power my 8,000W motor, at either 45V or 90V, the same amount of "actual" energy is drawn from the batt pack

...it's just that if running @ 90V (as opposed to 45V) the "pressure" (amps) will be less because it's running thru a "wider path" (higher voltage)

As far as speed vs. voltage, the motor specs listed 72 RPM's per volt of input.

Also, when I first did the conversion (back in 2017) I only ran it @ 36V (3-12V 35AH SLA's) & the top speed was ~25 MPH.

Then, when I upgraded it to 48V (4-12V 35AH SLA's) the top speed increased to ~35 MPH

The acceleration was SUPER (0 to top speed in ~3 seconds)

...but, it "topped out" (35 MPH) quickly & the motor really seemed to be "racing" all of the time

So, recently, in an effort to increase speed, I reduced the gear ratio from 5.4:1 down to 5:1

I figured that would/should increase my top speed a bit, with out sacrificing too much acceleration/torque

...& by adding a bit more "load" the motor shouldn't be "racing" so much.

I ended up finding out that this modification did reduce my acceleration level a bit (as expected)

...& it only brought me up, a few MPH (~38 MPH)

...but, (unanticipated) it also, reduced my "max" range a bit too (from ~25 miles down to ~23 miles)

* I consider ~20 miles (range) as my safe zone

As far as increased speed capacity, I don't really want to go a lot faster

...but, with only a 38 MPH top speed, I'm quite often running WOT (full speed) just to maintain/keep up with traffic

So, a 45-50MPH top speed would give me the ability to run ~40 MPH to "keep up with traffic"

...but, not be running @ "full throttle" (so, the motor isn't always "racing")

...& still have some acceleration power (more speed) "in reserve", if needed

Also, (another question) I got 1,600Wh out of my 2kWh pack, (last video) is this normal?

Thanks for the replies, fellas