Dan,
When you lift on an ordinary car it coasts with some engine compression braking.
Fork lifts are designed to get one shift out of a battery. When the operator lifts on a lift truck dynamic braking kicks in and that inertial energy is sent to the battery. Slowing can best be described as severe. Lifting your foot is almost like hard braking.
I have driven a Prius and that is programmed to regen but coast like an ordinary car.
See if you can find a 10 year old or newer 48 volt truck and ask if you can drive it. In 20 feet you will see exactly what I an describing.
The S10 conversion is different from a car in that it slows quickly after lifting, surprising both the driver and the car following. Often the foot brake is only used to hold the truck on a hill at a light. It took some fiddling to get the brake lights to come on when in regen.
Also when he floors it he surprises the hell out of everyone. Nothing beats DC torque and the battery in the back limits wheel spin.
Have driven forklift since 73. DC and then AC up to 6,000 lb capacity. Dynamic braking either AC drive or DC drive did not result in load sliding off forks. Panic braking did sometimes. Have no doubt I value dynamic braking.
I started studying electric drive in vehicles in 07 or thereabouts.
Have seen many small pickups with electric drive. Those done by owner using DC series motor lack torque at higher end ie 60 mph and for hill climbing they must have transmission - seems to me these motors are undersized. Every one I have checked after driving in Seattle seemed overheated to me. I did DC maintenance on Navy submarine and got my fill of it. I considered using forklift AC drive system in truck until I found that factory would not share information - and a forklift repair guy recommended against salvaging forklift motors due to inadequate HP - he is owner of White Zombie - took care of that idea.
So now my concept is to choose the motor that is correctly sized to meet the demands of the load.
1. KNOW THY LOAD measure torque needed to roll vehicle using torque wrench.
2. Calculate driveline speed and torque demand based on 1
3. Pick motor based on 2
So on 56 Chev pickup I did the above. THe motor was purchased from Boeing Surplus for $229 Leeson 3600 RPM 50 HP. Direct couple to driveline - no transmission. DICK DV and another advocate using 1800 RPM motor and I see their point and agree with it. Would give better starting torque for sure and more than enough torque thru baseline and up to about
2600 RPM where torque is just under 70 ft lb - corresponds to 58 mph
2800 RPM 60 ft lb and about 63 mph.
HOWEVER - this does not include windage which is nearly negligible at 35 mph or less but is a square function of relative velocity. I do not have a wind tunnel and I am sure I am unable to talk my neighbor (Boeing) into loaning me one to measure wind resistance and thus derive torque demand of wind resistance at speeds 40 thru 60. This evaluation will be done by road testing.
SO for now I am going to stay with the 3600 RPM motor for several reasons
1. I have it, brand new, low cost, should have adequate starting torque (other than very steep hills ie 15 or 20%) and it should meet my needs from 0 to 60 mph.
2. It will make a good pilot program motor and will give me good measurements to make the final decision to stay with 3600 RPM or switch to 1800 or maybe even 1200 RPM motor.