Battery Range?

[JohnnieB]

Originally Posted by Great white north

If you can get 20 + miles on a charge that would be very good
This 30 mile range I think is only in the best case , just like when you get a new truck and they say it gets x amount of mileage and it is no way near that even when you have broken in the engine

With the EPA MPG estimates vs real life
I suspect the EPA tests are done under ideal climatic conditions using real gasoline rather than an ethanol blend.

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My original goal was efficiency and then that goal evolved into range, which is essentially a continuation of efficiency with more stored energy on-board. My cart has a very good range because it is very efficient and it is a Sepex Drive, so I use regenerative braking to recover some of the stored energy that would otherwise be lost.

I'm not 100% sure on this, but I think regen braking alone extends my range by about 20%.
Measuring with and without the regen braking turned on is on my To-Do list for this summer.

The ranges I posted for the DCX400 and DCX500 are averages. Peak range recorded for the DCX400 feeding a stock PDS motor was 35.7 miles and peak range recorded for the DCX500 feeding a D&D ES-76-51 was 34.4 miles. Distance traveled for those tests were 10.0 miles and 12.4 miles respectively, over mixed terrain.

I'm putting together a spreadsheet to estimate range that has SoC vs Voltage look-up tables for Trojan type and US Battery type battery packs that I'll post in a new thread for anyone that is interested.

[Great white north]

Great Johnny I would look forward to seeing that
My cart is a PDS , 48 volt , I know I would not get any where near 30 miles
, but I think I have my regen turned off , uhmm something to ponder

[JohnnieB]

Originally Posted by Great white north

Great Johnny I would look forward to seeing that
My cart is a PDS , 48 volt , I know I would not get any where near 30 miles
, but I think I have my regen turned off , uhmm something to ponder

Un-check the Plug Brake and Turbo boxes and move the Brake Current slider to 100% for max range. (Brake Current % setting depends on the motor you are using. The D&D I'm using is designed for high levels of regen braking, with a stock PDS motor set it no higher than 80% and with other brand sepex motors, check with the manufacturer.)

The Turbo feature gives you more top end speed, but is very inefficient. IE: the motor get very hot when using Turbo.

I run with Turbo on, so I can probably get a bit more in the range department if I shut it off. Finding out what the difference is is speed and range is, is another thing on this Summer's To-Do list.

Last year, the city decided to revamp some storm sewers and closed some of the streets I was using in my test route, so I had to take alternate routes in some of my tests. They are about finished with the project and hopefully I'll be able to conduct my various tests over the same exact route, so there will only be one variable, or at least fewer variables, between tests.

[yurtle]

Originally Posted by JohnnieB

...it is a Sepex Drive, so I use regenerative braking to recover some of the stored energy that would otherwise be lost.

I'm not 100% sure on this, but I think regen braking alone extends my range by about 20%.
Measuring with and without the regen braking turned on is on my To-Do list for this summer.

I still believe that if you freewheel down a hill, you will expend less energy coasting partway up the next hill. Gravity is recoverable, and I'll bet the friction losses pale in comparison to regen losses. This assumes you aren't afraid to go 35+ MPH down hill. My driving consists of one or the other pedals always on the floor. If you normally apply brakes going downhill, regen wins.

[JohnnieB]

Originally Posted by yurtle

I still believe that if you freewheel down a hill, you will expend less energy coasting partway up the next hill. Gravity is recoverable, and I'll bet the friction losses pale in comparison to regen losses. This assumes you aren't afraid to go 35+ MPH down hill. My driving consists of one or the other pedals always on the floor. If you normally apply brakes going downhill, regen wins.

Carts are direct drive, so you can't freewheel, but zoom-climbing the next hill is an old trucker trick as well as aviators.

I was only doing 33 MPH (7600RPM) when my stock PDS motor exploded and took the DCX400 with it.

The max RPM D&D recommends for my motor is 6500 RPM (28.5 MPH with my gears and tire height), so I use regen braking to stay under that RPM going down hills.

I also use regen braking to slow down to 15 MPH or less before applying the regular brakes.

[DaveTM]

Well....my Alltrax controller is set to do a blinding top speed of about 7mph, but my torque is set to pull down California Redwoods. OTOH, there are no Redwoods here in Pa., but if I happen to run across a stray.....watch out!!! I have no regen feature in mine so I freewheel down hills. Consequently.....when my cart goes anywhere near 25mph or more....it feels like I'm breaking the speed of sound....compared to 7mph.

[yurtle]

I routinely hit 36.7 MPH with mine. Yes I know I'm not truly freewheeling, but I can go down a steep hill and up most of the way of the next without even touching the gas pedal. I then have to wait for my poor friend with regen.

[yurtle]

My "freewheeling" losses through the rear-end are the same as yours. The only difference is your motor is slowing you down, while mine is just idling.

Again, it depends on driving habits. Cars have to follow speed limits, even downhill, so regen makes sense. Driving a regen on a golf course also probably makes sense.

If I had the money, I'd love to do a side by side comparison with two identical golf carts and driving like the maniac that I am.

[yurtle]

I'm not trying to sound like a know-it-all, just questioning.

Is a Sepex motor more efficient than a Series motor at turning volt/amps into locomotion? That's another unknown to me.

[yurtle]

I'm guessing that since the stator on a series can't be separately excited, regen is not an option, regardless of what controller is available?