Quote:
Originally Posted by sleepyluke
I like the idea of lithium, but also don't want to spend double and have to change the way everyone drives it. Do you re-profile your alltrax with the conversion, or leave them?
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I did change my Alltrax when I went lithium.
*Caveat! This is for my cart, your cart will be different!
I changed the torque/throttle curve so it'd be less jarring. With that much less weight it wanted to accel a lot harder and I wanted more control. If I floor it I want accel, but if you press the pedal half way I don't want to have "yeeted my people off the cart" as my daughter would say.
I played with the regen a lot to get it right where I wanted it. I think I have regen set to 84 or 86 amps max and the shunt set to 0 amps. This way it slows the cart as if you are mildly putting on the brakes then when it gets to a crawl it rolls. This puts energy back into the pack but doesn't just shunt the power when the motor's not spinning fast enough. It works out pretty well.
I also set the controller to cut off at a different Low Voltage cutoff. The LV cutoff for lead acid was set at something like 28v or some such, crazy low. My DIY lithium pack maximum limits are 58.8v 100% charged to 42v fully discharged. I want my controller to stop the cart before the battery and when it's that discharged there isn't much left so I set the low voltage cutoff to 45.5v. Just for clarification I never charge to 58.8v for longevity but that's nothing to do with the controller.
I didn't need to worry about the HV cutoff, where I live there are no hills so I can't regen and go over the battery max. So I just maxed out the HV cutoff.
That's all done in the free software. I don't think I changed anything else.
If you're worried about max current then you can reduce it to 350. My max battery amp setting is 360 and I've done wheelies at 304 amps (and 54v). I haven't seen anything higher than 304 amps. When you drop that much weight you don't need as many amps to move it. I changed it to not be so aggressive so wheelies don't happen so my real world max amp draw is probably closer to 270 amps now. If your drop-in replacement tops out at 52 or 51v or any number less than mine then the amps will increase to do the same work. Wheelies at 51v will require more amps than wheelies at 54v.
As it stands now my neighbors new ICON cart with lead acid batteries and an AC drive out accelerates me for the first 10 feet then I whip past him. I could shift to a more aggressive torque curve and out accel the first 10 feet but I don't like the harshness. I did limit my top end to 24mph based on RPM so he will catch up after a while if there's a long enough stretch. I didn't like the handling of the lightened cart over 24/25mph.
$0.02