2009 eZip LS keeps getting better! (20mph capable w/ 7s 25.9V Li-ion battery pack & 16T mod.)
I built a 29.6V 31.2Ah recycled Li-ion battery for my 2008 eZip Mountain Trailz, early 2008 was the last production of a multi voltage capable controller, 24V rated but runs at 37V nicely ... or so I thought ...
Turns out my $258 2009 Trailz LS (Low Step sounds better than "Ladies"), runs at higher voltages also!
8s12p 29.6V 31.2Ah, stuffed into oem pack pushes me along at 22mph.
Original purpose was to allow a 20mph capability on an oem eZip.
Rather than regearing for higher speed, with the resultant lack of torque, upping the battery voltage increases torque and ups the speed capability towards the "legal" 20 mph.
Sadly, I have been too lazy to "un-mod" the bike back to oem gearing, so I have to constantly monitor my throttle to "keep it legal".
20mph w\9-16T mod / 25.9V x 29.6V = 22.86mph
16mph w\9-20T oem / 25.9V x 29.6V = 18.29mph
OEM Trailz w/road tires should cruise at 20mph.
Worse! I found that by removing the center screw and staggering the cells, I can shoehorn 9s12p 33.3V 31.2Ah into the oem pack!
20mph w\9-16T mod / 25.9V x 33.3V = 25.71mph
16mph w\9-20T oem / 25.9V x 33.3V = 20.57mph
So, until I drop my bike back to oem gearing I must apply constant throttle restraint ...
To maintain legal speed and ...
To limit heat production!
I have run an alternate eZip, unmodded, with 9-20Tgearing, at 37V for 4000+ miles with no overheat problems.
Fortunately! It looks like 33.3V will keep the oem eZips near the "legal" 20 mph limit!
Rather than the 20% torque loss associated with the 16T mod, going from 24V to 33.3V (100% /24 x 33.3 = 138.75% torque)
So a 25% speed and ~40% increase in, acceleration-hill climbing torque, turning the lackluster eZip into a reasonably respectable machine.
Upgrading to 36V controller will allow 33.3V and 37V Li-ion use, 30-31V low voltage cut off works nicely with 33.3V Li-ion, 37V DOD will have to be monitored more closely.
PAS function is sacrificed with most aftermarket controllers.
OEM 24V 10Ah SLA pack = .240kWh @ 10A discharge = .120kWh usable capacity (1C discharge rate).
Upgrade 33.3V 31.2Ah Li-ion pack = 1.039kWh @ 10A discharge = 1.000kWh+ usable capacity (<.3C discharge rate).
Oh! and the 1.000kWh usable Li-ion pack still weighs noticeably less than the .120kWh usable SLA battery!