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Re: (ET) NEED E-15 Traction motor profile to program Sepex controller (1268)-optimize things
Hi David (& all),
I would like some optimization, over the 50 year old relays & nichrome
design, and control panel upgrade/ modernization, of some type.
* * * REFERENCE:
I use a CC 48V electric ZT mower, with 4 BLDC motors (typically 10% more
efficient than brushed, if I can trust AI answer): 2 traction motors
(left * right), and 2 mower motors, and 4 controllers. Control system is
good. 2 speed range on mow motors (normal= low grass to save power,
turbo = taller grass), overload shutdown, and it can tell you which
motor was overloaded.
The ZT traction control works so well I can drive horizontally across a
wide slope, and not drift down (rear wheel motor controllers apply more
power to left or right wheel, depending on direction sensor on front
wheels !). (E-15 drifts so badly, it has damaged grass). [ I did add
dual rear wheels to spare E-15 and that improved the slope drift
problem, but otherwise not great around trees, etc. Then that (OEM)
control system died. So, I want to upgrade spare E-15 to PWM]
Point is, CONTROLS part of ZT is GOOD: turn radius / steering (wheel)
control is AWESOME !
* Foot pedal throttle is good.
* Display shows MPH. (not important, but interesting).
* Display also shows mow motor load by itself - not combined with
traction motor(s).
Added Safety features such as mower turns off in reverse (can override
via front panel).
* Deck height adjust is ultra fast- hand lever (important when you hit a
patch of tall grass & mow motors repeatedly shut down, so you raise
deck, use turbo mode, drive slow, etc)
* SLA batteries means NO frame corrosion. No watering. Also possible to
bring them inside, & connect to Inverter / UPS.
* Charger is fully automatic.
TERRIBLE part on the 2012 and broken / NON-repairable 2015 model I have
is gear boxes on each side (separate is OK, good actually): WEAK design.
one broke. no parts available.
OTHER CC ZT (2012/15 model, newer Li-Ion might have improved design, but
cost $5000) PROBLEMS & WEAKNESSES:
Previous owner or dealer set jumpers on automatic charger for WLA
batteries, not SLA, so it repeatedly did the equalization charge, vented
gas, and plastic sides of all 4 $$ batteries are now concave at every
cell. Repeated internet searches suggest I really should NOT try to add
distilled water (gel electrolyte). Pack not dead yet, but expecting
premature failure.
Moisture (stored under tarp a short time) fogged the LCD panel. No quick
way to dry it (wait hours, in sunshine). Panel cannot be dismantled. (my
2012 panel died, fortunately had 2015 spare to swap in). [side project:
cut open dead panel via band saw, while not damaging circuit board, to
troubleshoot & repair, for spare].
NO towing (guy I bought broken gearbox one from towed just a lawn cart).
NO plowing.
NO PTO. (could wire in, but pack is 48V 100AH, & I have no 48V motors
for implements.
More expensive battery pack (SLA). Over $1000, lower total pack energy.
(4800 vs 7560)
Mid-mount deck means no reaching under bushes.
* * * SUMMARY: When Electric ZT works, it is great (joyful even) for
what it does: weekly mowing on not very tall grass. for everything else,
need Elec-Trak.
When I use Elec-trak, it feels antique, or something (need a better
word), control wise.
* * * SO > > OPTIMIZE ET(s):
1) Upgrade ET variable motor controls to PWM. Traction, & maybe PTO.
2) Improve control panel operator feedback (approach or exceed 2012
electric ZT functionality):
- - Add separate ammeters for Traction & PTO.
[not sure if keep original for total amps, or use it for one of the 2
main loads]
OR
Fancy control panel option: Arduino summarizing current sensors feeding
into color LCD (showing real time individual graphs of amps), but then
maybe cold weather issues for the LCD, readability in daylight, etc.
Issue: though I won't be around in 30 years, will someone else be able,
or interested in maintaining it ?
Same panel could show real-time pack voltage, individual battery
voltage, individual mower motor amp draw, projected run time at present
rate (range, like a 2018 CR-V estimates pretty well), estimated time to
charge (like smartphone do).
* It would be great to have open-source control panel design:
Upgradeable, fixable, modular maybe.
* * Keep everything else about GE OEM design that worked well, improve
things that might be easy & low $, due to modern availability of
displays and microprocessors, not available in early 1970's.
I am open to / interested in suggestions on this.
On 12/27/25 21:13, David Roden wrote:
I think it depends on how much you want to optimize things. Bear in mind
that the later ET PM motors didn't (couldn't) have field weakening.
If memory serves, and it might not as it's been many years, Mark Hanson ran
an E15 with full field and 48 volts from his own homebrew PWM armature
controller. I think he got about the same top speed as on 36 volts with
the factory field weakening. He had a second controller to drop the 48
volts to 36 volts for the attachments. If he's still on the list, maybe
he'll chime in with comments and corrections.
David Roden - 25 Years with ETs
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