Fri Oct 15, 2021 8:17 am

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Fri Oct 15, 2021 8:17 am linkquote
resistor wrote:
One more thing... Last night when I was hashing things over in my mind instead of sleeping, I had a thought about something else to review when looking at your battery temperature issue.

In your Kelly Controller user manual (yes, I know most would rather lose a testicle than read a manual) there are settings for motor current (called phase current) and battery current. These are expressed as percentages. Phase currents are based on battery current, and a good phase/battery current ratio for a hub motor is 1.5X - 2X battery current. Your controller, using PWM (Pulse Width Modulation) converts battery current to phase current. Phase currents are much higher than battery current when accelerating, but become the same at mid-throttle. If you are really bored sometime, there are graphs depicting phase current/battery current through the throttle range. Phase currents are the "torque" you feel on take off that makes you scoot back in your seat.

OK, that's a lot to take in, but I told you all of that so I could tell you this: I'm sure your phase and battery currents are set at 100% in the user program. Since you have conquered the milestone of speed, perhaps you could play around with these two variables to try to maximize your efficiency. Any energy spent in excess of what is needed is lost to heat. So if you get these two settings right, you should see the same performance with lower temps on both your motor and your battery. It will extend your battery life and keep you from spending more time and $ on an exotic solution.
Fri Oct 15, 2021 12:11 pm

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Fri Oct 15, 2021 12:11 pm linkquote
I took Resistor's advice. I set the battery current limit to 40 (was 60 when I first got it from Jim), and the phase current percent to 60 (was 110).

That reduced max acceleration slightly with > 25% DOC, but had no affect on top speed.
As SOC got below 25-33%, top speed was reduced, as with lower voltage, more current is required for the same speed. This is good, as it keeps form depleting the remaining battery so fast. Even then, I was still able to maintain 55 MPH (63 is top) at 33% SOC, and 50 MPH even near 0% SOC.

I did a "speed run" to evaluate the thermal performance of the battery. Ambient temp was 77-80 F. Starting battery temp was 24C. Average speed was 42. I maintained above 50 MPH most of the time, usually 55-60. I was pretty close to WOT a lot of the time.

Total distance was 17 miles. Starting SOC was about 90% (81.8V). Ending SOC basically 0% (60V).

At the end of about 5-6 miles, the battery temp (as measured by the BMS) was 43C. At the end of 12 miles it was 51C, pretty warm, but, still within limits. At the end of the ride, it was 70C.

I would say that riding WOT as the battery gets near bottom is the most abusive, as even more current (amps) is required to get the watts needed. This results in higher temps.

This sort of riding is NOT my normal use case for a scooter, but, is an extreme worst case scenario.

I'm not going to worry about cooling the battery, so much as just not abusing it. Most of my riding on this will be 40-45 MPH without a lot of WOT, so, it should be fine.

That said, because the BMS has the bluetooth interface, and I'm a software engineer, I'm considering a Raspberry Pi project (using a Pi Zero-W) to monitor the battery temp, voltage and current, and display it, or at least have a bright red LED that turns on when the temp hits 50C, start flashing slowly at 55C, and then flash faster as the temp goes up. This will be my reminder to back off and save the battery pack, and also avoid waiting along side the road for it to cool down after the BMS cuts power for thermal protection.


Sat Oct 16, 2021 4:46 am

Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1992
Location: Rochester, Minnesota
 
Molto Verboso
2007 Stella 225
Joined: 02 Nov 2019
Posts: 1992
Location: Rochester, Minnesota
Sat Oct 16, 2021 4:46 am linkquote
If you get your second battery, paralleled in, theoretically you'll cut the current draw in half from the first battery and reduce temps. With the added bonus of more range. I can't remember which controller was used, can you up the voltage of the pack by having another set of cells added?
Sat Oct 16, 2021 9:36 am

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Sat Oct 16, 2021 9:36 am linkquote
Christopher_55934 wrote:
If you get your second battery, paralleled in, theoretically you'll cut the current draw in half from the first battery and reduce temps. With the added bonus of more range. I can't remember which controller was used, can you up the voltage of the pack by having another set of cells added?
The controller is a 72V controller with a max input voltage of 90V. The battery is 84V with a full charge, the 6V difference is a margin of safety.

And yes, a second battery would double range, which would be welcomed.
Tue Oct 19, 2021 2:36 am

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Tue Oct 19, 2021 2:36 am linkquote
I bought a mirror mount that replaces the clamp for rear brake master cylinder. It is a Moto Guzzi part for a V7.
This is SO much better than the one mounted down low on the leg shield.




Last edited by jas67 on Tue Oct 19, 2021 2:38 am; edited 1 time in total
Tue Oct 19, 2021 2:37 am

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Tue Oct 19, 2021 2:37 am linkquote
Yesterday's good and bad.

The good is that the BMS arrived, and is now installed and operational.


The bad is, I got a rear flat on the rear tire.



The problem turned out to be a loose valve core. I'd noticed that the valve stem on the rear was lacking a cap, so I put one on it.
I hadn't realized the reason there was no rear cap. There is very little clearance valve stem and the brake caliper. The cap was ground down on
an angle when I removed it. When I put air in to investigate the leak, it was coming out of the valve. So, I got my valve core tool and checked
to see if the core was loose, and it was. I guess the vibration of multiple impacts with the caliper caused it to loosen. I tightened it, and replaced
the cap with the lowest profile one I could fine in my garage, checked the clearance with the caliper, and was good to go.
Sat Oct 23, 2021 8:05 am

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Sat Oct 23, 2021 8:05 am linkquote
As this is now my primary grocery-getting/errand runner, I want cargo carrying capacity.
Top cases are ugly, but, extremely useful.

The rack by itself doesn't look to bad.


The adapter plate, not so great looking.


The top case, even less so, but, now I've got 55L of lockable, weather proof storage, plus whatever
I can carry at my feet.

Sat Oct 23, 2021 9:20 am

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Sat Oct 23, 2021 9:20 am linkquote
So, in an attempt to get the most life out of the battery, I set the BMS to stop charging at 82V (90%).
The other say, I learned one unintended consequence of that is that the regen braking doesn't work until you run the battery down at least
a little bit. This is a bit disconcerting as I've gotten used the regen braking that occurs at the slightest movement of the brake lever, before the
mechanic brakes start to do anything. Worse yet, is it can then start to work after you squeeze harder to apply the mechanical brakes.

Once I get the thumb control setup for regen, I may turn off regen on the brake light switch, then I'll at least stop the second part of this from happening.
Nothing too major, but, just something to consider.
Thu Oct 28, 2021 3:09 pm

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Thu Oct 28, 2021 3:09 pm linkquote
I've noticed that I'm seeing a 10 volt voltage sag on the displayed voltage on the battery monitor panel when at
a heavy throttle drawing 150 amps. That is a LOT of wasted power and heat generation -- 1500 watts!

I've not yet determined how much of this is in the battery, and how much is wiring and connectors. The battery
connector is a big Anderson type.

The battery is a 20s8p made with 21700 cells (not sure which ones). What sort of voltage sag should I see under heavy load with this?

160 amps would be a about 20 amps per cell, which seems reasonable for a 21700.
Fri Nov 12, 2021 2:41 pm

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Fri Nov 12, 2021 2:41 pm linkquote
I've put just over 300 miles on it now. It gets lots of attention where ever I go.

Sun Nov 21, 2021 4:46 pm

Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
 
Hooked
GTS250ie, P125X Electric Conversion
Joined: 28 Sep 2013
Posts: 137
Location: Palmyra, Pennsylvania, USA
Sun Nov 21, 2021 4:46 pm linkquote
Two of the three low-beam elements in the LED headlamp have failed, leaving me to rely on the high beam 100%
of the time. The high beam is real narrow. The whole assembly is no longer suitable for night riding (hard to avoid
on these short winter days).

So, I bought a new Vespa H4 reflector from ScooterWest.
https://www.scooterwest.com/px-halogen-head-light-h4-582946.html





I had an extra ADVMonster "Mesh Monster" H4 lying around, and put that in it (this image is missing the mounting flange).


The cheap Chinese H4 that I got off Amazon won't fit, as the hole in the reflector unit is too small for the
heatsink fins to fit through.
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