JimVonBaden
100 W
Just for fun. Older version:
Vespa PX125 (Large Frame) Electric Conversion.
- Thread starter JimVonBaden
- Start date
JimVonBaden
100 W
Beautiful day for a ride around the town.
SlowCo
1 MW
That looks great. :thumb:
Both the metal kit Vespa and the ride 8)
Both the metal kit Vespa and the ride 8)
JimVonBaden
100 W
Thanks!
Today I took it to Bikes and Breakfast in Clifton VA.
Saw some cool electric bikes too.
Today I took it to Bikes and Breakfast in Clifton VA.
Saw some cool electric bikes too.
The VespaLectric begins a new chapter. As Jim contemplates his next electric conversion adventure, I made the drive to the nation's capital yesterday to take possession of the VespaLectric, and become its new caretaker.
I took it for a short test ride while there, and can definitely say that this thing is properly quick off the line! The seat definitely does not have enough grip to hold me in place when accelerating full throttle from a stop, or slow speeds. I had to put my knees together in front of the seat to lock myself onto the bike to do full throttle accleration w/o sliding backwards.
Thankfully, the test ride was short, as I needed to get back home, because the BMS decided to let the smoke out, thankfully only about 1/4 mile from Jim's home, as my car and trailer had all his vehicles blocked in, and the key was with me (d'oh!).
When Jim was havin the issue with the BMW doing to sleep an hour after coming off the charger, the guy that made the battery had some not-so-good advice, to short the charge lead through a circuit breaker. This likely damaged the BMS, but, didn't kill it completely. It decided to wait until I was riding it to die completely -- Murphey strikes again!
Jim, being an upstanding ADVRider inmate is going to procure another BMS and ship it to me. So, I'll be anxiously awaiting its arrival, so I can do a proper ride on this very cool resto-mod Vespa.
I'll continue the thread with some ride reports, and whatever modifications I do to it. I'm contenplating doing something to leverage the Kelly controller's analog regen braking input.
I came up with a little work-around for the BMS problem. Don't do this at home, I'm a "trained professional."
I bypassed the power switching of the BMS. This, of course, defeats the safety shutoff of the BMS in the event voltages or temperatures are out of wack, so, I do NOT recommend doing this. Also, notice that is only a 10 AWG wire, rated for 30A, so, I made sure to not use too much throttle.
I took it out for a little 4 mile ride. I did 54 MPH at one point. The quiet is amazing! More later when I receive and install the replacement BMS.
I took it for a short test ride while there, and can definitely say that this thing is properly quick off the line! The seat definitely does not have enough grip to hold me in place when accelerating full throttle from a stop, or slow speeds. I had to put my knees together in front of the seat to lock myself onto the bike to do full throttle accleration w/o sliding backwards.
Thankfully, the test ride was short, as I needed to get back home, because the BMS decided to let the smoke out, thankfully only about 1/4 mile from Jim's home, as my car and trailer had all his vehicles blocked in, and the key was with me (d'oh!).
When Jim was havin the issue with the BMW doing to sleep an hour after coming off the charger, the guy that made the battery had some not-so-good advice, to short the charge lead through a circuit breaker. This likely damaged the BMS, but, didn't kill it completely. It decided to wait until I was riding it to die completely -- Murphey strikes again!
Jim, being an upstanding ADVRider inmate is going to procure another BMS and ship it to me. So, I'll be anxiously awaiting its arrival, so I can do a proper ride on this very cool resto-mod Vespa.
I'll continue the thread with some ride reports, and whatever modifications I do to it. I'm contenplating doing something to leverage the Kelly controller's analog regen braking input.
I came up with a little work-around for the BMS problem. Don't do this at home, I'm a "trained professional."
I bypassed the power switching of the BMS. This, of course, defeats the safety shutoff of the BMS in the event voltages or temperatures are out of wack, so, I do NOT recommend doing this. Also, notice that is only a 10 AWG wire, rated for 30A, so, I made sure to not use too much throttle.
I took it out for a little 4 mile ride. I did 54 MPH at one point. The quiet is amazing! More later when I receive and install the replacement BMS.
I've been posting a few other forums too, just catching up on this one.
The following is from Monday, Oct 11:
I am using this SOC (state of charge) chart for 72V Li-ion batteries for % SOC (it must be correct, it came from the internet, right?).
For some reason, the Daly BMS app is not properly showing % charge, but, does show voltage, so, I'll use that.
I did a proper speed run this morning on the VespaLectric.
Ride stats:
Distance: 8.56 Miles
Average Speed 36 MPH
Max Speed 61 MPH (GPS, indicated was 55 MPH).
Initial charge, 81.5V, 90% SOC
After ride, 73.6V, 56% SOC.
Battery use, 34% (about 982 Wh)
Much of the ride was at an inicated speed of 50 MPH, which is likely closer to 55 MPH, as 55 MPH indicated = 61 MPH on the GPS.
I was NOT light on the throttle. The point of this ride was to have fun, and feel the performance. It is defintiely quicker than
my GTS250ie up to 45-50 MPH.
Just as a test, I turned the regen braking up to 50%. The ride had several stops, and braking (to slow down for turns) points. I used pretty much no mechanical braking on the entire ride, except the final few MPH when the regen doens't do much. 50% is too much for brake-switch activated regen, as it is binary, all on, or all off. I'm definitely going rig up some sort of regen control for the analog regen input, perhaps activate by a thumb lever on the left, ala MotoGP
.
Power delivery is very different than an ICE engine. I experienced this with my test ride of a Zero SR-S as well. Instant torque off the line that pulls strong and then tapers, where an ICE engine builds torque to a torque peak anywhere from 3k-8k RPM depending on the type and displacement of the engine, and then tapers slightly to the HP peak, then falls off more rapidly.
As much as I love the sound of my Moto Guzzi and Ducati 90-degree V-twins, and the satisfaction of clutching and shifting, the electric Vespa is very satisfying to to ride. The sound of only the wind in my face (oddly, the 3/4 helmet is quieter than any full face I have) is very relaxing. I love to ride my motorcycles fast. The E-vespa is very enjoyable to cruise at 40-55 MPH; very calming and relaxing. It is a definite middle ground between my E-bicycle and my motorcycles.
I am actually seeing where I may end up riding it for more than just errand running. I will likely be my goto bike for when I don't have a lot of time for a ride, and just want to get out on a country road for a short bit to clear my head.
Range should be about 40 miles if I can refrain from enjoying the off the line torque so much, riding it hard, it is more like 25 miles. I definitely think that I'll be adding a second battery. A second same-sized battery will double the range to 80 miles taking it easy, and 50 miles having run. That will also make it usable for my commute, which is a 42 mile round trip on fun back roads, or 36 miles in primary roads with speeds up to 60 MPH. I don't want to rely on recharging at work for the return trip, in case I want to return home early.
The following is from Monday, Oct 11:
I am using this SOC (state of charge) chart for 72V Li-ion batteries for % SOC (it must be correct, it came from the internet, right?).
For some reason, the Daly BMS app is not properly showing % charge, but, does show voltage, so, I'll use that.
I did a proper speed run this morning on the VespaLectric.
Ride stats:
Distance: 8.56 Miles
Average Speed 36 MPH
Max Speed 61 MPH (GPS, indicated was 55 MPH).
Initial charge, 81.5V, 90% SOC
After ride, 73.6V, 56% SOC.
Battery use, 34% (about 982 Wh)
Much of the ride was at an inicated speed of 50 MPH, which is likely closer to 55 MPH, as 55 MPH indicated = 61 MPH on the GPS.
I was NOT light on the throttle. The point of this ride was to have fun, and feel the performance. It is defintiely quicker than
my GTS250ie up to 45-50 MPH.
Just as a test, I turned the regen braking up to 50%. The ride had several stops, and braking (to slow down for turns) points. I used pretty much no mechanical braking on the entire ride, except the final few MPH when the regen doens't do much. 50% is too much for brake-switch activated regen, as it is binary, all on, or all off. I'm definitely going rig up some sort of regen control for the analog regen input, perhaps activate by a thumb lever on the left, ala MotoGP
.Power delivery is very different than an ICE engine. I experienced this with my test ride of a Zero SR-S as well. Instant torque off the line that pulls strong and then tapers, where an ICE engine builds torque to a torque peak anywhere from 3k-8k RPM depending on the type and displacement of the engine, and then tapers slightly to the HP peak, then falls off more rapidly.
As much as I love the sound of my Moto Guzzi and Ducati 90-degree V-twins, and the satisfaction of clutching and shifting, the electric Vespa is very satisfying to to ride. The sound of only the wind in my face (oddly, the 3/4 helmet is quieter than any full face I have) is very relaxing. I love to ride my motorcycles fast. The E-vespa is very enjoyable to cruise at 40-55 MPH; very calming and relaxing. It is a definite middle ground between my E-bicycle and my motorcycles.
I am actually seeing where I may end up riding it for more than just errand running. I will likely be my goto bike for when I don't have a lot of time for a ride, and just want to get out on a country road for a short bit to clear my head.
Range should be about 40 miles if I can refrain from enjoying the off the line torque so much, riding it hard, it is more like 25 miles. I definitely think that I'll be adding a second battery. A second same-sized battery will double the range to 80 miles taking it easy, and 50 miles having run. That will also make it usable for my commute, which is a 42 mile round trip on fun back roads, or 36 miles in primary roads with speeds up to 60 MPH. I don't want to rely on recharging at work for the return trip, in case I want to return home early.
Tuesday Oct 12:
Another ride, quick stats:
23.4 Miles
31.6 MPH Moving Average, some stop and go for the first 5 or so miles, the rest at 40-45 MPH, mostly, some > 50, max 56 MPH.
Starting voltage: 82.5V (95% SOC)
Ending voltage: 70.0V (40% SOC)
Total battery capacity used 55%.
Extrapolated range, 42.5 miles, for "reasonable riding". This is pretty much spot on Jim's 43 mile range prediction.
I put my phone with a GPS app running in a map pocket on my sleeve and made mental notes of actual vs. indicated speeds on the speedo. The speedo largely reads 5-7 MPH high, no matter what speed. So, at least now I have a reference, and know how fast I'm actually going at any given time.
Some more observations:
--------------------------------------------------------------------------------
Wed, Oct 13:
Just ordered one of these: https://www.scooterwest.com/px-stella-rear-rack-for-top-case-px29.html
I did an out and back on some rural farm roads. I turned around at 13.4 miles. It was getting close to dark, and I
know that Jim ran the battery out at 28 miles once, so, I didn't want to push it beyond that.
Ride Stats:
Starting voltage: 82.8V, 95% SOC
Ending voltage: 60.4V, 0% SOC
Distance: 26.7 Miles
Moving Avg Speed: 37.6 MPH
Max Speed: 60 MPH
For most of the first 3/4 of the ride, I was doing between 45 and 50 MPH (GPS measured), with occasional 55 MPH, and
one runup to 60 MPH. As the numbers show, I used the whole battery range.
I had to baby it up the hills for the last 5 or so miles to keep the voltage above the 57 volt BMS cutoff.
So, I think I've established that a safe operational range for it with this battery is about 25 miles. The battery monitor is a very nice feature to have, I highly recommend it for anyone considering an EV conversion. Keeping an eye on it definitely helps manage the battery level and range, and likely will
prevent being stranded with no power, as knowing how much power is left lets you manage that power, and back off if need be to make it home.
More observations. At 40-45 MPH up even gentle hills, the motor draws 80-120 amps (6-9kw). If this motor
only put out the "rated" 4KW, this would not be very fun to ride. Thankfully, it can handle a lot more, and the battery can provide the juice. It draws 180-220 amps up steeper hills if I maintain my speeds (up to 15kw!).
Based on the ride data that I've compiled thus far, I'm consuming between 80 and 100 Wh per mile. This particular ride, it was 100 Wh.
For anyone considering an EV conversion, there are three things to consider with your battery selection. One is of course, voltage, the next is the instantaneous AMPs it can provide, the final one is Ah (Wh = Ah * Volts). I'd use 100 Wh per mile as a baseline for range. If you're going with the "4kw" QS205 motor, then 72V 38ah is probably the minimum sized battery that you'll want.
I'm very seriously considering a second battery. I might even just try my hand at building it myself.
I'm up to just shy of a 100 miles that I've ridden it, and I'm still having a lot of fun on this scooter.
I've ordered a left thumb throttle to use for analog regen braking control.
I'm pretty close to pulling the trigger on the Grimeca front disc brake conversion.
Start:
End:
Another ride, quick stats:
23.4 Miles
31.6 MPH Moving Average, some stop and go for the first 5 or so miles, the rest at 40-45 MPH, mostly, some > 50, max 56 MPH.
Starting voltage: 82.5V (95% SOC)
Ending voltage: 70.0V (40% SOC)
Total battery capacity used 55%.
Extrapolated range, 42.5 miles, for "reasonable riding". This is pretty much spot on Jim's 43 mile range prediction.
I put my phone with a GPS app running in a map pocket on my sleeve and made mental notes of actual vs. indicated speeds on the speedo. The speedo largely reads 5-7 MPH high, no matter what speed. So, at least now I have a reference, and know how fast I'm actually going at any given time.
Some more observations:
- When not accelerating, riding this feels a lot more like coasting down a big hill on a bicycle at 40-50 MPH than riding a motorcycle or scooter.
- Regen braking at 50% triggered by the brake light switch is too much. Normally don't brake that hard for normal stopping, so, I found myself on and off the brake a lot when stopping, so, I backed it down to 33%. Even that was too much, I think I'll put it back at 25%, where Jim had it when I picked it up. I definitely want to setup some sort of analog control for the regen, that would be ideal.
- I turned regen completely off to feel what the brakes feel like w/o out. The front drum brake is completely inadequate. To quote Jay Leno on his video on one of his old Brit bikes, "You know how modern bikes have anti-lock brakes? We'll this one has anti-STOP brakes". I will be upgrading the front to a disc brake over the winter.
- This is really fun to ride
--------------------------------------------------------------------------------
Wed, Oct 13:
Just ordered one of these: https://www.scooterwest.com/px-stella-rear-rack-for-top-case-px29.html
I did an out and back on some rural farm roads. I turned around at 13.4 miles. It was getting close to dark, and I
know that Jim ran the battery out at 28 miles once, so, I didn't want to push it beyond that.
Ride Stats:
Starting voltage: 82.8V, 95% SOC
Ending voltage: 60.4V, 0% SOC
Distance: 26.7 Miles
Moving Avg Speed: 37.6 MPH
Max Speed: 60 MPH
For most of the first 3/4 of the ride, I was doing between 45 and 50 MPH (GPS measured), with occasional 55 MPH, and
one runup to 60 MPH. As the numbers show, I used the whole battery range.
I had to baby it up the hills for the last 5 or so miles to keep the voltage above the 57 volt BMS cutoff.
So, I think I've established that a safe operational range for it with this battery is about 25 miles. The battery monitor is a very nice feature to have, I highly recommend it for anyone considering an EV conversion. Keeping an eye on it definitely helps manage the battery level and range, and likely will
prevent being stranded with no power, as knowing how much power is left lets you manage that power, and back off if need be to make it home.
More observations. At 40-45 MPH up even gentle hills, the motor draws 80-120 amps (6-9kw). If this motor
only put out the "rated" 4KW, this would not be very fun to ride. Thankfully, it can handle a lot more, and the battery can provide the juice. It draws 180-220 amps up steeper hills if I maintain my speeds (up to 15kw!).
Based on the ride data that I've compiled thus far, I'm consuming between 80 and 100 Wh per mile. This particular ride, it was 100 Wh.
For anyone considering an EV conversion, there are three things to consider with your battery selection. One is of course, voltage, the next is the instantaneous AMPs it can provide, the final one is Ah (Wh = Ah * Volts). I'd use 100 Wh per mile as a baseline for range. If you're going with the "4kw" QS205 motor, then 72V 38ah is probably the minimum sized battery that you'll want.
I'm very seriously considering a second battery. I might even just try my hand at building it myself.
I'm up to just shy of a 100 miles that I've ridden it, and I'm still having a lot of fun on this scooter.
I've ordered a left thumb throttle to use for analog regen braking control.
I'm pretty close to pulling the trigger on the Grimeca front disc brake conversion.
Start:
End:
I'm going to have consider cooling the battery on this build. Up until today, the highest temperature I've seen externally on the pack has been about 43C (110F). Being
a large, dense pack, the temperature of the cells toward the middle must be much higher. I may need to put some thermocouples in the middle of the pack when I open it up
to replace the BMS.
High temps for most of the week have been in the mid-60's (F), but, today was 75. I went out for a "spirited" ride today, about 14 miles of most 50-55 MPH, so, was working
the motor and the battery hard. When I got back and open the seat to remove the pack to charge it, I noticed it was quite warm. I pulled out the non-contact thermometer, and it was 55C (131F). From what I'm reading, you want to keep Lithium cells below 60C. I'm going to venture a guess that the inner cells were much warmer than this.
The motor was also much warmer than it had been on previous rides, also about 55C, vs. about 43C on cooler days.
I definitely have some concern about riding it in hot weather (85-90F).
The battery pack lives in an enclosed area of the frame with no airflow, so, not ideal for cooling. Unfortunately, to get fresh air in there, I'll have to cut holes somewhere
Maybe just putting a fan in there to circulate air around in the space will help a little, but, I doubt much.
What have others that have done EV conversions on Vespas done for battery cooling?
a large, dense pack, the temperature of the cells toward the middle must be much higher. I may need to put some thermocouples in the middle of the pack when I open it up
to replace the BMS.
High temps for most of the week have been in the mid-60's (F), but, today was 75. I went out for a "spirited" ride today, about 14 miles of most 50-55 MPH, so, was working
the motor and the battery hard. When I got back and open the seat to remove the pack to charge it, I noticed it was quite warm. I pulled out the non-contact thermometer, and it was 55C (131F). From what I'm reading, you want to keep Lithium cells below 60C. I'm going to venture a guess that the inner cells were much warmer than this.
The motor was also much warmer than it had been on previous rides, also about 55C, vs. about 43C on cooler days.
I definitely have some concern about riding it in hot weather (85-90F).
The battery pack lives in an enclosed area of the frame with no airflow, so, not ideal for cooling. Unfortunately, to get fresh air in there, I'll have to cut holes somewhere
Maybe just putting a fan in there to circulate air around in the space will help a little, but, I doubt much.
What have others that have done EV conversions on Vespas done for battery cooling?
I took Resistor's advice (on the ModernVespa thread). 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.
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.
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.
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.
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.
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.
Hillhater
100 TW
Sag will depend greatly on which cells you have in there.jas67 said:
Also , the sag could be the result of one or more bad/out of balance, cells , .....or a poor connection somewhere inside the pack... do you have a IR thermometer ?
But first, Identify the cell type and model, then you can establish what their normal sag should be @20A individual
EDIT::-
Early in the thread , jim stated the pack used “eon icr21700 cells”.
The only reference i can find for eon 21700 cells is this since the page has been deleted from the eon site ??
“Eon 21700-48X thunder cell delivers a significant power in the most compact form. the power density is higher than most 21700 and delivers a whopping continuous amperage of 15A. It is a 3C battery that everyone wants without breaking bank. Below is per cell specifications: Nominal voltage: 3.7V. Maximum voltage: 4.2V. Minimum voltage: 2.75V. Nominal capacity: 4800mah”
So, at least we know its a 3C cell continuous, but it dosent help much !
And from the tests i have seen on typical 4.8-5.0Ah 21700 individual cells, 0.5 volt sag at 20A is not unusual.
So that 10v sag on a 20s pack, at 160A , is likely to be correct .?
FYI... the “best” 21700 cell test i have seen is the Sony VT6A which still sags 0.3v @ 20A, ....but that is a “power” cell of only 4Ah capacity. !
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.
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.
mannydantyla
100 W
- Joined
- Dec 4, 2020
- Messages
- 126
Thank you jas for keeping updating on this project. I was a bit confused because the last time I read this thread, Jim was the one giving updates, but I understand now lol.
How do you like the thumb throttle for the analog regen braking? How does it compare to just on/off regen when the brakes are applied?
How do you like the thumb throttle for the analog regen braking? How does it compare to just on/off regen when the brakes are applied?
It looks like the 6 AWG wire isn't big enough (6awg good for 50A).
Also, the 50A Anderson connector is not up to the task either, as this thing draws 150A peak.
I've not had the time to build a second battery, but, need to, to extend the range, and also reduce the current draw from each battery by half.
Also, the 50A Anderson connector is not up to the task either, as this thing draws 150A peak.
I've not had the time to build a second battery, but, need to, to extend the range, and also reduce the current draw from each battery by half.
The Anderson connector failed. It could've been MUCH worse, as it was after 9pm, and completely dark out when it happened. Thankfully, it failed under regen braking as I was about to turn into my driveway. There was enough ambient light from the neighbor's big mercury-vapor light on his bar across the street for me to see enough to negotiate the turn into my driveway.
Also, I looked at the size of the wire from the battery, it is only 8 awg. Wow, that is dreadfully undersized. I'm not sure what Jim told the battery builder for what he expected to draw from the battery current-wise, but, in my book 8awg is only good for 40A, but, looking at the chart, depending on the type, maybe 55A. In any case, it is certainly WAY undersized for the current this thing was able to draw before I toned down the motor drive settings.
Temporarily, I'll be replacing the Anderson connector with some screw-lug type connectors from the home center with some heat shrink tubing over it.
Longer term, it looks like I need to replace the cables to the battery with something heavier, at least 2 AWG.
@JimVonBaden -- I couldn't find any markings on the larger wire going from the Anderson connector to the contactor and breaker. Do you recall what size it is?
Also, I looked at the size of the wire from the battery, it is only 8 awg. Wow, that is dreadfully undersized. I'm not sure what Jim told the battery builder for what he expected to draw from the battery current-wise, but, in my book 8awg is only good for 40A, but, looking at the chart, depending on the type, maybe 55A. In any case, it is certainly WAY undersized for the current this thing was able to draw before I toned down the motor drive settings.
Temporarily, I'll be replacing the Anderson connector with some screw-lug type connectors from the home center with some heat shrink tubing over it.
Longer term, it looks like I need to replace the cables to the battery with something heavier, at least 2 AWG.
@JimVonBaden -- I couldn't find any markings on the larger wire going from the Anderson connector to the contactor and breaker. Do you recall what size it is?
I'm finally going to build that second battery.
I pulled the trigger and bought 160 Samsung 40T 21700 Cells
And a Sunkko 907A spot welder
Nickel strip, copper foil, and other supplies also ordered.
Now, the real question is, can I make time to do the actual build.
I pulled the trigger and bought 160 Samsung 40T 21700 Cells
And a Sunkko 907A spot welder
Nickel strip, copper foil, and other supplies also ordered.
Now, the real question is, can I make time to do the actual build.
I very much enjoy the sound and character of my various motorcycles, especially the vintage ones. But, there is something magical about the vibration-free silence of the electric Vespa, and the only sound being the wind. I usually use it as my errand running vehicle, but, this evening, I took it for a pleasure ride.
mannydantyla
100 W
- Joined
- Dec 4, 2020
- Messages
- 126
The second battery will be in addition to the current battery, or will it replace it?
mannydantyla said:
Addition. I'm doing it for multiple reasons.
One, as that by sharing the load between the two, each battery will provide roughly half the current. This way sag due to internal resistance of the battery will be half what it is now, and thus power dissipation per battery will be 1/4 what it currently is. As a result, I'll be able to run 50-60 MPH continuously without heating the battery up too much. Currently sustained riding over 45 MPH heats the battery up to 60C on sustained high-speed running. That will shorten battery life.
Also, total range will go up from about 30 to probably 65 (more than double, due to less losses). I don't usually need that much range, but, my work is a 40 mile round trip, so, this way, I can use it to go to work w/o having to charge at work, and will have excess range for side trips on the way home. Also, I can keep the battery in the desired 20-80% SOC range almost all the time, which as we all know is best for battery life.
Based on the melting of the connector, it looks like there is tension on the wire that pulls it at an angle to the connector. Especially with the non-genuine-Anderson-made shells (which are softer plastic *and* less-springy-springs), if the wire isn't "floating" in the shell, then the contact doesn't make full flat mating connection with the other contact it's meant to--it gets twisted or lifted or otherwise only touches part of them together, making a much higher resistance connection that heats up much more than normal.jas67 said:
That heat then softens the plastic shell (which is a much worse problem for non-genuine Andersons) and the contact force is lessened even more, worsening the problem. Sometimes it gets bad enough to start a fire.
Anderson makes a number of different bits of hardware to help align wires and such to help prevent such problems, like these
https://www.andersonpower.com/us/en/shop/sbr50-bolt-on-cable-clamps-bk.html
https://www.andersonpower.com/us/en/shop/cable-clamps-self-attaching-for-discrete-conductor-bk.html
more examples in these pages
https://www.andersonpower.com/us/en/shop/wire-to-wire/sb.html?product_list_limit=36
But using genuine shells (contacts too, if possible), and ensuring the wires are centered as they enter the shell (not at an angle especially with any tension on them), and the insulation is not touching the shell (so the wire is free to move with the contact during mating so the cotnacts correctly self-align with each other), and there is no twisting force on the wires, will make the best use of Anderson SB/PP connectors.
FWIW, I've successfully used the genuine SB50 (which uses the same contacts as the PP75) at up to a couple hundred amps for a few seconds before dropping to the 10-40A continuous usage I might typically see with the SB Cruiser trike, with no damage to the connectors. IIRC it is all 10g or 8g wiring, in one case doubled-up 12g. (it's all re-used powerchair wiring with the connectors already on them).
amberwolf said:
In this application, loads are 100-140A for up to a minute or two when climbing some hills at speed (400# total scooter and rider at 45-50 MPH). Flat(ish) ground cruising loads at 50 MPH are about 50-80A.
I like overkill. The SB175 are definitely going to be overkill once the second battery pack is installed in parallel, as each will only see approx half the load.
UPDATE!
The second battery pack is built and has been tested. imgbb.com is down right now, so, I can't add my photos just yet (don't want to bother learning another photo hosting site). I'll post pics and details later.
The second battery pack is now finished. I had chosen Samsung 40T cells for their high-current capability.
The the first pack it is a 20s8p pack.
In retrospect, I should've chosen a higher-capacity cell such as a 4800mAh or 5000mAh cell instead of these that are only 4000mHa. As this scooter can easily pull 240A, I was thinking only one battery when I did the math on how much current per cell, which ends up being 30A per cell at 240A. In reality, with two packs in parallel, each pack only provides half the current, so, only 120A per cell. An this is peak. I typically keep it under 150A, which would be about 19A per cell for a single pack, or about 8.5A with both packs in the scooter. Long story short, I gave up about 6ah, or about 432wh. This ends up being about 4 miles of range.
With the existing pack, typical range was about 28-30 miles with average speeds around 45 mph. Despite this pack not doubling my total capacity 32ah + the current 38ah, I think I'll still nearly double the range due to less losses to heating the batteries. With it's high-amp cells, the new pack has about 2/3 the voltage drop at any given current load as the existing one. With both packs in parallel, voltage drop should be roughly half, or slightly less than that for one pack. The corresponding power loss will be half as well. That lower loss = more range. Also, the loss per pack will be about 1/4, meaning I can now ride it at speeds over 45 MPH continuously without overheating the battery as was the case with the single pack.
The pack was built with honeycomb arrangement cell holders for maximum density in 3 layers to make it fit the available space.
Cell interconnect is .2mm X 20mm nickel strip. I used .08mm copper strip for the interconnect between each layer, and also for the B+ and B- collectors. As copper has 5X the conductivity of nickel, this .08mm copper is twice as conductive as the .2mm nickel. I used .1mm nickel on top of the copper to facility welding as per the "copper-nickel" sandwich thread..
.1mm nickel tabs were added to the interconnects for connecting the balance leads.
I used a K-weld spot welder for all the welding. Settings were 60J for the .2mm nickel, and 80J for the copper/nickel. I used 20J for the .1mm tabs.
BMS is a Daly 20S 150A with bluetooth interface, same as was used in the first pack.
The main leads are 6 AWG fine-strand copper cable, soldered to the copper strip with a 280W Weller soldering gun before the copper strip was welded to the cells.
There is an XT60 connector for charging and an Anderson Power Pole SB175 connector to connect to the scooter.
The mating SB175 is connected to the motor controller with 4 AWG welding cable.
I will add a 200A breaker to connect this pack to the scooter, as the first pack is connected, thus there will be breakers between the packs in case of a failure that causes high current transfer.
I will be careful to make sure both are charged to the same voltage before putting both on the scooter.
The one last step will be getting a mount fabricated to hold one of the packs under the right side fender cover.
The the first pack it is a 20s8p pack.
In retrospect, I should've chosen a higher-capacity cell such as a 4800mAh or 5000mAh cell instead of these that are only 4000mHa. As this scooter can easily pull 240A, I was thinking only one battery when I did the math on how much current per cell, which ends up being 30A per cell at 240A. In reality, with two packs in parallel, each pack only provides half the current, so, only 120A per cell. An this is peak. I typically keep it under 150A, which would be about 19A per cell for a single pack, or about 8.5A with both packs in the scooter. Long story short, I gave up about 6ah, or about 432wh. This ends up being about 4 miles of range.
With the existing pack, typical range was about 28-30 miles with average speeds around 45 mph. Despite this pack not doubling my total capacity 32ah + the current 38ah, I think I'll still nearly double the range due to less losses to heating the batteries. With it's high-amp cells, the new pack has about 2/3 the voltage drop at any given current load as the existing one. With both packs in parallel, voltage drop should be roughly half, or slightly less than that for one pack. The corresponding power loss will be half as well. That lower loss = more range. Also, the loss per pack will be about 1/4, meaning I can now ride it at speeds over 45 MPH continuously without overheating the battery as was the case with the single pack.
The pack was built with honeycomb arrangement cell holders for maximum density in 3 layers to make it fit the available space.
Cell interconnect is .2mm X 20mm nickel strip. I used .08mm copper strip for the interconnect between each layer, and also for the B+ and B- collectors. As copper has 5X the conductivity of nickel, this .08mm copper is twice as conductive as the .2mm nickel. I used .1mm nickel on top of the copper to facility welding as per the "copper-nickel" sandwich thread..
.1mm nickel tabs were added to the interconnects for connecting the balance leads.
I used a K-weld spot welder for all the welding. Settings were 60J for the .2mm nickel, and 80J for the copper/nickel. I used 20J for the .1mm tabs.
BMS is a Daly 20S 150A with bluetooth interface, same as was used in the first pack.
The main leads are 6 AWG fine-strand copper cable, soldered to the copper strip with a 280W Weller soldering gun before the copper strip was welded to the cells.
There is an XT60 connector for charging and an Anderson Power Pole SB175 connector to connect to the scooter.
The mating SB175 is connected to the motor controller with 4 AWG welding cable.
I will add a 200A breaker to connect this pack to the scooter, as the first pack is connected, thus there will be breakers between the packs in case of a failure that causes high current transfer.
I will be careful to make sure both are charged to the same voltage before putting both on the scooter.
The one last step will be getting a mount fabricated to hold one of the packs under the right side fender cover.
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