Electric Bikes - Upgraded from 48 to 72 volt

Hi everyone,

I had a 48 volt LiFePO4 Crystalyte 408 rear hub setup for a year now. Loved it.

Just recently I added a 24 volt battery in series, for 72 volt and love the new setup, far more powerful and , for me, safer on the road where I ride.

The super helpful ebikes.ca people sent me the 24 volt battery already wired and labelled. All I had to do was plug and play (Justin, thank you very much for your help.).

The batteries fit in the same original bag that I originally had for the 48 volt setup. Basically I placed the 24 volt battery on top of the 48 volt one, the bag has an additional compartment on top, was very convenient.

The battery bag now weighs around 25 lbs. I'll weigh it when I get a chance and adjust the figure, but that seems about right.

Now, you may think this is weird, but I don't place the battery in the back; I place it at the front. I'l lhave to show you pictures of what I mean. (Imagine the gaz tank of a motor bike, that's where the battery is. I find it a better weight distribution which offsets the rear hub motor. So.. steering, then battery, me behind it, hub motor behind me, yep that works.)

As simple as the upgrade was, there are a few things I have learnt about 72 volt setup, and these are things that you cannot operate without:


You absolutely need the right controller, I blew my 48 volt controller as soon as I plugged the 72 volt battery. We're talking sparks, flames coming out of the power couplings ... . I now have a 72 volt pedal first controller and no smoke is coming out :p. I was so paranoid from the experience that when I plugged in the 72 volt controller I was wearing gloves and protective glasses, but thankfully that worked out pretty ok and the lesson learnt is: use the right controller for the voltage.
Torque arm, you MUST have one, no ifs/buts about it. Considering a 72 volt setup? Get a torque arm! This baby packs some huge torque and without a torque arm, you're asking for trouble real quick. Originally I was thinking since my drop out is rectangular in shape and the axle as well, how can the axle possibly twist out? Well, guess what ,without a torque arm, it did!

My brother, super great guy, came over and we went to Canadian Tire, bought steel bar, half inch thick, and a grinder and metal cutting plates and he fashioned a torque arm for me, which I must say has been holding out pretty well!

Did I mention you need a torque arm? :innocent: because ya do :lol:


Throttle. Be very gentle with the throttle. I have a half twist and in my case I had to add a normal-close pushbutton switch to the power cable going to the controller (red wire) since the battery would shut off when i throttle too quickly, especially when i take off; I'm guessing the BMS on my battery is doing this. I am yet to test this, will keep you posted. The wonderful folks at ebikes.ca have suggested an on/off switch to reset the power going to the controller when battery shutsoff, or add a rampup capacitor to the throttle. I'm guessing also if I were to use a full twist throttle it would be a viable solution, but haven't tested this yet.
Ok, now for the fun stuff:

You're probably asking, how fast does this thing go?

I don't know, my cycle analyst is yet to be repaired, but I can tell you it's way over 40 kph and as such I rarely twist the throttle all the way (I want to keep my bike and feel that doing 50 kph on the road for a bike is asking for trouble). Going up hill, at full throttle, I'm guessing I'm doing around 32 kph up a 30 degree incline, not bad. Riding against the wind, no problem. Taking off from a dead stop and keeping cars away from my tail, super good. And because I'm not using the full voltage I'm saving my battery, and that I feel great about :love:







Oh yes, I forgot: charging.

Ok, so yes you do need two chargers. 24 volt and 48 volt.
You can keep the batteris connected while charging them provided that your chargers are two pronged (the plug that goes from the charger to the wall, needs to have two prongs instead of three, and this for each charger, that was the advice I was given by ebikes.ca), I've been charging them in this fashion and so far no problems.
And as the funny guy from Hogan's Heroes says : i know nothing. .nothingggg about electronics. I'm just passing along the advice.

that has always and only been the problem with our eBikes... the Weight...

it's cool to have more power, to go further and be able to haul more accessories.... but, as the weight increases, it makes it less and less attractive, as whenever you want to go up/down a freight of stairs it turns into a back killer.

True it's a bit heavier, but only by about 5 lbs (and trust me, I can lose 5 lbs myself, eheheh); the extra benefit of power to spare is super great, especially going up hills and against the wind.

I've been riding with it now for two weeks, and I'm loving it!!!

Provided you have the right components, this setup is really cool, IMO.

I don't know which movie I got this expression from, but "I like it, I like it a lot!" :p

Pictures man, where are the pictures?






I don't know which movie I got this expression from, but "I like it, I like it a lot!" :p

^^^
It's from Robocop.
Emil Antonowsky's (Paul McCrane) line after Clarence Boddicker (Kurtwood Smith) hands him a huge rifle and he uses it to blows up Boddicker's SUX6000.

:thumb:ooh nice

Here's the video clip courtesy of Youtube.com

http://www.youtube.com/watch?v=tUyYace8318

Ambrose

184077109364Ok here's a picture of my bike now. The battery is the black thing in the middle.

The back thingy behind my seat is a shoe box duct taped to resist weather and it serves as an extension of my seat.

I got two red lights in the back and two white lights in the front... they 5 led each :D

that things a monster....lol

love it:thumb:. i see im not the only one that uses the bag up front balances out the weight better.

this is 86v plus a 18v booster pack= fast enuff:D

Wow 104 votls ! Insane! love it. :D

So, yesterday I plugged the cycle analyst, finally got it to work, had some issues, long story won't get into it right now.

Here are the stats: 50 kph on flat with pedalling to get it going
Range: 12 ah battery, gives me 60 km range , give or take a bit.

Listen to (or read) this: yesterday I got the analyst and plugged it at work. I headed home and found out that i only used 3 ah to travel 13.5 km. Ok.. this is super great news, because that used to take me far more than that before, on a 48 volt setup. I guess this is because I'm not taxing the battery as much and therefore i'm using less wattage to do the same thing _ whch means I don't go full throttle all the time, i barely use the thing to go 35/40. Makes sense?

so, the benefits are:
1. more power when I need it, going up hills, against the wind, keeping me at safe distance.
2. more range
3. battery gets less taxed, means it will last longer

Plus it's a great conversation piece. I don't know if it's good for picking up chicks, I haven't tried the line :"Hi, I drive a 76 volt electric bike" on anyone of interest yet :D

Latest update:

The bike is doing super great.

Diodes to protect BMS
Learnt a few things about diodes when connecting two batteries in series, otherwise you'll fry the BMS of each respective battery in that series (since the overall voltage will want to force the current back into the individual batteries; the diode stops the flow of current back to the battery).

Cycle analyst to prevent cut out during initial throttle up
I've set my cycle analyst to limt max amerage to 40 amps.. this to prevent the BMS from cutting out if I throttle too suddenly. Works great!

Pedal-first controller
Right now I'm using a 30A 72 volt pedal first controller, but I'm trying to get my bike to work on an immediate start , and so far I'm failing to do so. I'm still working on this.

Overall, I like it.. I like it a LOT !!! :D

AlfonsoPilato,

Good to hear that it's working well for you. Can you tell me exactly what controller you're using? Is it the one from ebikes.ca?

Thanks,
Ambrose

The pedal first is from ebikes.ca, and that one is working.

The immediate start controller (http://ca.itselectric.ca/Crystalyte_high_power_36_72v_35_Amp_controller_p/ctrl-crystal-c7235dc.htm)is from itselectric.ca _ that's the one I'm not having much luck with. I'm trying to figure out where the problem may lie. They tested the controller and said it's fine. It takes a 4 pin throttle, so to rule out a possible throttle problem, I bought one such throttle from them and still doesn't work. All that happens when I twist the throttle is an initial tug of the motor then nothing happens at all. The mini XLR connector is secure, the three phase wire also is securely connected... :crash: I would really like to get some form of immediate start controller working on this bike, would be really cool.

As soon as I plug the pedal first controller, it's all working fine...

so ... the problem may lie at the
a) digital controller
b) mini XLR cable (pedal first doesn't use this)

I've asked if they can send me another controller. We'll see. If the other controller still doesn't work, then that means the problem must be with the mini XLR cable. :crash:

It's all good.. i'm patient :) and good things come to those who wait right :thumb:

Oooh btw, totally unrelated: I rode in the rain today and it was super great !!!. Why was it so good, because I had those thingies (http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524442618318&FOLDER%3C%3Efolder_id=2534374302692723&bmUID=1256346072845)that cover your shoes. Bought them from Mountain Coop. Got home from really heavy rain, shoes were dry :thumb: (doesn't take much to get me excited :D)

On the conhismotor web site the company says more voltage equals more torque and better hill climbing but not much in the way of more speed. But you seem to have more speed and more hill climbing torque. I don't think I could hold your bike and get on it and if I could I would be afraid to ride it! Awesome!

My question is can any DC brushless motor just have more voltage applied to it? We just have to change the controller?

Any updates on the new controller vs. the mini XLR cable? Have you got it working? How much was shipping to Toronto? Have you had trouble with police, since your bike is not legal? Will you modify your front brakes to large rotor discs?

My question is can any DC brushless motor just have more voltage applied to it? We just have to change the controller?

That will pretty much work until you exceed the thermal limits of the motor. And, I've heard that voltages in the 100V range trigger other issues with the hall sensors and flux patterns, and other bad juju stuff...

Which controller model did you blow up?

Which controller model did you blow up?

I destroyed a controller on a 36 volt 400 watt brushed motor Callisto Tres Terra bike. It was my fault. While working on the bike to add much
larger capacity (but same voltage) batteries I crossed the wires.

I gave up on the uncomfortable Callisto one speed bike and I am not converting a regular comfortable multi speed bike. The very low one speed
was only good for getting the bike moving. I couldn't assist by pedaling on hills. The new bike will have derailers but I hope to eventually have
a bike with an internal 8 speed rear hub. The new conversion of the old comfortable bike will have a front hub motor.

I was just curious and wondering if I could add more voltage after reading about someone who apparently did add more voltage to his bike.

I destroyed a controller on a 36 volt 400 watt brushed motor Callisto Tres Terra bike. It was my fault. While working on the bike to add much
larger capacity (but same voltage) batteries I crossed the wires.

I gave up on the uncomfortable Callisto one speed bike and I am not converting a regular comfortable multi speed bike. The very low one speed
was only good for getting the bike moving. I couldn't assist by pedaling on hills. The new bike will have derailers but I hope to eventually have
a bike with an internal 8 speed rear hub. The new conversion of the old comfortable bike will have a front hub motor.

I was just curious and wondering if I could add more voltage after reading about someone who apparently did add more voltage to his bike.

If the bike you choose to convert has an aluminum fork you won't be able to use a front motor. So if you don't have the bike yet, when you're shopping make sure the fork is steel. Even with a steel fork you need torque arms. Torque arms don't prevent drop out failures so if you go for a very large motor, seriously consider getting a rear mounted motor for your own safety. I would suggest all e-bike owners add volt meters, especially if you're going to be using LIFEPO4 batteries. You can get the Turnigy Watts Meter/Analyzer from Hobby City for $25 right now. http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10080&Product_Name=Turnigy_Watt_Meter_and_power_Analyzer
It may not be quite as accurate as a Watts Up Meter/Analyzer, but it's getting good reviews on the Endless Sphere e-bike forums. Good luck.

I hacked my 36V-48V controller and overvolted. I am running 60V nominal. The only reason I am not running a higher nominal is because I don't have the battery size. I am looking to add a booster pack to raise the nominal voltage. I used 36V, then after awhile moved to 48V. It felt good. Then I moved to 60V, and it is much better.

I destroyed a controller on a 36 volt 400 watt brushed motor Callisto Tres Terra bike. It was my fault. While working on the bike to add much
larger capacity (but same voltage) batteries I crossed the wires.

I gave up on the uncomfortable Callisto one speed bike and I am not converting a regular comfortable multi speed bike. The very low one speed
was only good for getting the bike moving. I couldn't assist by pedaling on hills. The new bike will have derailers but I hope to eventually have
a bike with an internal 8 speed rear hub. The new conversion of the old comfortable bike will have a front hub motor.

I was just curious and wondering if I could add more voltage after reading about someone who apparently did add more voltage to his bike.

I see what you meant. The controller died because of crossed wires and not because of the voltage you ran through it. My controller would have died since it was meant for 36-48V, but it didn't because I hacked it. And not it can handle upto a maximum of around 82V nominal.

That will pretty much work until you exceed the thermal limits of the motor. And, I've heard that voltages in the 100V range trigger other issues with the hall sensors and flux patterns, and other bad juju stuff...

But anything at above 100V is getting to dangerous levels. We're talking at least 72km/h speeds here. It would be unsafe to ride like this on a bicycle frame.

Any updates on the new controller vs. the mini XLR cable? Have you got it working? How much was shipping to Toronto? Have you had trouble with police, since your bike is not legal? Will you modify your front brakes to large rotor discs?

Haven't had a chance to get the immediate start controller to work. I need to test the the hall wires, which I may have crossed when the hub motor spun out of the square when I didn't have the torque arm in place... I spoke to power in motion's tech lead and he seems to be ok with me taking my time to figure things out, which is nice since I'm overwhelmed as it is with family and work etc.. since the bike is working as it is it did not take priority, but yes I will need to get to it soon.

I actually have been stopped twice by cops, but not for speeding. My average speed is about 40 kmh. I was stopped for not stopping at a stop sign beside my home. The stop sign was at a T intersection where to my right there was no open road, so I just looked to my left saw no cars and just sped along, little did I know a cruiser was keeping up with me... pulled up beside me and yelled: YOU'RE SUPPOSED TO STOP! to which i replied: "Yes sir! You're right!". Ever since then I stop at all stop signs (actually not full stop, but just enough so that when i release the brakes the momentum is still enough to get the motor kicking in ). Cops have been happy with me since ...

I got stopped another time for taking a left turn, again beside my home.. oh btw, did i mention there is a cop station right across :-)))

ok so back to the second event. I took a right turn goig down highway shoulder against traffic, which in my area is sort of allowed since there is no real ideal road connection between where i live and the rest of civilized roads without making a huge detour. So... as i was saying, we're kind of allowed to ride the shoulder. in my case i was coming down the left shoulder which is for ucoming traffic.. and that is ok, as long as i'm on the shoulder, cops consider it as a sidewalk for our benefit i guess. now here is the catch... it comes to a light and of course cars on the far right lane can take a left.. and here i was with a green light, so i cross AND take a left turn while a honda is also at the green light on the far right lane , and btw i can see it clearly that it had stopped to flash its lights to take a left turn, and i knew it had seen me and that it had come to a stop before making its turn, so i turn left and it turns left after me. well... ladies and gents, the honda follows me down the path and pulls up beside me and the woman says: YOU KNOW YOU'RE NOT SUPPOSED TO TURN LEFT AT THAT LIGHT FROM WHERE YOU ARE.. to wihch i replied: YOU MEAN TO TELL ME THAT ALL CYCLISTS CANNOT TURN LEFT AT THIS LIGHT? YOU MUST BE JOKING ME! to which she replied: (and btw we are yelling at this point since we're talkiing back and forth across her car window and i'm on my bike and i got my helmet on etc.. so we had to yell) so she says : I'M JUST LETTING YA KNOW THAT YOU COULD GET HIT AND THAT BEST PRACTICE IS TO TAKE THE RIGHT LANE TO TURN LEFT,YOU'RE STILL CONSIDERED A VEHICLE YOU KNOW?! I WON'T GIVE YOU A TICKET JUST LETTING YOU KNOW. HAVE A GOOD DAY! to which i said: CHEERS! wondering why she said that last part..

well.. that little honda and that little lady was a cop, and in my rear view helmet mirror i could see her pulling into the cop station (did i mention there is a caop station beside my home?) ROFLLLLLLLLLLLLLLLLLLLLLLLLLLL

ok.. so i would put smiley faces and all but errrm. this forum just kills me i can't find all my old thingamies :-(((

ok.. regarding disc brakes: i would love that, i hear they are more reliable.. however my current setup doesn't allow disc brakes... so i got arch rivals and they are holding up pretty good. the brakes are very responsive, the only thing is you must absolutely change brake pads every couple of months or so , at least in my case. i go to mountain coop. brakes sell there for $3 a pair. i keep my brakes tightened at all times, the moment i see i've gone too far on the handle bar screw i know i need to replace my brakes. i change the back ones more often than the front ones, seen the back ones get used up more

Haven't had a chance to get the immediate start controller to work. I need to test the the hall wires, which I may have crossed when the hub motor spun out of the square when I didn't have the torque arm in place... I spoke to power in motion's tech lead and he seems to be ok with me taking my time to figure things out, which is nice since I'm overwhelmed as it is with family and work etc.. since the bike is working as it is it did not take priority, but yes I will need to get to it soon.

I actually have been stopped twice by cops, but not for speeding. My average speed is about 40 kmh. I was stopped for not stopping at a stop sign beside my home. The stop sign was at a T intersection where to my right there was no open road, so I just looked to my left saw no cars and just sped along, little did I know a cruiser was keeping up with me... pulled up beside me and yelled: YOU'RE SUPPOSED TO STOP! to which i replied: "Yes sir! You're right!". Ever since then I stop at all stop signs (actually not full stop, but just enough so that when i release the brakes the momentum is still enough to get the motor kicking in ). Cops have been happy with me since ...

I got stopped another time for taking a left turn, again beside my home.. oh btw, did i mention there is a cop station right across :-)))

ok so back to the second event. I took a right turn goig down highway shoulder against traffic, which in my area is sort of allowed since there is no real ideal road connection between where i live and the rest of civilized roads without making a huge detour. So... as i was saying, we're kind of allowed to ride the shoulder. in my case i was coming down the left shoulder which is for ucoming traffic.. and that is ok, as long as i'm on the shoulder, cops consider it as a sidewalk for our benefit i guess. now here is the catch... it comes to a light and of course cars on the far right lane can take a left.. and here i was with a green light, so i cross AND take a left turn while a honda is also at the green light on the far right lane , and btw i can see it clearly that it had stopped to flash its lights to take a left turn, and i knew it had seen me and that it had come to a stop before making its turn, so i turn left and it turns left after me. well... ladies and gents, the honda follows me down the path and pulls up beside me and the woman says: YOU KNOW YOU'RE NOT SUPPOSED TO TURN LEFT AT THAT LIGHT FROM WHERE YOU ARE.. to wihch i replied: YOU MEAN TO TELL ME THAT ALL CYCLISTS CANNOT TURN LEFT AT THIS LIGHT? YOU MUST BE JOKING ME! to which she replied: (and btw we are yelling at this point since we're talkiing back and forth across her car window and i'm on my bike and i got my helmet on etc.. so we had to yell) so she says : I'M JUST LETTING YA KNOW THAT YOU COULD GET HIT AND THAT BEST PRACTICE IS TO TAKE THE RIGHT LANE TO TURN LEFT,YOU'RE STILL CONSIDERED A VEHICLE YOU KNOW?! I WON'T GIVE YOU A TICKET JUST LETTING YOU KNOW. HAVE A GOOD DAY! to which i said: CHEERS! wondering why she said that last part..

well.. that little honda and that little lady was a cop, and in my rear view helmet mirror i could see her pulling into the cop station (did i mention there is a caop station beside my home?) ROFLLLLLLLLLLLLLLLLLLLLLLLLLLL

ok.. so i would put smiley faces and all but errrm. this forum just kills me i can't find all my old thingamies :-(((

ok.. regarding disc brakes: i would love that, i hear they are more reliable.. however my current setup doesn't allow disc brakes... so i got arch rivals and they are holding up pretty good. the brakes are very responsive, the only thing is you must absolutely change brake pads every couple of months or so , at least in my case. i go to mountain coop. brakes sell there for $3 a pair. i keep my brakes tightened at all times, the moment i see i've gone too far on the handle bar screw i know i need to replace my brakes. i change the back ones more often than the front ones, seen the back ones get used up more

Yeah, I have only been out a few times, but running 60V. So I haven't been going that fast. I haven't had any run in with any cops yet.

There was this one time the cops did a sting in Toronto. It was near a bike shop, Urbane Cyclist. There was a stop sign right near the shop and the cops new this. So they waited, standing right next to the stop sign. Then cyclist after cyclist kept getting pulled over and ticketed $120. As cyclists were getting ticketed right next to the stop sign, other cyclists continued to run past the stop sign, failing to stop. They were ticketed as well. This was this past summer, downtown Toronto. Hey, you're from Toronto?

Anyways, I am going to buy a bit more batteries in a few minutes. I am going to push my bike up closer to 70V.
It is an instant start controller. It was rated for 48V nominal MAX. If you put a ping 48V in, it would fry the board. The caps are rated at 63V, +/- 10% or 5%.

I hacked it, and not it works upto 80-something nominal. But, I haven't tested it yet up to that point.

Oh yeah, and if you switched to 6" rotors, for discs, you won't notice much of a difference. Maybe a bit more stopping power, but only a tad. The difference is huge if you go to 8" rotors.

You're on a rear hub motor, so you could try putting discs up front.

There is a sale at pricepoint. But go for the 200mm+ or 8" discs, you'll thank me for it when it saves your life on your 72V/ 51.2km/h set-up.

Hey Snowsurfer, yes i recall the cop sting near Urabne Cyclist. My experience back then was the cops stopped me for stopping under the red light where the stop was 20 feet back due to an uneven intersection, the white delimiter line was faded out so i couldn't see it. anyways, they let me go with a warning, all they cared about was that i had a helmet, bell and reflectors.

I agree with cops regarding bikes needing to follow road laws. You know, after that encounter with the lady cop, I now take my left turn by first crossing all the way, without turning left, then i stop, make a u turn on the shoulder and take a right turn with traffic. I do this not necessarily to be a model citizen but to keep alive on the road. :-))

rearding the disk brakes , yes I would like to have a look.. problem is my front fork doesn't accomodate disk brakes, so Urbane Cyclist says, I'd have to replace the fork $$$ .. so instead i got arch rival brakes, they do a decent job stopping me.

Hey Snowsurfer, yes i recall the cop sting near Urabne Cyclist. My experience back then was the cops stopped me for stopping under the red light where the stop was 20 feet back due to an uneven intersection, the white delimiter line was faded out so i couldn't see it. anyways, they let me go with a warning, all they cared about was that i had a helmet, bell and reflectors.

I agree with cops regarding bikes needing to follow road laws. You know, after that encounter with the lady copi now take my left turn by first crossing all the way, without turning left, then i stop, make a u turn on the shoulder and take a right turn with traffic. I do this not necessarily to be a model citizen but to keep alive on the road. :-))

rearding the disk brakes , yes I would like to have a look.. problem is my front fork doesn't accomodate disk brakes, so Urbane Cyclist says, I'd have to replace the fork $$$ .. so instead i got arch rival brakes, they do a decent job stopping me.

I am running V-brakes up front, but the fork allows disks, so I am going that route. The trouble is I need a new wheel with a disk-compatible hub. I will be forking out the dough for that, and also will be picking up some big rotor disk brakes.

What capacity Ping do you have? Is it 10Ah or 15Ah?
What sort of range are you getting using full-throttle, with no pedalling whatsoever?

I figure with the 10Ah, it would be something like 36km, and with the
15Ah pack, it would be like 48km. Am I in the ball park?

15 ah capacity

ok, full throttle? hmm, well, i don't really go that fast all the time, kind of dangerous, but i can tell you that the range exceeds 36 km.

here's how you need to see it, i think. How many km per ah am I getting. That i can better answer based on my experience:

if you're gentle with the throttle and accelerate slowly etc, and still rely mostly on the motor with very minimal pedalling, like i do, then you can get 4 km per ah, which means we're talking close to 60 km. i pedal to get the bike up to speed to help in the acceleration phase, which i would say lasts about 5 seconds (let me do this in my head again, yep.. one mississipi, two mississipi, three mississipi.. i'm losing track of the esses in that word :-:roflmao2: )

on a windy day, this goes down to 2 km per ah, 30 km.

makes sense ta ya? :thumb:

15 ah capacity

ok, full throttle? hmm, well, i don't really go that fast all the time, kind of dangerous, but i can tell you that the range exceeds 36 km.

here's how you need to see it, i think. How many km per ah am I getting. That i can better answer based on my experience:

if you're gentle with the throttle and accelerate slowly etc, and still rely mostly on the motor with very minimal pedalling, like i do, then you can get 4 km per ah, which means we're talking close to 60 km. i pedal to get the bike up to speed to help in the acceleration phase, which i would say lasts about 5 seconds (let me do this in my head again, yep.. one mississipi, two mississipi, three mississipi.. i'm losing track of the esses in that word :-:roflmao2: )

on a windy day, this goes down to 2 km per ah, 30 km.

makes sense ta ya? :thumb:

That's right. Full throttle is dangerous for an electric bicycle at that voltage. I was running around 77V full throttle on my 408 and it was fast. Didn't want to run it all the time since the braking was pretty scary.

Shocked at the range you were getting, then realized that you have 72V...and at 15Ah, which is a big battery pack(s). You're using about 18Wh used per kilometer, which seems good.

Assisting with accelerating definitely helps. Also, watch the headwinds. If you are getting a lot of headwinds, try to pedal as much as you can. I destroyed my booster pack when I tried to throttle it all the way.

50km/h is a really high speed, and should be used only sparingly on ebike. Generally cruising speed is probably around 32-40km/h. That about right to you?

32-40km/h is exactly right

and with a 72 volt system i can maintain that speed regardless of the conditions without taxing my battery pack

take for example a car. it can do 180 kmh, but in reality people don't usually drive at that speed. they cruise at 40-60. same idea.

I can go up to 34mph with a 48v Lifepo4 10Ah battery to work but reduce to 25mph when busy traffic on the street.

Oh yeah, and if you switched to 6" rotors, for discs, you won't notice much of a difference. Maybe a bit more stopping power, but only a tad. The difference is huge if you go to 8" rotors.

You're on a rear hub motor, so you could try putting discs up front.

There is a sale at pricepoint. But go for the 200mm+ or 8" discs, you'll thank me for it when it saves your life on your 72V/ 51.2km/h set-up.

i'll have to get a new front fork in order to get disc brakes on, is what i'm told. will cost me around 300 bucks.... one day

quick update:

regarding my new immediate start controller not working: problem is with the hall circuit on the 408 motor.

controller is fine.

how did i find out? I just recently upgraded to a 5304 crystalyte motor, my 72 volt immediate start digital controller works fine on that. it's really cool finally having immediate start again (woohoo )!!

this tells my that the fault was with my 408 motor (hall wires/circuit) ...

cheers