Over volting 36v hubs.

[Nealh]

As in the title, if I wish/decide to use 48v with my dual voltage KT controllers. What would you go for if using 18650/20700 cells 12 or 13s ?
Using lipo 12s is the easy option as I have 6s available but in due course I will need to replace one if not two of my 36v Samsung 22/26F crappier celled batteries.

 

[anotherkiwi]

You can start with one and move up to the other. I think 6S x 2 is the best option: 20% more speed and a little more power. 44.4 V x 17 Amps looks to be the best compromise between power and range.

 

[Deleted member 4366]

I haven't tried 12S with a KT controller myself, but I heard that some people had trouble when the controller didn't seem to know which voltage it was. If you want to use 12S lipos, you need to convince the controller that it's 48v, so make sure it's fully charged before connecting

 

[PC2017]

I am trying to get my head around over volting... as I did not want to start a new thread with the same title I thought I would just jump on this short post...

I am only thinking out loud and just want to see if I am on the right track...

(350w motor) now on 36v 17amp controller..

I was thinking 48v 14.5AH battery same motor 13/14amp controller just to increase the top speed by a few MPH... so 13amp 624max wattage or 14amp @672w max, my questions- Could this be done?, how much acceleration and/or torque would I loose for each AMP variant? would the motor over heat or burn with particular mention to hill climbing [quite hilly round my parts](obviously not maxing out all the time only on hills and acceleration)? and could I push it to 15amp? (assuming I am not already talking out of my back side and I have a reasonable grasp of over volting) oh and what kind of range would I be expecting I am happy @30miles?

Many thanks for understanding as always - I am still learning, or not as the case maybe!

 

[Nealh]

Which hub do you have and it's winding/rpm speed.

You will probably get away with 17 or 20a 48v controller and near 1000w in top assist.
Tbh you won't notice much difference running at 13 or 14a, however compared to you 36v set up torque/acceleration and speed will increase by 25%.

48v 14.5ah will have more range then 36v 17ah as it will have more watt hours.

 

[anotherkiwi]

You will start to have heat issues at 30 Amps X 52v continuous with small Bafang geared hubs.

I would stick to the 17 A controller - that's 864 W hot off the charger and about 650 W at the wheel at 48v if you take into account about 80% efficiency.

 

[PC2017]

Thanks for the response this is a positive step towards my future thinking and future proofing.

Which hub do you have and it's winding/rpm speed.

It's that dillenger 350w and sorry the contoller is 36v/15amp on my setup as of now - I have tried to ask about the RMP but dillenger don't really speak to me now I self fixed the motor lol or they don't know - however that said on PAS 5 I can maintain a top speed of 18mph full throttle no pedalling, I kinda know this is a true speed from biking with a friend who's limited to 15.5mph I have to down my settings so I don't fly away from him with pedalling included.

So it goes without saying but i'll ask anyway, with a new setup up of 48v if/when my motor dies I could just plug n play a 48v/500w motor and i'd be good to go.

 

[PC2017]

Glad you mentioned this...

with small Bafang geared hubs.

speaking of a friends setup, his is a 250w bafang, so we could over volt his too with a new 48v battery and another controller, is there anyway to knowing if the custom LCD (oxygen bike e-mate MTB old style, can't even find a good pic) can handle 48v or is it worth getting a new LCD?

 

[Nealh]

LCD will handle 48v but it will only be compatible with controller of the same manufacturer.
If it is a Lishui it won't work with KT & vice a versa.

 

[Nealh]

Thanks for the response this is a positive step towards my future thinking and future proofing.


It's that dillenger 350w and sorry the contoller is 36v/15amp on my setup as of now - I have tried to ask about the RMP but dillenger don't really speak to me
.

What is the no load speed ?
Full throttle with wheel off the ground.

 

[PC2017]

What is the no load speed ?
Full throttle with wheel off the ground.

On throttle flat ground PAS5 me riding 95kg (last weight with NHS nurse), tested it again today and reached 18.7mph no pedalling

 

[Nealh]

On throttle flat ground PAS5 me riding 95kg (last weight with NHS nurse), tested it again today and reached 18.7mph no pedalling

Not the right answer that's a loaded speed.
Lift the motor wheel off the ground and apply throttle in top assist note the speed reading.

 

[PC2017]

Not the right answer that's a loaded speed.

lol sorry nealh while we are on the subject of me not knowing the lingo what is actually meant buy "windings" I am assuming it is the amount of copper wire parts inside the motor wrapped around the internal parts and what kind of numbers do we usually see?

20.8mph no me on the bike(this time), wheel off the ground, full throttle and PAS5 max pas

 

[PC2017]

Another question has arisen looking into controllers, does it matter what wattage the controller states on it for example (and this is not actually me looking for a "350w" its just the first one I came across googleing)

https://www.aliexpress.com/store/product/36V-48V-350W-Brushless-DC-Sine-Wave-Controller-ebike-Electric-Bicycle-Hub-Motor-Controller-with-right/1314442_32759804535.html?spm=2114.12010612/itm2home-4.8148356.2.2506382f6Ck5W1

this on says 17amp but also says 350W should I ignore the wattage and just look at amps and volts?? because this is not a bad price guide or looking start point.

 

[Nealh]

Yes motor winding is copper coil wraps used to determine the rpm.

Ignore controller watts and use amp rating as it is the amps rating x battery voltage that will give you the watts/power at the motor minus a bit of inefficacy (cicrca 20%).

 

[Nealh]

https://www.aliexpress.com/store/product/36V-48V-350W-Brushless-DC-Sine-Wave-Controller-ebike-Electric-Bicycle-Hub-Motor-Controller-with-right/1314442_32759804535.html?spm=2114.12010612/itm2home-4.8148356.2.2506382f6Ck5W1

this on says 17amp but also says 350W should I ignore the wattage and just look at amps and volts?? because this is not a bad price guide or looking start point.

A good choice for controller but like all only compatible fully with matching lcd KT lcd's.

 

[Nealh]

lol

20.8mph no me on the bike(this time), wheel off the ground, full throttle and PAS5 max pas

NLS indicates a mid wound motor so approx. 250- 260 rpm upping voltage to 48v will increase speed/rpm and torque to value of approx. 25%, motor speed will increase to circa 325 rpm. Try to keep motor speed up and not bog down in high gear on hills. On long winding steep inclines motor may get warmer, high assist and lowest gear possible for speed and high cadence.

If the motor struggles it will get hot to the touch, tepid to warm is ok if you can hold your hand on it.
If it gets to hot windings will burn fail or gears will melt/deform leading to seizure over time.
Most 250/350W hubs are usually ok, 20a x 48v is about max before they start incurring issues.

 

[PC2017]

Amazing nealh many thanks... it food for thought any recommendations of what controller to buy and where from... around 17-20amp sounds good to me...

 

[Nealh]

Amazing nealh many thanks... it food for thought any recommendations of what controller to buy and where from... around 17-20amp sounds good to me...

The one you found and linked to on #14 from psw power also get lcd3 for it from the same store.

 

[PC2017]

Yep thanks nealh I was thinking the same plus I am already running the LCD3-kt unit so that saves a few bucks, Since it is a 36v/48v controller could this be used to add a little more power on my current setup??