48v controller on 52v system ?

M

Marcuz

10 µW
Joined
Dec 23, 2021
Messages
6
Hello everyone! a new ebike owner incoming !

Just bought a Fatbike with the following setup
Bafang 1000w Hub G062
Controller is 48v 1000w 30amp
Battery is a 13ah 52v
Display P850C HD.

so to my problem, the thing is that i bought it to be able to get "some" exercise but the motor helping me along so i can do longer rides, but with the PAS even at 1 (1-9) it is way to strong, and i dont feel any resistance in the pedals. so i browsed the internet to try and find some solution and i came across the display Key-disp KD986 witch allows you to set a % of power use in every assistance level, but it only comes with settings up to 48v.
What will happen if i replace the P850C ( settings set to 52v) and just slam on the KD986 and put it on 48v ? will i damage something ? or will it work ? i really dont know much about electricity, sorry if its a dumb question :oops:

Also is there any other good solution to my problem ? ( and yes i do have a thump throttle, but i kinda dont wanna start using it, prefer just to peddal and chill and not think about using the throttle, specially wintertimes my thumb just gets frozen )

all input greatly appriciated !
 
48V ebike stuff should always work on 52V batteries.

This is because 48V is a "nominal" (bullshit) figure. Fully charged they're closer to 55V, and near flat are... much less. everything gets built with parts that can handle more than that as a kind of safety margin, which is also enforced by what electrical components are made. Nobody makes a 55V capacitor for example, but you can buy a 63V one.

A fully charged 52V battery is 58V, which is still below that limit.
 
khorse said:
48V ebike stuff should always work on 52V batteries.

This is because 48V is a "nominal" (bullshit) figure. Fully charged they're closer to 55V, and near flat are... much less. everything gets built with parts that can handle more than that as a kind of safety margin, which is also enforced by what electrical components are made. Nobody makes a 55V capacitor for example, but you can buy a 63V one.

A fully charged 52V battery is 58V, which is still below that limit.
Click to expand...

So your saying it should work without problems just to slam on the new display ?
Thanks for taking your time to answear me :!:
 
khorse said:
Nobody makes a 55V capacitor for example, but you can buy a 63V one.
Click to expand...

Sure they do.

caps.png

The real question is would a 63V Chinese capacitor work at the spec limits for long. :mrgreen:

IMHO derating all Chinese products (not sold under known brand labels with actual standards and QC) by 20% is mandatory. Derate by 50% if you want long life. :lol:
 
That's very obscure, I've never seen one. My supplier goes from 50v to 63v with nothing in between.

I say if whoever is selling this controller is trustworthy the components they use will be genuine. As always, suck it and see.
 
It's not only capacitors, it's how they bring down voltage to logic level. I haven't owned many Chinese ebike parts, but everything I see online uses resistors. The capacitor might not explode, but a resistor might burn up. Or a voltage regulator. Or all of the above at the same time. :lol:
 
Comrade said:
khorse said:
Nobody makes a 55V capacitor for example, but you can buy a 63V one.
Click to expand...

Sure they do.

caps.png

The real question is would a 63V Chinese capacitor work at the spec limits for long. :mrgreen:

IMHO derating all Chinese products (not sold under known brand labels with actual standards and QC) by 20% is mandatory. Derate by 50% if you want long life. :lol:
Click to expand...
63V is a "standard" voltage and much more readily available.
That said, here is a link regarding "made in china" stuff being sold by the very company you posted. It is hard to actually tell who makes stuff now (even TDK!).
https://www.mouser.com/publicrelations_china_ceda_award_2018final/
Good advice regarding purchase capacitors rated higher (20%) no matter who the vendor/manufacturer.
My linear variable power supply rated for 50V (filtered DC primary voltage off transformer's full-wave bridge is 60V DC) has blown capacitors several times. I replaced with 63V the first two times and they blew (scared the crap out of me!) out within 60 minutes of use. I shelved the PS and bought a quality brand vs mess around with it anymore.
P
 
Hi there Marcuz,

A 48 V battery starts its discharge at about 54Volts and goes down to about 41 42 volts. At least that is the industry standard and a 48 Volt controller should work fine on a battery that reads 52 Volts fully charged with a voltmeter.

Andrew
 

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Marcuz said:
Hello everyone! a new ebike owner incoming !

Just bought a Fatbike with the following setup
Bafang 1000w Hub G062
Controller is 48v 1000w 30amp
Battery is a 13ah 52v
Display P850C HD.

so to my problem, the thing is that i bought it to be able to get "some" exercise but the motor helping me along so i can do longer rides, but with the PAS even at 1 (1-9) it is way to strong, and i dont feel any resistance in the pedals. so i browsed the internet to try and find some solution and i came across the display Key-disp KD986 witch allows you to set a % of power use in every assistance level, but it only comes with settings up to 48v.
What will happen if i replace the P850C ( settings set to 52v) and just slam on the KD986 and put it on 48v ? will i damage something ? or will it work ? i really dont know much about electricity, sorry if its a dumb question :oops:

Also is there any other good solution to my problem ? ( and yes i do have a thump throttle, but i kinda dont wanna start using it, prefer just to peddal and chill and not think about using the throttle, specially wintertimes my thumb just gets frozen )

all input greatly appriciated !
Click to expand...

Forget the voltage for a minute - do you know if that display will talk to your controller? There are a lot of different protocols for display-controller communications… it’s not just plug and play.

Instead of a new display would be worth checking if there is a software configuration tool for your controller that lets you change these values. Or there might be a open source firmware available for your controller that lets you customise these kind of settings if you’re happy to flash a a different firmware.
 
anddan said:
Hi there Marcuz,

A 48 V battery starts its discharge at about 54Volts and goes down to about 41 42 volts. At least that is the industry standard and a 48 Volt controller should work fine on a battery that reads 52 Volts fully charged with a voltmeter.

Andrew
Click to expand...

Hi!
Thanks for the answer Andrew !
only 1 thing im still wondering about, after trying to find some answear about this topic since i dont know much about electricity, since volts get lower when battery % go down, will a 48v display on a 52v battery show the % of battery left accurately ? or will that be the only thing that wont work properly ?
 
Blacklite said:
Marcuz said:
Hello everyone! a new ebike owner incoming !

Just bought a Fatbike with the following setup
Bafang 1000w Hub G062
Controller is 48v 1000w 30amp
Battery is a 13ah 52v
Display P850C HD.

so to my problem, the thing is that i bought it to be able to get "some" exercise but the motor helping me along so i can do longer rides, but with the PAS even at 1 (1-9) it is way to strong, and i dont feel any resistance in the pedals. so i browsed the internet to try and find some solution and i came across the display Key-disp KD986 witch allows you to set a % of power use in every assistance level, but it only comes with settings up to 48v.
What will happen if i replace the P850C ( settings set to 52v) and just slam on the KD986 and put it on 48v ? will i damage something ? or will it work ? i really dont know much about electricity, sorry if its a dumb question :oops:

Also is there any other good solution to my problem ? ( and yes i do have a thump throttle, but i kinda dont wanna start using it, prefer just to peddal and chill and not think about using the throttle, specially wintertimes my thumb just gets frozen )

all input greatly appriciated !
Click to expand...

Forget the voltage for a minute - do you know if that display will talk to your controller? There are a lot of different protocols for display-controller communications… it’s not just plug and play.

Instead of a new display would be worth checking if there is a software configuration tool for your controller that lets you change these values. Or there might be a open source firmware available for your controller that lets you customise these kind of settings if you’re happy to flash a a different firmware.
Click to expand...

It should work with my parts, since it was bought at as a kit, and the kitseller also lets you choose the KD986 controller with the kit, but this kit was with the P850C since it was only display with 52v in settings..flashing firmware and programming just goes over my head at this point :oops:
 
Comrade said:
Marcuz said:
Battery is a 13ah 52v
Click to expand...

How many cells does this battery have?

Is it 14 cell x 3.7v? That's 51.8V nominal, which would be closest to 52V.
Click to expand...

I dont really have any idea about it, the specs i do know is the following
52V 13Ah 200-1000W (14S5P)
Nominal Voltage: 52V
Rated Capacity: 13Ah
Max Constant Discharge Current:30A( BMS)
Apply for: 50W-1000W Motor
Charger : 58.8V 2A
Battery Cell: 2500mAH Cell

at full charge the display shows around 58.8v
 
Marcuz said:
52V 13Ah 200-1000W (14S5P)
Click to expand...

There's the answer. 14 cells in series, 5 cells in parallel.

So that 48V display won't show a proper charge level. Ever. If the kit seller says it will work with that controller, and you don't need battery level, give it a try. :lol:
 
Comrade said:
Marcuz said:
52V 13Ah 200-1000W (14S5P)
Click to expand...

There's the answer. 14 cells in series, 5 cells in parallel.

So that 48V display won't show a proper charge level. Ever. If the kit seller says it will work with that controller, and you don't need battery level, give it a try. :lol:
Click to expand...

Aight! appriciate the help! :thumb:
 
anddan said:
Hi there Marcuz,

A 48 V battery starts its discharge at about 54Volts and goes down to about 41 42 volts. At least that is the industry standard and a 48 Volt controller should work fine on a battery that reads 52 Volts fully charged with a voltmeter.

Andrew
Click to expand...

A fully charged 52V battery reads 58V+ on a voltmeter.
 
Marcuz said:
Comrade said:
Marcuz said:
52V 13Ah 200-1000W (14S5P)
Click to expand...

There's the answer. 14 cells in series, 5 cells in parallel.

So that 48V display won't show a proper charge level. Ever. If the kit seller says it will work with that controller, and you don't need battery level, give it a try. :lol:
Click to expand...

Aight! appriciate the help! :thumb:
Click to expand...

The SOC display is a lame way of keeping track of your battery charge anyway (my opinion). Either display has the option to display battery voltage rather than the SOC bars/battery icon, and that's always accurate regardless of using a 48V or 52V battery. Still an estimate, but better than bars.
 
Both your controller/system will have a maximum voltage... i.e. Grintech controllers used to be called 48V when they had a max rating of 62V.

Generally, your heavy duty DC equipment will stay cooler and last longer at 50-70% of maximum watts rating. Higher volts cause less heat, just match the document specifications.
 
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