P14 setting on SW-900 display

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salex1

1 µW
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Dec 3, 2019
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Hi all, I am planning to put together a 1500w ebike kit that I purchased online.

It is a 48v 1500w Violamart rear-hub kit with a built-in controller and waterproof higo connectors. This will be paired with a 52v 17.5Ah Samsung-3500 cell battery w/ 40A BMS

No information was provided about the "programmable built-in-internal controller", but it seems that it is programmable through the SW-900 display.

This SW-900 display has a parameter setting P14. It is described as follows:

"P14 - Current-limiting of Controller. The original Current is 12A. Range 1-20A"

I don't really understand this. My reading of this with my limited understanding would be that if this setting was set at the max 20A, and with a fully charged battery at 58.8v, this would equal about 1176w going to the motor at max load. However, this seems really low for a kit sold as a 1500w kit.

So my question is, Can anyone tell me what this setting does and how it might affect my performance with this kit? I was thinking that this kind of setup would have at least a 35A controller in order to get the desired wattage to the motor.

Thanks,
 
My take, others may have different opinions. From what you say, you may have a 20a bottleneck between your motor and your battery.

As far as supplying that controller with a 1500w motor, there's no way whoever put that "kit" together might have known you were going to use a high capacity battery to feed it. This is a big piece of checking out ALL of the specs when sourcing parts for a project like the one you've taken on.

I know for sure that 20a max controller rating would be perfectly suitable for other batteries.

I also know you can get a 1500w hub motor with a good 20a feed pretty hot under certain conditions. A long 10mph climb for instance....
 
salex1 said:
Hi all, I am planning to put together a 1500w ebike kit that I purchased online.

It is a 48v 1500w Violamart rear-hub kit with a built-in controller and waterproof higo connectors. This will be paired with a 52v 17.5Ah Samsung-3500 cell battery w/ 40A BMS

No information was provided about the "programmable built-in-internal controller", but it seems that it is programmable through the SW-900 display.

This SW-900 display has a parameter setting P14. It is described as follows:

"P14 - Current-limiting of Controller. The original Current is 12A. Range 1-20A"

I don't really understand this. My reading of this with my limited understanding would be that if this setting was set at the max 20A, and with a fully charged battery at 58.8v, this would equal about 1176w going to the motor at max load. However, this seems really low for a kit sold as a 1500w kit.

So my question is, Can anyone tell me what this setting does and how it might affect my performance with this kit? I was thinking that this kind of setup would have at least a 35A controller in order to get the desired wattage to the motor.

Thanks,
Click to expand...

Well yes, the 20 amp controller is not enough to provide 1500 watts continuous to the motor, but that's probably a good thing. The motor and controller have enough of a challenge staying cool, but when the controller is housed in the motor, you wouldn't be able to dissipate the heat if you ran it at 1500 watts continuous anyway. Great battery though, which you should be able to use when you upgrade.
 
Thanks for the input guys.

Still doesn't make sense to me.

So if I am reading the user guide for the SW900 that came with my kit correctly, the default value for the P14 setting i.e. "Current Limiting of the Controller" is 12A, and the max setting is 20A.

Okay that sounds straightforward, if I put this setting on 20A, and ran my motor at full-load, I would be limited to a max current of 20A at 58.8v resulting in around 1176w going to my motor. The full potential of the motor would never be realized and I would get more range out of my batteries and life out of my motor and its internal controller, etc.

But what about in the case of a 48v 3000w kit with a 65A external controller and the same identical SW900 display?

Surely the P14 Current-Limiting of the Controller setting on the SW900 display is doing something other than creating a 20A bottleneck in any ebike running this display, right?

Here are the links I am referring to:

https://ebikeling.com/blogs/news/how-to-set-sw900-lcd-display-parameters

https://ebikeling.com/collections/c...000w-26-700c-direct-drive-rear-conversion-kit
 
Is your kit like this one?
https://us.voilamart.com/voilamart-26-rear-wheel-electric-bicycle-conversion-kit-48v-1500w-e-bike-motor-kit-lcd-display-built-in-programmable-controller-pas-system-750w-power-limited-road-bike.html

https://endless-sphere.com/forums/viewtopic.php?t=97862
 
I think the answer regarding the amperage the sw-900 is capable of might be best answered by the vendor. I think the point is a darn good one, and have to wonder why they are offering this package - unless they are OK with a 20a max output.

That said, I think you may be better served with a KT based display (LCD3 for example) and KT controller when it comes to this type of "kit".
 
I would be curious if the PO8 speed limiting setting would make a difference. And in the advisement, what's that about a speed limited function wire?
 
Ok I got the kit installed and powered it up. Max setting for the current limit on this SW900 is 40A, not 20A as it states in the included manual. I guess this was just outdated info.

Bike is running good.
 
salex1 said:
Ok I got the kit installed and powered it up. Max setting for the current limit on this SW900 is 40A, not 20A as it states in the included manual. I guess this was just outdated info.

Bike is running good.
Click to expand...

What Wattage does the LCD state it is putting out? My SW900 only seems to go to 20A Maybe an older one?
 
salex1 said:
Ok I got the kit installed and powered it up. Max setting for the current limit on this SW900 is 40A, not 20A as it states in the included manual. I guess this was just outdated info.

Bike is running good.
Click to expand...

They dont care what they throw into the box for a manual. Your lucky if the manual is in English to begin with, and if the manual is in English then its probably horrible spelling and grammar and considered useless. If your lucky its understandable. Your again lucky if the information is correct, and not some other random manual they threw into the box on the human robot assembly line.
 
i just bought a 20inch 1000w 48v kit with the sw900 display.

its weird....with it set at 12 amps, max power is 576watts ....the sw900 osd watt metter will still go upto 1200watts at times..

the controller gets pretty hot though so i havnt tried upping the amp setting yet. i might go for the safer option of dowing them and see if it makes a difference to the watt meter.

would be nice if i could add some cooling and get a few more amps through it though if it does make any difference.
 
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