New KT 35A controller Shunt Shave question

S

Starslinger

100 µW
Joined
Jun 10, 2024
Messages
9
Location
Nottingham
Hi guys

I've recently copped a 35 AMP KT controller from Pswpower. I realised that my battery only has a 30A rated BMS (rookie move)... So I'm planning on shunt shaving it down to 30A or below.

So I just opened it up and found that solder was on the shunts already... Even though it's new from factory and purchased direct from Pswpower. Am I right in assuming the extra solder could be 5 amps worth of solder on top of a 30a board? Would KT do that and rebadge it 35A? I guess if so I could just shave the excess solder off. But wanted to ask your guys expertise.

Pics attached for model info and of the shunt with added solder.
 

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You can adjust the C5 parameter to limit the maximum operating current.

IMG_0198.jpeg
 
Thank you. So if I were to set to value 07 in c5 menu it will run 29 amps?

I've found countless threads online saying the 35 AMP controller will draw for 35 amps when needed regardless of being set lower or just while operating...

However I've lowered amps before on my mid drive setup and the motor doesn't suddenly draw higher than what is programmed. So I'm confused at the advice that's given for shunt shaving.
 
Try setting it at 7 or even lower for some contingency before shaving the shunt.
 
Starslinger said:
Hi guys

I've recently copped a 35 AMP KT controller from Pswpower. I realised that my battery only has a 30A rated BMS (rookie move)... So I'm planning on shunt shaving it down to 30A or below.

So I just opened it up and found that solder was on the shunts already... Even though it's new from factory and purchased direct from Pswpower. Am I right in assuming the extra solder could be 5 amps worth of solder on top of a 30a board? Would KT do that and rebadge it 35A? I guess if so I could just shave the excess solder off. But wanted to ask your guys expertise.

Pics attached for model info and of the shunt with added solder.
Click to expand...
I think your battery pack is probably sized correctly depending on the cells in your pack. The controller is rated fo 17A continuous, and can peak at 35A, and your cells will also have a continuous and a peak discharge current per their spec sheet. Your pack can definitely support the controllers continuous rating by a wide margin.
What is your battery pack configuration and cells used?
 
E-HP said:
I think your battery pack is probably sized correctly depending on the cells in your pack. The controller is rated fo 17A continuous, and can peak at 35A, and your cells will also have a continuous and a peak discharge current per their spec sheet. Your pack can definitely support the controllers continuous rating by a wide margin.
What is your battery pack configuration and cells used?
Click to expand...
Thanks for the response.

My battery was manufactured by greenway battery. It's 48v 17.5ah and contains Samsung 35E cells. BMS is 30A.
 
Samsung 35E's are rated for 8A and 3500mah, Your battery has five cells in parallel, so it's capable of 40A in bursts. The BMS probably can't throttle the current and will allow the controller to pull 35A, As long as you don't sustain that continuously, you'll be fine. Your 35A KT controller probably says 35A peak and 17A continuous? I wonder if even the battery wiring can handle 40A continuous.
 
As docw009 said, the 35E is good for 8A. It has a peak discharge rating of 10A, but voltage sags even at 8A. The pack will be good for range, but not something you’d want to abuse, since it’s a decent pack within its capabilities. I wouldn’t change the shunt.
 
I'm not looking to peak out in
docw009 said:
Samsung 35E's are rated for 8A and 3500mah, Your battery has five cells in parallel, so it's capable of 40A in bursts. The BMS probably can't throttle the current and will allow the controller to pull 35A, As long as you don't sustain that continuously, you'll be fine. Your 35A KT controller probably says 35A peak and 17A continuous? I wonder if even the battery wiring can handle 40A continuous.
Click to expand...
Thank you that's good to know. And that's correct it says that on the front. Thanks to the advice on here ive set the C5 parameter to limit the maximum current and feel confident that will help sustain a healthy life for the pack.

I mostly charge my pack at 2A if I'm not in a rush and occasionally charge at 5A if I need it quicker.

Done about 15,000 miles on my mid drives. And looking forward to trying a hub. I know the trade offs, pros and cons. But something about the simplicity of hubs is appealing to me atm. I hope I don't miss the torque too much.
 
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