Upgrading hub motor

vfr400

Esteemed Pedelecer
Jun 12, 2011
3,094
929
Basildon
Controllers don't have loop wire shunt for many years. They are all SMD now.
When did you see one of them last time?
Why are you being so contrary? Loads of controllers have wire shunts. Just because yours have changed doesn't mean everyone else has. Even so, I told OP how to deal with solid state shunts, which give more accurate results than soldering wire ones and is just as easy, though cost a couple of quid for the shunt.
 
Last edited:

Hux

Finding my (electric) wheels
Oct 8, 2019
19
1
You could probably go to 18 amps OK. In the old days when batteries were crappy - long before we had nice Samsung and Panasonic cells, I often increased the current to 18 or 19 amps without any problems. The increase in current has a proportional affect on torque and power.

The good news is that the cost to increase current is zero. You only need to add a blob of solder to the shunt, assuming that you have a wire one.

The shunt is normally a wire hoop, like a staple, and it often sits behind the end-plate of the controller, so is easy to access. The idea is to put a blob of solder on 20% of its total length. Sometimes they already have a blob from the factory, so you need to lengthen it to reduce the clear length by approx 20%. Don't overdo it. 30% is about as high as you should go. Here's a picture of one. You can see two blobs, one on each leg, totalling about 40%.


If you have a solid state one, you have to solder another one with 1/5 of its value over the top of it. Say you have 05 written on it, you get another one of the same size with 01 written on it.

Thanks for this, I will take the controller apart and have a look.
Is there a better controller I can buy? I live at the top of a big hill and the bike really struggles to get up
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
3,094
929
Basildon
Take the end-plate off (4 screws) and have a look inside. There's no need to open the whole thing until you've checked that. In most cases, the shunt is sitting there grinning at you, just waiting to be fed with a blob of solder.
 
Last edited:

Woosh

Trade Member
May 19, 2012
12,025
9,198
Southend on Sea
wooshbikes.co.uk
Why are you being so contrary?
I don't think I am, at least consciously.
Lishui for example will always refuse to push their controllers as far as KT. They won't let me have more than 18A from their 6-FET controllers for example, albeit than KT will let me have up to 20A.
When I looked at his spec list, his battery is the weakest link. The cells weren't specified suggesting that they should not be pushed too much. Even Samsung 29E cells should not be pushed to 2C, Panasonic even a bit less. It's clear that his 36V 10AH battery is the weakest link. If he pushes on the current, it will just sag more and risk oherheating.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
3,094
929
Basildon
I don't think I am, at least consciously.
Lishui for example will always refuse to push their controllers as far as KT. They won't let me have more than 18A from their 6-FET controllers for example, albeit than KT will let me have up to 20A.
When I looked at his spec list, his battery is the weakest link. The cells weren't specified suggesting that they should not be pushed too much. Even Samsung 29E cells should not be pushed to 2C, Panasonic even a bit less. It's clear that his 36V 10AH battery is the weakest link. If he pushes on the current, it will just sag more and risk oherheating.
It'll be absolutely fine at 18 amps.
 

Hux

Finding my (electric) wheels
Oct 8, 2019
19
1
I am going to look in the controller this evening! But can anyone recommend a controller to give more power. I am not worried about killing the battery
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,024
801
Brighton
I'm going to through another possible option put there.....a booster battery

Beg, build, borrow or buy a 2 or 3s battery

Cut the main power wire to the controller. Add the booster in series

Comes with risks of damaging controller and not always that cheap (if you have a suitable charger , soldering iron and basic skills as well as a multimeter then you are halfway there)

I've done this quite a lot in the past and currently occasionally do so on a 36v xf07 front conversion. I splice in a xt60 connector and then make a matching xt60 blank. Leave blank in for 36v or remove and and booster battery for more speed and torque)
 

Hux

Finding my (electric) wheels
Oct 8, 2019
19
1
Take the end-plate off (4 screws) and have a look inside. There's no need to open the whole thing until you've checked that. In most cases, the shunt is sitting there grinning at you, just waiting to be fed with a blob of solder.
No sign of any shunt

can you recommend a better controller for more power?
 

Attachments

Hux

Finding my (electric) wheels
Oct 8, 2019
19
1
I'm going to through another possible option put there.....a booster battery

Beg, build, borrow or buy a 2 or 3s battery

Cut the main power wire to the controller. Add the booster in series

Comes with risks of damaging controller and not always that cheap (if you have a suitable charger , soldering iron and basic skills as well as a multimeter then you are halfway there)

I've done this quite a lot in the past and currently occasionally do so on a 36v xf07 front conversion. I splice in a xt60 connector and then make a matching xt60 blank. Leave blank in for 36v or remove and and booster battery for more speed and torque)
This is defo beyond me!!
 
  • Like
Reactions: KirstinS

Nealh

Esteemed Pedelecer
Aug 7, 2014
8,290
3,121
56
West Sx RH
No sign of any shunt

can you recommend a better controller for more power?
If you change controller then it will also mean a compatible lcd is required, I doubt you will get a Bafang one on it's own. Bafang use Higo connectors (similar to Julet) except the pin outs are sequenced differently.
It will mean you need new pas sensor and throttle and 1t4 or 1t5 trunk cable.

You will need to get a KT controller one either 6 mosfet 17 or 20a but they do run hot if you climb slowly in PAS 5 or buy a 9 mosfet 22a on (which runs cooler), an LCD 3 will work with both.

KT lcd's https://okfeet.aliexpress.com/store/group/display/3521021_513150188.html?spm=a2g0o.detail.100008.25.5c5f346b8fyid7

KT controllers
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
3,094
929
Basildon
Take the screws off the other end and the three along the side, then slide out the pcb and show us some clear photos.

I've shown you the two types of shunt. It'll have one or the other. They're normally near where the black battery wire is soldered.
 

Related Articles

Advertisers