Can I swap battery from my old bike into new bike (both are 36v lithium)?

[Chrisg149]

It's a very basic controller ....

Thanks very much for your controller compatibility notes. I realise that it is not a good match after all. So this leaves with two options: attempting a Hall sensor replacement or buying the exact match KT controller for £49 (see link below). Thanks forum advisors for reaching the best conclusions. Chris D.

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[vfr400]

Thanks very much for your controller compatibility notes. I realise that it is not a good match after all. So this leaves with two options: attempting a Hall sensor replacement or buying the exact match KT controller for £49 (see link below). Thanks forum advisors for reaching the best conclusions. Chris D.

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Which LCD do you have?

 

[Chrisg149]

Which LCD do you have?

KT 880 with 5 pin block (not round) connector.

 

[vfr400]

KT 880 with 5 pin block (not round) connector.

You can get a KT controller with an LCD3 for about £60 from Topbikekit or PSWPower. When you buy a random KT controller, the settings might not be right for your motor, in which case you need the LCD to change them.

 

[Nealh]

KT880 doesn't allow for any parameter changes so as vfr has said a KTLCD3 will be required to access the C parameters or one could opt for the compact LCD4.

 

[Chrisg149]

What do I do now? I've decided to bite the bullet and replace the hall sensor. With basic tools I've surprised myself how far I've got dismantling the old rear hub motor (see photos); but don't know how to expose the hall sensors? I can't find a model number on my Befang 36v 250 rear hub motor to search for specific instructions. Could the knowledgeable forum advise me of next steps or relevant links. I have rudimentary tools and no bearings/gear pullers. Thanks. Chris

 

[vfr400]

You have to remove the side cover. Rest it on a couple of blocks and tap the axle with a soft mallet or put a block of wood on it and hit it with any hammer. Make sure you pull the wire right down into it's groove so you can't hit it.

 

[Chrisg149]

What do I do now? I've decided to bite the bullet and replace the hall sensor. With basic tools I've surprised myself how far I've got dismantling the old rear hub motor (see photos); but don't know how to expose the hall sensors? I can't find a model number on my Befang 36v 250 rear hub motor to search for specific instructions. Could the knowledgeable forum advise me of next steps or relevant links. I have rudimentary tools and no bearings/gear pullers. Thanks. Chris

P.S. Can I simply prize the top cover off with a heavy duty screwdriver, or is a more cautious approach needed. Is there perhaps more prior dismantling required?

 

[Nealh]

On the axle before the clutch there is hex nut and bearing, I wonder if those need removing so the clutch and motor come away.

 

[Chrisg149]

You have to remove the side cover. Rest it on a couple of blocks and tap the axle with a soft mallet or put a block of wood on it and hit it with any hammer. Make sure you pull the wire right down into it's groove so you can't hit it.

My prizing off suggestion must have crossed paths with your "couple of blocks and tap" in the ether. Noted.

 

[Chrisg149]

You have to remove the side cover. Rest it on a couple of blocks and tap the axle with a soft mallet or put a block of wood on it and hit it with any hammer. Make sure you pull the wire right down into it's groove so you can't hit it.

If I'm picturing this correct. Are you saying lay the flange/lip lid flat suspended between 2 blocks and then ensuring the cable is safely out the way in the groove, hit that same end down to open? Chris

 

[Chrisg149]

If I'm picturing this correct. Are you saying lay the flange/lip lid flat suspended between 2 blocks and then ensuring the cable is safely out the way in the groove, hit that same end down to open? Chris

Picture tells a thousand words. Is this what you mean? Chris

 

[Nealh]

Picture tells a thousand words. Is this what you mean? Chris

Yes, that is what vfr refers to.

 

[vfr400]

Picture tells a thousand words. Is this what you mean? Chris

Don't forget to put a hand underneath to catch it.

 

[Chrisg149]

Next Step? Covering successfully removed using your suggested method. How to expose the hall sensors? The face where the cable enters seems to be delicately mounded/attached, so does that mean removing all the gear mechanism and knocking the central spindle out from the other side? Looks involved. Advice or video link appreciated. Thanks guys.

 

[vfr400]

First, you should try to hook the hall sensors out. In many cases, they come out easily, but in some motors they're glued in tight.

If you can't get them out, you have to dismantle the rotor from the stator, which is tricky because they're held together by magnetism.

First, you have to remove everything off the axles - clutch, sun gear and possibly a plate behind the sun gear, then you can pull the rotor off if you have enough strength. The problem is to get enough pull. You need to hold the axle while you pull, so something like a securely fitted vice would help. If you have a vice, put a nut on the axle and hold that sideways so that you can pull sideways. A three-legged puller will work as long as you can pull enough distance. Another way is to get a strip of something and drill a 12mm hole for the axle, then put the axle through and put a nut on, then hold the strip on the ground with your two feet, one each side, while you pull the rotor off with your hands.

When you put the rotor back on, you have to be very careful because it can smash your fingers. It pulls itself on with incredible force when it gets close to the rotor.

 

[Chrisg149]

First, you should try to hook the hall sensors out....

I know from earlier testing that it is the green wire hall sensor that is faulty (close-up photo below). I'd much rather attempt replacement in situ without all the gear mechanism removal if possible. So how to approach it? Is there a best technique or tool? Just yanking on the three black insulated wires is probably not the way; but doesn't seem like much leverage wriggle room. Maybe I should I ask my dentist! Appreciating all your great tips. Chris

 

[vfr400]

I know from earlier testing that it is the green wire hall sensor that is faulty (close-up photo below). I'd much rather attempt replacement in situ without all the gear mechanism removal if possible. So how to approach it? Is there a best technique or tool? Just yanking on the three black insulated wires is probably not the way; but doesn't seem like much leverage wriggle room. Maybe I should I ask my dentist! Appreciating all your great tips. Chris

It's just a case of improvising with whatever tools you can get hold of. If you're lucky, they might just pull out.

I wasn't thinking before. With a suitable three legged puller, you only need to pull the stator up about 10mm to get access to the sensor and lever it out with a small screwdriver.

Don't forget to note which way up it goes. They're trapezium shaped in cross-section, so the front face is smaller than back one.

 

[Chrisg149]

First, you have to remove everything off the axles...

Going the full exposure route: I've removed end nut and bearings but not sure how to remove the clutch/gear assembly. I've found similar videos that talk about removing a snap ring, but mine does seem to have one (see photo), nor to I own snap ring pliers! So what is next step? I'm just concerned about use brute leverage in the wrong place and causing kink or damage.

 

[Chrisg149]

a snap ring, but mine does seem to have one (see photo), nor to I own snap ring pliers!

Correction. Meant to say "mine doesn't seem to have one..."