!!!!! HELP me with my 26" Bafang Rear Wheel Build please !!!!!

[bilabonic]

Did you check the effect of black-green at full-throttle?
I wouldn't recommend joining the cruise control blue wires. It's a great idea, but doesn't work very well in practice, and could be dangerous. I scared myself a few times when I tried it because it latches on whenever you use full throttle. It's difficult to engage at anything less, which is where you want it.

Yes. No effect at full throttle.

 

[Deleted member 4366]

Yes. No effect at full throttle.

It seems to be a bit of a lottery what you get from that switch.
The tests that they did on Endless-sphere seem to indicate that the controller lengthens the timed pulses when you connect those wires. Different motors seem to behave differently. My 350w CST increased its no-load speed from about 18mph to 33mph! I would have expected some difference on the 500w too.

 

[103Alex1]

This is what I got from tests on 500W CST :

Wheel factor used 2124 (700 x 25C) gives 26.1mph on normal and 2073 (650A) gives 25.5mph

Poked in the pins of the 3-speed switch and tried it ... the coulors don't match up though - there are 2 blacks and 2 blues on both the controller socket and attached to the switch pins, and then the red wire on the switch is only left with a green on the controller socket to pair to .. paired connection at the bottom of the pic here :

View attachment 5065

Connecting up this way gave about 1mph difference with no load speed readings between 25.7 and 26.3mph but no significant variances.

"Originally Posted by d8veh
You could try what I suggested above in case the switch wiring is faulty. Use a piece of wire to join the middle to each of the two sides in turn to see if it has any effect."

Test done and here are the results :

Wire poked into holes with black (middle) and blue wires coming from connector - 21.5mph

Wire poked into holes with black (middle) and green wires coming from connector - 26.7mph

Re-test with 3-spd connector not used - 25.5mph

Re-test with speed limiter connected - 20.1mph

 

[bilabonic]

DISASTER !!!!!!!

Had everything ready to go, just bagging all up in the sunshine and the controller was sitting awkward in the holder i made (the flanges at end), so i put a knife through and punctured a battery !!!!!!!

Results -







I am devastated !!!!

All the wiring is melted plus it has taken out another battery, can't look at the thing anymore !!!!

Also had to throw water over it as it was smoking like crazy !!!!

 

[Deleted member 4366]

That's a very sorry sight. You have my full sympathy.

Be very careful. If the insulation is burnt through on any of the balance wires or power leads on the remaining batteries, you could get another fire if they touch. Also. if any have already touched, they may have drained cells down to zero volts. You mustn't attempt to charge any cells like that. They'll only swell up and burst

 

[103Alex1]

You have my FULL sympathy too. I have an idea how you must feel. I had just got mine finally ready to test on road after weeks of setbacks, made a silly mistake and severed the cable to my motor. right by the axle after not tightening the bolt up.

Wound up rewiring the whole f*****g thing and being bailed out left right and centre by d8veh, Morphix and shemozzle999 jointly came to my rescue and managed to salvage my motor and supply a replacement lead - but had resigned myself to a £290 replacement in worst case after shipping and tax etc. .... and a very long wait.

SO sorry. Safe disposal of the lot, get some new batteries and a new controller if needed and keep at it - first major disaster is always the worst.

 

[Deleted member 4366]

Do you know what winding speed you got for the motor? It's the number in brackets stamped on the motor. Should be 15, 13, 12 or 11.

 

[Sacko]

Its an 11 Dave.

 

[Sacko]

This is not the end of the world, you can still make a 48v 10ah pack if those 4 packs are ok.

Obviously the wirinig harnesses being destroyed is a pain in the **** as they are time consuming to make, but PM me and we can arrange something to sort you out again im sure.

Isolate those balance wires if they are cut/burnt with electrical tape, you dont want another explosion.

Charge each pack up on the cellpro, if you have a bad cell, it will show you. Did you say you bought a balance board?

 

[Deleted member 4366]

I don't want to be a harbinger of doom, but Unless OP is very lucky, I'd be surprised if there's much to salvage from the remaining packs. My guess id one or two packs. Presumably the bag is burnt too, or was this done before insertion in the bag.

Moving on to salvage. OP needs to check the batteries individually before connecting to a balance board.

OP was expecting a 201 rpm motor, so 48v is needed to get a decent speed from it, but code 11 is 285 rpm, which will easily hold 20 mph, and it should give meaningful assistance past 22mph, which is the same speed as what the lipos would have given for the expected code 15 motor. If he decides he's had enough of lipos, he could think about one of these and an installation like Saneagle's Kraken, which is much more stealthy. This battery is simple plug-and-play. It wasn't an option at the time of order because of the speed, but it is an option now:
36V 20Ah Li-Ion Shrink Tube EBike Battery Pack - BMSBATTERY

It'll also save on postage for a new controller.

 

[103Alex1]

OP was expecting a 201 rpm motor, so 48v is needed to get a decent speed from it, but code 11 is 285 rpm, which will easily hold 20 mph, and it should give meaningful assistance past 22mph, which is the same speed as what the lipos would have given for the expected code 15 motor. If he decides he's had enough of lipos, he could think about one of these and an installation like Saneagle's Kraken, which is much more stealthy. This battery is simple plug-and-play. It wasn't an option at the time of order because of the speed, but it is an option now:
36V 20Ah Li-Ion Shrink Tube EBike Battery Pack - BMSBATTERY

The combo is a good one - very good at hill climbing too. The CST is 270rpm which is very similar and this gobbles up 1.5 miles of sustained >20% uphill gradient with the sort of pedal effort that in no way leaves me sweating profusely and out of breath at the top on 36V.

That sort of motor speed is very punchy on 36V and you can likely take the speed up beyond 22mph on the flat with a resonable cadence of pedalling using the big front chainring. To be completely honest, pushing more volts at a 26" wheel / 285rpm combo from what I've experienced of my own bike on 36V (sounds like a brand of steroids !) in 'normal' terrain, I'd personally consider fitting LiPos to a sturdier DH-style bike with 'sturdy' frame / geometry as a preference if using it in those conditions. It's right up the limit of what would 'feel' right for a regular push bike ... but that's only an opinion and I know others have different ones. Plus it may be different depending on rider / bike load weight.

 

[bilabonic]

Thanks for the sympathy guys, not looked at it in detail yet, but going to continue from where i left off.

I was literally about to fit the controller so it should be fine. Then put in bag and off to go.

Also about ten minutes later i had a delivery of the 11t cassette and the brake pressure switches !!!

I will check the remaining batteries before charging as well.

Got a load of EC5 connectors and a few jst male/females to sort batteries out.

I take it hobbyking is the next step again ?

Had some funny looks of the neighbours when it went up....could not stop it !!! You could see each cell just going up in smoke ......Think i will line the bag in an old fire blanket i have......lol

At least i can plod on and fit brae sensors/flywheel.

Cheers Guys.

 

[103Alex1]

Had some funny looks of the neighbours when it went up....could not stop it !!! You could see each cell just going up in smoke ......Think i will line the bag in an old fire blanket i have......lol

Glad you can see the funny side - I'm pretty sure it was true Monty Python looking at those photos

Also had to throw water over it as it was smoking like crazy !!!!

 

[bilabonic]

This is what i have salvaged. All the batteries fooked !!!

 

[Deleted member 4366]

This is what i have salvaged. All the batteries fooked !!!

That's a shame. I had a feeling they might be. That 20aH battery suddenly looks very tempting. It's about the same weight, but more capacity. You can still stick it in your bag. The price difference isn't that large, and you gain so much with it. I have three of them, and they're a perfect match for a code 11 BPM. Save yourself a lot of trouble while you have the chance!

 

[bilabonic]

Seriously considering getting above for triangle bag and putting charger in seat post rear pannier.

It does make sense, will i not get more distance but less top end ?

Why is this polymer much more expensive ?

36V 20Ah LiFePO4 Electric Bicycle Battery Pack - BMSBATTERY

Not read much on ion batteries.

 

[Deleted member 4366]

Seriously considering getting above for triangle bag and putting charger in seat post rear pannier.

It does make sense, will i not get more distance but less top end ?

Why is this polymer much more expensive ?

36V 20Ah LiFePO4 Electric Bicycle Battery Pack - BMSBATTERY

Not read much on ion batteries.

LFePO4 has a longer service life than LiMnCo. It's also a bit heavier, larger and more expensive. I chose the other one mainly for its light weight ans small size. Don't take too much notice of the sizes, weights or photos on the BMSBattery website. They seem to get a bit confused which is which.

Why do you want to carry the charger? A 20aH battery will take you a very long way.

The higher voltage makes the motor want to spin proportionally faster and would also give it a bit more power. I found that a bike capable of about 23mph is just about right. I've had faster ones, but, you have to ask what's the point. You can't pedal that fast and you're going to get noticed. Also, the bike starts to become less manageable because of the high torque from the motor. Naturally, the faster you go, the more power you need and the faster your battery goes down. The code 11 at 36v is a nice compromise between speed, efficiency and comfort. It still feels and handles like a bicycle, but has enough power to get you up any hill without puffing.

Li-ion battery just means normal plug-and-play ebike battery.

 

[Fordulike]

If money is no barrier, then I would personally go for one of these:

50V 18.5Ah Samsung Triangle Pack

Paul, who runs em3ev, provides excellent after-sales, which you are unlikely to get from BMS BUTTERY- spelling intentional

The triangle battery would fit in perfectly in your 18" frame.

 

[103Alex1]

Seriously considering getting above for triangle bag and putting charger in seat post rear pannier.

If you need to charge regularly at the other end (i.e. if commuting) then I'd think about ordering a spare charger to leave it at work. They can be funny sometimes when being carried around too much - a bit like laptops.

This is the one supplied with kits I believe ... (at least that's what I got with my battery - they come with one as standard) ... and it's cheapest to get it when you buy the battery, shipping-wise.

Alloy Shell 180W LiFePo4/Li-Ion/Lead Acid Battery EBike Charger - BMSBATTERY

It charges 36V at 4A. Might ask you nicely to order me a spare if you go ahead !

 

[bilabonic]

If money is no barrier, then I would personally go for one of these:

50V 18.5Ah Samsung Triangle Pack

Paul, who runs em3ev, provides excellent after-sales, which you are unlikely to get from BMS BUTTERY- spelling intentional

The triangle battery would fit in perfectly in your 18" frame.

Price not really a problem.

To many decisions now......I could get a nice alu case made up for that as i know a guy on another forum who lives near me who has said he could make one to spec.