talk about a learning curve!!

[Chuns]

Hello, all. I recently bought a pair of ebikes on ebay, one of which has proved to be faulty. They are not one of the prestige marques, rather the opposite end of that spectrum. We just use them to cycle to get the groceries or to the nearest bar when we are touring in our motorhome. I was about to abandon it, but being practical I pulled a few screws out, swapped batteries between the two, and have concluded that rather than junk the faulty one, I would try to, at least, replace the controller.

Although quite adept and practical, there are many areas where my knowledge is zero, electronics and anything that isn't 240v being a prime example. I have dug the controller out, and have gone the obvious route of trying to replicate it, and failed. However, as I read articles, I get a feeling that the 'right sort' of generic controller will do. However I am struggling to find out what that 'sort' might be.

I wonder if anybody here can advise me, perhaps just by giving me the right language to use when I am trying to buy what I need. Or I think I need. The unit is a Tianjin Santroll WZKD361 0KASZX9F4, and a photo is attached.

I'd be so grateful for any clue as to how I should proceed.

Kind regards, Peter

 

[saneagle]

You'll be very lucky to find a Santroll one because they're OEM only. All controllers work the same, but you'll need to do some wiring and change a couple of connectors when you get a different one. Without you telling us the what bike it is and showing us the connectors and controls, we can't advise further.

 

[Chuns]

Thank you for a good start for me. I'll go and take some more pix and furnish you with as much detail as I can.
atb Peter

 

[Chuns]

Hello, again. The bike is an eLife Air, the display and controller wiring pix are attached. I wondered whether I should disconnect all the wires and arrange them in a sort of fan, if so needed I will do that.

Please say if you need more.

atb Peter

 

[Chuns]

Would help if I attached the pix I said I would...

 

[Saracen]

Unless they were almost free, why would you want such bikes except as a hobby, something to do, too much work ?

 

[Saracen]

Have you contacted https://www.santroll.com/en ?????

 

[cyclebuddy]

You say you bought these recently... have you tried a warranty claim?

You can download the Elife Air manual here, which includes a brief troubleshooting section for your bike which may help (broadly, check ALL the electrical connections), or there're contact details for the bike maker on Elifes website; some of these cheaper e-bike makers can be surprisingly helpful (others less so).

You haven't actually said what is wrong with your bike or how/when that fault appeared, but having had a quick look at one it seems a fairly common design and simple enough that if all tests/remedies fail, there are members here who could guide you in fitting new parts (the likely ones being battery and/or controller/display), so don't write it off yet.

Plenty members here ride a similar style/cost of folding e-bike and are very happy with them.

 

[Bikes4two]

If the bikes are identical (at least in respect of their motor/battery/controller etc) and one of them is still working, is not the simplest thing to just swap pieces around (having checked the integrity of all connections and the PAS sensor and speedo fitment)?

 

[Nealh]

If both batteries work ok , then one can for about £80 -£100 buy a nice Kt controller , lcd and the peripherals.
Simply replacing everything means the parts will all be 100% compatible and approx .10X better then the current system used , the only wiring you would need to do is maybe the battery connection.

 

[Chuns]

Thanks, @cyclebuddy. I should have said that I have been down all the conventional and obvious (to me) routes. I contacted all I could and been ignored resoundingly. Conventional e-bike repairers were disinterested, unless they would be looking at the mainstream brands.

The faults were an erratic level of power assistance, deteriorating to none. From the outset the display sometimes was alive, sometimes not. Sometimes switching on and off worked, sometimes not. Now it is completely dead, except that when connected to the charger it works. 'Course I can't ride it then! I believe the battery to be fine, as it works on the other one.

By way of elaboration, and partly to address @Saracen's question, the bikes were bought to use solely on the motorhome. We already have a couple of Qwics, but they were a bit of a chore to get into the MoHo 'garage' - I had to take the front wheel off each time, plus they were quite heavy (I am not young). These two were nearly new, and I got them both for a quarter of the new price. They are a great deal lighter than the Qwics, and fit the bill for journeys that rarely exceed a handful of km.

So the reason "why would you want such bikes" is best answered by them being a very cheap solution. Of course I could have paid a lot more, but for a lot more I'd rather put up with the Qwics. And at 16kg they are quite light, and very easy to stow. And if I can't fix this bike I will not be weeping and wailing - when you buy on ebay you take that risk, and I still will have one good bike, which would have cost me, in essence, roughly half price.

And finally, I like to fix things - I volunteer at three repair cafés locally!

 

[Chuns]

Thanks, @Bikes4two, that is a great suggestion. It will identify (or confirm) the suspect part. I'll still have one dud bike, but if I can get the guidance here I am encouraged by the thought of buying and fitting a new controller, as suggested by @Nealh (thanks, Neal). I have nothing to lose. Not even sure that I won't do that anyway, if the guidance can be found here.

atb, Peter

 

[saneagle]

Your intermittent pedal sensor would most likely be that the magnet disc had moved away from the sensor. Again, you haven't given any details, so that's just a guess.

The LCD going off is very simple. It has a direct connection to the battery through the controller. It works completely independenly from the controller, so if it doesn't switch on, it has no connection to the battery, which would either be the red and black bullets in your photo or, more likely, the main battery connection to the bike. If it's neither of those, then a wire must be pulled off the LCD circuit board.

Neither of those problems would indicate the need to change the controller.

The controller is absolutely standard for a motor with hall sensors. You won't likely find one with the flat hall sensor connector, so you either have to change that or join the wires directly.

One interesting thing is that it only gives 10A max, which is very low. It could be an indication that the battery is weak, but you didn't give any details about that. Most batteries can manage 15 amps, except very small ones.

 

[Chuns]

Hello, again.

Taking the working e-bike as a starter, firstly I swapped the controller from the duff bike, and it still worked; next I swapped the battery, and it didn't work any more. Although I haven't swapped the displays over, knowing that they both work, I feel I have identified where the problem might lie.

I have taken the end off the battery, and see only a couple of volts coming off the cell bank. Same with the charger plugged in but not live, and both times with the switch on and off.

However with the charger connected, and powered, I see 42v. Of course I dont know if that is simply the output voltage of the charger, or the voltage of an awakened battery.

Does anybody have any further thoughts on this issue now, please?

I can upload a pic of the opened end of the battery if it would help.

I believe a retailer has replacement batteries in stock, but at £200 I'm reluctant to buy one, though if I have to, I will, but would like to be reasonably sure that buying a new battery will be the solution .

@saneagle , an interersting observation about the 10A. It seems to me that these bikes are pretty 'weedy', so I am not surprised that your view is the battery could be weak - it is!!

Thanks again to everybody for all the input so far.

Kind regards,
Peter

 

[saneagle]

Hello, again.

Taking the working e-bike as a starter, firstly I swapped the controller from the duff bike, and it still worked; next I swapped the battery, and it didn't work any more. Although I haven't swapped the displays over, knowing that they both work, I feel I have identified where the problem might lie.

I have taken the end off the battery, and see only a couple of volts coming off the cell bank. Same with the charger plugged in but not live, and both times with the switch on and off.

However with the charger connected, and powered, I see 42v. Of course I dont know if that is simply the output voltage of the charger, or the voltage of an awakened battery.

Does anybody have any further thoughts on this issue now, please?

I can upload a pic of the opened end of the battery if it would help.

I believe a retailer has replacement batteries in stock, but at £200 I'm reluctant to buy one, though if I have to, I will, but would like to be reasonably sure that buying a new battery will be the solution .

@saneagle , an interersting observation about the 10A. It seems to me that these bikes are pretty 'weedy', so I am not surprised that your view is the battery could be weak - it is!!

Thanks again to everybody for all the input so far.

Kind regards,
Peter

Photos would help, but from what you've described, you're measuring the charger voltage.
Here's how it works. The cell-pack positive is connected directly to the output terminal, sometimes via a fuse. All switching is done on the negative side by the BMS, which is basically an intelligent automatic switch. The BMS will switch off charging if any cell goes above 4.25v or below 2.5v. It switches off discharging if any cell goes below 3.0v (approx). It also switches off discharging if it detects current above some preset value, say 20A. It can also have a global external manual on/off switch.

The cell-pack negative is connected to one side of the BMS and the output terminal negative and charge negative to the other, with the switching inbetween.

What you measure depends on where you measure it. To measure the cell-pack, you have to measure directly on it or where the negative attaches to the BMS. Individual cell voltages can be measured on the multi-pin connector that connects to the BMS.

Some batteries have sleep mode that needs to be woken up if the battery is not used for some time. The wake-up procedure should be detailed in the manual.

Post#8 here shows a typical schematic I made:

Rewiring 36V battery ti 12V?

Hi there people! I'm very fresh here and I realise that my post might not be entirely within subject of this forum but as i take same principals apply around EV vehicle words I'm looking for help here. My question is: -Is it possible to rewire 36V bicycle battery for 12V? I don't have an...

www.pedelecs.co.uk

 

[Chuns]

Just and update and a thank you...

By swapping key components between the two bikes it was immediately obvious that the fault lay with the battery pack.

I sent it to the Battery Repair Shop, who were not only very competitively priced, but had the repaired battery back on my doorstep within 48 hours.

My thanks to all those who responded with positive input to my plea for help.

Kind regards, all

Peter

 

[Bikes4two]

Just and update and a thank you...

By swapping key components between the two bikes it was immediately obvious that the fault lay with the battery pack.

I sent it to the Battery Repair Shop, who were not only very competitively priced, but had the repaired battery back on my doorstep within 48 hours.

My thanks to all those who responded with positive input to my plea for help.

Kind regards, all

Peter

Good to know that all is now well. For other forum members is would be useful to know what the problem was and how much the fix was - thanks.

 

[saneagle]

Good to that all is now well. For other forum members is would be useful to know what the problem was and how much the fix was - thanks.

Fuse loose. Very expensive to screw it in tighter.

 

[Chuns]

Happy to do that, @Bikes4two. The diagnostic was £45, (waived should the repair take place). The total bill was £270, including return postage. Apparently 26 of the 30 cells were found to be faulty.

I was quite impressed with the positive approach of the Battery Repair Shop, which contrasted with the responses I got from several others.

I took the bike for a quick squirt through our village to confirm it was doing what it should, and it is now back in the Motorhome, awaiting spring.

Kind regards,

Peter

 

[saneagle]

They're not as competitive as you thought. A brand new battery is only £200, even less from Aliexpress:

eBike Air Battery

36V Battery - compatible with: eBike Air and eLife Air only This item is for a battery only. comes complete with a set of keys This battery is only compatible with the models above, if you are unsure whether this battery is compatible with your product please contact us before purchasing.

www.ebikes.co.uk

or just swap the cell-pack yourself for £90 - just 4 wires to join:

https://www.amazon.co.uk/Battery-Lithium-Electric-Lightweight-Portable/dp/B0CK62J6T3/ref=asc_df_B0CK62J6T3/?tag=googshopuk-21&linkCode=df0&hvadid=676225753321&hvpos=&hvnetw=g&hvrand=1412831874762215259&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007151&hvtargid=pla-2247287750158&mcid=0ba43440fd8b30fba47a045be269470e&th=1