BBS02 got error 07 before, now error 12

[greeneyes]

Two weeks ago I tried charging my 52V battery to 100% for the first time (I was using 85% until then). It worked fine for maybe half hour but then it started to occasionally show error 07 - high voltage protection. But after a few minutes it started to work again. Then I got the error again. Then it worked again. At one point it refused to work for maybe half an hour, even though the voltage was like 54V, which is odd since I regularly used it at that voltage before. Once it got below 53V, it started to work fine. Except it showed the error for a few seconds when it was at 48V. This was all in one day, and didn't repeat since then.

Today I tried charging to 100% again. First hour was fine. Then I started noticing that the motor shuts off for a few seconds sometimes, even though I'm pedalling and the display shows I'm actually using quite a lot of power. And the wattage indicator seemed to show nonsense, no way was I using 750W going 15kmh on an easy slope. Then I got error 12 - fault in the current sensor in the controller. It kept showing the error nonstop, but I was occasionally still able to use the throttle despite the error. Sometimes even the PAS kicked in. However, the throttle used too much current, I was practically doing wheelies the moment I touched it. It worked maybe half of the time I tried it. Eventually the battery got down to 50V and suddenly the error was gone and everything worked as normal.

I have a BBS02 750W and a 52V battery from em3ev. I use the grintech satiator charger. I have 800km on the bike. I did program the controller, but only to make it weaker - lowered the maximum current to 18 iirc, lowered the starting current, made the lower PAS levels a bit weaker. I usually only use the PAS and try to conserve battery. I checked for pinched cables and everything seems fine on that front.

Is there some controller problem in the hardware or could it be software? Somehow it can't handle higher voltage, even though it works at first.

[AZguy]

Those symptoms are a bit all over the place

Some BBS's have firmware that doesn't play well with 52V batteries and throw overvoltage errors above around 55V but hard to point to that with any certainty with what you have going... maybe it's a factor and you have other issues too?

How are you measuring voltage? Most voltmeters that don't cost hundreds of dollars aren't super accurate so you may need to take that into account... many have a stated accuracy of 0.5%-1% new (they do drift with age) and sometimes that's of the full scale but even if just at 0.5%-1% of 55V it still works out to ~0.25-0.55V which when looking at battery state is bordering on relatively significant

[greeneyes]

I'm measuring via display and connecting to the battery via bluetooth, the app shows voltage as reported in the bms. I don't have a multimeter since I'm out on a trip the past 2 weeks. The display reports voltage about 0.3V lower than the bms. But the voltage reported on the display seems to change from second to second, plus minus 0.4V from the average.

[greeneyes]

Wouldn't it be happening all the time if it was water? I only cycled in the rain maybe twice and not for long.

[greeneyes]

I guess I'll try to see if aliexpress will accept a return, there is supposed to be a one year warranty. Is it probably just the controller? But I voided the warranty by programming it...

[73Eldo]

So it is stable if its below a certain voltage like that 85% you have historically done? If so then it seems like you just have hardware or firmware that doesn't actually like a 52v battery. Or is still not acting right at the lower voltages? That is where I'm having trouble following whats actually going on.

[greeneyes]

It's stable below 85%. But once I charge to 100%, it works at first but starts to show errors even below 85%.

[greeneyes]

On Aliexpress they said it doesn't support 52V and that I damaged the controller by using a 52V battery... If I find no water, can I just buy a different controller or do I need to get a different motor for this battery?

[AZguy]

A different controller might address things, if and big if the high amperage wiring has no issues (I'm not so sure based on your descriptions)

However if you are confident in the high amperage wiring and are ready to pull the trigger on a new controller I'd try reflashing firmware that supports 52V battery... nothing to lose at that point...

[Circuitsmith]

I would spend a little more for a 52V rated controller from a more trustworthy vendor than Alixpress.
Luna is unfortunately out of stock.

[greeneyes]

You guys were right, water got in. Aliexpress is actually going to replace the whole motor within warranty.

I wonder if next time, I should first open the whole thing and seal it properly myself before I even use it. Is there any video that would walk me trough it?

Also, are there even any 52V controllers for BBS02 750W motors?

[73Eldo]

I know there are some videos on youtube about sealing the HD's so watching those should at least give you an idea of the areas to look at and what they used. Maybe there are also some 02 videos, I never have looked.

It also seems pretty common that during the factory assembly a gasket can get folded over or damaged so it may not need extra sealing just proper installation in the first place.

[greeneyes]

I've run into some trouble. Aliexpress offered to replace the whole unit, but I can't get the damn motor off. I had it tightened at a shop and they used some kind of loktite to make it really snug. I can't even get the outer ring off, and I'm using the 1/2" socket and a breaker bar.

If I only get the controller replaced , what are the chances that the rest of it is damaged too? What should I look for to check?

[AZguy]

As far as removing a loctited nut, heat is your friend - use a hot air gun and heat the fasteners up then go at it with the breaker bar...

If there's been water ingress I'd want to inspect the motor innards

[greeneyes]

Update: I was able to get the motor off with a heatgun, thanks for the help. The aliexpress shop told me I should send back the whole motor for warranty, so I did. Then they apparently lost my package - I have confirmation that it arrived at their warehouse, and they even admitted that they lost it.

Now they are offering me to send me a used motor as a replacement, but refuse to answer how many km it was used for. After several messages back and forth where they keep playing dumb and refuse to answer how many km it was used for, or if I'd have any warranty on it, they told me it was "60-70% new" which I have no idea what it should mean. Recently they started telling me that if I pay extra they can send me a motor that is "less used".

So I've basically been scammed, they are trying to offload some crappy ancient motor on me, and they want to scam me for some extra cash now too. I tried to contact aliexpress directly about it but can't find a way to actually talk to a human.

I wish I had never tried to return it. I could have just replaced the controller. Moral of the story: never try to get any warranty from aliexpress.