Bafang BBS02B 48 V 750 W with DM03 Display - Error 30 (and 40, 50, 54, 64, 68 :/)

[mrverissimo]

Hi all!

I am new to the wonderfull world of DIY ebikes and excited to be part of this community! However, I am not posting today for a very good reason :/

2 weeks ago I have installed a Bafang BBS02B 48 V 750 W with DM03 Display on a brand new commuter bike I have bought specifically for this.
The installation went well, no troubles, and everything worked fine using PAS and throttle. Went well until this week.. only after a total of 40 km, during my 6th ride with the bike, suddenly the display started showing ERROR 30 and the motor stopped working having a kind of kick in and out behaviour. I started pedalling to reach home and the display showed other errors such as 54 and 68.

I have done some research and it seems ERROR 30 is related to some sort of communication problem. I have checked all the wires and connections and everything looks just as good as when I installed them (I was very careful with cable management when installing the kit).
As for ERRORS 54 and 68 I could not find any information. I wonder if this is related to the fact that DM03 display is new...

I tried to disconnect/connect all plugs, reset the display and so on, but the problem persisted. I did a test ride yesterday and the bike had just the same behaviour:
1. When I turn on the display the error 30 shows immediately.
2. I lifted the bike to check on a stand by position and both throttle and PAS speeds up the wheel.
3. I ride for a few meters and the motor seems like it wants to start, kicking in, but stops right after. It does that if I keep pedaling.
4. After that, errors 54 and 68 start to show up on the display.

Do you guys have some tips on how to tackle this issue?

Any help would be appreciated!
Regards

 

[m@Robertson]

I can give you some only marginally useful info on your situation: The DM03 display is not new, despite the advertising that hawks it using terms like ' the successor to the SW102' or an upgrade to the SW102. Reality is they are two competing products made by two entirely different companies. My DM03 factory manual's release history starts in June of 2020. From that DM03 factory manual, Its Error Information section follows the Bafang error protocol exactly, so its error codes stop at 30.

Only issue I have found with the DM03 - which I have repeated across two different displays/motors/bikes, is when you set it for 9 levels of PAS it works for a couple of weeks and then the PAS levels suddenly turn to crap after I think PAS4 - power drops completely off when you go to PAS5 and starts ramping slowly back up again.

With that in mind, just for giggles set the DM03 to 5 levels of PAS and see what happens. That solved my problem.

Error 30 can be a loose connection. But it can also be a pinched or otherwise compromised wiring harness. I'd replace that first as the cheapest thing to test in your path forward. Really though if you want to try a free solution first, open up the motor and check that the controller is plugged in to the motor well and there are no damaged wires visible. This is free but its kind of a PITA to deal with, and you could possibly damage the gasket and require a replacement (you should have one on hand any time you are taking the motor apart) so I guess 'free' is sort of a maybe.

Next, maybe either replace the DM03 (they cost around fifty bucks on Amazon) or replace the display as cheaply as possible with a DZ40... I have actually replaced both of my DM03's with DZ40's because unlike the DM03 they are perfectly visible in bright sunlight. A DZ40 is just under $30. Here's a link to the one I bought. The same seller also sells DM03's.

If its not the display, and not the wiring harness, in the spirit of replacing the cheapest parts first I'd next replace the speed sensor. Once thats ruled out, you've traced the problem back to the motor itself. Next move would be to open up the motor and buy/replace the controller.

 

[mrverissimo]

Thank you so much for your inputs m@Robertson.

Since this is my first kit I do not have any replacement parts yet. I am also trying to debug the problem with the seller as it is brand new. They already told me that have never seen error numbers above 30 Let's see where I can get from there...

Today I did another tests and got more details. Also got different error numbers, such as 40, 50, 64...

1. If I lift the bike to check on a stand by position without the wheels touching the ground, both throttle and PAS speed up the wheel for as long as I push the throttle and everything looks working despite the error display.

2. It is when I sit on the bike (adding weight) that the motor has a turn on/turn off behaviour, kicking in every second or so. It feels like it has no power to transport me.

3. I have also tried different gears and one time, with the lowest gear (1) the throttle and motor worked for a longer period (20 seconds more or less). When I changed to a high gear (just above 2 - my bike has a shimano alfine 8 gear hub), the motor showed the same turn on/turn off behaviour.

4. The error numbers other than 30 only show up when I am riding and the motor has this weird behaviour. When I stop pedalling or pushing the throttle, error 30 comes back to the display.

Keeping all that in mind, I am not sure if this is a wire or plug problem. It seems that it is more likely a control related problem, whether from the display or the motor controller.

 

[m@Robertson]

It could be a controller problem, but given past experience you could easily be wrong. You want to approach this methodically, and as inexpensively as possible. A bad display could easily be the real problem here, for example.

A communication failure is an error 30 and that can commonly be caused by a bad wire inside the housing. Once that happens all bets are off all kinds of weirdness can be caused as secondary problems relative to the primary.

Stick to attacking the known problem and see if the unknowable ones go away.

 

[mrverissimo]

Thank you for all the replies. Let me share some developments of this case as it might be also useful for other users.

After getting in touch with the supplier, they sent me a new display and 1T4 cable. I have replaced both, but unfortunately the problem persists. However, the symptoms are a little bit different now.

I started by replacing the DM03 display and after I turn it on, I was happy because no ERROR appeared on the display. So I went for a test ride, just to find out after a few meters that ERROR 30 appeared again. However, this time no other error number appeared and ERROR 30 did not stay on screen permanently. It came and went while I was riding. Also, the motor did not show the same start and stop behaviour as before. It worked just as if I got no error on the display, both when pedalling or pushing the throttle.

So I went back and replaced the 1T4 cable and rechecked all the connections and other cables. Everything seemed well. I went for another test ride and nothing changed...

Right now, the parts that are still to me tested are:
- the throttle;
- the motor (controller) and its wiring;
- the battery.

I do not believe the throttle as something to do with this error since it also appears when I am not using it.
As for the battery, I have also rechecked all the connections just to be on the safe side. However it seems to me that a communication problem would not be battery related. It doesn't seem to have a digital connection with the controller, just 2 wires for V+/V-.
So... the next most likely part to be tested would be the controller.

I reported this to the supplier and they agreed. They are now presenting a solution to replace the controller.

Let's see what's next...

What unlucky I got with my first DYI kit... :/

 

[m@Robertson]

Unlucky indeed. Usually you just buy these things and they work. Sorry for your troubles but sounds like you have a vendor standing by the product.

 

[mrverissimo]

For sure.. I bought from Amazon Deutschland, and cannot complain about the customer service of this vendor. I am just hoping to solve this out as soon as possible and write them a very nice review!

 

[Chuy]

@m@Robertson I will be installing my mid drive kit as soon as I receive all the parts. I am liking a 5 PAS setting over 9. How does that affect the motor programming which has 9 assist levels (actually 10 with zero) in the Basic tab, #6-#9? Ate the last four values ignored or should they have zero values entered?

 

[m@Robertson]

@m@Robertson I will be installing my mid drive kit as soon as I receive all the parts. I am liking a 5 PAS setting over 9. How does that affect the motor programming which has 9 assist levels (actually 10 with zero) in the Basic tab, #6-#9? Ate the last four values ignored or should they have zero values entered?

Enter the levels as if you had 9 levels of assist. Different displays handle the reduction in levels differently.

Many translate 1, 2, 3, 4 and 5 to the settings you have for 1, 3, 5, 7 and 9. Some others do slight variations on this theme.

Honestly there's no way to know for sure whats what unless the manufacturer says how it is, or unless I plug in a second display, measure the real time watts and amps (an 860 display will let me do this), and then plug in a DZ40 and either try and use a butt dyno to measure the similarities, or plug in some sort of custom solution inline to use to compare measurements. I've never bothered to go to that next level of analysis.

Here is a chart from the Bafang Config Tool, v2.2b. the DPC18/500C displays follow what I describe above. But others do it differently.

 

[Rawly Old]

Enter the levels as if you had 9 levels of assist. Different displays handle the reduction in levels differently.

Many translate 1, 2, 3, 4 and 5 to the settings you have for 1, 3, 5, 7 and 9. Some others do slight variations on this theme.

Honestly there's no way to know for sure whats what unless the manufacturer says how it is, or unless I plug in a second display, measure the real time watts and amps (an 860 display will let me do this), and then plug in a DZ40 and either try and use a butt dyno to measure the similarities, or plug in some sort of custom solution inline to use to compare measurements. I've never bothered to go to that next level of analysis.

Here is a chart from the Bafang Config Tool, v2.2b. the DPC18/500C displays follow what I describe above. But others do it differently.

View attachment 11328

Gawd , I hate error codes. It's like when you dial something & an annoying voice tells you to press 1 to begin the run-around

 

[mrverissimo]

Hi all,

Just to give some feedback about my DYI eBike kit odyssey, as it might be useful for other users.

After two months unavailable, I was finally able to install the motor with the new controller. I ended up sending the motor for repair and the vendor changed the controller confirming it was malfunctioning.

And.... so far so good. I just did a quick test ride and no errors showed up.

Let's just hope my eBike have a long life now!

 

[Rawly Old]

Hi all,

Just to give some feedback about my DYI eBike kit odyssey, as it might be useful for other users.

After two months unavailable, I was finally able to install the motor with the new controller. I ended up sending the motor for repair and the vendor changed the controller confirming it was malfunctioning.

And.... so far so good. I just did a quick test ride and no errors showed up.

Let's just hope my eBike have a long life now!

Weather permitting, I still in the process of installing mine. It's taking a lot of tweaking as the wire harness so long.
& various attempts at routing are just ugly.