Shimano EP801 Motor Turning Off mid ride, will only turn back on after plugging into charger

[mxjames171]

Hi All,

I am looking to find out if anyone has had a similar problem that I am experiencing on my E Bike. I have a Polygon N8e with a shimano EP801 motor.

The issue is that the motor will just turn off mid ride. Usually after about 30min - 1 hour. Battery has been anywhere from 90%-20% when this occurs. I am unable to power the bike back up. Screen remains black and motor will not turn on. When I go back home and plug the bike into the charger, even for only 1 minute, then unplug it, the bike will turn back on. I can then go ride it, and will usually last another 30 min before doing the same thing.

It's just been at the shop for this issue. They had carried out a number of recommendations from Shimano, including replacing the head unit screen on the bar, cleaning connections, re-aligning the battery harness (i think this is what they said). I got it back last night, took it out for a ride, and same thing happened again. So it's going back to the shop. But I am curious if anyone has had a similar issue and what was done to fix it if so.

Thanks,

 

[ottoshape]

Hi All,

I am looking to find out if anyone has had a similar problem that I am experiencing on my E Bike. I have a Polygon N8e with a shimano EP801 motor.

The issue is that the motor will just turn off mid ride. Usually after about 30min - 1 hour. Battery has been anywhere from 90%-20% when this occurs. I am unable to power the bike back up. Screen remains black and motor will not turn on. When I go back home and plug the bike into the charger, even for only 1 minute, then unplug it, the bike will turn back on. I can then go ride it, and will usually last another 30 min before doing the same thing.

It's just been at the shop for this issue. They had carried out a number of recommendations from Shimano, including replacing the head unit screen on the bar, cleaning connections, re-aligning the battery harness (i think this is what they said). I got it back last night, took it out for a ride, and same thing happened again. So it's going back to the shop. But I am curious if anyone has had a similar issue and what was done to fix it if so.

Thanks,

Have you tried removing the battery and then replacing it? I haven't seen this behavior from my ep801 over 13 months and 3000 miles.

 

[digitale]

I had the same issue on my Spectral:ON, ended up being a bad wiring harness that Shimano was aware of and replaced. I'm having another issue now where the bike will turn off and I can't get it back on until I push the battery connector back onto the motor. Seems like the power cable goes bad, so yeah not stoked on EP801.

 

[mxjames171]

Have you tried removing the battery and then replacing it? I haven't seen this behavior from my ep801 over 13 months and 3000 miles.

I havent tried a replacement battery, as I don't have anything available to try. I have removed it and re-installed it, but not try a new battery. I'll see what Shimano say. Bike shop suggested the next step is likely a replacement battery, and my ChatGPT research seams to indicate that might be the likely cause (BMS failure). Fingers crossed, and hopefully covered under warranty!

 

[mxjames171]

I had the same issue on my Spectral:ON, ended up being a bad wiring harness that Shimano was aware of and replaced. I'm having another issue now where the bike will turn off and I can't get it back on until I push the battery connector back onto the motor. Seems like the power cable goes bad, so yeah not stoked on EP801.

Argh, frustrating to say the least when you just want to ride your bike! Agreed. not a great run with my EP801. The motor has already been replaced under warranty, now this issue.

 

[ottoshape]

I havent tried a replacement battery, as I don't have anything available to try. I have removed it and re-installed it, but not try a new battery. I'll see what Shimano say. Bike shop suggested the next step is likely a replacement battery.

Remove and re-install. That is what I was trying to say! FWIW, I have two Darfon batteries and I run them both enough to say neither have acted in this manner. What brand are your batteries?

 

[mxjames171]

Remove and re-install. That is what I was trying to say! FWIW, I have two Darfon batteries and I run them both enough to say neither have acted in this manner. What brand are your batteries?

It's the genuine Shimano battery that came with the bike (Shimano BT-EN806 630Wh (36V, 17.5Ah))

 

[ottoshape]

It's the genuine Shimano battery that came with the bike (Shimano BT-EN806 630Wh (36V, 17.5Ah))

Did the bike dealer tell you what the Shimano e-tube diagnostics showed on that battery? Curious to see what you can see because e-tube will not read the Darfon BMS....

 

[mxjames171]

Did the bike dealer tell you what the Shimano e-tube diagnostics showed on that battery? Curious to see what you can see because e-tube will not read the Darfon BMS....

No they didn't, but I'll ask when I'm in there next week

 

[Martin Sadecký]

The most common cause of this problem with Shimano is
1. Battery wiring harness
2. ON/Off button
3. Motor to display cable
Also have the error codes from the motor cleared. If the system is shutting down there will be a lot of them.

 

[bmxmarty]

I've had a similar problem, though on a Santa Cruz with an EP8, so this may not help you - but then again, it might. The issue ended up being a dirty connection between the battery and the battery mount. So the metal pins weren't making proper contact, which would cause the bike to shut off. See my post in this thread for what I did to resolve it. Good luck!

 

[MOG]

Not the same but similar. My Magishine bar light does the same. Just switches off mid ride for no reason and won't work again until plugged into a charger. I now carry a small power pack and usb cable which I can plug into the charge port mid ride when needed and it will start it up again. I guess there is a loose wire somewhere which causes the BMS to shut down and can only be reset via the cgarge circuit.

 

[Dwoo]

Hey Y’all,
Does anyone know where to source a Darfon battery E4C0G-S, for a 2023 Heckler? I’m dealing with the same crapola.
Contacted/took it into original store/shop, no go, tried contacting Darfon, nada no way to contact.
Cleaned contacts, made sure it is a tight fit. I think it’s time for a new battery. It has 1660 miles on it. But shouldn’t the battery last longer than that? Anyways…
Any ideas welcome. Thanks in advance!
Anything that yields results, I will shower you with praise and appreciation and yell thank you every time I ride.

 

[hctagalong]

There is a fairly long thread about this same problem, different bikes, here. I struggled with my bike cutting out, sometimes multiple times in a ride, for months prior to giving up and getting rid of the bike. During the time I owned it, I tried different batteries, different wiring cables and trips to the LBS and never found a solution. That said, some changes would seem to improve the situation for a little while and then...it wouldn't.

The lack of fault codes was frustrating (see the referenced thread). Above, @Martin Sadecký has a good list of things to try. Hopefully you'll find a solution; good luck!

 

[Dwoo]

There is a fairly long thread about this same problem, different bikes, here. I struggled with my bike cutting out, sometimes multiple times in a ride, for months prior to giving up and getting rid of the bike. During the time I owned it, I tried different batteries, different wiring cables and trips to the LBS and never found a solution. That said, some changes would seem to improve the situation for a little while and then...it wouldn't.

The lack of fault codes was frustrating (see the referenced thread). Above, @Martin Sadecký has a good list of things to try. Hopefully you'll find a solution; good luck!

Thanks for the lead. I read through it, people are having the same or close to the same dilemma. What to do? I’ve tried of the trouble shooting, I’ll try some more. It feels like there’s a problem with the battery and possibly a drainage via the motor (shorts out or fast drainage) frustrating as HE double hockey sticks.

 

[bmxmarty]

Hey Y’all,
Does anyone know where to source a Darfon battery E4C0G-S, for a 2023 Heckler? I’m dealing with the same crapola.
Contacted/took it into original store/shop, no go, tried contacting Darfon, nada no way to contact.
Cleaned contacts, made sure it is a tight fit. I think it’s time for a new battery. It has 1660 miles on it. But shouldn’t the battery last longer than that? Anyways…
Any ideas welcome. Thanks in advance!
Anything that yields results, I will shower you with praise and appreciation and yell thank you every time I ride.

I would hit up SC directly and see what you can find out. You can also take the bike to any shop that has the Shimano diagnostic tools. Look at this link to my Heckler problem to see if any of that info helps you out. My battery had about 2,000 miles on it when it was replaced as a result of their recall, and it was still working fine.