Issue, looking for help

[image360]

New to e bike's and I'm not an engineer. But here's my issue. I recently purchased an Xtreme fat tire bike. It worked great for the first 12 or so miles, and now it has what I would think would be a fairly easy problem to fix or at least to point to a possible solution. But the local bikes shops have no clue and even the manufacturer seems to be clueless on what is the component that's failing if that is the case.

The bike has a Bafang c961 throttle/controller which is different from what the web site shows. The battery is a Sony 48V11.64h(557Wh). I don't have the hub info as I write this, but it's stated to be a 500W.

The bike works now for about 3-9+ blocks, then it cuts out. the LCD on the Bafang shows all is well, but the motor does not engage. If I turn the Bafang off and immediately back on, the motors works for 1/4 to 1/2 a second. If I turn the Bafang off for 1-2+ minutes, the motor will work again for 3-6+ blocks.

This will happen on the road or on a bike bench and I've had a local bike shop look at all the connections, etc. and they all seem fine so it has to be somtehing in the software or failing component in the controller or hub.

Any one with any ideas?

Any thoughts much appreciated.

Robert

 

[e-beach]

Robert, first things first.



It sounds like it is a connection problem, but if your connections are all fine,.....

have you checked to see if your battery is balanced?

Also, do you have any pictures you could post?
Do you have a web site link where you can point us to what you bought?

 

[Jon NCal]

Have you checked the battery voltage?

 

[image360]

Thanks.

The battery has a power level check, that seems fine, also the Bafang shows full, but I have no idea how to check voltage. Perhaps one relevant issue is the battery can be pulled off it's mount without the key. But I can't see how that would be a issue, it is secure in it's mount and this can be replicated in a bike service mount and why turning on/off the Bafang controller quickly vs 1-2 minutes would make a difference in how long it works again seems to not be the issue.

I also have no idea what is meant by a balanced battery. I have a charger that has basically a red and a green light. When green the battery is fully charged. I have no way that I'm aware of to discern any other info on the battery condition.

Link, again note the controller I got is a Bafang c961 not the one shown.

https://www.fattirebikeparts.com/index.php/xtreme-e-grizzly

And I'm going to take a picture of the connection tomorrow of the hub connector as it's always looked a bit off to me, even though I have no experience in this.

And thanks for the welcome. I'm in Austin TX.

 

[image360]

On a balanced battery? When I first charged the battery to "full" - before any use - green light on on the charger I tested the on battery level indicators. This model has I think five little bars that are either red or green as far as I can tell to indicate charge level. Regardless of how long I left the battery on the charger - never longer than 6 hours, I could never get all indicators to go all green. The last one was always red.

Is that normal?

Robert

 

[e-beach]

Unfortunately the kind of battery indicators in the link you showed us aren't all that useful. Checking voltages with a digital multi meter is always preferred. If you don't know how to do that, it is time to learn. :wink:

Sounds like your battery has Sony VTC(x) cells in it. Those are good cells, but the 6 hours you charged your battery may not be enough to have balanced the cells. All the cells in your lithium pack need to be the same voltage for your battery to function properly. That is what balancing means. It is a bit more complicated then that but that is the start of the concept.

Do this, charge your battery for at least 12 hours and see if that changes things. That little 4 amp charger might not be powerful enough to balance your pack in 6 or less hours. Ignore the green light this time. Just let it charge all night long and into tomorrows afternoon. There is probably a BMS or PCM in the battery pack that needs extended time to properly balance you cells.

Also, take pictures of the controller and battery and post them so we can see what you got. Be sure to show a clear picture of the connectors.

 

[amberwolf]

If there is no overheating of controller or motor (usually pretty obvious if you put your hand on the casing and feel it uncomfortably hot, where you can't keep your hand on it), then it's pretty likely to be a battery issue of one type or another, and the most common is balancing.

As noted above, it just means that not all the cells are at the same level of charge--some are full and some are not.

This usually means that some cells don't have as much capacity as others, and/or that they are not able to put out as much current as other cells without "losing" voltage (sag) more than the others. To fix that kind of problem means replacing those cells, but most of the time you can get around it simply by leaving the battery on the charger (for balancing) longer than normal.


Sometimes the problem is caused by weather--when it's colder, batteries dont' work as well as when it's warmer. (just like me ).

That little 4 amp charger might not be powerful enough to balance your pack in 6 or less hours.

As a note, it doesn't really matter too much how powerful a charger is for balancing a pack that's already mostly charged--that is up to the BMS in the pack, and how much balancing current it can handle.

To the OP: it's not something you can change readily, so don't worry about that part, and just leave the pack on the charger as long as is practical (a day or more, if possible). You may see the charger's lights change momentarily every so often.

Normally a battery won't need to be left balancing on it's charger that long, but one that has either not been balanced yet (is new, may have been sitting for months, etc) or is older and having problems, may need to periodically sit on the charger for significantly more time than just enough to get the "green light" on the charger.


Note also that it is possible the charger is not designed to do balancing, and fully shuts off after reaching "full charge" as far as it can tell, so that to do balancing it requires the charger be powered off until it's lights shut off completely, then back on to restart the charging. I have one like that; the rest seem to restart as needed.

 

[TheBeastie]

One thing to check is if you have dodgey brake signals going to the controller.
If your LCD displays a symbol when your brakes are engaged then make sure to check the LCD when your cut out occurs.
I battled with mystery cut outs for a while and it turned out to be simply my break wire was sending the 'brakes engaged' signal to the controller when I didn't intend to.. I was stumped by it for a fair while till I worked it out... I then upgraded to a controller/LCD combo that clearly displays it on LCD so I can never be chasing my tail on that problem again..

 

[image360]

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Well, as far as balancing I might be screwed. It appears to me that the charger stops after it "thinks" the battery is fully charged. At least the fan turns off and the charger is silent.

 

[Ykick]

Balancing these sorts of battery packs can take a very long time because it’s not using any significant current from the charger. Or, at least until more charge’s burned off by the balance/equilibrium BMS circuit inside the battery pack.

Sometimes balancing is going on even though the charger lights indicate charge is over. I’d leave it on for days, maybe all week. Can you feel the area around the battery pack housing where the BMS is likely located? Sometimes, they’ll get warm if there’s bleed balancing going on?

However, some chargers disconnect once they reach “FULL” condition and never turn back on in order to top-off the pack once the BMS burns off some charge across the high cells. One of those would be a problem for balancing the battery pack. Sorry, I dunno how to best determine if you've got one of those or not?

Try leaving it plugged in for couple days and if problem persists, maybe post in the wanted section for local help to assist with some tools/knowledge? I know I’ve seen guys from Austin, TX floating around here?

 

[image360]

The battery is not a Sony, but appears to be made by Greenway Battery. But I can not find it on their site. When I search for the product number nothing shows up on their site. Was trying to find a manual as I do not think the light status should show a red light when fully charged or balanced. I'm go to leave it connected to the charger but don't think it's going to work as it does not appear to be doing anything.

 

[e-beach]

The battery is not a Sony, but appears to be made by Greenway Battery. But I can not find it on their site. When I search for the product number nothing shows up on their site. Was trying to find a manual as I do not think the light status should show a red light when fully charged or balanced. I'm go to leave it connected to the charger but don't think it's going to work as it does not appear to be doing anything.

The Xtream website says the battery uses Sony high density cells.....

About it not appearing to do anything,...If one of the cells is extremely out of balance, then it could take a loooooong time for the bms to ballance. Days maybe. It is because the bms only bleeds off a tiny bit of capacity at a time. It can take for the low cell to catch up.

Do you have a Digital Multi meter?
Is that battery under warranty?
Will you void the warranty if you open the battery?

 

[Jon NCal]

Perhaps call the bike dealer/manufacturer and find out if they know what the red light on the battery means.

 

[image360]

Thanks folks for continuing to try to help me.

I have contacted both the seller in the US and Greenway for comment. At this time I have to say do not order anything from Xtreme Fat Tire bikes. The owner was helpful at first but when the two local bike shops could not find or fix the issue and it started getting to the point of return or more expensive components for whatever reason he has gone silent. I will be contacting my CC company tomorrow to reverse the charges for the bike.

And whats the link to the Xtream web site. I did a google search but only found a X-tream site that was so poorly designed I would have had to look through 100's of pages to try and find a possible match.

Thanks again folks.

 

[wineboyrider]

What Ypedal said. Sometimes it takes hours and hours to balance a pack with a BMS was that way with my Ping lifepo4 packs. 8)

 

[amberwolf]

It appears to me that the charger stops after it "thinks" the battery is fully charged. At least the fan turns off and the charger is silent.

I have a Modary charger like that for my A123 LiFePO4 pack, and IIRC mine will turn back on after the voltage on the pack drops from balancing, but I am not totally certain of that.
https://endless-sphere.com/forums/viewtopic.php?f=2&t=59426&p=889790&hilit=modary#p889790

https://endless-sphere.com/forums/viewtopic.php?f=2&t=12500&p=848590&hilit=modary#p848590

If it doesn't, (and if yours doesn't), this post
https://endless-sphere.com/forums/viewtopic.php?f=2&t=59426&p=889790&hilit=modary#p887959
tells how to fix it so it does do balancing. FWIW, you probably could just add a switch across those pins described in the post linked above, instead of a jumper or removing the part, so you could switch between it's present functionality and the balancing version, should you ever need to.

 

[image360]

Thanks for all your suggestions, finally found what appears to be a highly qualified e bike shop service in Austin, took the bike their today.

Electric Avenue Scooters

 

[image360]

Well the bike shop says the controller is overheating. Only problem now is the seller is not responding to them for replacement parts request even though the bike is still under the 90 day warranty, not even 30 days in. Ugh!

 

[e-beach]

Where is your controller positioned in the bike? Does it get wind while you ride?

 

[image360]

the controller is enclosed in a tight plastic enclosure on the frame for the seat. It's closed for water proof.

Do NOT buy from this seller, he is not honest or trustworthy.

https://www.fattirebikeparts.com/

Robert

 

[Jon NCal]

Try to open a complaint with the Better Business Bureau for his area. He may not reply, but worth a shot.

 

[e-beach]

the controller is enclosed in a tight plastic enclosure on the frame for the seat. It's closed for water proof.

Do NOT buy from this seller, he is not honest or trustworthy.

https://www.fattirebikeparts.com/

Robert

Sorry for your troubles. But most of us around here advocate for a air flow over the controller to keep it cool. So for your controller to be tucked away and getting hot is not surprising.

What does surprise me a bit is that it is the cause of your described problems....I don't recall anything around here that I read that found that the cause of a motor going intermittent in such a short ride was because of an over heating controller....I feel a bit puzzled about that one. But, hay....I am not the best and greatest around here. :lol:

Edit: I am still thinking battery balance.

Anyway let us know how it goes.

 

[ecycler]

I would be a little surprised too if their diagnosis is correct. Please post some pictures of the controller and box. It should take a lot longer than 3-6 blocks for the controller to overheat (especially in cooler temps now) unless it is extremely undersized for the application or complete junk. You should go visit Chalo's shop.