Odd fault

[mikew8760]

I have an odd fault that ha recently happened. When attempting to drive off the bike suddenly stops dead. There is a small screen that shows some values, like speed, battery etc that disappears, i.e. goes blank. It will do nothing, e.g. switching the key-switch ON/OFF has no effect. However, I have found that plugging in the charger, even for a couple of minutes although the battery is fully charged, the display comes on. Then the process happens all over again. I'm really puzzled as to what is happening! There must be a fault somewhere, possibly in the controller, but not sure how to fault find this peculiarity.
Any useful suggestions welcome.

 

[saneagle]

I have an odd fault that ha recently happened. When attempting to drive off the bike suddenly stops dead. There is a small screen that shows some values, like speed, battery etc that disappears, i.e. goes blank. It will do nothing, e.g. switching the key-switch ON/OFF has no effect. However, I have found that plugging in the charger, even for a couple of minutes although the battery is fully charged, the display comes on. Then the process happens all over again. I'm really puzzled as to what is happening! There must be a fault somewhere, possibly in the controller, but not sure how to fault find this peculiarity.
Any useful suggestions welcome.

It's going off because it's lost its connection to the battery. You have to find out why.

Here's a description of how it works. You have two thick wires, red and black from the battery to the controller. They don't power the controller. Inside the controller, a branch is taken from each. A thin red and black go up to power the control panel, which activates when you switch it on. As well a switching on the control panel, the switch also switches on a third, normally blue, wire that runs back to the controller to power it. In other words, the control panel works a s remote switch for the motor controller. The control panel will always switch on as long as it has power, except occasionally when they get water inside.

You need to check where the circuit is broken when it's not working. There's not much point in checking it when it is working, other than for dirty connectors or damaged wires. An electric test will tell you exactly where the problem is. If you tell us more about your bike, we might be able to help with that.

 

[mikew8760]

Many thanks for your response. The bike in question is an EZee Forze made by Cycleezee. I think they are now defunct.
I'm still a bit puzzled as to why the application of the charger, which doesn't actually do any charge, seems to 'reset' the system. The LCD shows all the values and the little ON/OFF button works. A value of pedal assist can be changed, but as soon as the pedals turn and wheels move it all stops, again. I don't see this as an intermittent fault, unless the blue wire you mention is broken. I don't have any circuit diagrams, so I don't understand the purpose of the blue wire. I shall now go and have a good look under the bonnet!
Regards.

 

[saneagle]

Many thanks for your response. The bike in question is an EZee Forze made by Cycleezee. I think they are now defunct.
I'm still a bit puzzled as to why the application of the charger, which doesn't actually do any charge, seems to 'reset' the system. The LCD shows all the values and the little ON/OFF button works. A value of pedal assist can be changed, but as soon as the pedals turn and wheels move it all stops, again. I don't see this as an intermittent fault, unless the blue wire you mention is broken. I don't have any circuit diagrams, so I don't understand the purpose of the blue wire. I shall now go and have a good look under the bonnet!
Regards.

The break in the connection might be in the battery. If there's a fuse in the battery, check that it's in tight. As I said, a meter will tell you where the problem is, otherwise we can only guess.

 

[Nealh]

One possibility is the Forza's age and a knackered battery, even a kackered battery wiil show good charge.

Try rigging up a voltage meter to the battery and if need be the charger to allow power, with the drive wheel off the ground power the bike on to drive the motor wheel and watch the volatge meter and see what the voltage tells you .

 

[saneagle]

One possibility is the Forza's age and a knackered battery, even a kackered battery wiil show good charge.

Try rigging up a voltage meter to the battery and if need be the charger to allow power, with the drive wheel off the ground power the bike on to drive the motor wheel and watch the volatge meter and see what the voltage tells you .

That's a good point. I remember testing an old Ezee battery. It always showed 42v when charged and a nice evenely balanced cell set, but every time I tried to draw any current, the voltage totally collapsed.

 

[thelarkbox]

Plastic battery mounts can warp with age/elemental exposure removing battery contacts from optimum connecting positions, if the case, you may hear the odd pop and find the battery contacts appear to have arcing damage.
shims and wedges can help reposition a battery in its mount and make solid reconnections.

One older battery mount I use on my 'older backup bike' lost some of its retaining lugs and the battery could momentarily bounce out of contact if a bump was hit on the path at the wrong time, swapping the hailong battery connectors from spade type to the round pin type resolved the issue.

 

[Nealh]

If as siad the Forza is on it's original battery , then it is very highly likely at the end of life stage for the cells.
Ezee forza's must be at least 9 + years old now if not some will easy be 15 years.

 

[mikew8760]

If as siad the Forza is on it's original battery , then it is very highly likely at the end of life stage for the cells.
Ezee forza's must be at least 9 + years old now if not some will easy be 15 years.

I have now pinpointed the nature of this fault. The battery may be a bit old, but I doubt that's the problem.
Connecting an LED across the battery contacts, as in situ on the bike. Of course, the LED lights, showing that the expected voltage is present. Selecting a pedal value, say 3, I can cycle away. But only for about 50 metres. Then the power shuts off and, behold, the LED has gone out. Using the 'main' switch ON/OFF several times has no effect. Waiting for a while still does nothing. BUT as soon the charger is plugged in the battery power is "magically" restored.
This clearly shows that some kind of over current device is operating incorrectly. All I need now, apart from relieving the BMS from the battery box, is a schematic diagram! The rest I can easily fix.......
Regards.

 

[saneagle]

I have now pinpointed the nature of this fault. The battery may be a bit old, but I doubt that's the problem.
Connecting an LED across the battery contacts, as in situ on the bike. Of course, the LED lights, showing that the expected voltage is present. Selecting a pedal value, say 3, I can cycle away. But only for about 50 metres. Then the power shuts off and, behold, the LED has gone out. Using the 'main' switch ON/OFF several times has no effect. Waiting for a while still does nothing. BUT as soon the charger is plugged in the battery power is "magically" restored.
This clearly shows that some kind of over current device is operating incorrectly. All I need now, apart from relieving the BMS from the battery box, is a schematic diagram! The rest I can easily fix.......
Regards.

Your battery is knackered. That's the BMS shutting down because the voltage collapsed. After a rest, the voltage recovered, but there's no capacity in the cells, so it collapses every time you draw current.

An LED is no test at all. A 36v ebike battery should vapourise one.

An 18650 cell-pack just about fits inside the case, which is the cheapest repair. Another option is to empty the case and use it as a tool-box, and fit a downtube battery. You can also get your case re-celled. There was a guy offering that service on the forum about a month ago. If you use that service, tell him that you need an absolute minimum of 20A, and ideal would be 25A, as you should have a 20A controller.

 

[Nealh]

I concur , any slight current draw and the voltage is collapsing.

One has to look at the facts , an aging battery and a slight load and it cuts out.
Just because a battery can hold good voltage doesn't mean it is in good condition and this is typical of an aged battery. Cells will have low capacity retention and high internal fesistance.
At nine years one has done well with the battery.
One can confirm this by temporarily rigging up a volt meter a nd ride the bike , watch the voltage reading on rthe the meter collapse if you get a chance before te bikes cuts out.

 

[saneagle]

One can confirm this by temporarily rigging up a volt meter a nd ride the bike , watch the voltage reading on rthe the meter collapse if you get a chance before te bikes cuts out.

Good point. You don't need a voltmeter though. You can just watch the LEDs on the control panel while you ride the bike. If you see them going down before the cut-off, the battery is knackered. They show the voltage, so as the voltage goes down, the lights go out.

 

[mikew8760]

Thanks for your reply. I can see the reasoning for the fault. I have only been able to test the battery with 6 amps, which is fine, but nowhere near the full current supply for the motor. I might try this. Another oddity is that monitoring the charging the current supply is intermittent. That is, at the start current is 3.5A. As the charging comes to near full, at about 1A, current stops momentarily, about 1 second, then starts again for about 5 seconds. I've tried 3 different chargers and this behaviour is the same. This is why I'm thinking there is a fault in the BMS. Even so, I'm reluctant to dive into the innards of the battery; but the battery pack is no longer available and I can't afford a 18650 type repair.

 

[Nealh]

The charging behaviour is normal and is controlled by the BMS , as the voltage near's it max the current required is reduced to a trickle . The final part is top end balancing and the BMS willopen bleed resistors to cells which are highe rin voltage to balance out other cells that need topping up.
Balancing occurs as a mere trickle of 60 - 100ma so sometimes one may see the stop start sequence in the latter stages.
Some BMSmay be more sensitive then others , it doesn't mean they are faulty. If a BMS is faulty then it simply will ot allow charging let alone discharging.

One doesn't even need 6a for the fault to show in aknackered battery, as little as 2 - 4a is enough .