We’ve noticed the electronic system cut out twice under load – riding up steep inclines. The bike was set to BO+ (boost mode) and we were powering up a slope of about 30 degrees. About five metres up the slope the electronics cut out entirely. It would not power up again via the power switch, until after the battery was removed and reinstalled. This was a recent development (five months after unboxing). We’ve ridden our QiCycle up the incline before on several occasions without problems.
Googling didn’t return a specific answer for the QiCycle, but we found a forum discussing battery failures under load. The comments indicated that failure under load is symptomatic of degraded batteries. They also reminded us that batteries are consumables. However, given the steep price of a new battery, we’re none too eager to pull that trigger.
| ITEM | AUD$ | USD$ | EUR |
| Spare QiCycle Battery | 270 | 200 | 165 |
Perhaps one of the more cynical comments suggested that manufacturers re-use old laptop batteries for electric bikes to keep costs down. So the bikes come shipped with pre-aged batteries. Being cynical folk ourselves, we can’t help but entertain that notion. Afterall, there’s no knowing for sure.
One possibility that occurred to us was diminished battery efficiency at lower temperatures. We’re in mid-autumn and temps have dropped from mid 20s (celsius) down to low teens. If temperature is the cause, we need to figure out a way to keep the battery warm.
Under the QiCycle teardown guide (step 18), it is shown that the battery pack contains 20 Panasonic NCR18650PF Li-Ion batteries assembled in a way that makes individual replacement difficult. That isn’t good news for a cheap repair.
It wouldn’t be till later that we solved the problem. As of April 2021, we benched it.
Skipping Forward in Time
It’s now February 2022, a full 10 months since this post was commenced and this problem has been such a nuisance that we shelved the bike. Power cutting out is a reliability issue and the bike is too heavy without the assistance.
Early on we had considered that it was battery degradation, or unbalanced cells. So we tried some forum suggestions for balancing the cells. Didn’t work.
Now, we’ve come up with something else. We think the contact between the control unit and the battery terminals is poor, so we consulted the teardown reference to disassemble the control unit to investigate our theory. This theory was brought to our attention when we were Googling for an answer and read on a post that the power issue might not be the battery but the quality of the connection to the battery.
The headlight at the front had to come off the bike and the connector disconnected from one end of the motor controller. We snapped the light off – whoops. There are two screws holding the remaining fragments of the light unit against the frame.
The plug at the bottom into the motor controller had to be disconnected, it has two screws holding the plug in place.
The motor controller has an aluminium guide rail bolted to it, and a single screw fastens the rail to the tube (hidden under a sticker near the free end). On the left side of the tube.
The motor controller itself is held by a screw to the tube on the underside.
From our examination, the motor controller is mounted too deep in tube (by about 2mm). Even with the battery fully inserted into the bike, the prongs on the motor controller don’t reach deep enough into the battery to make good contact against the battery terminals, Figure 2. Additionally, the aluminium guide rail is long and prevents the battery from making intimate contact with the motor controller.
Thus, we unscrewed the guide rail from the motor controller, connected the battery … all the way, Figure 3. This was the most important part, the connection, and we could feel the resistance of the prongs against the battery terminals. We also cleaned the prongs with isopropyl alcohol – for good measure. With the motor controller connected firmly to the battery, we slotted the guide rail in place to maintain controller/battery alignment, without fastening the rail. Especially since the holes on motor controller no longer align with the holes on the rail, Figure 4. We also found that the hole at the end of the rail doesn’t align with the hole on the bike. We don’t care. We want the battery connected, and now it is, so we used some tape to hold the assembly (motor controller, battery, rail) together.
Then we slotted the whole thing back into the bike, wondering if we could get away with not using some of the screws. The battery itself has a push button tab that clicks into the bike, holding that end in. The motor controller doesn’t sit snug against the tube and rattles unless screwed down. However that mounting screw-hole no longer lines up with the bike. So we had to enlarge the existing hole a little (it was an ugly job using a cordless drill, with a scattering of aluminium shavings).
Not only had the mounting screw-hole alignment shifted, so too did the port on the underside of the motor controller, so the plug cannot be cleanly attached. We had to cut away a large amount of the rubber housing (off the plug) to allow the plug to connect.
That was it. Job done.
We were left with a lot of screws we no longer needed:
- two screws from the front light (that we cracked getting off)
- two screws that secured the plug underneath the motor controller
- two screws that held the rail to the control unit
- one screw that fastened the rail to the bike
Seven all up. The front light was simply slotted back in, but it sat loose and needed to be taped in place. The plug on the underside no longer has screws to keep it in, however it plugs in firm and seems unlikely to come loose. If it does, we’ll cable tie it in place.
Final Word
While the battery is nominally a removable one that allows it to be charged separately from the bike, we believe that too many removal/insertions degraded the battery terminals. Thus, we’ve decided to leave the battery in permanently. Charge it while it’s on the bike.
The battery has been working well since. Even under heavy pedalling going up hills as it had in the beginning.