Battery/motor lag

[Raymond Bleesz]

This is my first post to this forum, so please be helpful. I purchased a Chinese made e bike, manufactured by the Peerless bike company in 2004 ((Guangzhou Peerless bikes ltd).

There has been a consistant problem since day one which I describe as a battery or motor lag when peddling, in any of the gears. When the battery is "active", one can tell that there is "battery assistance", however, when in the middle of peddaling, either the battery or the motor gives out-- it suddenly feels almost as if there is an "anchor" dragging behind one's peddaling & then after peddaling "through the pain", the battery/motor kicks in only to "die" once again. It's fustrating and the bike sits in the garage, unused as it is not reliable.
Tech notes: Intelligent assistanc power, electric motor w/brush, 24 V 220W. battery is 24V 7Ah nickel-hydride

I'm at a loss on where to start in solving this issue--no idea--Please provide insight & workable suggestions.

I think the motor works fine where as I think the battery is the questionable issue.

I purchased this bike at a trade show & purchased it for my handicapped wife. I would like to get it operational for her.

One of the questions I would have is how to go about replacing this particular battery & who offers such, etc etc etc The batteries fit inside a metal "container" which sits vertically under the seat to the main gear where the contacts reside. There is no single battery but it appears there are a multitude of batteries all connected which are gelled into the metal housing. Then again, is it a battery problem??? I do not know.

Photos are available for someone who would like to tackle this particular issue.

Raymond in Colorado

I contacted the company in China to no avail although they initially gave me positive feedback.

 

[torker]

Can you hook a multi-meter to the batt and see if the voltage is right? You would have to put a load on the battery with some lights or something and monitor voltage under a load. It does sound like the low voltage cuttoff on the controller may be cutting power. Also make sure the contacts where the battery sits are clean and that the battery is staying tight against them. I never have liked that type of setup. I like solid connection with some good connectors. Post up pics or a link to them if you can.

 

[amberwolf]

I can think of a couple of possible causes.

The first is that a pedal assist function is not working right, and is only engaging past a certain level of effort, which might be normal, but that something is wrong with the sensor and/or the controller that causes the level to be much more than usual. If the sensor or controller has such a problem, it's possible that it also cuts out again once pedalling drops below that level, or even just after a certain period of time. If there is a way to disable any PAS or pedal-assist sensor, at the controller (sometimes a jumper wire to disconnect, sometimes a programmable option), then this would no longer happen if the pedal-assist function (sensor or controller) is at fault.

The other possibility is that a security e-brake is engaged somehow until the pedal speed is high enough, which would probably be something wrong with the controller. This probably would not cause it to cut back in after you were up to speed, unless pedalling speed/effort drops below the critical level again.

It's also possible that if there are regular brakes on the bike, that it has one of them rubbing enough to cause a lot of effort to be required to push past it, just as with the ebrake, and when pedal speed goes high enough to activate the assist, the motor is able to power thru it enough to make it easy to pedal. If this is the case it's easy to check by verifying if there are gaps between the pads and the rims on all the brakes. If one doesn't have a gap, it's probably rubbing and you can manually disconnect it or adjust it. This problem could cause the motor to cut out again after you were already pedalling and motor was running, due to overcurrent or overheating, inside either motor or controller.

A problem inside the battery is possible if there is a thermal cutout, if something is overheating inside it from current draw. It probably does not have a BMS to fail because it is NiMH. Most of those only even have a thermal sensor for charging, not for anythign else, so it probably doesn't have a thermal cutout to cause this either.



I suppose other issues like a battery connection could be faulty, but then it would probably not just ahve a problem before a certain level of effort/speed, but rather just randomly no matter what other conditions (for the most part).

 

[dogman dan]

my guess is the batteries are going bad, and the controller shuts off when the voltage gets low under load. Then the batteries recover, the voltage goes up, and it turns on again, only to shut down soon for the same reason.
The drag you feel is called motor cogging, and is basicly from the motor becoming a generator that causes resistance when the power to it is turned off.

Checking the battery voltage, both after a ride when the problem is happening, and after a full charge may tell you if the battery is dead. The best test though, requires a wattmeter and a load, like a bunch of headlights or a hot plate. Then you can measure voltage drop under a load.

Chances are, you need to replace the battery. Chances are you will have to carry that new battery on a rear rack. finding one in the same case will be a bit hard. Even dealers that have something that works may not sell them by themselves. Once you find it really is the battery, you might look at pingbattery.com. A 24v 20 ah battery would be a good size and give you huge range.

Of course, like auto mechanics, just because you find one problem and fix it, does not mean there are no other problems. It sounds like the motor is activated by pedaling, and it could just be that device malfunctioning. Does it have a throttle at all? On many controllers, you may be able to disconnect pedelc, and splice on the wires to a regular throttle, assuming there is a throttle plug on the controller. Or maybe just replace the controller once we determine what kind of motor you have.

It could be that you need everything, and replacing it all with a new kit in 36v tends to cost about a thou, unless you use sla batteries. If your ride is short enough, Sla batteries could be an option though.

 

[TylerDurden]

Generally, troubleshooting begins at the power supply... a voltmeter can tell you if the charger is working properly; it can also tell you if the batteries are functioning properly.

If you are willing to take things apart, there are plenty of people here to help you diagnose and repair.

 

[Gregory]

I'd guess 6 year old SLA batteries are probably due for a change.

You'll be able to do that easily, even with no electrical aptitude. Open up the old case, see what size batteries there are and get new ones, being careful to rewire them the same way.

P.S. Photos always help.

 

[Raymond Bleesz]

Responders--thank you for do so--I have a bit more info to work with. There are mechanical hand brakes brakes, not ebrakes.

There is a horn as well as a lighted headlight when the battery is turned on, however, I have not noticed any fluxulation in the tone or brightness of either unit with usage/peddaling. There is also a gauge indicating battery charge/usage. At this time, the indicator says the battery is fully charged when I feel battery/motor lag or a "dragging anchor".

I did take the battery case apart but did not actually take out the batteries as they were gelled inside the housing. I did notice a bit of white residue (corrosion) inside the casing. There appears to be 4 elongated batteries atop the casing and 4 elongated batteries at the bottom of the casing with a 40amp fuse. (I have to check on this as I might be wrong). If "Dogman" is correct in his assumptions that the batteries are outdated (bike purchased in 2004), then why would the battery gauge register "fully charged"??? Please respond to this specific question as I think it may be important.

And if batteries are needed for this particular bike, (Dogmans' suggestion of 24v 20ah), would that be compatible with the existing motor---do I need to be concerned with "burning out" the motor?

I would like to keep this topic an on going one until I solve the problem, so I may lag in responding/testing/work etc , so keep tuned.

I think my next step will be to jury rig up the bike stationary in the garage, "hand crank" the pedals & test the voltage with a wattmeter & see what gives.

Please explain "motor clogging" in more detail

From what most of you are saying, the batteries may be the culprit--I need assistance from my mechanic to find out if this is the issue.

Raymond

 

[torker]

As far as the battery reading fully charged. This may be a surface charge. That is why testing under load is needed. Doing it in the garage on a stand won't do it unless you apply the brakes while pedaling. Might take 2 people to do this unless you have some rollers/trainer that you can use. If you had a couple sealed lead acid batteries that you knew were good you could test with those but those contacts on the frame would have to be bypassed. Not too hard really. On mine there was a plastic cover to remove and the ends of the wires connected with ring terminals so all I had to do was remove a couple screws. You almost need to do it anyway so you can get a voltage meter hooked up to test under load.

Motor cogging is resistance when trying to turn an electric motor by hand. It is the magnets in the motor attracting and repelling. Stronger motors/magnets have more cogging. Yours shouldn't have much resistance when trying to spin the wheel while it is off the ground.

 

[TylerDurden]

For stationary testing, a "training stand" that holds up the rear wheel and adds resistance would be very helpful. Perhaps you have one, or can borrow one.

 

[John in CR]

It sounds like the Intelligent Assistance isn't so intelligent after all. Maybe it just needs adjustment, if that's possible.

 

[dogman dan]

If the battery guage does read full when the motor is running, then it may not be the battery at all. It might read full though when the problem occurs since the controller is likely turning off, or at least the controller is not powering up the motor. At that time the battery would recover to normal voltage, even if it can't supply any amps without sagging to a low voltage.

Cogging. A motor is either a motor or a generator. It's a motor when you put power into it. It's a generator when you spin it without power, and you can feel a lot of resistance then.

No throttle? I start suspecting the pedal assist stuff then, which I know little about. I think they have hall sensors in them, so a bad one, or more likely a bad connection in the wiring to them could be the culprit. The controller may have a throttle plug on it though, so maybe you could add a throttle, and remove the pedal sensor stuff.

Replacing the battery. All you need to do is stay within the voltage limits of the bike. 24v nominal. AH is a measure of the size of the battery. In cheaper lifepo4 batteries, 15-20 ah is the right size to not have the motor too big for the battery.

 

[buzzfirst]

Just for clarity, the OP states nickel hydride. Wouldn't that be nimh not lead acid?

 

[torker]

Just for clarity, the OP states nickel hydride. Wouldn't that be nimh not lead acid?

Yes you are right.

 

[TylerDurden]

Just for clarity, the OP states nickel hydride. Wouldn't that be nimh not lead acid?

Yes you are right.

That is the main reason to suspect the batteries, OP states the mfr date = 2004.

 

[dogman dan]

What I thought too. I bet they charge, but can't take a load.

 

[Raymond Bleesz]

Thank you for the info guys--yes, the bike was purchased in 2004, so the batteries date from that time. So it's possible that even though the gauges (the one on the bike itself & the indicator on the charging unit) suggest full battery charges, the units can not deliver a "load".

If the batteries are a culprit, then of course, I will need to find replacements.

Question: I suggested that a test would be to jury rig up the bike in the garage(I do not have a bike stand) & hand crank the peddals to check battery usage. Someone said that would not be a valid test---is that because there is no "resistance or load" to the spinning wheel?

And to clarify, no there is no throttle on this bike--it just peddal assist.

And what is a controller and can you provide a photo of a controller?

 

[dogman dan]

The controller takes the signal from the throttle, or in this case a pedal sensor, and adjusts the amount of power is allowed to reach the motor.

In your case the controller will be under a cover on the bike somewhere, with wires leading from the battery to the controller, and then to the motor.

Two basic types, brushed controllers, that have 2 wires to the motor usually. and brushless that usually have three fat wires and 5 skinny wires going to the motor.

Some nice photos of a powerfull controller here. http://endless-sphere.com/forums/viewtopic.php?f=31&t=18214

You have to let them take a while to load, and then it's a slide show. So you are looking for a box, sometimes black, with lots of wires to it.

 

[Raymond Bleesz]

2nd attempt today--1st one failed----Since the bike was purchase in 2004, more than likely then is that the batteries can be dated at that time as well---hence they may charge but not carry a "load".

There is no throttle on this bike, just pedal assist.

Can you guys post a image of a controller? what does it look like and what does it do, etc, etc, etc, (if the controller is at fault rather than the batteries.

Have any of you guys run across this particular brand of Chinese bike---Peerless out of Guangzhou, China (Guangzhou Peerless bikes co. ltd? I did have correspondence with the company of recent, so they are still in business. (former name is Huadu Hongye Bic Factory--Maluwang) stating that is one of the biggest bike & ebike manuf in China established in 1989. They manuf racing, mountain, suspension, bmx & ebikes.

 

[katou]

Who's an enlightened ebike shop out that way? I can't think of any shops offhand.

Send us pictures. More info needed.

Picture of charger, picture of bike
picture of batteries out of box, bare minimum.

Katou