Intermittent power loss

[commuter]

Hello again
I went and got three 12 V 12 ah batteries and soldered them in series.  Bike is all set.  I rode it for a day for a short time just to test and all seemed well.  Today I hopped on and rode it for about two miles including some off road testing.  Near the end of the ride my power would cut out every ten seconds or so then turn back on.  It continued to do this until I got home.  I checked all of the external connections and they are OK.  Is this normal for riding full throttle up hills with pedalling, or do I need to check something.  Also, when I am riding there is metallic gallop sound that is very rhythmic, it does not go if there is little to no weight on the wheel.  Thanks again for the previous advice.

[Dalecv]

For the noise, check out this thread - http://goldenmotor.com/SMF/index.php?topic=10.0 and see if it might be what your are experiencing. Another quick test is to loosen the nuts on the motor axle and then rotoate the wheel, if the noise goes away then this thread will explain the problem.

On your motor cutting out, check the two connectors that are between the controller and the motor, look at the pins where the wires enter the connector and make sure all of the pins are down into the connector. When you plug the connectors together it is possible for the pins not to mate correctly and for one to be pushed out backwards and then only make partial contact. I had this problem on my connectors.

I had the thermal cut off activate once, but it did this after some heavy dirt road hill climbing and the motor didn't start again for about a half hour. There was a loud click just before the motor started working again.

Good luck

[OneEye]

How long before the low-voltage cutoff resets?  A bad cell and moderately heavy load might induce enough voltage sag under load to activate the cutoff.  Once the load is gone, the voltage climbs.

[Dalecv]

When I ran my batteries to the cut off point it began to cut off after I had stopped and was trying to get going again. Turn the throttle the bike would start to move then the motor would quit, turn the throttle off and try to start again and the motor would pull and then quit. By turning the throttle on and off I was eventually able to get up to cruising speed again. Luckily I had been on a distance test and this was happening right in front of my home.

[commuter]

Thank you for the thread on the noise and the connector tip. 
This your (Dalecv) last post sounds similar to whats happening to me.  Does the system heal itself with time or should I start tickering?

[Dalecv]

My noise got worse the more I rode. If your noise is bearable I would ride it some more to see what happens before opening up the motor.

I am curious to hear more about your motor cutting out. Is it a low voltage situation or?? I don't think 12 amp hours is much for SLA batteries so it could have been low voltage. Do you have a volt ohm meter to test the voltages?

Lead acid batteries need to be charged after use to keep them in good shape.

[commuter]

I unfortunately don't have a DMM.  The supplied led indicator says all is well, and that is voltage dependent right?  even after a short ride should I recharge the battery pack?  If I hold down throttle the engine stops and restarts about as quick as if I let go upon it stopping and rethrottle it.  Did that make sense?  If it shuts down and I let go and retwist it won't start up again until it's ready.  I tried to hold throttle when off and bump the controller and connectors a little to see if it is a moody connection, no reliable conclusion.  I will try to plug in the battery and see if it is happier after.

[erdurbin]

My motor cuts out intermittently whenever my batteries are getting low. There is a low voltage cutoff for the batteries to prevent damage. As far as recharging after even a short ride...YES! SLA's are very sensitive and like to be fully charged at all times. Since this can't occur because you actually use them, they must be put back on the charger as soon as they have been discharged even slightly. As soon as I get off my bike from work, I plug in the charger.

[commuter]

Thank you.  Thank you.  I am so technologically challenged.  A day drained and a bit of riding past that won't kill them right?  I am charging them now and will maintain this habit of immediate charging.  Any other super basic knowledge that I should know?  Can I turn the batteries over? Should I protect them from shock with foam, towels, egg crate, temperpedic mattress?  Is it safe to cover the contacts of the batteries?  I don't mean to be a nuisance, I just don't know where else to learn "common sense" for this realm.  Thanks again for the advice.

[myelectricbike]

Depending on many factors SLA/AGM lead acid batteries appear to be relatively fragile. You can do a pole, but of the four I have had that failed at least one and maybe two had symptoms of an internal short (standalone high temperature) even though I take the precaution of using layers of foam. Although SLA/AGM batteries can be constructed in a manner to handle a high shock environment I don't think they are. Did not take any that failed apart (yet). Think they were designed for no-shock use like UPS or power outage lighting or maybe a light shock environment like wheelchairs but not the kind of shock a pothole represents. I'll post the question on the battery space forum to see what those guys have to say.

[commuter]

thanks

[commuter]

So, I went and bought a multimeter and the batteries are fine.  The individual batteries and the three in series are all at the correct voltage.  I am still having the power for five seconds no power for five seconds etc when riding.  I am going to try and test the connectors for continuity, but I don't think this is a problem.  What do I check next?  Should I pop open the controller?  Where do I find information on what I should find in there?

[Dalecv]

I wouldn't try to disassemble the controller just yet.

Set the bike up in your work area so that the motor driven wheel is off the ground and can spin freely. Use the throttle to see if the same problem occurs when the motor isn't under load. Report back what happens.

Check the wire where it exits the hub, it is very easy to damage the wire here.

Check the wire  and connector to the throttle.

[commuter]

The wheel can spin freely for as long as I can hold it with no load.  The hub wire and controller wires seem fine.  The best I could test they are continuous.

[myelectricbike]

A load test is required to determine if you have a dead cell. You can not make that determination by simply connecting a voltmeter to your batteries and gettng a reading without also connecting the proper load and getting a series of readings over time.