Whats going on here, serious voltage drop?

[#boosted]

When I'm on power, the voltage is all over the place. If I take the scooter for a drive, it will go from 5 bars to 3 on the battery Guage, when its fully charged. Its a Zero 9 52V 600w scooter.


https://youtu.be/zyMtz7cEKlo

 

[Chalo]

When I'm on power, the voltage is all over the place. If I take the scooter for a drive, it will go from 5 bars to 3 on the battery Guage, when its fully charged. Its a Zero 9 52V 600w scooter.

That’s called voltage sag. The higher the current draw, the greater the depression in voltage. It happens to every battery when under load, but it’s its worse with some chemistries, and battery states of health, than others.

The battery voltage when resting should reflect its state of charge, but the amount of sag represents how badly you’re drop-kicking it.

 

[amberwolf]

When I'm on power, the voltage is all over the place. If I take the scooter for a drive, it will go from 5 bars to 3 on the battery Guage, when its fully charged.

By "all over the place", do you mean a voltmeter (or battery bar meter) keeps constantly changing the reading from very high to very low and back, regardless of what you and the scooter are doing at the time? If not, what specifically do you mean?

If you simply mean that while stopped the bar style battery meter stays at 5 bars ("full"?), but when you start moving or keep moving, it drops to 3 bars, that means either:

--your battery is incapable of fully supporting the load the system places on it under the conditions it's being used.

--your battery meter is overly sensitive, or is the wrong voltage range for the battery voltage / chemistry.

Are you riding on flat terrain, with no wind? Or up hills with gusty high winds? Etc.

Are you gently using the throttle, or riding it hard, using full throttle for acceleration, etc, when you see the battery bars drop?

Exact description of sequence of events would be helpful to troubleshooting.

 

[#boosted]

I've been doing some reading on voltage sag and that sounds like what I'm experiencing. The drop is only under throttle, not at idle. I'm a 140lb rider so I'm not a big guy and when I take off (full battery) the battery status goes from 5 to 3. Flat ground, no wind.Then back to 5 when I let off.
Its pretty wild for almost a brand new scooter/battery... I got it from China so I probably got screwed on this one, granted the seller had very good reputation.
My other scooters do not have voltage sag as far as I can tell.

 

[Chalo]

I've been doing some reading on voltage sag and that sounds like what I'm experiencing. The drop is only under throttle, not at idle. I'm a 140lb rider so I'm not a big guy and when I take off (full battery) the battery status goes from 5 to 3. Flat ground, no wind.Then back to 5 when I let off.
Its pretty wild for almost a brand new scooter/battery... I got it from China so I probably got screwed on this one, granted the seller had very good reputation.

If you feel adventuresome, it might be worthwhile to open up the battery and check for continuity problems (like iffy welds, cold solder joints, etc.) If any connection in the main power circuit has unusually high resistance, that would cause major voltage drop under load. There might also be some signs of heating.

Don't do that if you intend to pursue any recourse from the seller.

 

[amberwolf]

The drop is only under throttle, not at idle. I'm a 140lb rider so I'm not a big guy and when I take off (full battery) the battery status goes from 5 to 3. Flat ground, no wind.Then back to 5 when I let off.

You might want to measure the actual battery main output voltage with a multimeter, and watch that under the same conditions, and then note the voltages here in the thread.

It's possible there's nothing wrong and its not actually a serious sag, but that it's just a battery meter that is overly sensitive. Not likely, but possible. More likely that the battery simply can't handle the load very well, for whatever reason.