Voltage sag on used Lectric normal or battery quality issue?

[pedalpluspower]

I'm just getting into eBikes and recently got my hands on a used Lectric XPedition (with dual batteries) and an XP 3.0 for my partner. Overall, I really love the bikes, but I've noticed something a bit odd with both: there's a significant voltage sag.

Even when the batteries are fully charged, if I push max PAS for a hill or a quick sprint at an intersection, the battery indicator drops several bars, then it bounces back up once I stop pedaling. Initially, I figured it was due to the cold weather, but it's been in the 60s recently, and I'm still seeing the same issue.

Is this something that's normal for eBikes when they're under load? Or does it tend to happen more with specific types or brands of batteries? I didn't experience this on a higher-end eBike I tried before, so I'm curious if less expensive batteries are more susceptible to this.

I'd love to hear from anyone else. Is this just how it goes with eBikes, or should I be wary of this in future upgrades?

 

[cardiganjay]

Voltage sag like that is pretty common on eBikes, especially when you're pushing max assist or tackling hills hard and even fully charged batteries can show a quick drop in the battery indicator under heavy load because the voltage momentarily dips when the motor demands more current. It's kind of like your phone's battery percentage dipping when you're running a power hungry app, higher end batteries and controllers usually handle this better coz they have stronger cells and smarter management systems that minimize the visible sag

As long as the voltage bounces back and you're not losing actual range or performance, it's usually not a big red flag

 

[oldnick1964]

Under load the voltage drops, it's called sag and it's perfectly normal. It'll bounce back up after you start cycling, my newish 48v 20ah battery dropped a bar in a mile due to the cold (February) Depending on the batteries cells, manufacturers recommended 500-1000 full charges. I has one battery a 48v 16ah last six yrs by which time I was getting 5-6 miles from my 1000w rear hub. With my newish 48v 20ah I can get to my mother's and back, a total of 33 miles