Throttle and speed stops working and battery indicator flashes

[borgqueenx]

I have this generic chinese ebike 1000w conversion kit with lcd and noticed today that after giving some throttle that it refuses to work. When then pedalling it works fine but on higher speed of assist it also stops working after a bit. The battery indicator then starts flashing. Again i can still use pedal assist 1 or 2 without a problem.
Is this because the battery is bad or voltage is too low to handle it? Or...?
Thanks!

 

[Nealh]

Looks like you have bad voltage sag which the battery can't handle under a higher amp load, throttle use demands more amps then PAS. In most cases the throttle doesn't feather in the amp load but gives max amps straight away.

 

[awol]

I had the same problem and was due to the LCD detecting the voltage dipping below the set limit, so could be due to bad voltage sag as Nealh says, however my problem was caused by a bad connection between one of the pins which contacts into the battery. I noticed when I went to clean the pins one of them had some black burn mark on it. I bent the pins slightly for better contact and all was then good.

 

[borgqueenx]

Looks like you have bad voltage sag which the battery can't handle under a higher amp load, throttle use demands more amps then PAS. In most cases the throttle doesn't feather in the amp load but gives max amps straight away.

What is a voltage sag and is there a fix?
It worked fine when the battery was above 50% charge.

 

[Nealh]

Voltage sag is when a load is applied drawing high amps causing the battery voltage to drop quite rapidly. So in your case at 50% charge applying the throttle instantly draws high amps = a high load causing sag, your battery is unable to cope with the demand so the low voltage protection cuts in to protect the battery cells. In assist 1 or 2 the amp draw is low so any load is quite low so your battery can cope with this as the sag is less, high quality cells will cope a lot better then low quality ones however even with good cells if one or two are weak then this will also cause sag.
Low assist level will draw low amps 3 or 4 depending on the controller used, applying throttle will draw higher amps so could be asking for 15 or more amps straight away.
Once your battery is at 50% use the throttle little and use lower assist to prevent cutting out.

 

[borgqueenx]

if the low voltage protection would kick in, it would shut down giving power right? the lcd still works and displays the error when this happens.