Ecotric Swallow 14 inch information needed

[Chalo]

My experience has been that when a battery sits for a long time what happens is that the battery management system (which uses a small amount of electricity) actually discharges the battery to a level that the bms no longer recognizes the charge in the battery. When this happens the bms will not allow the battery to be charged and in some cases the individual cells deteriorate.

It's unfortunately common for cheap e-bike packs to have a BMS that draws on just one or two cell groups rather than the whole pack, so long periods of idleness push it way out of balance. Hopefully yours doesn't have that problem, but it happens a lot.

 

[E-HP]

At 34V, one might assume that all cell groups may be close to 3.4V, but while noted, the BMS can have a parasitic drain on the pack, I don't think it can be assumed that drain is equal across all groups. Some BMS's may only drain one cell group, rather than all, so it's hard to say what state the groups are in without opening the pack.

EDIT: ooops, was typing at the same time as Chalo lol

 

[zort]

Since I ordered a new display, I decided to saw this one open and see if there was a loose wire. I could not find one.
I created a very short video of what happens when the display is moved ebike display. It is only about 4 seconds long so don't blink.

My assumption is that somewhere in the last 5 or 6 inches of the cable a wire is broken and it loses contact when the display is moved.

Just in case anyone notices, there is a yellow wire soldered to the board. I think this wire is for a light which this bike does not have, There is not a yellow wire attached to the JST, which is probably a clue why the JST is 5 pin and only 4 used.

 

[zort]

It's unfortunately common for cheap e-bike packs to have a BMS that draws on just one or two cell groups rather than the whole pack, so long periods of idleness push it way out of balance. Hopefully yours doesn't have that problem, but it happens a lot.

Good to know, I'll investigate when I open up the battery pack