Denver E-scooter empty battery indicator blinking while fully charged

[rick9999]

Hi all,

Yesterday I bought a broken Denver SEL 80130 second hand, with the seller claiming it only had a loose wire.

Checked it out: no loose wires, but also no moving scooter.

When I turn on the display, an empty battery indicator flashes. Headlight works fine though.

Any ideas on where to start looking?

Checked: battery voltage is 41 volts. Voltage is properly supplied from the motor controller to the display, also measured at 41 volts.

This scooter has a closed blue block as a battery, with the BMS inside, so I can hardly check it. However, the charger stops properly when the battery is full, resulting in a green light.

What could cause the display (or BMS) to still think the battery is empty?

Edit: I also connected a different new 24 volt battery to see what happens: exactly the same.

I actually bought this scooter to repair my other scooter, that display (same display) doesn't do anything at all, despite receiving 24 volts (it's a 24 volt battery/motor system).

Thanks for any tips in advance!

 

[amberwolf]

If a battery outputting 41v was connected to a 24v system, it could have damaged parts in the system, if they were not rated for that voltage. The LVPS in the controller that provides 5v/etc to the system is the first place that could have parts damagable by that, the FETs might be rated high enough, caps could be only 35v for a 24v system (which would be less than 30v full).

 

[rick9999]

It's a 36volt battery fully charged to 41v. The motor controller and display are 36v as well.


I'm thinking maybe the display is configured wrong. It's a generic E-scooter display like this:

https://nl.aliexpress.com/item/1005006346113164.html?spm=a2g0o.detail.pcDetailBottomMoreOtherSeller.7.3010Imz9Imz9xl&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.40000.326746.0&scm_id=1007.40000.326746.0&scm-url=1007.40000.326746.0&pvid=16278a79-9df9-427c-b229-e40b0328d10a&_t=gps-id:pcDetailBottomMoreOtherSeller,scm-url:1007.40000.326746.0,pvid:16278a79-9df9-427c-b229-e40b0328d10a,tpp_buckets:668%232846%238115%23876&pdp_npi=4%40dis%21EUR%2123.47%217.56%21%21%21176.60%2156.87%21%402103834817136994370171192e8f7c%2112000036837147928%21rec%21NL%21%21AB&utparam-url=scene%3ApcDetailBottomMoreOtherSeller%7Cquery_from%3A

Maybe it's been set to a different voltage or something, thinking it has an empty battery.

But I cannot seem to change a lot of settings when I enter the parameters. Only switch between m/ph and km/h and if the light is on.

Seller says it worked fine with this display before.

I found one blue wire coming grom the display that isn't connected, but that is also not connected on my other E-scooter, I don't know the purpose for it.

 

[E-HP]

Return it and get your money back if the seller is dishonest, or just suck it up, accept that you made a mistake, and buy the correct (24v) version of the display. If you know your scooter is 24v, why even try to get a 36v display to work with it in the first place? It won’t work, even if it looks the same.

 

[amberwolf]

It's a 36volt battery fully charged to 41v. The motor controller and display are 36v as well.

Maybe you need to start over and re-explain what exactly you have and what exactly you're doing with it all, because your first post clearly states

(it's a 24 volt battery/motor system).

so at this point I can't really help; it's too confusing to be able to give you any useful advice.

 

[rick9999]

To clarify: I've got 2 e-scooters. One with everything at 24v and one with everything at 36v. Only thing I've tested was if connecting the 24v battery to the 36v scooter if the display would turn on and check if it shows anything different. It did turn on and showed the same blinking battery indicator as with the 36v battery. This was for me to check if the 36v battery + BMS was ok.

I've already ordered new controller + display for both scooters. It will probably arrive in 10 days. Keep you posted!

 

[amberwolf]

Ah, ok.

Is the controller an autodetecting type that can run on 36v/48v?

It's pretty common for them to misdetect the voltage of a battery that's at a charge level similar to that of the other voltage battery--so a full 36v seems like an empty 48v, or an empty 48v seems like a full 36v.

Usually to fix this, you disconnect the battery and try to turn the system on, which clears any voltage out of it's caps. For a 36v battery, you'd discharge it down some (say, 40v or less) and then reconnect it and try to run the system.


BTW, most 36v batteries would charge to 42v full, for 10s at 4.2v/cell. If yours only goes to 41v, either it has different cells or BMS limits, or the charger is not quite the right voltage, or there's a problem with the cells so at least some of them aren't fully charging.


A 24v battery, even full, should show empty on a controller for a 36v or 48v system.

 

[rick9999]

Good news! Both scooters are working with the new controllers + display. I can hear that the 36v version has more torque though (obiously)

These displays, although they look the same, can be pre-set to what nominal voltage the battery should be. If I put the value higher then the battery indicator in this new display will drop and start blinking! I cannot get the 36v version working on the 24v scooter and vice versa. Even if I manually put the voltage down. So probably the display that came with the broken scooter has it's settings messed with, although I can't change almost nothing except light on or off.

In these new displays I can change everything.

Couple of challenges:

1. While the 36v scooter is going forwared the 24v scooter drives backwards. Could it be that manufacturer messed up and mixed cables inside the controller? How could I check this out?

2. connectors are different. Since in the 36v scooter the controller is at the bottom I need to extent it, cannot find the right extension cable yet. Does someone know what this cable type is called?

Questions:

For both scooters I only have to connect the 3 fase cable, the battery and the throttle+screen (6 pin signal cable) in order for them to fully function. Can I just let the other connector coming from the motor disconnected?

Thanks!