LLT SmartBMS killed my battery.

How-Tos & Esk8 mechanics Esk8 Mechanics
,
#62

To reiterate, do not, this is a fire waiting to happen if attempted revival.

3 Likes
#63

=== :fire::fire::fire::fire::fire::fire::fire:

4 Likes
#64

Ok think ill build a new pack then with the new molicell 45b
And a switch to turn off the bms :sweat_smile::sweat_smile:

#65

The drain comes from the ble module, @xsynatic did a hack to stop it from fully draining the pack

3 Likes
#66

Really could bite my ass up for tht. I didnt realize tht the battery is tht low because a friend of mine stored his board with the same bms at my place and i always dot his info on my phone and thought the battery is in fine condition​:roll_eyes::roll_eyes:

1 Like
#67

What was the hack?

#68

Wouldn’t call it a hack :grin:

BLE physically disconnected for 1 month:

IMG_20230715_123810_116
IMG_20230715_123810_1161080×554 28.3 KB

IMG_20230715_123826_104
IMG_20230715_123826_1041080×640 32.1 KB

BLE plugged in for 2 weeks:

IMG_20230715_123832_302
IMG_20230715_123832_3021080×543 26 KB

50% more sucked juice in 50% less time.

12s6p P42A

4 Likes
#69

Thanks for doing that experiment.

#70

So, simple, take care of your boards and you’ll be fine :grin:

#71

Also tossing my hat in the ring for this, my 12s4p P42A is toast

A Bluetooth module that is looking for a connection will take about 1W of power, so if it gets stuck in pairing mode it will drain a pack in a couple months (~750Wh/month)

Might pull the 5v line for the Bluetooth off the ESC next time so when the ESC is off the Bluetooth is off too

2 Likes
#72

That’s how i do it - Cut a flap into the heat shrink and pull the connector

PXL_20230715_163316212
PXL_20230715_1633162121920×2560 206 KB

3 Likes
#73

Do you know if it’s sufficient to just pull the positive lead? Might get an inline switch

1 Like
#74

I considered it but haven’t tried it.

#75

I’ll do science on the Evo then

#76

Another LTT victim here.

#77

Interesting, I had my LLT bms plugged into my battery for like 6 months and didnt see noticeable drain. Could it be because of the variants of Bluetooth modules that ship with them?

#78

Just gonna link this thread whenever people ask why I don’t use smart BMS in my production builds

5 Likes
#79

It’s not about smart BMS bad, it’s about CHEAP smart BMS bad.

Ennoid doesn’t seem to have those problems…
Voltage sense to turn it on only when your board is on or when a charger is present - so genius nobody else can do it? :grin:

1 Like
#80

ennoid does not have bluetooth module tho which seems to be the main problematic part

1 Like
#81

Exactly, that’s why it doesn’t drain your pack.
It uses the bluetooth you already have on your VESC and interfaces with an app you already have on your phone.

2 Likes