Ride safe - a short story of ride gone bad

And just for clarification. I had my battery on waterproof box and electronics on other waterproof box. Those boxes were in a compartment under a hatch and after riding for an hour there was little water “on the floor”. But the battery and electronics stayed dry.

1 Like

Where did you buy your battery?

If we are looking in to a pattern here it will be interesting if we had the data to see at what % soc this happened! Below 20% soc in normal conditions discharge rate is much lower than nominal discharge rate which can cause a fast thermal runaway l. Cheap bms that doesnt have cell tyoe specific profile will not care about this.

A company in Finland made it for me from Samsung cells.

do you roughly. remember at what % of charge it happened?

I had been riding max 15min so I’d say 90%. Maytech remote was displaying still 5/5 bars on battery voltage.

I don’t use any BMS on my battery at all when discharge them. I have balance leads wired out to external conector. In charging mode I connect an external balancer which take care to not overcharge the cells.
Here’s my setup:
https://louiss13.rajce.idnes.cz/Esurf
Boston battery 42Ah, 12s 8p (16p in reality), charge limit set to 4.11V/cell. Modified 15A charger.
Limiter schematic in the link.
Works great, after ride battery stay well balanced, no problem whatsoewer, 60-90A batt. current, 120-190A motor current.

Are those boston swing 5300 batteries???

Which setup you run? Motor esc etc

Yes, they are BostonSwing 5300 batteries.

1st. board setup:
BS batt. 12s8p, AP C80100 motor 350KV passive cooled, neugart 7:1 gearbox, A200S ESC, torqeedo housing, torqeedo prop.
2nd. board setup:
BS batt12s8p, Turnigy C80100 motor 300KV switched from delta to star now 160KV direct drive water cooled, A200S ESC, custom prop.
These are all Esurfs not Efoils.

Thought i was the only one attempting to use them. How are you findibg them?

I would really love to see your build, got any video or photos?

Did you check the balance of the cells after removing the BMS?
How many cycles did you get before it burned and did you check balance in between charges?

First try with the newly purchased 24V charger…
It was supposed to stop charging at 24V acording to spec but continued to charged and overheated the battery pack to the degree that the plastic casing ignited… and the fire kicked off the battery pack.
Lesson learned… Watch out when ordering a Chines manufactured charger…