Is there a fuse on my bike?!

[John F]

I strikes me there is a lot of energy in a 36V 15amp battery. What electrical safety features are there on my Woosh Santana CDL?

There is, what seems to be, an in line connector near the battery, but no reference in the documentation

Just thinking of the Boeing Dreamliner batteries!

John F

 

[banbury frank]

Hi John Dont Panic There is something inside your battery called a BMS ( battery management system)

It controls the input and output from the battery it is using Mosfets ( High power switching transistors )

If it sensor a overload it disconnects the output from the battery in milliseconds by switching the mosfets off
then if you remove the load / fault it turns back on It is a resettable Fuse

The same thing can happens if you try soldering the shunt in the controller drawing more amps

as you open the throttle wide open the battery will cut out until you unplug the controller the it will work again till you try to give it some

hope this Helps

Frank

 

[flecc]

Many e-bike batteries do have an internal fuse, some even have two, one in the charging circuit and one on the supply side. A few have the latter accessible on the outside.

 

[trex]

The controller normally deals with reverse power connection, under voltage and over current load and some (sine wave controllers) also cut off connection to the battery on reverse power flow.
The battery's BMS should instantly cut off the power if there is over-voltage charge, over current load, battery under-voltage detected, over voltage charging and unballanced cell.
There is almost certainly a 30A blade type fuse on the 36V line.
If it's not accessible from the outside, it's because the BMS must have been damaged for the fuse to blow. The fuse is the last resort protection. If it's blown, your BMS needs replacing.

 

[John F]

If it helps - two photos showing 4 cables coming out of the black box and the in line fuse(?)

Haven't had chance to look closer as it's all tie wrapped together.

Any ideas?

John F

 

[John F]

cable photos

pics attached this time!

 

[peerjay56]

pics attached this time!View attachment 6761View attachment 6762

That looks more like a connection plug and socket than an inline fuse. Does that cable run to the motor?

 

[Deleted member 4366]

This is what happened when I tried to connect Morphix's battery to a KU123 controller with reverse polarity. I broke my own rule of never checking with a meter. His battery had the same connector as my two similar batteries, so I thought I didn't need to check. I was lucky because the Deans connector blade vapourised and gave me a nasty burn on my forefinger from the plasma ball, so it didn't cost me anything. If I had used a switch and connected first, the controller would probably have burst into flames and set fire to my house. The main capacitors always blow in these circumstances and fill the room with pungent smoke. I've never yet seen a controller with reverse polarity protection, so always check and then check again.

 

[John F]

Good question. Of the 4 cables on the pic - 2 are larger diameter than the other 2. One of the larger ones does go to the motor, but it's dificult to tell which one as they all run down inside the frame and space is very tight down near the motor. I agree it does looks like a low voltage plug/socket, however it is long enough to house a fuse I would say.

I think it's important to know the answer. If there is an unexpected complete power failure, how do I know that there isn't something somewhere that needs investigating or renewing or resetting or what?

That looks more like a connection plug and socket than an inline fuse. Does that cable run to the motor?

 

[103Alex1]

This is what happened when I tried to connect Morphix's battery to a KU123 controller with reverse polarity. I broke my own rule of never checking with a meter. His battery had the same connector as my two similar batteries, so I thought I didn't need to check. I was lucky because the Deans connector blade vapourised and gave me a nasty burn on my forefinger from the plasma ball, so it didn't cost me anything. If I had used a switch and connected first, the controller would probably have burst into flames and set fire to my house. The main capacitors always blow in these circumstances and fill the room with pungent smoke. I've never yet seen a controller with reverse polarity protection, so always check and then check again.

That doesn't look good. Seeing things like this makes me look back and realize how lucky I was to have only ripped up a motor lead and blown a charger during 4 months of learning some fundamentals. Can never check too many times it seems !

 

[flash]

This is what happened when I tried to connect Morphix's battery to a KU123 controller with reverse polarity. I broke my own rule of never checking with a meter. His battery had the same connector as my two similar batteries, so I thought I didn't need to check. I was lucky because the Deans connector blade vapourised and gave me a nasty burn on my forefinger from the plasma ball, so it didn't cost me anything. If I had used a switch and connected first, the controller would probably have burst into flames and set fire to my house. The main capacitors always blow in these circumstances and fill the room with pungent smoke. I've never yet seen a controller with reverse polarity protection, so always check and then check again.

d8veh may I suggest you lose the watch when working on electric bikes. When I was serving my apprenticeship, as an auto electrician, in the 1970s a colleague nearly lost his hand when his metal strapped watch shorted out a starter motor circuit. He was off work for 2 years and it took several skin grafts to repair the damge.

Safer to keep it in your pocket. Same goes for metal rings on fingers.

 

[Deleted member 4366]

When reaching into older car engines, your watch can touch the bare terminal of the starter solenoid, and at the same time touch any other part of the motor, whereupon it becomes instantly red hot. My friend did that on his boat a couple of weeks ago except that it was his ring that shorted. It gave him a very nasty burn.

I don't think that this type of accident is very easy on an electric bike because it's unusual to have bare terminals, and there's no massive chunks of metal connected to earth The only wires that can carry enough current are the battery wires, and I can't see a scenario where both would touch a watch or ring at the same time.

When working on ebike batteries, it's very important not to have two bare wires at the same time. Whatever one you're working on, always make sure that the other is insulated.