Ebike Circuit Protection, Fuses and Circuit Breakers

[fechter]

What about 10x38 1000V DC rated solar fuses? Largest ive seen are 25A but ~1$/piece.
Never seen anyone added servo control for circuit breaker? Why? because high current latching contactor/relay is damn expensive.
Im gonna do it.

I've thought about that too, as those solar breakers are really nice but I'd like to use it like a relay. Cheap car door lock solenoid might do it. Even a mechanical setup using some old brake cable and a spring might work for me.

 

[DVDRW]

Servo + arduino.
Waiting my 4$ 63A 125V DC breaker arrival.

 

[teklektik]

Too complicated.
Keep the microprocessors and fussy little linkages away from critical main power switching - particularly for kill switches.

• Use the breaker mounted near the controller to power up before mounting the bike (so - short high current wires, easy to mount big breaker away from bars). Also use the controller 'ignition' wire for keyswitch and kill switch. Together this gives protection, main ON/OFF, low power keyswitch, and low-power kill switch - with light gauge wires to the bars and short wire runs for the high power stuff.
  
  
• If you want a contactor for absolute emergency power kill, then use this guy in combination with the breaker in lieu of the controller 'ignition' wires - still low power for keyswitch/kill switch. This contactor is available in a variety of coil voltages and isn't too huge. Simple, reliable, built like a brick ....
  
  Albright Solenoid Contactor Relay 60V 150A SU80AF-5067M

 

[fechter]

Midnight Solar and other suppliers have some breakers with a remote trip feature. This can be triggered by low current wires (can to to handlebars or tie into kill switch). I haven't seen the details on these work, but having a manual on but remote off would be OK with me.

 

[Alan B]

Remote trip breakers have an extra coil that magnetically trips the breaker. These generally operate on 24V. It is a good way to trip a breaker.

Switching with a breaker may reduce its service life, some are rated for this and others are not. Even those that are rated for this may suffer rapid contact wear or damage from the large inrush currents from controller capacitors.

 

[BeachRider2016]

Im curious why cant the regular household circuit breaker be used in Ebike application?
Theyre a dime a dozen and everywhere.

 

[amberwolf]

cuz theyr for ac not dc and cant extinguish the arc if it forms sso they may not be able to break the circuit.

 

[DVDRW]

Im curious why cant the regular household circuit breaker be used in Ebike application?
Theyre a dime a dozen and everywhere.

Instead of breaking they may go up flames with DC.

Polarized DC circuit breaker cannot be used with regen?

 

[cal3thousand]

With respect to fuses that will handle our pack voltages and currents, make sure you get the ANN fuses, which are fast-acting. It's not just the rating, but the speed at which it breaks the circuit.

 

[BeachRider2016]

cuz theyr for ac not dc and cant extinguish the arc if it forms sso they may not be able to break the circuit.

Instead of breaking they may go up flames with DC.

Polarized DC circuit breaker cannot be used with regen?

I've been using them in my bat pack as an on/off switch. I guess its unsafe. Time to get a solar breaker !
Thanks

What you guys think of this one:
http://www.ebay.com/itm/Antiflame-DC-1P-25A-250V-Solar-energy-Air-breaker-DC-MCB-Electrical-swich-/142143905274?hash=item21186fddfa:g:c7cAAOSwzaJX-y18

250vx25A=6260W safe ?

 

[DrkAngel]

DC Fuse Sources ... 32VDC - 58VDC - 80VDC


DC Fuse Sources ... 32VDC - 58VDC - 80VDC + 125VDC +250VDC +500VDC

 

[mkp007]

'
Confused: Cell, sub-group, sub-pack or full pack level protection?

It seems most comments in this thread are related to full pack level protection with breakers. Whereas, you look at the Tesla car batteries they have cell level wire fuses. I have created a design that protects sub-groups of four cells with a blade style fuse. My sub-pack has 9 rows of these making a 1Sx36P. These sub-packs are then connected in series up to 22Sx36P.

discussion of the pack design can be found here:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=84412&start=50#p1238235

So I have been scratching my head a bit trying to figure out exactly what scenarios I'm protecting my pack with using a fuse in this way. Under what conditions will that fuse burn out?

Well, I guess if there was a short in the motor/controller/wiring, it would burn out all the fuses (9*22=198). That's not smart. So maybe a breaker should be added just below the level that burns out all the sub-group fuses. So what does the sub-group fuses do other than add resistance. If a cell was shorting internally it would just get hot and catch fire. If one of the cells start to go bad, does it start to output a ton of current? That is the only thing I can think of that I'm protecting the rest of the pack against. If this is true, how much current does it put out? If it's like 20A while the rest of the cells are 5A, then that is still under the 50A fuse protection (20+5+5+5 =35A). I'm sure there is a good reason for it or else Tesla wouldn't have gone through the trouble and the extra resistance hit.

feedback is appreciated.

 

[Alan B]

Fuses must be voltage rated for the full system voltage, and designed to break the arc that forms when they pop. Otherwise the arc continues and melts the fuse and anything in the vicinity which could lead to further shorts, etc.

The purpose of a fuse or breaker is to open the circuit in case of overcurrent whether that is due to a short or other mechanism. The fuse should protect the wiring loom and the batteries.

 

[mkp007]

Fuses must be voltage rated for the full system voltage, and designed to break the arc that forms when they pop. Otherwise the arc continues and melts the fuse and anything in the vicinity which could lead to further shorts, etc.

The purpose of a fuse or breaker is to open the circuit in case of overcurrent whether that is due to a short or other mechanism. The fuse should protect the wiring loom and the batteries.

The four cells are in parallel. So 4.2V max. That blade fuse would be fine. Just like the cell level wire fuse. Please review again.

 

[Alan B]

If these cells are in series with others, when it opens it will see the whole pack voltage. We need to see a system diagram to interpret this correctly, you have not presented enough information, so assumptions are made. I see you imply there are more groups in parallel with this, which would contain the voltage.

In general fuses have not worked out well in ebike battery packs. They usually melt the environment near the fuse and often fail to open in time.

Having a bunch of fuses in the battery adds a lot of complexity and resistance and heat.

What exactly are you protecting against here?

 

[Alan B]

Placing a fuse on each cell has some merit, it will disconnect a shorted cell (which is not a very common occurrence). But on a group of four a shorted cell will still be connected to the other three, which are quite capable of igniting the conflagration you are trying to prevent.

I wouldn't do it. I don't see the point.

But it is your battery.

 

[mkp007]

If these cells are in series with others, when it opens it will see the whole pack voltage. We need to see a system diagram to interpret this correctly, you have not presented enough information, so assumptions are made...

More about the pack design is here https://endless-sphere.com/forums/viewtopic.php?f=14&t=84412&start=25#p1237927

Placing a fuse on each cell has some merit, it will disconnect a shorted cell (which is not a very common occurrence). But on a group of four a shorted cell will still be connected to the other three, which are quite capable of igniting the conflagration you are trying to prevent. I wouldn't do it. I don't see the point. But it is your battery.

Maybe I don't see the point either. That's why I posted the question. Can anyone think of any other reasons to have cell level fuses? My initial thought was to prevent shutting down the whole pack if there is a localized problem. But is there a localized problem worth considering from a probability standpoint.

 

[amberwolf]

If you fuse a pack such that some parallel sections cut out of it, and allow you to continue to operate it (without any way to know this has even happened), you must also design the pack so that a single remaining parallel section can support the full current draw the system will put upon the pack (the cells, their interconnects, and the fuses must each be capable of handling it without being outside their nominal operation specs).

If you do not, then if something causes the system to be reduced to a single section at some point in the pack, then that section will be damaged, or overheated, or the fuses will pop, etc., with the various other failures that may go along with those. (including being stuck without any power).

 

[mkp007]

If you fuse a pack such that some parallel sections cut out of it, and allow you to continue to operate it (without any way to know this has even happened), you must also design the pack so that a single remaining parallel section can support the full current draw the system will put upon the pack (the cells, their interconnects, and the fuses must each be capable of handling it without being outside their nominal operation specs).

If you do not, then if something causes the system to be reduced to a single section at some point in the pack, then that section will be damaged, or overheated, or the fuses will pop, etc., with the various other failures that may go along with those. (including being stuck without any power).

If a few sub-groups go out it will not overload the remaining cells as there is 25% overhead (not sure if that is the correct usage of the term). Each sub-pack will be monitored during use and when charging.

Here is a quick summary of the pack design: Each sub-pack has 9 rows of 4 cells joined in parallel (see the drawing in my previous post). Each row joins to a cable in parallel. The sub-pack is thus 1Sx36P. Sub-packs are then wired in series to achieve 22Sx36P. The primary reason for me to do it this way is the space I'm trying to fit into is triangular. Secondary reasons include 1) 4x9 cell holder is readily available, 2) I don't want a big battery that is mechanically joined together 3) 36 cells in parallel per sub-pack is easy to make 4) current balancing of cells is easy.

 

[dfarning]

I've got nothing of value to add to this thread....Except my heartfelt thanks to everyone for sharing their knowledge and experience.

I was hoping to sit down this morning and fit up my wiring harness. For bench testing I have just been soldering 30amp auto fuses inline with the main battery cable. I was just looking into a more permanent circuit protecting system when I came across this thread

 

[Kirill]

Hi.
Which circuit breaker should I use for the Kelly KBS48051X?
Is a 220 volt household circuit breaker suitable?
How to calculate the amperage of a circuit breaker?
Battery 48 Volt 20 Ah
Bafang 500 Watt

 

[amberwolf]

Is a 220 volt household circuit breaker suitable?

You should read the thread for the answer to that.

 

[Kirill]

Is a 220 volt household circuit breaker suitable?

You should read the thread for the answer to that.

Step by step!))

I found this. Siemens 5SL4163-7

Main circuit
Operating voltage
● minimum 24 V
● at DC / rated value / maximum 60 V


https://www.distrelec.de/Web/Downloads/_t/ds/5SL41637_eng_tds.pdf?pid=30137423