Post by: daveson on May 12, 2019, 07:10:36 AM
Because these bricks will be pushing forty years old before we know it, and these wiring looms aren't as pliable as when new, its worth considering the protection of a circuit breaker. I chose the manual disconnect type, so it doubles as an immobilizer, but I will state straight up that the market for stolen bricks wouldn't be much greater than the market for stolen mortar. It could also be used like a battery isolator, in a limited sense.
Step 1. I bolted the circuit breaker to the top of the coil cover.
Step 2. Removed the fuel injection relay positive from the positive of the battery (the thinnest of the three red wires to the battery positive) and connected it to the breaker aux. terminal. I cheated by cutting one inch of the loom sheath from the end opposite the battery, to free it from the alternator loom sheath. A bit of WD40 also helped in sliding it out.
Step 3. Snipped the red ignition switch (combined) wire to the starter relay at the relay positive terminal (the thinner of the two) and crimped a connector on to connect it to the breaker aux. terminal.
Step 4. Ran a new wire from the battery positive to the breaker battery terminal.
If I did it again, I would reinstall the accessory socket a little further back, making it easier to press the switch.
Post by: daveson on May 12, 2019, 07:18:35 AM
Post by: natalena on May 12, 2019, 08:03:27 AM
Post by: daveson on May 12, 2019, 08:16:25 AM
I used a 40 Amp, it was cheap and close by. I thought it would show in the photo, unfortunately the focus is bad, but it was the best of about ten photos I took.
Post by: Chaos on May 12, 2019, 09:08:48 AM
Post by: daveson on May 12, 2019, 09:21:33 AM
I was never worried about the starter relay problem until I got my K75 which suffered from it. From then on I kept my steel fixers insulated snips in the glove box, which makes me even more worried.
Post by: trek97 on May 12, 2019, 02:15:52 PM
Would you please post a link to the breaker you bought?
Mine did this twice.
I disassembled and cleaned the start button and hasn't happened since. But, I still think about it EVERY time.
Post by: daveson on May 12, 2019, 04:37:01 PM
I don't even remember which supplier I clicked on, there were so many options. Try eBay, type in 40 Amp circuit breaker, choose the automotive option, and you should get many options nearby.
I usually prefer a shop. Although I'm happy with this circuit breaker, it doesn't even have a brand name. I would happily pay a bit extra for at least a name, this one was $23. I'm not much worried though, if it fails I'll simply bolt the wires together. On the top is written waterproof, on the bottom is 40 Amps, and ignition protected.
Post by: rbm on May 12, 2019, 05:08:42 PM
Post by: Martin on May 12, 2019, 05:29:38 PM
Regards Martin.
Post by: The Mighty Gryphon on May 12, 2019, 07:15:47 PM
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https://www.ebay.com/itm/1-Pair-Amass-AS150-7MM-150-AMPS-Anti-Spark-Connector-Plug-For-HV-Bettery-ESC/302268569659?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3D378bc444206641b18e1b6c828bcaf9b8%26pid%3D100005%26rk%3D4%26rkt%3D24%26sd%3D222090307045%26itm%3D302268569659&_trksid=p2047675.c100005.m1851
Post by: daveson on May 13, 2019, 01:32:28 AM
I like the idea of a circuit breaking when overloaded (as opposed to auto resetting or adapting) as it warns me of a fault and to look for its cause.
From memory the add says trips at 47 Amps, hopefully not too high.
The only test was to start it without it tripping out, before I called it a day.
Hopefully on the weekend I will take it for a longer ride, and to short a 0.5 and 0.75 wire in the hope that the circuit breaks within one second. On second thoughts, I should have done these four tests before I posted this thread, and included the results.
Post by: natalena on May 14, 2019, 11:20:47 AM
Is there a reason not to have a more direct pathway for the breaker set-up?
Battery positive terminal to 40A breaker to 3 Red wires that are usually attached to the battery positive terminal?
Post by: daveson on May 14, 2019, 05:12:39 PM
All questions welcome, l love talking about bikes, it's a new, reborn passion of mine.
It's a big job to crank the engine, I guess it would break 40 Amps in a flash. If you go really high Amps to cope with the starter, it probably wouldn't trip if a small wire shorted. It would be nice though, if you could have it both ways.
I can't find the add where I got it from, from memory it said trips in a few milliseconds from a short. I'm going to do some tests and make a post, but so far I'm happy with it. But I can already say now I wouldn't recommend this brand as it hasn't even got a brand name. I tried a Jaycar shop but the smallest one they had was 70 Amps.
Post by: natalena on May 14, 2019, 06:30:42 PM
Post by: daveson on May 14, 2019, 07:52:50 PM
Another thing I would do differently, as well as in post one, I would cut the starter switch positive to the starter relay an inch or two from the relay, instead of up against it, since the wire was still too short anyway to reach the circuit breaker. I had to add a piece.
Post by: daveson on May 18, 2019, 07:15:01 AM
Tried to trip the circuit breaker with a 0.75mm wire, it didn't trip. Held for at least one second, possibly three, wire was sizzling and melting, chickened out and let go. Tried a 3.5mm wire, tripped seemingly instantly. Surprised me first but spose it makes sense now.
Load test: high beam on, hazard on, brake on, fan off, horn off (forgot it); 25 Amps.
Stall test: clutch switch disabled, 5th gear, rear brake on, start button pressed; 100 Amps.
I'm scratching my head with this a bit. Maybe 35 Amps would be better.
Thoughts anyone?
Post by: daveson on May 18, 2019, 07:33:53 AM
...There are difference trip characteristics for circuit breakers and you'd have to be certain that the characteristic you chose will trip at the right current and in sufficient time to protect what it is you are trying to protect. ...
Hi Robert, in the hope you revisit this thread, I'm not certain, 40 Amps was a guess. What do you make of all this? I would be grateful for your opinion whichever way it falls.
My aim is to prevent damage caused by a short in an unprotected wire.
Regards, David.
Post by: rbm on May 19, 2019, 08:00:46 AM
The other aspect to consider is the trip curve characteristics of the breaker (https://www.c3controls.com/wp-content/uploads/2018/05/c3controls-Understanding-Trip-Curves.pdf). A magnetic circuit breaker will trip differently than an AGM automotive fuse.
All breakers are designed to accommodate short periods of overload so they won't trip immediately. You don't want too large a breaker so that it doesn't trip at all but you don't want it too small so that you get nuisance trips. And you don't want to select a breaker with the wrong trip curve so that the wire insulation starts to melt before the breaker trips.
I would be guessing but maybe chose a B-curve DC breaker of 12A - 15A.
Post by: daveson on May 19, 2019, 08:22:14 AM
Post by: natalena on May 19, 2019, 09:04:20 AM
Post by: The Mighty Gryphon on May 19, 2019, 12:40:46 PM
That is the reason why the best protection is a mechanical disconnect that the operator can easily reach. A high current connector in the ground wire is, in my thinking, the most reliable and cheap solution for the problem. No matter what the situation, if I need to Kill the electrical system I can do it in just a couple of seconds.
Post by: rbm on May 19, 2019, 01:01:28 PM
... No matter what the situation, if I need to Kill the electrical system I can do it in just a couple of seconds.There are situations where you only become aware of an electrical problem when you see smoke and smell burning. By then, damage is done. This suggested modification is to try and trip the breaker before that damage is done.
In the case of the stuck starter relay contacts, the components that could be damaged are the battery, the thick cable between the battery and starter motor, the ground cable or the starter itself. This suggested modification is not trying to address that failure; your idea of a master disconnect on the ground return is highly recommended.
Post by: The Mighty Gryphon on May 19, 2019, 01:48:35 PM
There are situations where you only become aware of an electrical problem when you see smoke and smell burning. By then, damage is done. This suggested modification is to try and trip the breaker before that damage is done.
I doubt you can accomplish that. If you are trying to protect the primary power wiring, you need to accommodate the full simultaneous current draw of the entire electrical system. Unfortunately, the current necessary to burn up one of the wires in that primary circuit(the fuses protect everything but the headlight) is much lower than what you will have to have as the trip point for a main disconnect, otherwise you will have the disconnect shutting down the power at very inopportune moments.
Post by: beemuker on May 19, 2019, 03:39:55 PM
I'm using one of these connectors in the negative battery cable. Makes it possible to break the line quickly, disconnecting the battery from the electrical system. For #8 AWG wire, gold plated, rated for 90 Amps surge /60 Amps continuous.thanks,I just ordered one, seems like a simple emergency disconnect
Post by: rbm on May 19, 2019, 03:55:22 PM
There are a number of constant voltage unfused circuits in the motorcycle:
- FI relay feed
- injectors
- temp sensor
- LSR
- Ignition sw
If ever there was a fault that caused a short circuit current draw from the battery on any part of the wiring upstream of the fuse box, then that wiring would burn up. Daveson has chosen to install a protective device in a subset of of the above listed circuits to protect the wiring.
He stated his objective was to add such a device because the ageing insulation in the bike could increase the risk of such a short happening.
You're right, this device needs to bear the typical current that would flow through this part of the circuit without tripping. And it has to trip when current through it exceeds that which can be carried by the wiring before the wire heats up and burns the insulation. The BMW engineers would have designed the system to only draw sufficient current to not exceed the safe operating envelope of the upstream wiring. For example, once the engineers knew all the system current requirements under typical operating conditions, then they would select a wire size that could safely handle that current after being suitably derated. Therefore selecting a protective device like a circuit breaker that is rated for the maximum current bearing capability of the diameter of wire means that it can also safely handle the typical system load under normal conditions without tripping. It's only when a fault occurs in the wiring upstream of fuse box that causes a short circuit that the breaker trips.
Post by: daveson on May 26, 2019, 04:42:40 AM
I did some more tests and replaced the circuit breaker with one of 10 Amps.
First I repeated the short test on the first circuit breaker, but this time measured the current as well. It was about 100 Amps, again it didn't trip, so I think it's crap, because it was supposed to trip at about 47 Amps.
Next I tested three ETA circuit breakers, 10 Amps, 15 Amps and 20 Amps. They all tripped with the trip test. Then I did the load test with the 10 Amp, it didn't trip, and didn't get warm, so I assumed the others wouldn't. This time I remembered to include the horn. It's also good to think that all components will never be powered at the same time while riding anyway.
I haven't done the test ride as the weather is lousy, but I'm confident it's less than the load test.
Since it passed the load test and short test (test ride to come) I think I can now consider this as job done.
If there are any unwanted trips, it will be replaced with a 15 Amp.
Was I right in assuming this method covers all the unprotected wires except those to the starter relay and alternator/battery?
Post by: daveson on May 26, 2019, 06:35:48 AM
Post by: daveson on May 29, 2019, 04:30:55 AM
I spose I'll leave it at that.
Thanks everyone, not just for the steep learning curve, but I just found this one really interesting. And thanks again Rob for fixing this modification.
I'm bloody rapt.
Post by: daveson on June 08, 2019, 05:48:23 AM
After about ten rides of one hour, and say another ten at fifteen minutes, the last two rides of fifteen minutes resulted in a total of two unwanted trips. The low beam headlight was on for all rides, but while the indicators and brake lights were also on, the circuit breaker tripped.
So from today on I will be riding with the 15 Amp relay, and see how it goes.
Post by: Laitch on June 08, 2019, 06:26:05 AM
. . . while the indicators and brake lights were also on, the circuit breaker tripped.During the next testing phase, also beep the horn. Just don't inadvertently launch anybody into road rage. :giggles
Post by: daveson on June 08, 2019, 07:47:19 AM
All three passed the load test, with all lights on for one minute, but I only pressed the horn for about one second, didn't want to draw attention. I guess it failed the test ride because the engine was at operating temperature. The first of the two trips was after three sweeping left hand turns, so lights on longer than usual, plus I spose 10 amps is just too low.
Hopefully the 15 Amp will last a year with no trips, if not, I'll go 20.
Post by: daveson on June 17, 2019, 05:37:48 AM
At normal operating temperature, on a long straight empty road I had the horn and all lights on for one minute, that is hazards, brake, low beam plus horn and high beam flasher buttons pressed at the same time. It's hard to appreciate how long one minute is until you ride with all lights and horn on for one full minute. It's a really, really loooonng OCD amount of time.
Plus I'm going to push a proper battery isolator further up the "To Do" queue, as so many here have already done.
Post by: Laitch on June 17, 2019, 08:53:28 AM
It's hard to appreciate how long one minute is until you ride with all lights and horn on for one full minute.It's easier to appreciate if you've stood in front of a stranger who was pointing a loaded firearm at you.
Post by: daveson on June 17, 2019, 09:29:11 AM
Post by: daveson on June 18, 2020, 05:33:12 AM
One year and 3,000+km later, I think I can call this job done. There have been no unwanted trips, and as originally tested with a deliberate dead short it tripped with no noticeable damage.
It still seems odd to me that with the load test showing 25 Amps, that a 15 Amp circuit breaker doesn't trip, but I accept the reasons given and this example also shows that 15 Amps is good.
Post by: alabrew on June 18, 2020, 04:26:19 PM
Maybe put a flip switch in the line...would also work to disconnect the battery during non-riding periods...
Post by: Arktasian on June 18, 2020, 06:16:53 PM
Not that I recommend doing this, I can advise where/ how to source that breaker. Pollak type thermal breakers, different amp ratings and the above link for the manually resettable version
Post by: daveson on June 19, 2020, 03:08:49 AM
I hate to admit it but a kill switch is still on my "To Do" list. Dunno what the sold out comment refers to.
Post by: alabrew on June 19, 2020, 12:29:15 PM
Anyone seen johnny lately?
Post by: Laitch on June 19, 2020, 01:00:11 PM
Sorry, the anti-spark connector TMG linked from eBay is sold out.Not exactly. When you copy the product title and paste it right back into the eBay search window, you get this (https://www.ebay.com/itm/5-Pairs-AMASS-AX150-AS150-7MM-150-AMPS-Anti-Spark-Connector-Plug-Lipo-ESC/274100393549?hash=item3fd1a8164d:g:myUAAOSwTO9d0QTz).
Post by: volador on June 19, 2020, 04:55:47 PM
Anyone seen johnny lately?
yeah, he fell in the fecking lake while bird watching in the chee
Post by: daveson on July 04, 2020, 05:54:21 AM
The circuit breaker can be seen on top. Is this the only time you could get away with using a white cable tie, since the circuit breaker is white? I know the coil cover is black, so I'm wide open for attack on that front.
Post by: Laitch on July 04, 2020, 07:50:13 AM
I know the coil cover is black, so I'm wide open for attack on that front.It isn't black; it's shale or maybe graphite.
Post by: milq on July 09, 2020, 10:55:31 PM
I'm using one of these connectors in the negative battery cable. Makes it possible to break the line quickly, disconnecting the battery from the electrical system. For #8 AWG wire, gold plated, rated for 90 Amps surge /60 Amps continuous.Connectors.jpg (16.75 kB . 576x576 - viewed 1852 times)
https://www.ebay.com/itm/1-Pair-Amass-AS150-7MM-150-AMPS-Anti-Spark-Connector-Plug-For-HV-Bettery-ESC/302268569659?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3D378bc444206641b18e1b6c828bcaf9b8%26pid%3D100005%26rk%3D4%26rkt%3D24%26sd%3D222090307045%26itm%3D302268569659&_trksid=p2047675.c100005.m1851
Do those clamp down on the cable as you tighten the shroud? Or do you solder them to the cable?
Post by: The Mighty Gryphon on July 10, 2020, 09:36:56 AM
Post by: BrickDad on July 11, 2020, 12:32:22 AM
Finally fitted a battery kill switch. The green circular knob at the bottom, it can be unscrewed and removed for anti theft, or just screwed out to disconnect (I moved the cigarette lighter for the photo)
I use these, well-made and at a very low cost:
https://www.tills.de/motorcycle-battery-disconnect-adaptor.html
Post by: daveson on May 20, 2023, 09:55:38 PM