Reliability of Bosch Relay for coil relay mod??

[Darin Jordan]

I haven't read of too many issues, but wanted to ask... How reliable have the Bosch relays been in holding up to the relay mod, as described on BassCliff's site?? I used the recommend Bosch relay part number given in one of the tutorials there (5-pin, etc.).

I wouldn't think there would be much current flowing through the relay, so I wouldn't expect it to fail too often, but figured I'd ask....

[posplayr]

I haven't read of too many issues, but wanted to ask... How reliable have the Bosch relays been in holding up to the relay mod, as described on BassCliff's site?? I used the recommend Bosch relay part number given in one of the tutorials there (5-pin, etc.).

I wouldn't think there would be much current flowing through the relay, so I wouldn't expect it to fail too often, but figured I'd ask....

It is a reliable mechanical part; but if you shake rattle and roll it it can fail; shock/vibe isolated Mounting is required for the highest longevity

[koolaid_kid]

It is a 30 Amp relay and all the current to the attached parts flows through it. That is its entire purpose, to offload the current from your old 18 gauge wiring harness to the new wires in your relay circuit.
Your charging system only puts out ~20 Amps or so, so electrically it is not challenged. It is an electro-mechanical part; there is a set of points inside that move depending on the input, and a coil that activates the points. Ignition coils use ~8 Amps, aftermarket horns ~4 Amps, grip heaters ~3 Amps.
Like most parts these days it will fail almost immediately or last quite a while, depending on how many times you beat on it with a hammer.
You car, for example, has relays for the fuel pump, the rear window defogger, etc. When is the last time you replaced one of them?
Your starter solenoid is another example of a relay. How is it mounted to your bike?

[Darin Jordan]

Your starter solenoid is another example of a relay. How is it mounted to your bike?

I've taken several apart and they are pretty solid.

Mine is mounted as shown in the tutorial I used (see picture).

When I get a little extra time, I'm thinking of extending the wiring down the harness, like BassCliff did, and mount it up with the rest of the electronics to get it away from the motor.

Where it currently is, the mounting tab is pretty flexible, and I think will absorb some of the shock, as the relay can slightly move up and down by this tab flexing. It's a high-temp plastic material. I'm thinking it should be just fine for awhile.

[posplayr]

I think there are better places to mount the relay than where yours is. Heat is a partial concern, virbration is the biggest. Access a secondary concern.

This is how I mounted mine, off a flexible piece of plastic mounted to the battery box . I used one of the igniter bolts. This gives the relay two levels of isolation; the rubber mount of the battery box and the flexible plastic mounting extension.

http://www.thegsresources.com/_forum/showthread.php?t=141055&highlight=relay

P.S the picture is actuall part of a Dyna S concersion where teh ignitor is replaced with the relay mount. I now am using a stock ignitor so I made a little 4" plastic extension to isolate the relay to. A peice of old rear inner fender well works.

[Nessism]

I agree with soft mounting the relay in some way. Also, get a name brand relay and you should be good for many years.

[gtsg01]

Soft mounting is OK, but may not be necessary. According to the data sheet, these relays are able to withstand vibration of 10-100hz @ 5G. (I guess the High Frequency buzz of our bikes might cause an issue)

Also, to answer the OP, the relay is rated for 250,000 cycles at rated load. (2.5X10 to the 5th)

So, if you turn your bike on and off 10 times a day, every day, the relay should last over 68 years

http://www.datasheetdir.com/V23234-A1001-X036+download

[tkent02]

Bosch relays are good, I still have a bag of them from when I parted out a few Opels in the 80s. Been using them on projects like these ever since, none have ever failed.

[koolaid_kid]

We tend to over-engineer our mods. As an engineer, I can say that. I remember my 60s bikes where everything was solidly mounted. And they ran just fine.
So I suggest that we temper our mods with a bit of practicality; these are old bikes that will most likely never gain value, so be good but frugal in our mods.
I admit - I have purchased and used ~15 (cheap) relays. 1 immediate failure, 9 success, the rest untested. They are manufactured to a standard which posplyr has published a link to.

[Darin Jordan]

So, if you turn your bike on and off 10 times a day, every day, the relay should last over 68 years....

NICE! I might be over thinking this just a tad then!

[posplayr]

Soft mounting is OK, but may not be necessary. According to the data sheet, these relays are able to withstand vibration of 10-100hz @ 5G. (I guess the High Frequency buzz of our bikes might cause an issue)

Also, to answer the OP, the relay is rated for 250,000 cycles at rated load. (2.5X10 to the 5th)

So, if you turn your bike on and off 10 times a day, every day, the relay should last over 68 years

http://www.datasheetdir.com/V23234-A1001-X036+download

While it is a different mechanism, I solidly mounted a VDO bourdon tube oil pressure gauge to my engine and it destroyed the pivots within a very few thousand miles.

If you notice all GS electronics are mounted on rubber isolated mounts (side plate and battery box) most likely a countermeasure to vibration. The relay is probably much more susceptible than a potted solid state device.

[Darin Jordan]

Due to the housing that the Bosch relay is in, if you mount it hanging off the tab with a single screw, as I have, it "should" absorb some of the vibration and shock, simply due to the flexing of the plastic mounting tab.

I still will go ahead and over-engineer this system and move the relay back to the "electronics" area under the seat... Will have to wait until I get back from my little trip this next week.

[posplayr]

Due to the housing that the Bosch relay is in, if you mount it hanging off the tab with a single screw, as I have, it "should" absorb some of the vibration and shock, simply due to the flexing of the plastic mounting tab.

I still will go ahead and over-engineer this system and move the relay back to the "electronics" area under the seat... Will have to wait until I get back from my little trip this next week.

That is why they put a tab on the device.

You might consider just leaving you relay where it is and "run it to failure"; let us know how many miles it lasted.

Or mount it so it is unlikely to fail and forget about it.

[Darin Jordan]

That is why they put a tab on the device.

You might consider just leaving you relay where it is and "run it to failure"; let us know how many miles it lasted.

Or mount it so it is unlikely to fail and forget about it.

I'll likely leave it where it is for now, and see how things go

I don't consider taking the tank off, even on the road, that big of a hassle, so it's not like it's hard to get to, even in a pinch. I'll get a spare, or some jumper wires, and see how it does.

Thanks guys! Love these conversations we have...

[posplayr]

I'll likely leave it where it is for now, and see how things go

I don't consider taking the tank off, even on the road, that big of a hassle, so it's not like it's hard to get to, even in a pinch. I'll get a spare, or some jumper wires, and see how it does.

Thanks guys! Love these conversations we have...

Most time it is not an issue, but I just went across the Golden Gate on my way home from the Western states GSR rally. On approach to the bridge; there was a spot that had 4 lanes and zero shoulder between barriers.

Two years ago I had a fuse blew in the same area; I was very fortunate that there was a turn off right on the freeway. Mine is under the seat and it was a hassle to get all the camping gear off so the seat could come up.

There have been previous discussions and designs for parallel relays for redundancy. I'm content to have a nice mounting location for my relay rather than go overboard.