Roof Relays

H

helmik

Member
Mornin all,
I’ve just changed the roof relays as my car is now 5 years old which seems to be when roof problems can start.
My question, I see the part. Umber on here to order from LLL Parts, wry slow delivery but that’s another story. They arrived today and it’s a simple job to swap them over. But, the old ones say 52amp, the new ones say 71 amp. Was there an update for them and is this a problem do you think with the higher amperage?? Roof works fine with the new ones but just wondered.
Ta
Mick
 
A higher rating relay can only be beneficial..enjoy..useful to note on LLL Parts..Autodoc seems to be a 7 day net turnaround..
 
Pbondar said:
A higher rating relay can only be beneficial..enjoy..useful to note on LLL Parts..Autodoc seems to be a 7 day net turnaround..
Click to expand...

Thanks, put my mind at rest, appreciated.
LLL Parts, ordered 24th July, arrived today, 7th August, after being told a few lies by their customer service people. Not impressed at all. Just my experience with them.
Mick
 
helmik said:
Pbondar said:
A higher rating relay can only be beneficial..enjoy..useful to note on LLL Parts..Autodoc seems to be a 7 day net turnaround..
Click to expand...

Thanks, put my mind at rest, appreciated.
LLL Parts, ordered 24th July, arrived today, 7th August, after being told a few lies by their customer service people. Not impressed at all. Just my experience with them.
Mick
Click to expand...

Pondered using them a few times..useful to know..think I’ll stick with Autodoc, Hubauer and Schmeiden…

Plus eBay sellers like BMW UK / main dealers if I’m in a rush..

Pays to compare prices..not always consistent..
 
Hey guys,
You are very joky as always.
The xxA info on these relays has absolutely nothing to do with any amperage! It's a prod/supplier info only.

Cheers
Rob
 
RobbiZ4 said:
Hey guys,
You are very joky as always.
The xxA info on these relays has absolutely nothing to do with any amperage! It's a prod/supplier info only.
Click to expand...
:rofl: :rofl:
Robbie; please don't ever leave. :thumbsup:

Did it not occur to anyone that a 71 amp relay (odd number anyway never seen one so specific) is rated higher than the highest fuse capacity of the car? It would have at least 16mm2 cables into it :)
 
Pondrew said:
RobbiZ4 said:
Hey guys,
You are very joky as always.
The xxA info on these relays has absolutely nothing to do with any amperage! It's a prod/supplier info only.
Click to expand...
:rofl: :rofl:
Robbie; please don't ever leave. :thumbsup:

Did it not occur to anyone that a 71 amp relay (odd number anyway never seen one so specific) is rated higher than the highest fuse capacity of the car? It would have at least 16mm2 cables into it :)
Click to expand...
To be fair, I'm pretty sure Robbi has mentioned this in previous discussions too.
 
enuff_zed said:
To be fair, I'm pretty sure Robbi has mentioned this in previous discussions too.
Click to expand...
Maybe a "search for whatever RobbiZ4 says" should be a sticky when it comes to anything roof related, or electrical related; because he knows his sh*t (unlike some others) which can be dangerous IMO :thumbsup:
 
Whilst it’s good that Robbie has clarified the issue (as usual) it’s churlish to suggest the OP was asking something illogical or obviously not valid.

Switching inductive loads, which is what these relays are doing in starting the electrical pump motor, are always more taxing compared to switching a simple resistive load.

Therefore the initial surge current may well exceed the recommended constant current capacity of either fuses or cables.

In fact often fuses used in inductive circuits are designed to cope with initial surges..so called slow blow fuses.

It could be argued that BMW should have a higher rated relay set fitted originally…I assume there wasn’t such an off the shelf option..
 
Tyco (TE) do a 60 amp relay, on Farnell site about £18, but need to check the pinouts.
There are type A or B in this style relay.
https://uk.farnell.com/te-connectivity/v23134a0052x278/automotive-relay-spdt-60a-12v/dp/2885529?gclid=CjwKCAjw3riIBhAwEiwAzD3TieojpQXM5GhUrjIsVZUmrPxxphxCMOFhIxvn5lcFKvnAuQVMDfz9HRoCLLUQAvD_BwE&mckv=scOTZdFLW_dc|pcrid|459864482144|plid||kword||match||slid||product|2885529|pgrid|114464709744|ptaid|pla-305901136920|&CMP=KNC-GUK-GEN-SHOPPING-SMEC-WHOOPS-Test725-minROAS-Step1&gross_price=true
Anyone have picture of bottom of relay so we can see numbers?
 
Pbondar said:
Whilst it’s good that Robbie has clarified the issue (as usual) it’s churlish to suggest the OP was asking something illogical or obviously not valid.

Switching inductive loads, which is what these relays are doing in starting the electrical pump motor, are always more taxing compared to switching a simple resistive load.

Therefore the initial surge current may well exceed the recommended constant current capacity of either fuses or cables.

In fact often fuses used in inductive circuits are designed to cope with initial surges..so called slow blow fuses.

It could be argued that BMW should have a higher rated relay set fitted originally…I assume there wasn’t such an off the shelf option..
Click to expand...
Peter; ever heard of quitting while you're ahead?
Your initial reply was ill-informed (and logically inept). Then Robbi put it right. I would have thought that was job done.
Don't worry, your reputation as the E89 technical guru will hold while you still have Google :thumbsup:
 
Morning guys,

Just calm down. :tumbleweed:
Like to support you as well behind your Brexit curtain. :P
 
RobbiZ4 said:
Morning guys,

Just calm down. :tumbleweed:
Like to support you as well behind your Brexit curtain. :P
Click to expand...
Morning Robbi.
Working on the theory that we're not due to beat you at the football again until 2076, I'm all for keeping you on our side :D
 
Just ordered mine from LLL on eBay

Over on the other thread someone had said they had removed the cover post removal to have a look at the quality of the contacts that remained. If I was to do this once I swap mine over & let’s say the contacts seem decent enough is this something that can be recapped to be stored & re used in 5 years time?

Or should I just sling them?

I’m assuming the relays have never been changed before but until I remove them have no way of knowing for sure
 
PointedMarlin said:
Just ordered mine from LLL on eBay

Over on the other thread someone had said they had removed the cover post removal to have a look at the quality of the contacts that remained. If I was to do this once I swap mine over & let’s say the contacts seem decent enough is this something that can be recapped to be stored & re used in 5 years time?

Or should I just sling them?

I’m assuming the relays have never been changed before but until I remove them have no way of knowing for sure
Click to expand...

The short answer is no..the longer one is..

In the process of opening up the relay box you MAY damage one or more of the components

Anything in or around the spring / coil area could be very bad news if damaged..

The reason being..

These circuits are permanently live..so they run if commanded or fail closed irrespective of the ignition setting.

As discussed the load is inductive which means a big fat spark is generated as the main contacts open /close.

This spark is a bit like an electic arc welder..

So..if the spring condition is compromised /weakened with age and /or there is serious pitting then once the contacts are made they may not release..

In this case the motor runs until it overheats and can catch fire /melt..the only recourse to pull the relays out of their holders or disconnect the battery terminals..

Since they are right next to he motor its going to be abrave person who knows what to do and can tackle it whilst the motor threatens to torch the car..

The relays won't self heal with time

Further you or a later owner may forget /be tempted to use them if a fault develops..

So its a no.. £15 worth of relays against possible loss of the car / most likley serious damage in and around the pump area..
 
:thumbsup:
Backgrund info:
https://translate.google.com/translate?sl=de&tl=en&u=https://www.zroadster.com/forum/threads/z4-e85-e89-z8-e52-1er-2er-3er-e93-4er-f33-6er-e64-f12-8er-f91-g14-minir57-ersetzt-die-dachrelais-alle-2-5-jahre-durch-neue.133521/
 
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