Roof Relays

[helmik]

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

[Pbondar]

A higher rating relay can only be beneficial..enjoy..useful to note on LLL Parts..Autodoc seems to be a 7 day net turnaround..

[helmik]

A higher rating relay can only be beneficial..enjoy..useful to note on LLL Parts..Autodoc seems to be a 7 day net turnaround..

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

[Pbondar]

A higher rating relay can only be beneficial..enjoy..useful to note on LLL Parts..Autodoc seems to be a 7 day net turnaround..

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

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..

[helmik]

Yep, it was price that made me use LLL, expecting a few days delivery. I was wrong!!
Mick

[RobbiZ4]

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

[Pondrew]

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.

Robbie; please don't ever leave.

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

[RobbiZ4]

[enuff_zed]

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.

Robbie; please don't ever leave.

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

To be fair, I'm pretty sure Robbi has mentioned this in previous discussions too.

[Pondrew]

To be fair, I'm pretty sure Robbi has mentioned this in previous discussions too.

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

[Pbondar]

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..

[flybobbie]

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/ ... price=true
Anyone have picture of bottom of relay so we can see numbers?

[Pondrew]

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..

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

[RobbiZ4]

Morning guys,

Just calm down.
Like to support you as well behind your Brexit curtain.

[enuff_zed]

Morning guys,

Just calm down.
Like to support you as well behind your Brexit curtain.

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