Chicken Switch Problem

[crazyhorse]

Just too add to this. Thinking of adding a chicken switch (Just to be safe)

Thinking of using my rear window demister switch under the hazard and fog lights on dash to toggle on and off.

Mr Itchy, when you do go and do it can you add pics like you did with the accelerator cable, that way a novice like me can make myself feel good for doing this mod

[Oldiebut goodie]

Are you putting the 30A fuse in the 50A side? Might explain why the fuse is blowing. Check the 50A relay/strip fuse by the earth crowns.

Ahh - so are you saying the 30 amp in line fuse should go between the relay and the fan? Rather than where I've put it - between the power source (cranking battery) and the relay?

As you will have guessed, my knowledge is quite limited so this is a great help. Never too old to learn...

The 50A circuit is dealt with by the relay and fuse by the earth crowns.

[syncroandy]

Next question, does the fan give the full power when only stage 2 is activated?
I never tried just triggering stage 2, I wonder if it has two seperate coils inside and needs both feeds for full power?
if so just doing stage 2 will be less power than stage 1

Sounds like you have the 200/300W setup. I've only had experience of the big fan which has a dropper resistor to reduce power at the low speed.

Regarding the switch though, I think Pete should get clear advice on that if he's wanting to switch the low speed. When shopping for switches they're typically rated at 250V, and IMO a 250V / 30A is grossly excessive for this task, think electric cooker type power..

[itchyfeet]

Thats why you get a vehicle switch not a mains switch
It doen't need the creepage and clearance distances needed for mains so can be alot smaller for the same current rating.

[syncroandy]

There's a lot of bandwidth being used here to little benefit to the OP.

If you're so clever why haven't you simply posted a link to a suitable switch ?

BTW his van has a different fan setup to yours if you haven't already figured that out.

I'm out.

PS. Pete, Polevolt.co.uk product ref. E895 should do, IMO.

[itchyfeet]

BTW his van has a different fan setup to yours if you haven't already figured that out.

.

Yes that's a very important point, but earlier you said probaably not definately the higher power setup.
I have no experience of the syncro setup, this wasn't posted in Syncro and so I missed the signature details, I can't say which is the right switch/solution for the syncro.


I'm only trying to help as I'm sure you are, discussion is what forums are about.

[PetenAli]

Thanks very much to everyone for your contributions. I'm going to try the 25A switch in parallel with the the thermo switch on the stage 1 circuit first.

I'll have to give some more thought to the stage 2 circuit as ideally I'd like to be able to use that manually because it will bring down the rad temp a lot quicker. We spend quite a bit of time in mountains in southern Europe and want to be able to climb confidently.

Andy - PM gone to you about something else.

[itchyfeet]

looking at this diagram kindly provided by syncroandy stage 1 for both fans is the same from a switch point of view and powered by a 30A fuse except the wire colours are red/white and red for the higher power fan, ( also a resistor in series but that doesn't change the switch )you will tell which you have by looking at the thermoswitch plug wire colours.

search for 30A 12V toggle switch on ebay.

http://syncrosport.com/info/wiring/T3_Radiator_Fan.jpg" onclick="window.open(this.href);return false;

I'm going to try triggering stage 2 without stage 1 but maybe they are both needed.

nothing to stop you having a second stage 2 switch ( or a 2 pole switch) red/white to red/blue as said before this triggers a relay so can be a small switch.

[syncroandy]

OK, I didn't want to leave this at that, for two reasons. Firstly apologies for getting grumpy last night.

Secondly to provide the OP with the choice to manually set either 'normal' OR 'high' speeds, a dual-throw switch could be used, and I would recomend fitting it as follows, after removing any other modifications that have been made. The connections are all just above the relay plate so access should be OK.

[CJH]

Useful discussion, and diagram. I'd just like to query the use of a 'centre-off' switch. I made a few rough measurements a while ago (post here) and found that the surge current when the high speed fan is started up from off is higher than when it is started up if it's already running at low speed. In normal use the high speed fan wouldn't normally come on unless the low speed fan was already running. But a 'centre-off' switch would allow this, and might result in a higher start-up current. It's very short duration, and the wiring will take it, but I wonder if the fuse might object.

I went for a headlight (0-1-2) switch, which doesn't allow the high speed setting to be reached without going through the low speed setting.

[syncroandy]

I can confirm that switching straight to 'high' speed on the 450W fan does *not* cause the fuse to blow.

The ON-OFF-ON switch was suggested as a fairly readily available and low-cost option. A more ergonomic and nicer option would be a rotary OFF-LO-HI switch, but possibly finding an easily panel-mountable one with a suitable rating might be harder.

That looks like a foglight switch in the pic. As foglamp bulbs are 55W, I think I'd be reluctant to recommend using that switch when a big fan motor on 'normal' speed might be drawing a couple of hundred ?

Anyway I'm concerned this thread is obsessing a bit over what is TBH a bodge to workaround another issue. Better IMO to fix the original issue by improving the basic cooling capacity.

[CJH]

Anyway I'm concerned this thread is obsessing a bit over what is TBH a bodge to workaround another issue. Better IMO to fix the original issue by improving the basic cooling capacity.

Agreed - but for the record my switch is a headlight switch, flipped over, with a custom chicken logo lovingly printed on a laser printer. Tatty as anything now though.

[itchyfeet]

Just to comfirm what you knew already that you can just trigger stage 2, thats what I'm doing as both wires are above fusebox on the standard design and it's low current.

As with the OP this is my first hor summer with a new engine it's just for piece of mind.