Hello guys..

I am preparing for the HOOPA Hillclimb and they want a Battery Disconnect Switch. On the outside of the car. The rules state that it must be the Positive cable that is switched and that the "Key" is marked and easily accesable from the outside of the vehicle. also need to have the key as close as possable to the battery itself...

So I have a disconnect switch and was thinking about mounting it in the rear bumper just below the drivers side tail light.

They did mention that a cable can be attached to work an inboard switch.

Any feedback suggestions woul be apreciated.

 

I'm thinking that is not a good place for two reasons. It seems that it would be vulnerable to a rear impact but mostly the workers how would be looking for the switch during and incident wouldn't look there first. They would look in the front near the drivers window.

Just my first thoughts.

Rich (who wishes he looked closer at the Mini at last weeks MARRS race at Summit Point)

 

thanks for the reply

The area just below the light on the bumper is just about verticle (not on the rear edge of the bumper) but do agree about being vulnerable. The specs say "drivers side of vehicle if possable" and most importantly "as close to the battery as possable" ...it does also require approved sticker for identification.
I could put it in the bonnet vent but that still leaves the battery cable "live" all the way to the engine compartment and the live cable to the fuse box at drivers feet.

See this is why I am confused ... it is an interesting project

 

Well, these rules sound kinda strange, but...
The best remmedy may be the remote switch from Summit Racing. http://store.summitracing.com/partde...5&autoview=sku
Fact is though that you really need a four post switch so you can also shut down the alt. If you just shut down the battery, the car will continue to run.

 

the vent is where the first person on any incident scene will look. And you are correct that the wire will be live from the back all the way to the switch. But if the switch is off it should cut power to the fuse box as well.

Building a race car is about two things. Tradeoffs and money. Money is usually a problem but in this case it is a tradeoff between the theoretical and practical most safest position. My feeling is that if you are upside down or on your side, the workers will never see a cut off in the back so what good would it be? In the vent, yes, it would be live up to there but at least it could be turned off by you or the workers that get to you.

All race projects are interesting.

///Rich

 

Great info ...thanks onasled and Rich.W for the last posts.

I have built a few different racers and race motorcycles (vintage cars are the hardest)

I did have an "alternator saver" key switch ... but the summit solenoid is very cool...
My sister is a big mucky muck with Summit so a call tomorrow is in order.

Perfect combination of switch placement and being able to put the solenoid where I want it.

My plan is to mount the solenoid switch in the extra room of the battery box and mount the switch in the bonnet vent ... PERFECT ... thanks

 

Consider using the big red regular race car disconnect switch. I have been to a LOT of races and worked a corner or two. When the corner workers get to your car you don’t want them to have to think about what switch to hit. The regular disconnect can be used with that solenoid so all you would have to do is get through tech with it and I am sure there would be a discussion if the inspector 1-saw it and 2-knew what he was looking at.

Good luck.

Rich

 

That's a good relay, but you have to take into consideration a couple of things with the Painless relay.

1st the MINI S has two battery cables go to the front of the car. One is fused the orange box in the battery compartment this goes to the fuse block. The 2nd goes to the starter and is not fused but, pyrotec protected, (part of the airbag system) the large positive terminal at the battery. The alternator charges the battery through the starter cable.

If you break the first or second cable the car will still run, you need to cut both. We also added a 2nd small relay 30 amp to cut the feed to the ignition switch at the same time as the Painless relay is cut. This will prevent run on.

The other problem with this relay is that it is energized if you do not push the switch in, and it pulls a lot of amps and will kill the battery in no time. I know first hand, almost missed the grid because of a dead battery.

 

I like your idea of the "traditional key" switch ... the workers would know what to do with it (and it would be marked).
That with a solenoid ...right at the battery positive terminal could cut BOTH positive cables.


Here is what I have now and I'll do a wiring diag in a bit

 

Think this is close to a good solution ???

 

Yea, that's exactly what I was thinking. But Rich has a good point about that solenoid switch always drawing power. I think.

 

A gool 'Ol ford starter sol doesnt always drain power.(when OFF)
When switch is on it gets power and makes the circut.
I see that if it was left ON ...it would draw power. And my little DEKA could die fast.

When off the car wouldnt have any power or any draw.

I could bypass the solenoid, by connecting the positive cables to ONE of the terminals, when the switch wasnt needed (so it would be off)

Thanks guys.

 

Here is right from Painless install sheet

Caution: The solenoid current requirements may fully discharge
the battery if left activated for extended periods of time.

If you use this, you either have to turn the relay off with the disconnect switch or wire in a cut off from the ignition switch. Once the relay is energized it stays that way and draws power to stay on. When you cut the switch the field drops and the relay turns off.

Now if you are planning on using this on a daily driver you'll drain the battery in no time if you do not turn the switch off. Also when you cut the power remember you'll loss all of your setting on the radio, no door locks, no power windows, no power to anything. It's also acts as a reset of the ECU.

 

Good drawing, here is how I made the changes. Now when you turn the key on it energizes the relay and you can start the car. Turn the key off and all is off. Turn the emergency switch and all is off.

Someone might have a better way, but this works.

 

Very cool mr rpterson.

It is not daily driven so either just turning it off, or you neet method are both options.
THANKS

 

Hi... I never posted any followup or photos.
The switch is to big to put in the vent... It gets in the way of the wiper mechanism.
I also looked at the side repeater ...but the switch seemed prone to damage

well this is a auto-x and track (very little daily driving..) so ...



I did add a fuse in the power line to the switch.

 

Mine's all mechanical. Remind me at MMMT and I'll show you how we did it.

 

I will ... we will be parked next to eachother in the tent.

I did have to change the solenoid to a continious duty "switching" solenoid.
One impulse closes the circuit and another opens it ...No current draw in either position.

 

Long way we've come together, huh, Brian?