Berlingo Brake light modification

[arsharpe]

I'm pretty sure there is a way using a current coil around one of the motor wires

I dont think will work as essentially the current to the motor is DC. You can only pick up current passing through wires using this method if the current is AC.

This is why it would have to be something like a hall-affect device.

The other option is to use the volt drop of across one of the motor wires. I assume that it will be more than 0.7v which is what is required for a typical silicon transistor (this maybe old fashioned now, but this is what I am used to ). If we are lucky if might be more than 7v in which case just a simple relay across the wire would work.

Anyway assuming that it is between 0.7v and 7v at the minimum regenerative braking then the following circuit should work.

I am generally quite busy so if someone could help me with some fo the measurement side of thing then we can up with a viable design.

See attached proposed diagram.


Once I know the volt drop range across a selected motor wire during regenerative mode then I can calculate the component values and build a prototype.
Is this something that people would like ?
If so can someone determine a suitable motor wire and the volt drop above ?

Regards,
Rob

[ChrisB]

Your quite right Rob regarding hall effect , I said current coil cos a lot of folk dont understand/even know about hall effect transducers just trying to keep it simple

Mr Green Machine posted a link to me about some nice hall effect units that I think would do the job nicely. I'll locate the mail and put a link up unless he spots this post first

Certainly I'm up for doing something as only this weekend I nearly had someone wipe the back end out AGAIN , perhaps its just me driving on the regen to much

ChrisB

[gooroo]

I have now had the instrument cluster out and located the correct signal cable running the ECO meter, at stand still it gives a nice steady 6v dc, as the vehicle is being driven and regen is not taking place the votage steadily drops with current draw and steadily climbs with regen.

All the electrics to produce a signal are already taken care of with the built in ECO meter. I can easily monitor this voltage and switch the brake lights on at any predermined amount of regen.

I have also had the throttle pot out and taken min and max readings for no and full throttle and can also easily monitor this signal.

I am in the process of writing some code for a pic micro processor circuit to monitor these signals with a view to producing an easy to install regen brake light and ultra eco mode switch, stay tuned people

Regards, Simon

[ChrisB]

Nice one Simon

As fast as I keep trying to get on and do something things just seem to get in the way I'm desperate to get it on the ramps and check the brushes

Mr Green Machine posted a link to me about some nice hall effect units that I think would do the job nicely. I'll locate the mail and put a link up unless he spots this post first

But I did find this link though
http://uk.farnell.com/jsp/Industrial+Co ... ku=9135715

They look like nice units.

ChrisB

[arsharpe]

Yep - well done Simon.

I would certainly be interested in the unit, especially if the enhanced eco drive will fail-safe under all conditions and you can also disable it.

Regards,
Rob

[Flying John]

I must say that I like the idea of a mercury switch to detect the de-celaration as you come off the throttle. bit like the old mechanical thingy on the pillion of a motorcycle. Just have the mercury switch wired across the microswitch that normally operates when you brake. Altering the phsical position of the mercury switch determines how much deceleration you need before the switch works.

Can you still get mercury switches, perhaps there is a solid state replacement thats a bit "Greener" than mercury swishing about. Then there is the pendulum I suppose, you used to find them in some car alarm control boxes.

John

[qdos]

I must say that I like the idea of a mercury switch to detect the de-celaration as you come off the throttle.

John

I guess there's no hills round you in Kent then

[ChrisB]

I must say that I like the idea of a mercury switch to detect the de-celaration as you come off the throttle.

John

I guess there's no hills round you in Kent then

Good point , hadnt thought about that problem

ChrisB

[Flying John]

Whoops - forgot to reply to the post about the LEM hall effect devices.

These are brilliant if a little expensive and I have one in the electric CF to give me what is in effect the same as the econometer in the Blingo.

So as Rob said you dont really have to re-invent the wheel just look at the voltage across the eco meter in the blingo and detect when it is in regen and drive a relay in parralel with the brake light switch. (Have you written up how to remove the panel Simon?) I am all for keeping it very simple tho and would shy away from the use of a uPro. A simple voltage level detector (op amp) and a driver transistor for a relay should do the trick. Just tie one input of an op amp to a reference voltage and when the other input goes (wherever it goes on regen) and get a nice output for a relay driver transistor.

Having said that , and dismissed the idea of a mercury switch coz of hills, I looked at the accelerometer devices. These are not affected by going down a hill like a mercury switch so this could still be a useful way forward.

But .... It occured to me that whenever you let off the throttle for full regen you must be able to mount a small switch on the top of the travel of the accelerator pedal. This would seem the simplest solution but havent had a chance to look at the mechanics of doing it yet. I think Chris suggested same earlier on.

John

[gooroo]

I must say I find it a little odd when I hear "keep it simple" and "avoid a microprocessor" in the same sentence. I guess if you are referring to keeping it simple from your own point of view then it makes sense if you have little experience of microprocessors.

You see when it comes to adjustments and differences with what one user would consider "just right" for the correct amount of regen before bringing the brake light on and another, I find a microprocessor the "easy" option. I plug in a laptop, alter a couple of lines of code, reprogram and away I go, or better still, I change a few lines of code, add a button and let the driver "adjust" to their hearts content.

Now consider mapping the brake operation switch between speed and regen, again, a simple enough task with a micro.

As for any mechanical option, it will always be a fudge of some sort. A switch on the throttle pedal would mean the brake lights would always be on at stand still, not very enviro friendly runnign two brake lights when sat in traffic for 10mins. Not sure also if this would be considered an MOT failure, "incorrectly operating brake lights".

Just my tuppence worth guys...

I will press on with my easy option of a microprocessor, I am a little biased being an auto electrician and one who loves microprocessors

Regards, Simon