Prestolite Leece Neville alternator control

[Tony Brooks]

I think Sir N and myself have said much the same thing in different ways and Nick seems to be working along that way as well.

 

I did not find it difficult to program a BBC model B and Master computer to measure a variety of input voltages and switching outputs as required. This was in BBC Basic (real programmers will now be holding their heads in their hands) and I suspect with suitable input-output add ons the Pi would be the same, especially if Tiny Basic that is available for the Pi gives access to input & output modules. I think and Basic will be fast enough for what looks to me like a fairly trivial task and there is no way I can see there will be any need to go to the lengths of needing to use interrupts. Simple input polling should be enough and that can be developed and implemented in a modular fashion. I doubt any simple Basic is available for an Andrino though. Probably have to use a modern language like C that I find all but impossible to understand.

 

PS like Nicks idea of putting a small battery in series and using that to feed the sense wire. Seems a very simple test to see what happens.

Edited February 17, 2020 by Tony Brooks

[Dr Bob]

53 minutes ago, Sir Nibble said:

 Perhaps the only way to get the required derating would be a on off duty cycle of alternate full chat and shut down for cooling.

 

27 minutes ago, nicknorman said:

Ok well that pretty much confirms what I’ve told Dr B - he has to suck it and see.

 

 

Thanks both. All good information.

I will try and call both Barrus and Prestolite to see if I can get any information on how the sense wire works. Its going to be quite a while before I get the kit to play with so its all theory up until then. I would be happy with the on/off strategy as I think although it is not elegent - it will work.

I will also look at the Adverc type solutions.

[Dr Bob]

3 minutes ago, Tony Brooks said:

 

PS like Nicks idea of putting a small battery in series and using that to feed the sense wire. Seems a very simple test to see what happens.

I agree. That is real out the box thinking. May be a good semi permanent solution if the sense wire will work and the current flow is low.

[Sir Nibble]

Current flow should be negligible. It's only a voltage reference.

[Sir Nibble]

Current flow should be negligible. It's only a voltage reference.

How about a 15V regulator such as Texas instruments LM2576T-15 and a potentiometer?

[Dr Bob]

2 hours ago, Sir Nibble said:

Current flow should be negligible. It's only a voltage reference.

How about a 15V regulator such as Texas instruments LM2576T-15 and a potentiometer?

Very cheap!

[Sir Nibble]

9 minutes ago, Dr Bob said:

Very cheap

Won't do anything but shut down the charge mind

[Dr Bob]

13 minutes ago, Sir Nibble said:

Won't do anything but shut down the charge mind

Yep, I understand.

I've emailed Prestolite UK - still waiting for a response from my email last Thursday.

[nicknorman]

4 hours ago, Sir Nibble said:

Current flow should be negligible. It's only a voltage reference.

How about a 15V regulator such as Texas instruments LM2576T-15 and a potentiometer?

That is a step-down regulator, ie it can’t produce a higher voltage than it’s fed with. A step up regulator could be used and you can get such a module cheap on eBay, but if you are going to that trouble you might as well make something that tracks the battery voltage plus a fixed (well, adjustable) offset. That, if the sense wire works as we hope, would allow the regulated voltage to be adjusted, not just all or nothing.

[Sir Nibble]

11 minutes ago, nicknorman said:

That is a step-down regulator, ie it can’t produce a higher voltage than it’s fed with. A step up regulator could be used and you can get such a module cheap on eBay, but if you are going to that trouble you might as well make something that tracks the battery voltage plus a fixed (well, adjustable) offset. That, if the sense wire works as we hope, would allow the regulated voltage to be adjusted, not just all or nothing.

According to the data sheet it's happy down to 4V input.

[nicknorman]

Something like this (cheap!) https://www.ebay.co.uk/itm/XL6009-DC-DC-Voltage-Step-Up-Boost-Converter-replaced-LM2577-3-32v-input/162904112503?_trkparms=ispr%3D1&hash=item25edd77d77:g:utcAAOSwi4dau3m5&enc=AQAEAAACUBPxNw%2BVj6nta7CKEs3N0qWaGjslNgZ6KjlxMmJPtZ4aMEU3jRoq8dUb1dvShub5vhNTzJbLFX4qtsFo4Y%2B56BrL89vrRS5l6QoJ0x%2F2FooOUgojX6tKPzSM02muRkRbUSy%2B65qeoUsEmyfgDJl8%2BPd%2BArps8JSyrxv86SiwRhlSMJnbY4GkX337V95MOhywwm6ubxS%2Bg8n5zMIe8WElUzz7%2Bi4aynJR3vPbA5F1iI5IAQNYZ%2FCm78koA4Zz5Jm8BVqS%2BzFubiH9zQcEfK35wipgytxog2cElVIcYIBwz2nVePogKDe4N%2F1m9jVbF22%2FytgsUOwlk3H6bc1FgaMNz45CyCviUgNCwqvZ2finiyvN7dJcyK6Z%2FWVR2vjkcSdNJaEKX5t0gpN18eCaSZzQRSResxuHtmEh28GWosRHIiaRKLIzUvs0mdAhhWtu557VNqw8Kmzbaqq5%2FDHPhYSJFPyFTuq0zpWe2MQezitKgdobiQpoXrqX%2B%2F6D8JO2%2Fm0VOojMb%2FRgYTpxd3IpBES5TAIKYMLKS5J%2BVgiv%2FB3aobnN0tlGW419RM%2FbEZ7qkfyE3XEn5BenB9SEP3bnQnJVISvTtQa0aKGeS6cvgdHOqCJDC3XMBX%2BkXnWpQ0HIUE%2FXijiHl9XeDGLQN8br8SR%2FsnLJuptjfEyzuNQpK4veYjDnIOfXxslJnGJqjQTyNGjzAplBmVMB%2FaorfovA2UmZ9jIWK9jpLfrs5um0iPOLUtq5Lb1my9fOcIkDOp%2BzanCZwpSou02bTbKcehK0A7lvABg%3D&checksum=162904112503f6909ce2c28d4ebb87fb6e429a63cbf9

 

to generate say 18v or so, to a  resistor, to a 2.4v zener diode to the battery +ve terminal. So one end of the zener would be at battery voltage, the other at battery voltage + 2.4v. Then fit a potentiometer across the zener, wiper to the sense wire, so the sense wire would be at battery voltage plus some proportion of the 2.4v depending on the potentiometer setting.

4 minutes ago, Sir Nibble said:

According to the data sheet it's happy down to 4V input.

It’s a step down regulator. Did you mean the LM2577T-15 which is step up? Either way, you need some other circuitry (inductor, diode etc) so I think it’s a lot easier to get a ready made module cheap from eBay.

[Dr Bob]

That's great Nick. I will put it on file to get one nearer the time .....and I'll be back for a circuit diagram!