Fuel Pump Safety Cut-Out Controller for 24vdc

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Haf-e
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Location: Mount Vernon WA USA

Fuel Pump Safety Cut-Out Controller for 24vdc

Post by Haf-e » Tue May 09, 2017 11:05 pm

I was looking into this issue - what are people doing when they switch from a mechanical fuel pump to an electric fuel pump to prevent the pump from continuing to run when the engine stops - especially if there was an accident or roll-over? The same issue applies to trucks running propane conversion systems also...

I have been emailing with a guy who builds a nice little unit that provides this protection by sensing the ignition pulses - if they stop then it kills the fuel pump (or would shut off the LPG supply). The controller also provides a 3 second "priming" period before the engine starts when power is applied.

Is anyone aware of other devices that do this what work for 24vdc systems? The company is open to making a 24vdc version but would like to see how much interest there is in it being available.

So - would you want one? Thoughts? Other options / opinions?

Here is a link to the company's webpage on their current 12v version: http://www.revolutionelectronics.com/Fuel_Pump.html

Its cost is $65 retail - but I would think a 24vdc version might cost a little more due to the very low volume they would produce.

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1971 Pinzgauer 710M

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GRCameron
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Joined: Tue May 27, 2014 7:32 pm
Location: Yarnell, AZ

Re: Fuel Pump Safety Cut-Out Controller for 24vdc

Post by GRCameron » Sat May 13, 2017 7:08 pm

A few years back I purchased one of these and began a dialog with David Heath, owner of Revolution Electronics. I dug back through my email heap and found the following. I haven't taken the steps to make the install, but I did find a small 24-12V DC-DC converter on ebay that is waterproof and should work to drop the input voltage.

Hope this helps

_____________________________________________________________________

On 11/5/2014 8:40 PM, David Heath wrote:
> Hello George,
>
> that is certainly an interesting application. Yes, this can be done, but there will be a little work required on your part.
>
> You are correct that the purple wires feed into legs on a relay so there is no issue there. Yes, the diode suppresses the back EMF when the pump shuts off. Really helps keep the electronics happy. I would definitely install the diode in your application.
>
> The tach wire (green) should have a simple voltage divider. This line will draw 6 mA with 12v, so it should draw about 12 mA at 24v (the green wire connects to a 1.5K resistor feeding a 4.7v zener to ground and 10K pull down resistor.)
>
> On the red wire, current draw is about 3 mA when the relay is not activated and about 65mA when the relay is on. I don’t think you will be able to come up with a resistor which gives suitable drop under both conditions. Perhaps you can wire in a 7812 regulator (or similar).
>
> Let me know if you have any other questions.
> Dave
>
>
>
> David Heath
> President
> Revolution Electronics, LLC
> dheath@RevolutionElectronics.com
>
>
>
>
>
>> On Nov 5, 2014, at 7:04 PM, Sales <sales@revolutionelectronics.com> wrote:
>>
>>
>>
>>> Begin forwarded message:
>>>
>>> Date: November 5, 2014 at 7:26:28 AM PST
>>> From: George Cameron <grcameron@reagan.com>
>>> To: sales@revolutionelectronics.com
>>> Subject: Info on 12003 Electric Fuel Pump Controller
>>>
>>> Hi Revolution Electronics,
>>>
>>> Please pass this request on to your technical/engineering support people -
>>>
>>> I have a 1979 Steyr Puch Pinzgauer (Swiss military high mobility utility vehicle) with a 24 volt system. I wish to convert the current mechanical pump to electric and need the safety your unit provides. I was wondering if there is any way to get your unit working with 24 VDC? Here are my thoughts and questions.
>>>
>>> I am assuming that the purple wire from the battery or switched power source goes to a relay contact which is controlled by the electronics and should work at 24 VDC without issue. Yes? No? Does the diode across the pump suppress back EMF that triggers a reset of the 3-second interval timer?
>>>
>>> The ignition on this vehicle was originally a Bosch breaker-point system with ballast resistor that was upgraded to a Pertronix Ignitor that eliminates the points and is triggered by a magnetic ring. I can get a signal from the points side of the coil as with a conventional ignition. In this case the signal will be roughly 2 times the voltage of a conventional 12 volt system. Can your module handle this higher voltage without issue? If not, I was considering the following: The green lead for the tach input might be fitted with a 2:1 resistive voltage divider to cut the signal from the coil in half if the input can't withstand 24-28 volts when the engine is starting (ballast resistor is bypassed during starting). What is the input impedance of your tach input (ie. how much current is required to make the input true)? I'm guessing the tach input provides a constant stream of reset pulses to the 3-second interval timer that keeps the signal to the control relay high while the engine is running. Correct?
>>>
>>> Can the switched 12V input (red wire) be handled by a 2:1 divider, or would a simple regulator like a 7812 work better?
>>>
>>> I've been looking at my own solution using an programmable timer, but your product is so much better and has been designed for the purpose.
>>>
>>> I look forward to your comments.
>>>
>>> Regards,
>>>
>>> George Cameron
>>> Yarnell, AZ
George Cameron
Yarnell, AZ
1979 Pinz 710M
Molon Labe

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