Switched Timer?

F

firefighter_2000

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May 22, 2010
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Bauxite Arkansas
We keep having trouble with people NOT turning off the inverter in our ambulances. They have a simple on/off switch in the back of the truck on the switch panel. What I'd like to do is add a timer... Say... 30 minutes worth that comes on when power is applied, and thirty minutes later it shuts off, and wont come back on until the switch is turned off then back on. Anyone familiar with anything like this that might work for us. We've had to replace two inverters recently due to them being left on and not being used. Any help or ideas are appreciated.


Thanks


Craig
 
Chargeguard?


I also have some basic dip switched auto timers, which would probably work as well.. 12 volts. Anywhere from 10 min delay to 12 hour delay.
 
I dont think the charge guard is what Im looking for. I want it to shut off after about 30 minutes or so. Crews will use the inverters to charge the cots, run an IV pump, etc but rarely should have to use it for more than thirty minutes or so. They get out at the hospital to drop off a patient and leave the inverter on. Not returning to the area of the truck where the switch panel is. The truck may sit idling with the master switch on for the next two hours or next two days and the panel is never looked at and no one notices that the inverter is on. With a timer... They turn the switch on for the inverter and 30 mins later is turns off. Turning off the inverter. To restart the power to the inverter, the switch must be manually turned off then back on. Pretty much dummy proof is what Im aiming for.


SO.... tell me more about the dip switch timers.. I'll call them the dip $#it timers for this application!!! :mrgreen:
 
Sounds more like you need a toggle switch with a timer built in, and a auto switch off.... I've seen them once.. in the 90's on an old ambulance..


More than that.. I got nothing. Those timers require the vehicle to be turned off (voltage under 13 volts) before they start "timing"
 
Yea, Im kinda wondering if I could take a household timer... Like one for the heaters in a sauna or bathroom, and make that work. Its made for 110v but why wouldnt it work with 12v. That way, you just spin the dial and in a few minutes it clicks off. All mechanical.


Craig
 
Maybe someway to hook it to the ignition sense so if you shut off the motor it shuts off the inverter. Most ambulances are always running the engine when in service.
 
I would do that, but my goal is to have the switch turn off after 30 mins and that not be dependent on the truck shutting off. Lets just say that after a run, we plug the cot up to give it a charge. Going to post different districts, going from point A to point B, the truck doesnt get shut off for another few hours. A few hours that the inverter needlessly runs and the crew forgets to turn it off. This way, its like the Ron Popeil Showtime Rotisserie.... SET IT AND FORGET IT... Because thats exactly what the crews are doing now.


Thanks


Craig
 
unlisted said:
Chargeguard?

I also have some basic dip switched auto timers, which would probably work as well.. 12 volts. Anywhere from 10 min delay to 12 hour delay.
Click to expand...

I'll second that.
 
we use wall mounted rotary timers on our ambulances that would work for you. I don't know if they are 110v or 12v, but we use them to power our lights when we service the rigs and the master is off. This way they can not accidentally drain the batttery. sounds like it is exactly what you need. I'll look into it.
 
Thats exactly what I was describing. We actually have the same thing on some of our trucks. Not sure who makes that switch or where I can get them. Looks like that might be the ticket. Let me know if you find anything out on that.


Craig
 
Hi there


We supply an electronic timer. It is normally used to shut down the vehicle radios once the keys have been removed. I have pasted a description of the unit below. All you need to do is have a big push to make switch next to the inverter which will start the timer going, then you just need to set the time to say 1 hours, or whatever and it will automatically switch off the inverter.


On the first ignition-on signal (or your push to make switch!), the items connected will automatically power up and a maximum of 20 amps can be drawn via the timer. A second relay is integrated to provide a voltage free switch over if required. The product offers on-site programmable timing from 15 minutes to 3 hours 45 minutes (In 15 minute time frames). Available in 12volts or 24volts


* Length: 4.5" Width: 4.75" Height: 1.75"


If you need more current capacity, just tag on a bigger relay, or if you want more than one we could look at getting you a bigger relay installed inside the box maybe.


Costs £45, its small and light so shipping is cheap (we're UK based), even to the USA.


Hope this is the kind of thing you're after


Cheers


Dave
 
trafficlear said:
Hi there

We supply an electronic timer. It is normally used to shut down the vehicle radios once the keys have been removed. I have pasted a description of the unit below. All you need to do is have a big push to make switch next to the inverter which will start the timer going, then you just need to set the time to say 1 hours, or whatever and it will automatically switch off the inverter
Click to expand...
... Link? Web based ideally? Photos? etc?
 
Yea, that kinda sounds like what Im looking for. Have a direct link and or photos?


Thanks


Craig
 
trafficlear said:
http://www.trafficlear.co.uk/product.php?id_product=103

As you can see it's easy to mount and connect up to with standard spade crimp connectors.


Apologies for not supplying in original post - it's late here!
Click to expand...


That is basically the exact same type of "timers" I have here.. the OP is looking for an option where the engine can still be on- yet the timer still counting down.. If i read correctly.


At this time, I have to say + 1 to the INTERMATIC idea..... I've seen them in old ambulances up here so it must work..
 
Looks really good, but I think its going to be more than we want to spend. Im looking for as inexpensive as we can get it. Would be an excellent idea when specifiying a new unit.


Thanks


Craig
 
This timer will work irrespective of the status of the engine. It does not depend on voltage sense to start the timer running. It simply needs a +ve voltage to fall to 0v on the trigger wire. As could be achieved by pressing a push to make switch momentarily. As I read it this is what is required.


I guess the inverters would switch off if the engine was stopped as their undervoltage protection would kick in anyway.


But... if you want inexpensive, you can buy those vacuum delay light switches (or at least you can buy them in the UK). You press the button down and a vacuum inside means it takes ages for the button to pop out again. Maybe wired through a relay it would work OK as it doesn't rely on any voltage to work the mechanical style switch.


http://www.tlc-direct.co.uk/Products/EK400A.html
 
Heh, trafficlear- you are right... also, thanks, I just realized I can do the same with my timers as well! (never thought of using a momentary switch on the IGN sense)


:)
 
Re route the inverter switch to the cab, have a very noticeable pilot light on the switch...
 
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