If anyone gets bored, I need a simple circuit diagram that will be able to cut power to something hooked up to a 12v+ at a predetermined voltage (11.2v).
The circuit should have an LED that is only lit when the power is cut to that component.
Trying to isolate a parasitic power draw in my Cav, and I think its the alarm system that is the culprit.
TIA
wouldnt it be easier to throw an ammeter on it to see what its drawing?
My car may run 18s, but I can do your taxes in 10 seconds flat.
JBO lube - they would never have enough in stock and we'd never see RodimusPrime again
Machzel08 (Teh Jew) wrote:wouldnt it be easier to throw an ammeter on it to see what its drawing?
The only one I have won't register below 1 amp draw and its below that, but just enough to kill the battery after 24+ hours of the car not running.
Also, this would be used on the cig lighter where I have a power inverter used every so often... the low voltage cutoff on it is lower than is allowable for the car to be started.
Edited 1 time(s). Last edited Sunday, January 28, 2007 7:35 PM
Perfect. That tied with a relay should be just what I need.
You might not need a relay if it is a low amperage draw, but wouldn't hurt at all. You can use alligator clips to tap into stuff to simpilify your troubleshooting.
As mentioned, it is a low draw over an extended period of time, but high enough to kill the battery, so the relay would be put in to cut power in case the battery should reach the critical voltage while I'm sleeping (kind of a "just in case" thing so I can still start the car in the AM)
Good call, good call. Lemme know what you find.
Interesting, but the $90 pricetag is a little high for the simple use that I need it for.
Its more so for circuit isolation to determine if its the culprit (which may be a good thing to use for car show people depending on the final cost/unit).... cut power to say the stereo by putting something like this inline with the ACC wire, at a preset voltage if you happen to not be in an area with a power supply (outdoor show for example)
This is a rough design that I came up with.(the term is electronics engineer, lol)
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Quote:
(the term is electronics engineer, lol)
That's probably why I can't do anything over simple circuits
Is it just me but is there no power input on that circuit?
there r 2 power sources: the cars battery and the ref volt coming from a 9 volt battery
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Ahh. Ok. Thanks for the clarification
kar... why not just buy one???
i dont know where your located, but up north here at Canadian Tire they have a battery guard that they just recently came out with.
Battery Guard
its actually pretty cool. what happens is if you leave your lights ( only an example, should work with any load) it actually monitors the voltage level of your battery and will isolate the battery from the rest of the electrical system if the voltage reaches below a value that is needed to start the car. it also comes with a remote to cut battery power as a theft deterant so the car can not be started.
the unit is $70 CDN, and is on sale for $60 CDN. im sure if your in the states that they might be able to ship it to you. if not check ebay or let some one north of the boarder know, like me, and we can ship it down to you.
even if you could build this thing for less, this will save you the hassle and will also give you that added theft protection by being able to cut the battery out by remote.
1997 RedR - ZedR
I'm looking at less than $20US in parts, etc for the components (some of which I already have on hand...)
I'm tired of having to reset the presets on my radio, which battery isolation will cause... single circuit isolation will keep that from happening
thats true... just let me know how long it takes for that cicuit to issolate and your alram to turn off so i can come by and scoop up your car
1997 RedR - ZedR
Well, on the old battery, 8-9 hours or so... just got it replaced under my other car's warranty (both have the same battery, just bought at different times)
This weekend I'll put that circuit thing together and see if it works
Why couldnt you just use an NPN transistor? They're like $2 for a pack of 5.
Could... the LED would indicate that the voltage has dropped to critical, whereas the transistor would just trip the relay and no visual indication (lets just say I'd rather know before I get in the car, get comfy and turn the key to get *click* then swear a bit, get out, go get the cables and the other car, jump it... etc)
The setup I've made uses a comparitor and when it drops below that voltage then it will turn on the led and/or relay
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