Need some electrical knowledge help! (12v)
Discussion
I have a 12v car battery, I want to use it to heat up a pipe for short periods of time, a few minutes at most. How would be the safe way to do this? I'm hoping it can be done. I'm guessing it will be similar to how glow plugs and cigar lighters work, although I don't need it to get that hot!
The pipe is permanently earthed so I am assuming I will need some array of resistors and/or fuses etc on the switched live side to make sure that I don't simply short out the battery. But I have no knowledge of what I need to do.
How would I make sure that the heat generated by the battery would heat the pipe rather then the cables in between the pipe and the battery?
Thanks
The pipe is permanently earthed so I am assuming I will need some array of resistors and/or fuses etc on the switched live side to make sure that I don't simply short out the battery. But I have no knowledge of what I need to do.
How would I make sure that the heat generated by the battery would heat the pipe rather then the cables in between the pipe and the battery?
Thanks
You cannot directly heat a pipe with a 12v battery.
the internal resistance of the battery will likely be many times higher than the pipe, so if you short the battery to the pipe you'll just heat up the battery far quicker than you'd heat the pipe, you'd get some heat into the pipe if it was a small section it might get quite hot but if it was large it wouldn't even get warm, and you'd screw the battery fairly quickly, if you add in any resistors you will simply heat the resistors instead.
the internal resistance of the battery will likely be many times higher than the pipe, so if you short the battery to the pipe you'll just heat up the battery far quicker than you'd heat the pipe, you'd get some heat into the pipe if it was a small section it might get quite hot but if it was large it wouldn't even get warm, and you'd screw the battery fairly quickly, if you add in any resistors you will simply heat the resistors instead.
quiraing said:
Need more info mate. What's pipe used for?
Wait a minute - what kind of pipe????!!!
Do you have an old VW camper van?
Its on a old peugeot 405 that is running on veg oil, I'm trying to think of ways to heat the veg oil during the winter to help with starting. The pipe I mention is the metal fuel pipe up by the injectors.Wait a minute - what kind of pipe????!!!
Do you have an old VW camper van?
quiraing said:
Oh right. Interesting one. What kind of temperature do u think you need?
Only upto about 10 degrees Celsius. It starts ok at about 10 degrees but gets harder to start quite quickly below that.The trouble is to be effective I need the heat to be right near the injectors, the only other option I can think of is some sort of heated blanket type thing wrapped around the pipes. I have a secondary battery so current draw is not too much of an issue.
ETA, the warmer I can get it the easier it will start but I think 10 degrees is the minimum.
Heated grips got me thinking, how about the elements used to demist mirrors? If I could find a way to safely wrap an element pad around each of the 4 injector pipes that should give enough heat to liquify the fuel enough. It should also withstand engine temp as it won't get any direct heat, only residual heat as the fuel pipes don't heat up too much when the engine is warm.
Thanks for the replies, trace heating cable sounds exactly what I need, although I am having trouble finding any that is 12v. I have a 150w 240v inverter, do you think that would be sufficient to run some 240v trace cable? It doesn't seem to say on the various websites I've looked at what the wattage is.
Its simpler and easier to set up a twin tank system.
Fit a 2nd small tank and just before shutdown switch the fuel suction over using a 3 way valve to the small tank with diesel in it. Then when you start you are running on diesel and once the engine is warm you switch over to vegoil.
Yes your returns will pump a small amount of diesel into the veg oil tank but that won't harm anything
And WTF is this doing in homes and garden?
Fit a 2nd small tank and just before shutdown switch the fuel suction over using a 3 way valve to the small tank with diesel in it. Then when you start you are running on diesel and once the engine is warm you switch over to vegoil.
Yes your returns will pump a small amount of diesel into the veg oil tank but that won't harm anything
And WTF is this doing in homes and garden?
thinfourth2 said:
Its simpler and easier to set up a twin tank system.
Fit a 2nd small tank and just before shutdown switch the fuel suction over using a 3 way valve to the small tank with diesel in it. Then when you start you are running on diesel and once the engine is warm you switch over to vegoil.
Yes your returns will pump a small amount of diesel into the veg oil tank but that won't harm anything
And WTF is this doing in homes and garden?
I have looked into doing that but it seems a lot more work to me, also it would be harder for me to fit a twin tank system as I am very immobile at the moment and am unable to get under the car. It is definitely something I have thought of doing for next winter though.Fit a 2nd small tank and just before shutdown switch the fuel suction over using a 3 way valve to the small tank with diesel in it. Then when you start you are running on diesel and once the engine is warm you switch over to vegoil.
Yes your returns will pump a small amount of diesel into the veg oil tank but that won't harm anything
And WTF is this doing in homes and garden?
I have no idea why it was moved to homes and garden!
annodomini2 said:
Nichrome wire, potentiometer, thermal fuse and switch. (Assumes the pipe is metal and can take the heat).
Can you elaborate on what specs I would need, having had a quick look at nichrome wire they seem to be rated by an 'SWG' number, what rating should I be looking for if I want to heat it up to around 30 degrees Celsius?Similarly with the potentiometer, what spec should I be looking for? Sorry for all the basic questions but I don't know a lot about vehicle wiring.
JM said:
Is it 100% veg oil you are running?
If so why not just dilute it with some diesel during the winter?
Yes I run 100% veg most of the time, unless I run out then I just use diesel. I would just mix diesel with it but I have found I have to mix it about half and half for it to start easily in the cold, if I do that then I only get half the savings of using the veg oil.If so why not just dilute it with some diesel during the winter?
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