Any know wher I can get a 12volt to 6 volt transformer......
16 February 2005, 08:16 PM
#31
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Originally Posted by kingofturds
ok smarty pants i fooooked up a dcdc converter then that will give ya a regulated 6v from a 12v supply im off for a beer my brain hurts
LOL I guessed as much when you mentioned Live & Neutral
rather than Negative & Positive 
Get me a beer whilst you're at the bar 
16 February 2005, 08:30 PM
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Originally Posted by mj
I knew that, that's why I suggested 2 batteries. 
"Add concentrated nitric acid, concentrated sulphuric acid and glycerol together..... then stir vigorously!"
*Sponsored by Stella*
16 February 2005, 08:52 PM
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And tonight mj explains how to make a common angina medicine....
"Add concentrated nitric acid, concentrated sulphuric acid and glycerol together..... then stir vigorously!"
"Add concentrated nitric acid, concentrated sulphuric acid and glycerol together..... then stir vigorously!"
I would'nt go to that trouble, some of the ingredeints can be a bit tricky to obtain.
Take a small air compressor and fill the air tank (reciever) with Amyl Nitrate.
connect to a 2 bar regulator and face mask
gaffer tape the face mask on.
Lie down and switch on the compressor.
take three times a day, before meals.
anyone else have any questions?........
16 February 2005, 09:08 PM
#35
Originally Posted by CharlieWhiskey
LOL I guessed as much when you mentioned Live & Neutral rather than Negative & Positive Get me a beer whilst you're at the bar
rather than Negative & Positive Get me a beer whilst you're at the bar 
16 February 2005, 10:32 PM
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This is the car..... I very much doubt if I could buy ANY of the electrical components, there are only two of these in the UK, and only 20 or so in France where they were made..... Still thinking....
16 February 2005, 10:45 PM
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It is perfectly easy to buy almost any electronic components online these days
Any idea what your current requirements for the remaining 6v circuits would be?
Any idea what your current requirements for the remaining 6v circuits would be?
Last edited by CharlieWhiskey; 16 February 2005 at 10:52 PM. Reason: neva kud spel
16 February 2005, 11:15 PM
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Its late so prob not thinking correct but I'll say it anyways:
Could you not supply 12volts to the 6Volt equipment and use a suitable resistor in parallel (or is it series) to each piece of equipment?
I'm sure I remember doing something along those lines umpteen years ago at college and the resistor takes some of the power thuse reducing what goes through the equipment?
Bob
Could you not supply 12volts to the 6Volt equipment and use a suitable resistor in parallel (or is it series) to each piece of equipment?
I'm sure I remember doing something along those lines umpteen years ago at college and the resistor takes some of the power thuse reducing what goes through the equipment?
Bob
17 February 2005, 01:15 AM
#42
How about a few voltage regulators?
The biggest one I can find is 7.5 amps which adjustable voltage from 1.2 to 26volts...so just set it at 6volts, use the chassis as heat sink (with mica sheet to seperate it )
This is the part number: MIC29752BWT
Datasheet: http://www.micrel.com/_PDF/mic29150.pdf (pdf) about £12 from RS, there are similar chip based regulators on the market you can use instead.
Note that you'll need capacitors across the terminals and ground on any electric motor powered by the regulator to soak up any back emf which can damage the regulator...nothing big a few 0.1uF to 10uF ceramic disc types should be enough....a lesson I learnt from my RC car days
You mention you can't upgrade the ignition....why not? A aftermarket 12volt coil with a ballast resistor will still work the contact points no differently.
The biggest one I can find is 7.5 amps which adjustable voltage from 1.2 to 26volts...so just set it at 6volts, use the chassis as heat sink (with mica sheet to seperate it
)This is the part number: MIC29752BWT
Datasheet: http://www.micrel.com/_PDF/mic29150.pdf (pdf) about £12 from RS, there are similar chip based regulators on the market you can use instead.
Note that you'll need capacitors across the terminals and ground on any electric motor powered by the regulator to soak up any back emf which can damage the regulator...nothing big a few 0.1uF to 10uF ceramic disc types should be enough....a lesson I learnt from my RC car days
You mention you can't upgrade the ignition....why not? A aftermarket 12volt coil with a ballast resistor will still work the contact points no differently.
Last edited by ALi-B; 17 February 2005 at 01:18 AM.
17 February 2005, 07:19 AM
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Originally Posted by 4X4BOB
Its late so prob not thinking correct but I'll say it anyways:
Could you not supply 12volts to the 6Volt equipment and use a suitable resistor in parallel (or is it series) to each piece of equipment?
I'm sure I remember doing something along those lines umpteen years ago at college and the resistor takes some of the power thuse reducing what goes through the equipment?
Bob
Could you not supply 12volts to the 6Volt equipment and use a suitable resistor in parallel (or is it series) to each piece of equipment?
I'm sure I remember doing something along those lines umpteen years ago at college and the resistor takes some of the power thuse reducing what goes through the equipment?
Bob
- if the load needs to draw a power surge, all the voltage will be dropped across the resistor, so it'll basically get switched off;
- if the load current reduces for any reason, the voltage across the resistor will fall, and the load will see the full 12V from the battery and could be damaged;
- the resistor will dissipate exactly the same power as all the 6V loads put together. In other words, it'll get very, very hot.
17 February 2005, 07:26 AM
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Originally Posted by ALi-B
How about a few voltage regulators?
The biggest one I can find is 7.5 amps which adjustable voltage from 1.2 to 26volts...so just set it at 6volts, use the chassis as heat sink (with mica sheet to seperate it )
This is the part number: MIC29752BWT
Datasheet: http://www.micrel.com/_PDF/mic29150.pdf (pdf) about £12 from RS, there are similar chip based regulators on the market you can use instead.
Note that you'll need capacitors across the terminals and ground on any electric motor powered by the regulator to soak up any back emf which can damage the regulator...nothing big a few 0.1uF to 10uF ceramic disc types should be enough....a lesson I learnt from my RC car days
You mention you can't upgrade the ignition....why not? A aftermarket 12volt coil with a ballast resistor will still work the contact points no differently.
The biggest one I can find is 7.5 amps which adjustable voltage from 1.2 to 26volts...so just set it at 6volts, use the chassis as heat sink (with mica sheet to seperate it
)This is the part number: MIC29752BWT
Datasheet: http://www.micrel.com/_PDF/mic29150.pdf (pdf) about £12 from RS, there are similar chip based regulators on the market you can use instead.
Note that you'll need capacitors across the terminals and ground on any electric motor powered by the regulator to soak up any back emf which can damage the regulator...nothing big a few 0.1uF to 10uF ceramic disc types should be enough....a lesson I learnt from my RC car days
You mention you can't upgrade the ignition....why not? A aftermarket 12volt coil with a ballast resistor will still work the contact points no differently.
To protect it from ignition noise, back EMF and other nasties, you'll need a lot more than 10uF - these components aren't really designed for such a hostile environment.
17 February 2005, 09:13 AM
#45
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This is the part number: MIC29752BWT
I have seen an automotive application which uses a reverse diode across the regulator in-out and a few capacitors spread liberally around.(0.1uF In-Ground, 100uf Across the out)
If you mount the regulator on a suitable heatsink (rather than just trying to bolt loose electronics to the bodywork of the car)
it will dissipate the heat and keep things nice and cool 
I'm sure there are lots of 'Bug' owners who have had to deal with this problem so it's hardly a first. Have a search on some of the classic forums.
Last edited by CharlieWhiskey; 17 February 2005 at 09:34 AM.
17 February 2005, 09:37 AM
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I agree that somewhere there's bound to be a 'standard' answer to this problem. Unfortunately my own experience is more limited to equipment that's designed to be powered from a nicely regulated supply in an air conditioned comms room rather than under the bonnet of a car!
You could try downloading this document which describes (amongst other things) a range of dc/dc converters that will give you at least 30A with over 90% efficiency. One of those might just do - though I couldn't vouch for how long it might last depending on what sort of load you're driving.
We really need more details of what the 6V supply is required to power here.
You could try downloading this document which describes (amongst other things) a range of dc/dc converters that will give you at least 30A with over 90% efficiency. One of those might just do - though I couldn't vouch for how long it might last depending on what sort of load you're driving.
We really need more details of what the 6V supply is required to power here.
17 February 2005, 11:00 AM
#47
To protect it from ignition noise, back EMF and other nasties, you'll need a lot more than 10uF - these components aren't really designed for such a hostile environment.
it'll get very hot
As long as the load doesn't exceed 7.5 amps it won't be a problem. Using 3 or 4 and spliiting the load between them. The biggest problem is they require a minimum current to be drawn in order to operate correctly (a few milliamps).
Last edited by ALi-B; 17 February 2005 at 11:06 AM.
17 February 2005, 11:05 AM
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17 February 2005, 11:07 AM
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OK, I'll believe you - but don't forget that in this case we're dealing with both a noisy 12V supply AND a potentially noisy load. Not saying it won't work, but that there's a need to look carefully at where the inductive loads are in the system and ensure that the regulator is adequately protected against them.
Still don't like the idea of using a linear regulator to provide much power though - 10A dropping 6V = 60W being dissipated in a package smaller than a 5p piece. It is going to get warm...
Still don't like the idea of using a linear regulator to provide much power though - 10A dropping 6V = 60W being dissipated in a package smaller than a 5p piece. It is going to get warm...
17 February 2005, 11:09 AM
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The biggest problem is they require a minimum current to be drawn in order to operate correctly (a few milliamps).
17 February 2005, 11:12 AM
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The minimum load on that 7.5A one is 10mA, so just stick an LED on it
It also has a disable input which limits the current drawn form the battery to uA so you could leave it connected all the time and just enable it from the ignition.
It also has a disable input which limits the current drawn form the battery to uA so you could leave it connected all the time and just enable it from the ignition.
17 February 2005, 11:19 AM
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Good link ajm
Sound advice, but I would add a fuse on the output side which is less than the fault current (15A on the 7.5A reg) so a 10A automotive fuse will be ideal.
The key to making the regulators work is keeping them cool, so be sure to use a good heatsink and put a thin coat of silicone grease on the regulator and transistor and any insulating hardware. Mount the heatsink where it can get some air circulation, don't put it in an airtight box. Don't mount it where the heat it genereates can cause trouble for any plastic or rubber parts nearby. Remember that the body of the transistor and all the other parts are electrically 'hot' when the regulator is powered up, so make sure nothing can come in contact with it and short anything out. It's a very good idea to put an inline fuse on the input side of the regulator in case 'something bad' happens
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