zardos

Clearly you might know something about electronics, but it is also clear you have a problem reading as this is a second time you have missed reading previous posts.

It is true that I'm no electronics designer, but again HoSS is making guesses about the gauges design that the permanent live only powers the memory part of the gauge, it could be that it powers all of the gauge and the accessory power just acts as a switch. I go back to my initial question - what is the power consumption by measuring it, a simple multi-meter can do this, instead of guessing.

While Hoss might know capacitor equations he fails to take in to account that diodes are not perfect. Looking at the 1N4148 diode spec sheet (instead of using the equations) it looks like the voltage drop across this diode will be about 0.8v for the load and expected temperature when using my example of the SPA EGT gauge. If you are interested in diodes then https://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/introduction-to-diodes-and-rectifiers/ gives some background plugging the numbers in of 11.2V start voltage (12v - 0.8v) 250hms (48mA @ 12v - this is a bit of an estimate as we don't know the current consumption at 11.2V) 5 second crank time and a 10.5v target voltage Gives a capacitor of around 300 mF need (about 20 times bigger than HoSS example) But then again your particular gauge might have different parameters. You could also think about the initial charge current of the capacitor being higher than the diode can handle, you could calculate this or you could work around it by initially charging the capacitor without the diode in place. (this would be a one off concern as once connected the charge in the capacitor would not go low enough to cause a high current spike after initial charge) or add a current limiting resistor. You could also do a parameter sweep DC simulation in QUCS (Quite universal Circuit Simulation http://qucs.sourceforge.net/), this is something I have just started playing with but that is probably overkill.

Anyway to move this forward for Will, may be instead measuring the key parameters to determine the capacitor size, may be you can tell us the make/model of the EGT gauge or a web link to the gauge? Though a quick google for example EGT parameters did not turn up many useful specifications, a few gauge manuals said just to put a 2 or 3 Amp fuses on the permanent live wire I did find that SPA did actually provide some useful details in their manuals ( http://www.spa-uk.co.uk/SPA/docs/DG60 manual issue 1.1.pdf for example) This gave an operational voltage range of 10v-16v (so in my opinion using 10v for this type of gauge is a bit borderline, I would calculate using 10.5v) and 48mA power consumption when on and backlit (it is better to use this higher consumption number as you don't want the capacitor only working some times) I would also be a bit more generous on the crank time than 3 seconds just to build a bit more of a buffer in the calculation.

Now you are being offensive. People ask questions, to give the best help possible, it's best to ask questions back if more info is need instead of making assumptions which tend to lead to bad answers.

There are many ways to store that data (like which colour to use) without power. E.g. A small internal rechargeable battery A large internal capacitor Flash memory ... But as Will says:- and he does not say the gauge is the wrong colour when the ignition is turned on (therefore it has a method to remember it, most likely from the permanent live), only that it changes when cranking

You quote a lot of equations that I'm well aware of, BUT as in your example you are making assumptions. We don't know about any of the electrical properties of the gauge to use with these equations. I did also suggest getting the data so the equations could be used to remove the trial and error of trying a couple of capacitors or combinations (combining capacitors might get you a better cost vs a single capacitor) or go for overkill and just buying a very large capacitor (which RS suggest was not cheap)

Some flat silver ones at 11.6Kb

It might be worth suggesting a max size as the current one is 2.98kb Mine is 27.3Kb but is over twice the size at 400x200 I think part of the old logo's problem is it on 198x40 so it is stretched on higher dpi screens

My first attempts with some shape (the 4x4 is driving over the .com ) With background colour Note the for other people the blue RGB seems to 60,101,147 (SVG's available for these)

I always wondered how these create a vacuum, looking at these pictures it seems it may be using the Venturi effect From the manual is seems to use a lot of air (180 ltr/min) to create up to a 60% vacuum.

No you need the right type of diode and one with a suitable breakdown voltage, current rating and forward voltage. They also create a voltage drop which if enough could mean that it could run off the capacitors or second batteries stored charge when ignition is on but engine not running (engine running would be ok because of the higher voltage from the alternator) But saying that the ones used with your led spotlights might be OK as they probably have a suitable breakdown voltage and forward voltage BUT might not have a suitable current rating. You should be able to look up the specs of the diode from it's number.

Good thought Bowie, as on more thought the gauge sounds very electronic (having a programmable colour scheme) and therefore probably is internally running at 5V and so to get a on crank voltage drop to below 5V would probably mean your car battery is on the way out and needs replacing.

Sizing the capacitor might be a lot of trial and error and getting the right capacitor or capacitors (multiple for 12v) needs some thought and could be expensive to get the right capacitors It might actually be better to replace the capacitor with a small 12v battery rechargeable and again using a blocking diode to stop cranking from drawing power from the small battery. It might be worth doing some measurements of the gauges characteristics before deciding what to do. i.e. measure at what voltage does the gauge reset at (if the gauge resets at 11.5v for example then you will probably need a very large capacitor) measure the current draw of the gauge

I run mine with an intermotor dual temp switch and just 2 relays as the dual speed fan only takes 18/24 Amps (So the second speed additional windings only take an extra 6 Amps) so a 40Amp relay is plenty to run a fan. Fridge probably means this post

My brother had something similar to this which worked very well, you did not need to keep topping up the reservoir and thus you did not run the risk of running out and pulling more air in to the system. It provides pressure similar to manual brake pumping. The only downside is the cost.

I agree fit a second alternator is probably the best and cheapest route and adds redundancy. Very high output alternators are very expensive and not easily replaceable/fixable when they go wrong. I used a Gwyn Lewis second alternator kit on v8, they also do a kit for a 200tdi disco engine https://gwynlewis4x4.co.uk/product/200tdi-discovery-range-rover-classic-engine-twin-alternator-mount/ You can then fit a 100A alternator with this (for the v8 it was a standard landrover part, for the 200tdi it looks to also be a standard Land rover part)

They still can leak even if you don't use them, both my sunroofs had good rubber seals but still leaked, the problem can often be the seal of the unit to the body not the seal between the glass and body. I removed both units fully and re-siliconed them to the body. I did also fill various clip holes with silicone sealant as well (less permanent than araldite ) for the same reason.

or May be

A lot of people have used old conveyor belt for wheel arches, or strips of Kaylan (https://www.kaylan.co.uk but not cheap)

Alternative with built in Bluetooth https://www.adafruit.com/product/3406 ARM Cortex M4F (with HW floating point acceleration) running at 64MHz and 32 bit And very small

A long time ago I had a rs-232 jumper box, very handy. But long since lost it :-(

Looking at parts book I see nothing about "light duty" only "lightweight" and the 6 bolt unit does weigh more or it could mean the weight feel of the steering, but it does seem that Landrover did stop using 6 bolts for some reason (may be because they were not as good?)

The general consensus seems to suggest that the 4 bolt is more robust than the 6 bolt. But if you do want to try and repair it then the post Might help

Solution replace the 6 bolt box with a new or reconditioned 4 bolt Box (that is what I did as 6 bolts are obsolete and no longer made which makes reconditioning more difficult where as the 4 bolts are still manufactured by Adwest) (you need to change the steering arm as well for this conversion)