24v through 12v bulbs

[solarman216]

OK peeps, just a bit of hands on, 5w bulb lasted 30 seconds before the cap got two hot for me to hold, two 21w bulbs blew instantly, this was of course direct onto a 24v battery not on charge, but fully charged so voltage 25.5, on the car you will have voltage drop due to cable length so the 21w may not go instantly but would not expect them to last very long, poor connections will of course vary this, Rick

 

[macabethiel]

Wher are you measuring 24 volts ?

One for the electrically minded...

So being a Japan import the 4.2 is a 24v lighting system. It has a 7 pin socket fitted for the towbar and checking with Daemo I knew there was a fair chance that the 7 pin would go through a reducer to turn it into a 12v output.

I had a look and it looked to me like my shorty was probably 24v at the 7 pin as the 7 core looked to be just scotch locked (yuck ) straight to the 24v lighting circuit.

To be sure though I decided to test the 7 pin on a spare lightboard thinking (probably wrongly) that if it was a 24v output it would blow the 12v bulbs in the lightboard. Lightboard test was successful though and all 12v bulbs worked fine. :nenau

Looking at it again today it still looks to me like the 7 core cable is just spliced straight into the 24v system with no obvious reducer so my question is, could the 7 pin socket still be a 24v output even though it worked fine with the 12v lightboard?

My r3mR PR50 was an import from Japan all 12 volts including the fitted towbar. Have you got two 12 volt batteries under the bonnet connectted in series ?

 

[Barrbeast]

My r3mR PR50 was an import from Japan all 12 volts including the fitted towbar. Have you got two 12 volt batteries under the bonnet connectted in series ?

Two 12v in series.

I checked with Daemo (who's had a few Safaris) and the Patrol forums. Safaris are definitely 24v at the lights (bulbs are all 24v). All 12v components have to be ran through a reducer.

 

[Barrbeast]

OK peeps, just a bit of hands on, 5w bulb lasted 30 seconds before the cap got two hot for me to hold, two 21w bulbs blew instantly, this was of course direct onto a 24v battery not on charge, but fully charged so voltage 25.5, on the car you will have voltage drop due to cable length so the 21w may not go instantly but would not expect them to last very long, poor connections will of course vary this, Rick

Cheers for the practical test Rick :thumb2

 

[macabethiel]

Two 12v in series.

I checked with Daemo (who's had a few Safaris) and the Patrol forums. Safaris are definitely 24v at the lights (bulbs are all 24v). All 12v components have to be ran through a reducer.

I am never too old to lean only come across 24 v lights on HGV's etc.

 

[Barrbeast]

only come across 24 v lights on HGV's etc.

I was the same until I bought the 4.2 :lol

 

[jims-terrano]

At last a reason why not to have a Patrol:

 

[Barrbeast]

At last a reason why not to have a Patrol:

Now you're being silly

Just means some things need a little extra planning :thumbs

 

[solarman216]

Nothing wrong with 24v system, in fact much better than 12v as much less amps needed so wiring can be slimmed down to suite, Rick

 

[rustic]

Nothing wrong with 24v system, in fact much better than 12v as much less amps needed so wiring can be slimmed down to suite, Rick

I agree with Rick, but jump starting could be a challenge, you would need 2 cars, separated by an insulating distance, because if the doors touched, they could be welded together...:doh

You could jump start from a lorry, but not many of those in the multistory car park. :augie

Re Patrols, I assume it's only certain models that are 24 volt, like the Safari model.
You have to consider the Patrol market, many are sold to the UN, and they prefer 24 volts, and their Land Rovers are so equipped. Then they can jump start any vehicle from any vehicle, use longer but thinner jumper cables.
They also use NATO hooks, so again any trailer, any vehicle.

Just my thoughts..
Rustic

 

[Barrbeast]

I believe they have them in Japan for better cold starting in the cold winters there.

Jump starting is possible with one car, you just charge each battery on the Trol separately and disconnect the jump cables before trying to start the Trol to make sure the other car doesn’t get a dose of 24v.

Jumping another vehicle from the Trol is even easier, actually did it yesterday to get the tractor going. You just connect up the jump cables to the bottom battery and crack on as normal :thumb2

 

[rustic]

I think this has been an interesting topic, not many of us knew about 24 volt systems in cars. From our discussions we have all learnt a bit more.

I doubt many of us will encounter cars with it, but we will now be better prepared should we have to help with a jump start.

It certainly got my brain cells working.
Great to learn something new.

Uncle Rustic :thumb2

 

[Barrbeast]

It certainly got my brain cells working.
Great to learn something new.

Uncle Rustic :thumb2

You and me both Rustic :thumbs

 

[rayf3262]

Norfolk fire service used these for 12V gear on the 24V vehicles:
http://uk.farnell.com/alfatronix/pv24s/converter-dc-dc-24-12v-24-30a/dp/1182702
There are various other units in the range offering different power ratings and isolated output options too.

 

[rustic]

Norfolk fire service used these for 12V gear on the 24V vehicles:
http://uk.farnell.com/alfatronix/pv24s/converter-dc-dc-24-12v-24-30a/dp/1182702
There are various other units in the range offering different power ratings and isolated output options too.

Wow what a great find, if the fire service use these for their equipment, and you consider the conditions at which they work, then this unit is good enough for me.
:clap:clap
Farnell an extremely reputable company, equal to our favourites RS components.

Now the big decider, it only takes 15 mA background current when sitting idle, an led on the dashboard can take more than that. So this is a fit and forget product.

Price wise... expensive ... yes in a way, but this is a fit and forget product, that you could quickly remove to another vehicle. If you found a cheaper product that you had to switch off each time due to the current draw, and let's say you forgot for a few days, or a week, then you could get back to find a flat battery, now this could mean replacing a battery, say at £ 90 maybe a couple of times over the years, so that puts the price in perspective. :thumb2

Would I buy one if I needed one? Yes I would. :thumb2:thumb2
The first ever product, with Uncle Rustic's endorsement. :thumb2
:bow:bow
Uncle Rustic

 

[Barrbeast]

I do like that as with that small draw it means you could maintain the power supply to the stereo for the memory as opposed to it stopping when the ignition is off like I have at the moment.

Too many other mods in the wings though to justify the price ticket at the moment!

 

[rustic]

I do like that as with that small draw it means you could maintain the power supply to the stereo for the memory as opposed to it stopping when the ignition is off like I have at the moment.

Too many other mods in the wings though to justify the price ticket at the moment!

Something you might want to consider, once you start drawing current at 12 volts, there may be a point, ie a few mA or more, where the unit fully switches on, and starts to draw more current. I don't know, but keep that in the back of your mind, as 15 mA is a very very low standby current.
:nenau

 

[Lazy-Ferret]

If it is only the radio back-up, you could just use a cheap Buck module from Ebay, most take up to 30v in, and you set the output voltage and current to what you want... I used some for running 5 volt christmas lights, and 10w LEDs in the car.

Sent from my SM-G930F using Tapatalk

 

[rustic]

If it is only the radio back-up, you could just use a cheap Buck module from Ebay, most take up to 30v in, and you set the output voltage and current to what you want... I used some for running 5 volt christmas lights, and 10w LEDs in the car.

Sent from my SM-G930F using Tapatalk

They use an LM317 variable output voltage regulator, very reliable circuit. Just bought 2 at £1.45 the pair from ebay far east, they are preassembled, on a pcb, but the heatsink is quite small, not capable of delivering the full 1.5 Amps as per the LM 317 spec under All conditions.
I bought two to fix the output from a couple of solar panels. Project in progress, waiting for full sun, to test how good the heatsink is lol.

Not sure why I'm telling you all this, I doubt anyone is interested lol..:doh

I guess these days I am doing memory dumps !!