Outer Limits 4x4 Board

well, I pulled have the dash apart to wire in my MP3 player, found heaps of 12V sources, but when the stereo is wired up, the power flicks on and off like there is not enough current there..

I thought "hmm weird, could be a rooted stereo", so tried plugging it straight to a 12V battery for a test, and she worked fine..

anyone know what the problem is?

do all the 12V actives do this? it could be a poor connection somewhere else in to loom.,

they all seem to do it..

they power on, and off, on and off every few seconds.. like there is not enough current coming through?

okay, do you have a multimeter? if you do, check the voltage between the active and an earth, if the voltage is jumping around, there is a problem, maybe you have a bad earth somewhere along the line.....do your dash lights do this, cig lighter?

voltage wasnt jumping up and down, was steady on ~13V..

cig lighter = 24V.. there are only a few 12V places behind the dash I can grab power for the stereo..

could just be actual connections. is the 12volt connection you made nice and solid? also check earth, bad earthing will cause troubles

most stereos i've installed have had one earth, one constant 12volt for internal memory (clock, radio stations on pre-select etc) and then 12volts that comes on when turn ignition to accessories (this is the one that turns on the radio and supplys the majority of current)

speaking of current, mp3 player shouldnt draw much current, thats what power amps do (if you have one)

can you wire this up directly to battery by running power wires (earth and 12volts) from engine bay (if needed, join acc wire and 12volt wire together to cable from battery)? then all you need to remember to manually turn off. this can be a PITA and can cause flat batteries if current draw on mp3 player is high enough (and long enough time left on)


Lance

well.. the reason I think its current is because when the radio is going, no dramas.. but when a CD is put in there, it starts playing up..

works fine straight off the battery.. dont want to do this though..

find out where the 12V converter is and what current rating it has (should be written on it somewhere) - chances are it's only good for maybe 5 - 10 amps which will be exceeded by any decent stereo.

Don't run anything at all off one battery, you'll kill that one (or both) batteries very quickly.

you can get 24 -> 12v converters from jaycar/dickies/truck supplies places, that are good for anything from about 20A and up.


good choice for your first offroad mod - the STEREO!

dumbdunce wrote:good choice for your first offroad mod - the STEREO!

it's the stereo out of the bundy.. my old mp3 player..

brian, I didnt intend on running anything straight off the battery.. gotta sort out this wiring dilema, no music in car sux

by the way, will there be only 1 24 -> 12V converter with heaps of wires coming out of it?

robbie wrote:

dumbdunce wrote:good choice for your first offroad mod - the STEREO!

it's the stereo out of the bundy.. my old mp3 player..
... no music in car sux

agreed! music will cover up all the evil grindy ni$$an noises

just checked the jaycar site.. they have 1.1A converters..

any other sites online?

robbie wrote:by the way, will there be only 1 24 -> 12V converter with heaps of wires coming out of it?

hrm should be a box about palm size (+or - , it could be as small as a matchbox or as big as a VHS cassette), should only have 3 - 5 wires coming out of it, Nissan/Hitachi components are usually pretty well labelled.

would be good if you could get your hands on a manual with wiring diagram, even if you don't understand the wiring diagram there are people here who can.

if I was looking for it I'd start under the driver/pass seats, then kick panels, then up under the dash. might have some luck looking at the fuse for the converter and tracing the colour of the wire from the fuse, if it doesn't involve unwrapping too much of the wiring.

robbie wrote::armsup:

just checked the jaycar site.. they have 1.1A converters..

any other sites online?

http://www.dse.com.au/cgi-bin/dse.store ... View/M9814

they also have a 2A one but 20A is plenty for stereo and pretty much whatever else 12v you want to run... but no inverters, compressors etc.

The original converter is probably a tiny little thing only capable of delivering a small amount of power for a few instruments. It probably has an overload thermo switch, which causes it to switch on an off when it's overloaded.
Go fo a new converter, and buy one that provides enough for your stereo and other things you're gonna get that runs off 12 volts.
Remember fuses on the 12-volt-side, cheaper to buy them than a new converter if you shortcut something by mistake.

totto

Get a 20A convertor from Dick Smith ($99) or Jaycar ($120). The Jaycar unit costs more but is fan-cooled and looks a lot beefier; my gut feeling is that it would have a real output much better than the DS unit, which has no active cooling. And the current output of these things turns to shit when they overheat.

OR a better option for the long haul is to fit a 2nd alternator and a third battery for an independent 12V system. With this, you can run heaps of 12V stuff and you can even jumpstart yourself if you have to Go deep cycle for the third battery and you can run a fridge etc one day.

Obviously this is more work - but probably worth it at least as a future project.

Jason

2nd alternator.. hmm.. now you're giving me some ideas..

robbie wrote:2nd alternator.. hmm.. now you're giving me some ideas..

Well, that would be the official Serious Solution.

It's also got merit as an off-road mod; if your 24V alternator dies and you're in the middle of nowhere, you can limp home with the 12V alternator only, switching between charging up the 1st and 2nd battery.

So, $50 for a 60A alternator out of a camry or even something smaller from a daihatsu or zuk or something, $whatever for a third battery, $20 for a longer belt, and some messing around with angle iron and threaded to make a mount and tensioner arrangement.

I'd think it would be a full weekend of stuffing around to get it all working though.

Jason

got a link for the $120 jaycar converter?

robbie wrote:got a link for the $120 jaycar converter?

http://www1.jaycar.com.au/productView.asp?ID=MP3068

ok, that looks like what I need..

if I were to get that, where should I get the 24V power from? does it need to be 24V with 15A current already?

for 20A @ 12v you would need an input of 10A @ 24v. so if you get a 15A from the 24v supply that would be good and have a 'safety margin'.

ok that all sorted.. now I need to figure out where I need to run the converter..

does the most power get drawn from the 'constant power' or the 'accessories power' on a car stereo?

reason I ask this is because I dont know whether to wire up the converter to a constant 24V rather than an accessories 24V..

any ideas/feeback appreciated..

constant is the most power drawn. the accessories is just a switch wire to turn it on.

id probably wire a relay into it tho, if it doesnt have a accessories switch wire from the convertor. so that it turns off when you switch your car off.

MaccA

383FJ45 wrote:id probably wire a relay into it tho, if it doesnt have a accessories switch wire from the convertor. so that it turns off when you switch your car off.

Definitely do this unless it is already built in to the convertor. I don't know, but I wouldn't be totally surprised if there were a triggering terminal included in it, kinda like an external amplifier.

If not, what you should be able to do is use one of the 12V wires (one or all of these should be "acc" only... I'd think) you've got built into the car to trigger a 12V relay such as a Jaycar part # SY-4068 ($5.95). The coil on these is 12V but they will still switch 24V just fine. Failing that you'll have to find a 24V relay but this could be more costly.

Yes. You need to suss out whether you have both 12V continuous and 12V switched (acc) already. If you do, you will want to use the continuous for the memory on your stereo, too. Might as well use what's in the car; otherwise you're gonna need a second small convertor ($23 for 1.1A... too expensive imho).

Hmm. Only problem is that newer stereos sometimes use their main power cable for memory and a low-current wire just for switching, unlike older ones where the memory was low-current continuous and the main power switched on and off. Dunno which yours is. Is it the red wire or the yellow wire that's fatter?

Jason

G'day guys.

Sorry, I've only just jumped into this topic, so I'm lagging a bit.
I dunno if this would work, but instead of mucking around with converters, would it be possible to run 2 x 12v batteries in series (to give the main 24v), and then grab 12v from the bridge between the 2 batteries. This 12v source can then be switched using relays (like mentioned earlier), and you'd have the full current of the first battery for this 12v source (enough to power a stereo, an amp, and then sum).

Just a thought.

what is normally the best place to grab power for the 24-12V converter?

Spank wrote:G'day guys.

Sorry, I've only just jumped into this topic, so I'm lagging a bit.
I dunno if this would work, but instead of mucking around with converters, would it be possible to run 2 x 12v batteries in series (to give the main 24v), and then grab 12v from the bridge between the 2 batteries. This 12v source can then be switched using relays (like mentioned earlier), and you'd have the full current of the first battery for this 12v source (enough to power a stereo, an amp, and then sum).

Just a thought.

No, the bridge across the two batteries (from the +ve of B1 to the -ve of B2) has zero volts across it - if that's the thing you mean.

If you mean getting power from one battery only, this is not recommended because the alternator favours the stronger battery when charging. Therefore, if you run much off one battery only, it dies a rapid death because it doesn't get charged. This is why it's also important to install two new batteries if you have to, and to make sure they are identical, when you have a 24V system.

Jason

383FJ45 wrote:id probably wire a relay into it tho, if it doesnt have a accessories switch wire from the convertor. so that it turns off when you switch your car off.

MaccA

that will mean no memory on my stereo