View Full Version : Where does the live feed from the battery go to?
I've had battery problems with my XE Nova for a few months and have now (kind of) found the problem.
If you put a multimeter across the battery when its running it shows 14+ volts, that's fine.
When you turn the car off and leave the meter on the battery, it loses charge at a substantial rate until it's completely dead.
Finally found the problem to be the main feed that goes into the car, behind the dash and splits off into 5/6, thinner red wires.
I've tried pulling each fuse out 1 by 1 to no avail, the charge still drops.
So next of the list is to remove the dash and find out what these red wires go to.
Has anybody had this problem before or know what this thick red wire splits off into?
Many thanks.
Royston
13-10-10, 07:55 PM
Are you sure the battery isnt stuffed, does it die in minutes or hours?
what is the current draw with everything off?
The battery is brand new, the problem is deffinatly whatever the red cable goes to.
When the cars been running it stays at 12v when nothings connected. As soon as the red cable is attached it drops a ton and keeps going.
novacabrio
13-10-10, 08:01 PM
I'd try a new battery. Possible that it isn't holding its charge rather than a drain on it. The large red wire that comes from the batter runs to the fuse box to power all the cars electrics and to the starter motor.
Could also be possible that LEDs from an alarm could be taking some of the volts
novacabrio
13-10-10, 08:02 PM
Try reconnecting the fuses one by one? Also test the battery. New batterys can still be faulty
The battery was replaced because it killed the old one and it's done the same to this one.
The battery is holding its charge when its not got the red cable attached..
The car also has no alarm.
Royston
13-10-10, 08:05 PM
Has the wiring been messed with
Main red cable should go to the starter first and then a sprag to feed the main loom, are things getting hot?
Alternator connected properly?
Both of the above aren't fused!
interior light/radio are always live
The wiring is fine. Ive had it running since June until about a month ago when it just wouldnt start one morning.
There's already a wire going to the starter, this is a seperate one.
Alternators fine
Interior light goes off, no radio.
how long did it take to kill the new battery?
maybe the alternator is fooked...
About a week. Used everyday for about 10-15miles. Then one day, nothing.
yeh, IMO if it was the alt, it wouldnt of lasted that long...
my friend had a similar problem, new battery etc and done it again. turned out to be the rear heated screen was staying on.
check to see if any small things are staying on.
Royston
13-10-10, 08:30 PM
My range rover dies after a week! if not used.
I would disconnect the battery and measure the mV drawn using a multimeter with everything switched off from the battery to the connector
Yup. Plus when its running, you can drive it for aslong as you want until your turn it off, then it's completely dead.
My range rover dies after a week! if not used.
I would disconnect the battery and measure the mV drawn using a multimeter with everything switched off from the battery to the connector
With everything switched off it goes from 12v to 0v in about 90seconds.
stupid question, can you start it after it drops to 0v
Nope. As soon as the car is switched off, even before it gets chance to drain the battery. If you turn the key, the dash lights fade and it can't even crank slightly.
have you tried a known working battery of a daily used car or something...
novacabrio
13-10-10, 08:43 PM
12v-0v in 90 seconds? That would take a serious discharge! In 14 years of playing with novas i've not once had to replace a loom due to a short or a drain or any kind. Even any electrical component fitted to a car will run for a good few minutes 10-15mins id say before you even see any kind of drop in power. I'd book it in to an auto electrician personaly as if your not experienced in that field of work your always going to just be guessing.
Nope as i'm 99% sure its not that.
This red cable is deffinatly draining something.
you might as well try another known battery, and just jump it if it does discharge it.
and you havent got a massive sound system wired into the perm live or something lol.
Ill try the battery next. My mates got a Combo so ill use that.
No mate, completely the opposite. It's got a dash, 2 front seats and a bit of front carpet! lol
MattBrown
13-10-10, 09:32 PM
you might as well try another known battery, and just jump it if it does discharge it.
and you havent got a massive sound system wired into the perm live or something lol.
Its not happening that a 380ah battery is flat in 90 seonds
That cable will melt way before 250amps
if you stick a proper discharge tester across a battery, it gets hot as hell in about 5 seconds... after 90 seconds of rapid discharge, you'd have a fire & an exploding battery......
try this. with the battery disconnected & every switch turned off, things like the clock disabled & the door switches for the interior light taped shut, put a multi meter set on ohms across the battery terminals on the red & earth cables, then you'll see if there is a short circuit, then remove fuses & things like the alternator wires till you find the short.
i would also advise you get a discharge test done on the battery for peace of mind.
I would stop assuming its something to do with the red cable.
If you've pulled all the fuses and it still does it, pull the relays instead and see if the problem persists. If it doesn't, re connect them one by one until the problem returns.
This also included the fuel pump relay, which will be in the engine bay, not the fuse box, and there is also a relay in the boot on the nearside, behind the arch liner trim.
i have 2p on the alt over charging and cooking the battery.
also disconnect the earth, connect the meter in the amps aetting and see what amperage is being used. anything over 0.15 amps is high.
MattBrown
14-10-10, 04:59 PM
if you stick a proper discharge tester across a battery, it gets hot as hell in about 5 seconds... after 90 seconds of rapid discharge, you'd have a fire & an exploding battery......
try this. with the battery disconnected & every switch turned off, things like the clock disabled & the door switches for the interior light taped shut, put a multi meter set on ohms across the battery terminals on the red & earth cables, then you'll see if there is a short circuit, then remove fuses & things like the alternator wires till you find the short.
i would also advise you get a discharge test done on the battery for peace of mind.
Please be carefull playing with this.
The ohm setting is to measure resistance accross a dead circuit, so make sure you take the battery off, then measure the resistance.
It should be very high, like 100+kohms.
General Baxter
14-10-10, 05:23 PM
does the battery charge light go out when running ?
It's got a digi dash in. The charge is always on the 14v bar, sometimes creeps up one when you boot it.
Please be carefull playing with this.
The ohm setting is to measure resistance accross a dead circuit, so make sure you take the battery off, then measure the resistance.
It should be very high, like 100+kohms.
matt, thats why i told him to disconnect the battery first......my multimeter (which cost less than a tenner) will cope with high & low resistance, you actually cross the terminals to zero it......
t would be far easier to eliminate an alt fault by plugging in a fresh battery and seeing if it discharges BEFORE you try starting the car.
C612DNM
15-10-10, 09:39 PM
Disconnect the alternator and then view the volts dropping off.
Leaky regulator would be my guess here.
While the alternator charges fine when the engine is running, it sucks the battery like a $10 whore when the engine's off.
Have seen it happen before.
General Baxter
15-10-10, 10:13 PM
i bet is something to do with a ****ty digi dash
i bet is something to do with a ****ty digi dash
agree there
The digi dash should still have a battery light in it shouldnt it ??
novacabrio
15-10-10, 10:18 PM
I think it could be the fofo value!
MattBrown
15-10-10, 11:29 PM
matt, thats why i told him to disconnect the battery first......my multimeter (which cost less than a tenner) will cope with high & low resistance, you actually cross the terminals to zero it......
Mine was alot more than that lol
Well yes, it's no use if it can't measure extremely low resistance!
I mean, I've seen people shove a meter on an ohmic reading across a live 690v motor.
Nice, bye bye meter, bye bye fused leads, bye bye overload and contactor lol
hence why you buy a tenner meter....
agreed, i won't cry over it if it breaks..... i use it on mains, dc, continuity.. it works fine.
i have 3, all from lidl, £5.99 each. i still think the alt is cooking the battery somehow.
So you'd reckon new, bigger battery. See what that does?
Regulator?
Voltage regulator. It's part of the alternator and does exactly what is says - or at least it should! lo
Try a new battery first.l
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