Tracing voltage escape?

[Winchweight]

I have disconnected the battery +ve, then using a voltage tester with light bulb, I removed each fuse in turn, replacing each after testing until the light went out.

The only one that conclusively indicates a leak was the third in from the left, radio, courtesy light and number plate light.

Next to disconnect each in turn. Anyone had the same? Any clues that might speed things up?

[itchyfeet]

Strictly speaking voltage can't escape only current can flow
are you measuring current or voltage?

[CJH]

Are you looking for a circuit that's draining your battery? Your courtesy lights and number plate lights won't be drawing any current when they're off, but your radio might well do - they usually draw a little bit of current to maintain the memory (preset stations, tone settings etc).

I'm not sure I follow what you've done to test this so far - is your tester between the battery +ve and the +ve cable? Do you have a multimeter to measure the actual current flowing? The radio memory usually uses only a very small amount of current, so it shouldn't flatten your battery except after a very long time.

By the way, if your tester is between the +ve terminal and the +ve cable, and it's actually showing current flowing, then you can equally well do this between the battery -ve and the earth strap (current is the same anywhere in the circuit), and you'll avoid the risk of a short.

[Winchweight]

Hi,

Trying to eliminate the likely causes, starting with the easiest option first, I was disconnecting the +ve and joining it to the battery +ve terminal with the circuit tester. One by one I removed the fuses until the light on the tester went out. Good idea on preventing a short though.

Only when I removed the radio/courtesy light/ number plate lights fuse did the tester go out. The courtesy light doesn't work, or even seem to have a voltage at it and I will investigate it next weekend. The radio is the prime suspect, but as you say it should be minimal. What else is on this circuit!

However, If the van is left for 3 to 4 weeks, the battery is killed stone dead and will not accept a charge. That's two brand new batts in 3 months.....

The Eber is from the leisure batts and I hope it isn't affecting the vehicle battery, don't see how it could.

I want to isolate and fix the leak, so next weekend (weather permitting) I'll go in with the multimeter.

[ninja.turtle007]

You need to measure the actual drain amount in amps. Anything up to about 0.15 ish wouldn't be extraordinary. A cheapo multimeter will measure up to 10 amps.

[craigy345]

Hi,

As CJH says remove the - lead at battery and connect you meter inline between the - battery terminal and - lead.
You dont want to cause a short (can be done on + side but very easily to accidentally earth and cause a short)

See what amps are being drawn when everything is off on each circuit (you should hopefully see one that is high)
Then investigate this circuit, earth points, wiring and components.

Very important do NOT crank the engine, turn anything on whilst the meter is inline (all current will be flowing through the meter and this will likely break your meter or meter fuse)

Good Luck

[ghost123uk]

The radio is the prime suspect, but as you say it should be minimal. What else is on this circuit!

If the van is left for 3 to 4 weeks, the battery is killed stone dead and will not accept a charge. That's two brand new batts in 3 months.....

From the tests you have already done it sounds like you have nailed it. I have seen radios that draw a fair old current even when switched off (as said ^^^^ to keep the pre-sets and clock etc running). 98% certain you have found the problem. You could re-wire the radio so the "permanently live" wire (usually yellow) is re-routed to a switched live, but you would need to re-tune the radio every time you turned it on (no big deal). Or, you could re-wire the radio so both live wires (Red and Yellow) are fed from the leisure battery, then fit a low voltage disconnect. These are essential in my opinion, they "save" your battery every time they kick in and pay for themselves in no time by making your battery last for years as it never is allowed to run damagingly low. LINK to LVD unit. Everyone should have one fitted. If you need help with the rather ambiguous instructions (unless they have changed them) shout out.



Slight "aside" = In our Scirocco, the Sony head unit has a strange "2 stage off" function. If you tap the power button, the radio appears to go off, but the power light stays on, if you hold the power button in for around 4 seconds the whole thing goes off. Turns out he single "tap" of the button is a form of "mute" for if your phone rings etc. This had me going for a while, as in the "tap the button" mode (mute ?) it was still drawing about 1 Amp ! (I then read the instruction book for it ).

p.s. =
Re "what else is in this circuit" - do you have an alarm system fitted, that could be in that circuit.

[1664]

As said, it'll be the radio but the VW dash clock is also on fuse 3 and this requires a permanent feed too and will draw a small current.

[Winchweight]

As said, it'll be the radio but the VW dash clock is also on fuse 3 and this requires a permanent feed too and will draw a small current.

The clock is dead....... only right twice a day.

Thansk for the advice guys, weather permitting I'll have a look next weekend.