Battery and wiring problem

Peter said:

When the charger is on the RCD trips over night and some times when it is
not charging?

If the mains RCCB is tripping it sounds like the charger is at fault.
If the charger isn't a 'plain vanilla' transformer plus rectifier one,
and has fancy control electronics to charge the battery and then switch
into a maintenance trickle charge mode, it's possible that there's an
intermittent fault that causes the charger to cut out before full charge
is reached.

I suggest you take the battery out and try charging it on its own,
monitoring the battery terminal voltage. A fully charged battery, on
charge, should show arround 14V.

Jim Ford

Quoted message said:

Finally when I connect a volt meter between the +RED terminal on the battery
and the out going red battery lead it reads 12 Volts.
An I reading the batter voltage or drain?

Using a Voltmeter like that wont tell you anything much.

To measure if something external is draining the battery then you need
to use an ammeter to measure amps and current (connected as you
described) and not a voltmeter which measures volts.

A lot of multimeters will have a 10Amp range, and with most things not
connected you should not exceed this (if you do it suggests a fault).

I would charge the batteries with another charger, just to see if that
suggests the built in charger is duff.

Incidently, when the battery goes flat, whats the longest period of
time the batteries have been left in the discharged state ?

<[email hidden]> wrote in message
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Quoted message said:

Quoted message said:

Finally when I connect a volt meter between the +RED terminal on the
battery
and the out going red battery lead it reads 12 Volts.
An I reading the batter voltage or drain?

Using a Voltmeter like that wont tell you anything much.

To measure if something external is draining the battery then you need
to use an ammeter to measure amps and current (connected as you
described) and not a voltmeter which measures volts.

But you could measure the voltage across the terminals when it is
disconnected and again when it is connected but with nothing
switched on. If the voltage drops then there is a fair old current
flowing that shouldn't be if nothing is actually turned on.

Nick Wagg <[email hidden]> wrote

Quoted message said:

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Quoted message said:

Quoted message said:

Finally when I connect a volt meter between the +RED terminal on the
battery
and the out going red battery lead it reads 12 Volts.
An I reading the batter voltage or drain?

Using a Voltmeter like that wont tell you anything much.

To measure if something external is draining the battery then you need
to use an ammeter to measure amps and current (connected as you
described) and not a voltmeter which measures volts.

But you could measure the voltage across the terminals when it is
disconnected and again when it is connected but with nothing
switched on. If the voltage drops then there is a fair old current
flowing that shouldn't be if nothing is actually turned on.

Make sure you have the radio code handy, and know how to set it. :-)
--
Gordon Harris

Quoted message said:

This AM from a full charge last night it was in the orange AM Put on charge
and showed full after one hour? Battery green dot showing Full as well.
Why did it recover so quickly?

That is really a key bit of information that suggests the problem is
not related to an unknown device in the caravan draining the battery.

Lets assume the orange light is on at circa 25% discharged, and that
then the caravan charger recharges to full charge in one hour.

Its really not feasible to put 75% of 85Ahr back into the battery in
one hour, the charger would need to output a charge current of around
70Amps, and that is a very very serious bit of electronics indeed.

So what you say suggests that either the batteries have very low
capacity (i.e a lot less than 85Ahr) or the charger is knackered.

The OP reported he had already taken the fuse out of the radio.

Quoted message said:

If the voltage drops then there is a fair old current
flowing that shouldn't be if nothing is actually turned on.

True, if you assume the battery is in good nick and fully charged.

But you could also get a reasonable voltage drop if the battery is
knacked and whatevers connected is some relativly low current device.

For the battery to discharge from an apparent 85Ahr to flat in 12 hours
(as reported) is an apparent current drain of 7A, and thats a lot. Its
85Watts of power, which is a reasonable amount of heat, you ought to
spot some unoticed device generating that much heat.

[email hidden] wrote

Quoted message said:

Quoted message said:

This AM from a full charge last night it was in the orange AM Put on charge
and showed full after one hour? Battery green dot showing Full as well.
Why did it recover so quickly?

That is really a key bit of information that suggests the problem is
not related to an unknown device in the caravan draining the battery.

Lets assume the orange light is on at circa 25% discharged, and that
then the caravan charger recharges to full charge in one hour.

Its really not feasible to put 75% of 85Ahr back into the battery in
one hour, the charger would need to output a charge current of around
70Amps, and that is a very very serious bit of electronics indeed.

So what you say suggests that either the batteries have very low
capacity (i.e a lot less than 85Ahr) or the charger is knackered.

This sounds the most likely answer, IMHO. Someone else asked if the
battery had been left in a low state of charge for any length of time,
in which circumstance the battery capacity would be seriously reduced.
This happens to any lead acid battery left uncharged.

I'd have the battery tested properly if it's history is not clear, or it
has not been kept well charged.
--
Gordon Harris

Have you set the voltmeter to DC (NOT AC)?

First of all you had the voltmeter in series with every circuit that the
battery is connected to (including the charger).

Now then, normally with everything off there should be zero volts i'd have
thought, because all the loads are open circuit and the bridge rectifier in
the charger should block the back voltage.

If the charger was on you may have read about 14v. The reason for this the
charger should knock out approx 14v and the voltmeter is very high impedance
and would see the battry as no resistance.

Testing current drain.

With everything switched off (inc charger) disconnect the batt +. Connect an
ammeter red lead to battery +, black lead to battery cable. Your multimeter
may have a 10A one built in. You should have zero amps.

Anything else and something is drawing (maybe the charger if faulty). If
this is the case you need to isolate circuits. Start with the charger. You
need to disconnect it from the battry side. (taking the mains fuse out is no
good if the rectifier is gone).

Testing the battery.

There are 2 tests basically.

Specific gravity of the electrolyte with a hydrometer if it's not a sealed
battery.

A High Rate Discharge Test. With a HRD tester. OR Connect it to a car
without the vehicle battery connected. Imobilize the iginition so that the
car can't actually start. Connect the voltmeter (NOT ammeter) across the
battery. Get someone to crank the engine. Withe the vehicle cranking (but
not firing) the voltmeter on a good battery should not drop below 10V for 15
seconds.

Testing the charger.

Disconnect the output leads from everything. make a 21w test lamp up. (bulb
holder and two flying leads) Connect it to the charger.
With the charger on the bulb should light. Measure the voltage across the
bulb - it should be 12-14.5v. Leave it on all night and see if it trips.

----- Original Message -----
From: "Peter" <[email hidden]>
Newsgroups: uk.rec.walking
Sent: Tuesday, May 02, 2006 10:27 AM
Subject: Battery and wiring problem

Quoted message said:

Hi

I am sure there is some help out there with some reasonable advice, unlike
Swift (Abbey) or my dealer who don't seem the bit interested in sorting
this out.

Van 1 year old Abbey GTS.
Problem is that the battery 85 Amp drains in storage over 24 hours some
times and a week other times?
Van stored alongside my home and on 240 connection at all times.
Battery brand new one of two (New) which both drain as quickly when
connected?
When the charger is on the RCD trips over night and some times when it is
not charging?
Checked all switches are off. That the fuses are removed from radio, alarm
and fridge is off.
Still it falls.
This AM from a full charge last night it was in the orange AM Put on
charge and showed full after one hour? Battery green dot showing Full as
well.
Why did it recover so quickly?
Finally when I connect a volt meter between the +RED terminal on the
battery and the out going red battery lead it reads 12 Volts.
An I reading the batter voltage or drain?
Help please.

Regards

Peter.

--
Regards

Peter
[email hidden]

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Quoted message said:

Now then, normally with everything off there should be zero volts i'd have
thought, because all the loads are open circuit and the bridge rectifier in
the charger should block the back voltage.

Assuming the charger is still connected on the caravan side of the
wiring, I would have thought exactly the opposite, a voltage reading of
some level is highly likely.

The electronics of the charger are going to leak a tiny bit of current
and with a modern high impedance (electronic) meter the one reading I
would definetly NOT expect was zero volts.

12V is perhaps a little high, but that could be 'normal' depending on
the electronics in the charger.

I replicated the described situation on my own charger and leisure
battery that I have in the workshop, I got a reading of 2.2V.

Quoted message said:

Assuming the charger is still connected on the caravan side of the
wiring, I would have thought exactly the opposite, a voltage reading of
some level is highly likely.

I meant to say;

"Assuming the charger is still connected on the caravan side of the
wiring but not connected to the mains ......... "

Quoted message said:

The electronics of the charger are going to leak a tiny bit of current
and with a modern high impedance (electronic) meter the one reading I
would definetly NOT expect was zero volts.

12V is perhaps a little high, but that could be 'normal' depending on
the electronics in the charger.

I replicated the described situation on my own charger and leisure
battery that I have in the workshop, I got a reading of 2.2V.

Yeah well, I was trying to point out that he had his meter in series and set
to volts so it's only showing volt drop across the rectifier must be
battery voltage - 2.2V (in your case).

My point was it shouldn't be 12v (which you proved).

My other point was the nature of high impedance meters used on vehicle
systems - they can mislead (they will conduct through "[censored]"😉

I did say with "everything off" including the mains. When I said isolate
later, I mean isolate (this doesn't mean just turning the mains off) which i
also said.

Please - i don't wanna get into any theortical arguements - i just gave the
guy some pratical pointers (as a PSV electrician).

I'm currently on the sick with a fractured ankle, otherwise i'd have rigged
something up at work before i answered, with definative answers.

The rest of what i said still pretty much stands - use a test lamp!! Load
the battery blah blah.

No more needs to be said until there is a responce of the original poster.

<[email hidden]> wrote in message
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Quoted message said:

Quoted message said:

Now then, normally with everything off there should be zero volts i'd
have
thought, because all the loads are open circuit and the bridge rectifier
in
the charger should block the back voltage.

Assuming the charger is still connected on the caravan side of the
wiring, I would have thought exactly the opposite, a voltage reading of
some level is highly likely.

The electronics of the charger are going to leak a tiny bit of current
and with a modern high impedance (electronic) meter the one reading I
would definetly NOT expect was zero volts.

12V is perhaps a little high, but that could be 'normal' depending on
the electronics in the charger.

I replicated the described situation on my own charger and leisure
battery that I have in the workshop, I got a reading of 2.2V.

Quoted message said:

My point was it shouldn't be 12v (which you proved).

Please dont invent what I said, I did not say or 'prove' it should not
be 12V.

A reading of 12V is possible in the circumstances.

Quoted message said:

My other point was the nature of high impedance meters used on vehicle
systems - they can mislead (they will conduct through "[censored]"😉

Correct, and because of that you cant say the reading should be zero
volts or should not be 12V.