Battery charger issue or not

[Pjfair]

:Hi, I’m looking for some advice, I recently bought a Compass Rallye 482 2005. Included was all sorts of things including mover etc etc. . With it having a mover and having the knowledge that the van had been stored inside for almost 3 years, I chose to buy a new battery from Halfords 115ah leisure. Since installing the battery it seems to be getting weaker all 0f the time and the multi meter put it at under 12v. I plugged the van onto mains and it has been on mains now for 3 days, the battery has got to 12.4v but that’s it and when I went to move the van the mover was stop start which highlighted the battery issue. If I use multimeter on the charger outlet cables right at the charger is is putting out 13.6v which I think are correct but at the battery terminals it is only 12.4v when power is on 240. I have now taken the battery off to charge in the house on my portable charger but am unsure what the real issue is. Could it be a dodgy new battery? Should the terminals have 13.6v at them so cables are faulty? Is the charger at fault even though giving out correct voltage and also showing 13.6 on the meter in van when master on and battery out of the van. Sorry it’s a bit lengthy but it’s getting stressful now and we are away this weekend which is why I am charging the battery in house (if it will)

 

[Thingy]

Ok, firstly a daft question from me but are you sure the charger is switched on. On many caravans, mine included, there are switches for charger, water, and heater, so firstly make sure you are actually turned on. Secondly, have a look at this youtube video which may expalin what you need to be looking for

https://www.youtube.com/watch?v=p4gJeV3yNOo
Its unlikely that a Halfords battery has been stored flat, but leisure batteries are notoriously difficult to bring back from a fully discharged state. I recently thought my own motor mover was faulty, turned out the battery was dying on me, but I was getting readings of 12.8 at the battery, below what the motor mover needed.

 

[ProfJohnL]

Hello Pjfair,

As I am sure you will appreciate it can be very much easier to diagnose problems if we can physically see the caravan and take measurements with equipment we can trust, so trying to do it remotely can be difficult.

but using generalisations - A new battery is unlikely to be faulty, so I strongly suspect its something else.The small difference in the battery voltage you describe, 12 to 12.4V could be down to a couple of effects. If you have used a battery then it will naturally display a slightly lower terminal voltage, but over a while it can sometimes recover a little. and 0.4V is certainly within that range. But equally batteries are temperature sensitive, and a tenth or so of a volt difference might just be caused by a different ambient temperature. Also the fact the batter will still power the Mover, again points to the battery being probably OK.

But the most telling part of your report is the fact you have used a multi-meter on the output from the charger and get 13.6V. This is what I would expect to see from a functioning charger of that period, so that suggests the charger is also probably OK.

So the problem seems to be that chargers power is not reaching the battery, and I would suspect either you have not fully understood all the various switch options or that there will be an in-line fuse between the battery and the charger which has blown. This would certainly prevent the battery from charging.

One way to check this fuse, would be to remove the 230V hook up cable, and to see if any of the 12V gear operates without the charger powered up. They should if the switches are set correctly and fuse is OK.

Because Caravan movers take their power direct from the battery terminals, using totally separate wiring to the 12V power circuits in the caravan, the mover will continue to get power even if the charger circuit fuse is blown.

 

[Gafferbill]

Check 25 amp main blade fuse.
This will be in the cable inside the cararavan behind the battery box.

 

[Grey13]

When a charger is on and working if you test the battery terminals it must be way above 12V You should be looking for 13.5 or 13.8 or even more or the battery will not charge. Reading the limited information available, if you test at the charger and it is 13.6, you simply must have 13.6 on the same 2 wires at the battery. You say all you have is 12.4, which is what you also have with no charger connected, which is exactly what your problem is. You have no charger connection! There is a break between charger and battery terminals.
I am no expert of van wiring but I doubt the 25 amp fuse is in the charger circuit.

 

[ProfJohnL]

When a charger is on and working if you test the battery terminals it must be way above 12V You should be looking for 13.5 or 13.8 or even more or the battery will not charge. Reading the limited information available, if you test at the charger and it is 13.6, you simply must have 13.6 on the same 2 wires at the battery. You say all you have is 12.4, which is what you also have with no charger connected, which is exactly what your problem is. You have no charger connection! There is a break between charger and battery terminals.
I am no expert of van wiring but I doubt the 25 amp fuse is in the charger circuit.

Hello Grey
In most installations there is an inline fuse between the battery and the caravan wiring, certainly with modern caravan power supplies the peak charging current can be 16A, but that is only the charging current, the current will also need to be able flow in the other direction for when the battery supplies the caravan, and could be more than 16A, so a quite large fuse is not uncommon. However back in 2005 an 8 to 12A maximum charge current was more common, but the battery could still be called on to proved quite large currents so the in line fuse wold still be substantial. Whetehr it would be as big as 25A would depend on the manufacturers own assessment of current demands. or wire guage.

 

[Grey13]

Prof; I agree, however I said Quote; I am no expert of van wiring but I doubt the 25 amp fuse is in the charger circuit. I agree fully on the van supply circuit having a large fuse. That fuse withstanding I would imagine a mover would have it's own fuse in addition to that.

 

[Pjfair]

Hi and thanks for all of the advice on here, clearly some knowledgable folk in the caravan world.

Just an update, I have now fully charged the battery on my portable charger,(yes suitable for leisure) so will monitor it closely to see if it is maintained with the van charger.

I will when I get chance look for the fuse in line from the charger to the terminals as that sounds like a possible cause, I do however get 12.4 at the terminals when battery removed so if fuse had blown I wouldn’t get any if I am correct? I would have thought that 12.4 must be coming from the charger when 230v hooked up suggesting continuity.

 

[Grey13]

OK so if you get 12.4 V on charger wires at battery box but with battery disconnected, that points to a problem with the on board charger circuit. It should be higher. That fits with your problem, can be charged for days and not get a good charge. IMO

 

[ProfJohnL]

OK so if you get 12.4 V on charger wires at battery box but with battery disconnected, that points to a problem with the on board charger circuit. It should be higher. That fits with your problem, can be charged for days and not get a good charge. IMO

I would tend agree with Grey given the latest information, but we were also told at the chargers output terminals the OP was getting 13.6, That's not making much sense.

I think we are reaching the point where the symptoms are suggesting its not as simple as it could have been.

What is the make of the charger? as there are some makes that do seem to fail.

 

[VicMallows]

Pjfair,
With the battery now fully charged and connected, and with the charger switched on, what readings are you now getting at
a) the charger end
b) the battery end.

My next step after that would be to measure the voltage (again with charger switched on) between the + on the charger output and + on the battery. Then repeat between the - on charger and - on battery.

I would also suggest that if possible you repeat tests with a different meter, or at the very least make sure your meter has a fresh new battery in it. (Some digital meters can give very weird indications with an ageing battery, even though they don't indicate a low-battery condition).

 

[Pjfair]

Just to clarify. I get 13.6v at the charger, where the red and black wires come out of it, this then reduces to 12.4 at the battery terminals suggesting loss between the two points. I have a pic of where but not sure as yet how to insert it, hope this makes more sense now.

 

[xtrailman]

Just to clarify. I get 13.6v at the charger, where the red and black wires come out of it, this then reduces to 12.4 at the battery terminals suggesting loss between the two points. I have a pic of where but not sure as yet how to insert it, hope this makes more sense now.

sounds like you have a poor connection between the charger and battery.

 

[VicMallows]

Just to clarify. I get 13.6v at the charger, where the red and black wires come out of it, this then reduces to 12.4 at the battery terminals suggesting loss between the two points. .

You said earlier that you had removed the battery and fully charged it on a separate charger. What voltage did your battery have after having being disconnected from the charger for an hour or so but not connected to anything else? It should be at least 12.7v

Have you now re-installed the battery in the van? Are you saying that you are STILL seeing 12.4v at the battery and 13.6v at the charger?

 

[Pjfair]

Hi. After some time been disconnected from portable charger. Battery was at 13.7 so all good. Now connected to van all seems good so now a bit of a waiting game to see if it discharges even if been connected to 230. So it does at the moment seem line a poor link between charger and battery terminals. I will monitor over weekend as will be away in van and feed back any more findings. Once again thanks all for the pointers and advice.

 

[Parksy]

This reply is probably daft, but are the inner surfaces of the terminal lugs on the ends of the battery connection leads clean?
Are they making good contact between the battery lugs and the leads?

 

[Hutch]

Just an out of the Blue, coming off a pitch, Stop Start. Turned out to be , the connecters to the Motormover Fuse, not tight. GOOD LUCK.

 

[ProfJohnL]

The big unknown is why there is an apparent voltage drop between the chargers potential of 13.6 to the battery. Fundamentally it should just be a pair of wires, and to get 1.2V drop , (0.6v per wire) would only happen if a lot of current was being used somewhere.

I discount poor battery connections, because the again the volts drop would only occur when current is being used, and when no current is being used the poor contact resistance would have little effect on the voltage from the charger

We have reached a point where the limitations of communicating via the forum, aren't likely to provide the necessary information to enable any of us to accurately understand whats going on and to produce a copper bottomed answer. Its moving beyond the realms of a simple DIY fix and its looking more like it needs an expert to visit and diagnose the problem.

 

[Pjfair]

Hi prof John, absolutely right next port of call was an engineer to look, however after reading I’ll of the posts I followed the cables out of the charger to a union connector which was in tact, the +red then went into fuse box, the -black went to another connector which went straight to Neg- on the battery. As I touched it it fell out of the terminal.

Therefore I stripped the sheathe back, installed into the spade connector on the plug and clamped in securely.

Now have 13.7v at the terminals for the battery which should charge the 115AH battery no problem.

I will of course leave on 230v mains now and check the battery voltage tonight but all at the moment seems to be sorted. Sometimes worth a bit more investigation saving me a lot of money so after all that, the chager is in good working order.

Many thanks for the support on here, will certainly be back on the next problem of which I’m sure won’t be long
:cheer: :cheer: :cheer: :cheer: :cheer:

 

[VicMallows]

Pleased you have sorted it. 12v systems are pretty straightforward and as long as you maintain a strictly logical approach faults can nearly always be identified and resolved.

The outstanding mystery is precisely why you were seeing 12.4v (rather than 13.6v) on the battery connectors once the battery had been disconnected. My guess (and it is only a guess) is that you had in fact at that point turned off the charger.....and what you were seeing was a residual voltage on an output capacitor of the charger. (It is likely you would still see this voltage due to some high-resistance leakage across the faulty connection you discovered).
Another possibility is that you inadvertently activated the 'HOLD' button on your meter earlier ...... I have been nearly caught out by this more than once!!

 

[xtrailman]

Easiest way to locate a problem to a poor connection is to test under load, testing off load can give misleading voltage readings, you need current flow.

I learnt that lesson long ago when working on a no voltage relay circuit on a overhead crane.