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12v system seems to have no charge despite new battery


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Hi folks,

 

I couldn't find a better way to describe the multiple problems I'm having in one headline.

 

I bought this elderly van which had been used, as many of them are, as a spare bedroom in a garden. Schoolboy error, but now I'm stuck with it. I've put a new 130ah Leisure battery in, but I still get the same syndrome: when the system is hooked up to 240v, the battery meter shows well into the green and the lights etc all seem to work fine (well, except one Lumo 3 which blew after 5 minutes, as did the replacement - but that's another thread) and so does the water pump. But in this mode, the Carver water heater won't try to ignite. If I switch the mains off, the meter still shows in the green, the water heater igniter clicks, but the battery seems to "die" in about five seconds. Also, using just one light, it burns feebly but turning on a second one kills everything in a couple of seconds. So effectively I can't use the van off grid and I can't get hot water, on or off  grid. Is there some switch or setting that has to be changed when operating off the mains?       Does anyone recognise these symptoms?

 

Any help appreciated.....

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Suggest there is no connection between the 12v power unit and the battery .. remove the battery and check the voltage on the leads when connected to mains ..

 

Roughing it . . but in comfort . .

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It does sound like you have multiple issues. 
The first place to start. Is there a switch marked “car, off, van” or similar. If so, this needs to be in the van position. 
Do you have a multimeter. If not, suggest you get one, then check the battery voltage, with mains off, and then on. If all ok, the battery should show around 12.7v with mains off, and around 13.5v with mains on. 

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The battery meter in most old caravans is of very poor quality and should not be relied upon unless checked with a decent voltmeter.

As LIW says you should get a cheap multimeter, £10 should cover it,  and find out how to measure voltage at the battery posts.

It should read :-

Over 13v when plugged into mains.

Around 12.7v after 24 hours plugged in and another 24 hours standing unplugged.

Turn on lights until they dim and check again, turn off the lights and check again.

Come back with some numbers and between us we will come up with some serious suggestions.

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Van seems to be an Elddis Shamal XL. 

Graham

 

Unless otherwise stated all posts are my personal opinion 

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It sounds like a break in the battery wiring or a blown battery fuse.  The battery charger/power supply probably has a capacitor across the output which will probably supply power for the five second that you mention.

 

The water heater is harder to explain.  It is just possible that the power supply from the mains without the smoothing effect of the battery is upsetting it so I would sort the battery out first and then see if the water heater works.

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Thanks everyone. Yes, it's a Elddis Shamal XL.

 

Are there fuses anywhere else, besides the row of round ones in the bottom of the control panel? They're all intact. I'll try to trace the battery wiring. The capacitor theory sounds exactly right. And tomorrow is multimeter time :)

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OK so I found what looks like the battery charger/ 240v input controller. It has two fuses - 2A 240v and 15A 12v. Both appear intact. There's also an inline fuse that seems to be an afterthought - it didn't have spring in, seemed the fuse was just rattling about in there, so I put a bit of ball point pen spring in to make sure there's contact. This fuse is also intact.

And - here's the puzzling thing. The brand new battery now appears to be completely flat, despite being on 240v all night with everything switched off.  What position should the "Leisure/Off/Car" battery switch be in, to enable charging from the mains?    

 

Finally some more good news (it's a mixed bag!) The Cascade water heater works on 240v - I assume it's the switch in photo 3 that did it, correct? And the fridge lights and works on gas, as well as mains. Soon we will be caravanning! 

battery charger.jpeg

inline fuse.jpeg

water heater.jpeg

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The missing spring and Scotchlocks are causes for concern, but may not actually be serious.

It is not impossible for a new battery to fail almost immediately, particularly if it has been allowed to go flat.

Testing as per my earlier post is still a good next step.

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3 hours ago, MMBG said:

What position should the "Leisure/Off/Car" battery switch be in,

To use the van and charge battery, switch should be in leisure position. 
Some vans require it to be in the off position to permit charging from car whilst towing (some need it in leisure)

Finally, the car position is used to power the caravan from your car battery , rather than using leisure battery, when parked up

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18 hours ago, MMBG said:

And - here's the puzzling thing. The brand new battery now appears to be completely flat, despite being on 240v all night with everything switched off. 

What makes you think that the battery is flat?  Have you checked it with a multimeter yet?

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19 hours ago, MMBG said:

OK so I found what looks like the battery charger/ 240v input controller. It has two fuses - 2A 240v and 15A 12v. Both appear intact. There's also an inline fuse that seems to be an afterthought - it didn't have spring in, seemed the fuse was just rattling about in there, so I put a bit of ball point pen spring in to make sure there's contact. This fuse is also intact.

And - here's the puzzling thing. The brand new battery now appears to be completely flat, despite being on 240v all night with everything switched off.  What position should the "Leisure/Off/Car" battery switch be in, to enable charging from the mains?    

 

Finally some more good news (it's a mixed bag!) The Cascade water heater works on 240v - I assume it's the switch in photo 3 that did it, correct? And the fridge lights and works on gas, as well as mains. Soon we will be caravanning! 

battery charger.jpeg

inline fuse.jpeg

water heater.jpeg

 

The wiring coming out of the floor is the original wiring, so I wonder why it has been chopped ?

 

1) Does the white wire  go into the battery box, if so what is it connected to ?

2) Is the black fuse connected to the white wire under the tape by the short bit of red  wire ?

3) Is there a red and white wire connected to the other end of the fuse ?

4) What wire in the loom is the scotch lock at the bottom of the white wire connected to ?

5) Is the top scotch lock just connecting the two red wires ?

6) Can you send a photo of the inside of the battery box showing all the wires.

7) As others have said, start by checking battery voltage with a multimeter and come back with the reading.

 

There is a chance that for whatever reason, the battery input cables to the vans 12v system have been disconnected for whatever reason.

 

This would result in the 12v consumers operating when the van is plugged into the mains but not when disconnected to the mains, i.e. running on battery power.

 

When you check the battery voltage, don't have the mains connected, note the voltage, (a) then with the battery selector switch still in the van position, connect the mains, you  should  see a rise in voltage (b) due to your charger appearing to be OK.

 

If no voltage rise, this confirms no continuity between the battery and the vans 12v system.

 

You really need a wiring diagram to identify all the wires that come out of the loom, where they go to and why they may have been disconnected, hopefully reinstating the wiring as it should be, according to a diagram, may solve your problem, however, they may have been chopped due to faults / problems further down the line.

 

Edit:  If when you check the battery voltage with a multimeter and it is in fact flat, you need to recharge it then re- fit it with the battery selector switch to off and with all 12v consumers, lights etc switched off, and see if it is drawing any current, it shouldn't be unless, as in some instances a radio or alarm has been wired in on a permanent live, note this current draw if there is one it should be minimal, then switch the battery switch to van, all consumers switched off  and see if there is any current draw, there should be none, switch on a few 12 lights you should see some current draw.

 

If no current draw in doing this, it again proves no connection between battery and van 12v system.

 

 

 

 

Edited by Silversurf

Common sense isn't a gift, it's a punishment because you have to deal with everyone who doesn't have it.  :rolleyes:

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Hi everybody.... and thanks so much for all the help and suggestions.

 

First: everything is now working! The Carver water heater works on gas and electric, but I had to put a new second hand burner in, the old one was very rusty and burning yellow.

 

As to the mysterious electrics.... well, for interest to all those who took time to offer suggestions, here's what happened. Voltage at the battery was 13.something, charging, or connected, or not. Voltage at the converter/charger output was 14-ish, and behind the  control panel, was also 12.8. But when the mains was off, it dropped to 7.2 with all the symptoms previously described.  I disconnected every circuit, no difference except the #2 lights circuit, which was the one which showed the symptoms worst.     

 

Tracking and checking this, I discovered that an ancient 4-track tape/car radio that somebody has put in the top right corner had been wired to the lights circuit! Took it out and... whooshka! Everything worked :D  Seems it soaked up enough power for its standby mode, or whatever, to trip some overload circuit when only the leisure battery was in use, but the charger has enough oomph to keep it up *and* keep the 12v circuits live.  I intend to convert them all to LCD at the earliest opportunity. 

 

Tomorrow we load up the van, and hopefully Wednesday set out on the maiden voyage.

 

Thanks again to everybody, and I now have a multimeter in the toolkit!   

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