12v electrics not working/ problem with control panel?

Macy0161

We're having problems with the 12v electrics in the van. Off hook up and without the engine running, it's completely dead. On hook up it is working to a degree - water pump is ok, but lights come on fine but then fade (with a buzz from control unit). Also, when we first turn on the kettle on the 240v, we're getting a buzz from the control unit for a few seconds, but all 240v lights, sockets and fridge are working fine.

Anyone any ideas? Could it be as simple as a fuse, or does it sound like the control panel is knackered? I initially thought it was a battery problem, but there's a brand new energy bull in there now! 98 lmc van if it matters. I don't know much about electrics, so if it's anything above simple I'll be calling someone, bit if it is simple I'll have a go first!

We're heading away in an hour so (on hook up) so we'll survive tonight, but we're supposed to have a night off hook up next weekend, which doesn't look like it'll happen as things stand!

Not a fuse or it just wouldn't work. Sounds like a loose connection or bad ground.

Mr.Fred

Are you sure your second battery isn't buggered. It may not be holding a charge so might be time for a new one.

Aidan_M_M

Sounds like Liam's suggestion, bad connection. Try the back/bottom of the fuse holders taking the charge into the battery. Is it a Calira charger? They often burn the pins on the multi plugs.

Macy0161

Aidan_M_M wrote: »

Sounds like Liam's suggestion, bad connection. Try the back/bottom of the fuse holders taking the charge into the battery. Is it a Calira charger? They often burn the pins on the multi plugs.

Cheers guys, just home so won't be looking tonight. Definitely not the battery - that was my initial thought, so i changed it with no difference.

All works fine when the engine is running, if that narrows it down any?

Mr.Fred

Macy0161 wrote: »

Cheers guys, just home so won't be looking tonight. Definitely not the battery - that was my initial thought, so i changed it with no difference.

All works fine when the engine is running, if that narrows it down any?

Have you tested if you're getting 12V at the battery when the engine is running may be a loose connection someplace between the battery and alternator.

I'd expect you to see closer to 14volt from alternator charge.

Given that you may potentially have two good batteries now, it may be worthwhile seeing if you can redeem the eldest. If they're both flooded batteries with the same Ah rating you can perform a specific gravity test after charging both batteries individually and letting them sit for a day. Test all 12 cells (6 per battery) and if they are all giving you the same reading (give or take a slight margin) then you can parallel the batteries for double the Ah.

Macy0161

Macy0161 wrote: »

All works fine when the engine is running, if that narrows it down any?

There probably isn't any easy answer here. A multimeter is your best friend for this sort of work. Personally I rather spend money on tools than professional help.

You may get lucky by a visual inspection of the system and gentle tugging at connections to find a loose culprit. I'd start with the chassis ground and make sure it's not corroded, loose or insulated by paint etc.
If it's not the chassis ground then switch to chasing the positives from the start of the system (alternator or battery) after this try the remaining grounds.

You may have to chase 12volt or continuity systematically across the setup until it doesn't appear where you expect it. Whereby you can deduct the problem is between where you are at and the previous connection that was good.

It's usually rare but it could also be a broken core inside the insulation of a cable. Wriggling the lead while testing for continuity will confirm this.

Remember to disconnect your battery before checking for continuity as 12volt will (probably) damage your meter on a continuity setting.

Or as you say it may be the charge/distribution unit. I wouldn't condemn it until I can confirm everything else is in good working order. The best way I can think to check this is to temporarily swap it with a known working unit and see if the symptoms persist.

If you can find a circuit diagram it may help immensely, I can never understand the things myself. I have found though that if you can track down a factory service manual (available online in pdf format on popular vehicles) for the vehicle, as opposed to an after-market version, the wiring diagrams in these are circuit specific and much easier to understand.

...I know I said earlier it wasn't a fuse. Generally speaking though when faced with an electrical problem it is best to check them all, as sometimes a system tertiary to the one you are looking at can be causing the problem.

Macy0161

Thanks. Going to try and have a look this evening and I should be able to borrow a multimeter.

I'd assumed it was the battery, but only fitted it before we went on Saturday, and discovered the same issue remained (left the presumed dud battery at the place I brought the new one - was a small nasty halfords one anyway). I don't think there's a charging issue, but will check to rule that out.

Only occured to me this morning, but the previous owner retro fitted an air conditioning unit, which is wired off the leisure battery, but is wired seperately (not through the control panel) to the sockets/ light/ water pump. It's showing no fault and a fully charged battery as of this morning.

What size is the new battery? What rating is the air con.? Could be that the air con. is simply too power hungry and running the battery down in a matter of minutes/hours. It could certainly do this on a old small & weak battery. When you say battery monitor does it present you a volt reading or % charge.
In most cases I'd advise having at the very least a cheap voltmeter installed correct to one decimal point.
Without a reliable meter you risk harming your batteries and electrics.

Macy0161

Sir Liamalot wrote: »

What size is the new battery? What rating is the air con.? Could be that the air con. is simply too power hungry and running the battery down in a matter of minutes/hours. It could certainly do this on a old small & weak battery. When you say battery monitor does it present you a volt reading or % charge.
In most cases I'd advise having at the very least a cheap voltmeter installed correct to one decimal point.
Without a reliable meter you risk harming your batteries and electrics.

Don't think its the air con - we had no issue last season with a small battery. There was nothing obviously loose, but the ground on the chassis is pretty rusted/ corroded. I can't get the screw out to try and clean the contact (which maybe naively suggests it could be the issue). Any tips on removing the screw?

Could be.

Blowtorch.
Metal expands when heated so heat what's surrounding the threads and not the screw (or wire insulation) it should come out easy when it's hot enough. That and/or penetrating oil and leverage after a few taps of a lump hammer.

Or an easier solution may be to leave it where it is, cut the wires and crimp on a new connector into a new ground. Or cut the terminal to clear the wires from the blowtorch and give better access to the screw then use a new screw and ground terminal.

If you are going to re-use any of the old connections it'll be fine after you blast it with a wire wheel or sand paper to shiney metal.

Careful not to round it or you may have to drill it out or use a screw extractor. Quick link (you'll get cheaper if you look around...sometimes in aldi/lidl bargains). The trick with screw extractors is be patient and go slow.

Other solutions are use a hack saw to cut a line into the screw head so you can get a big flat-head screwdriver to purchase it or grab the outside of the screw head with vice-grips.

To be honest usually its a slow and persistent combination of all of the above that works.

Macy0161

Gave it a couple of good sprays of WD40 - not sure the blow torch is an option now! I have those screw extractors. I could actually get at the threaded side of the screw, so tried vice grips with what I now see as predictable results - snapped off screw.

munsterabu

sounds like a dodgy earth/negative connection ..can remember an issue like this
I found a new location for my earth disconnected the battery removed old connection,made up new connection .. just as Sir Liamalot suggested ..i think this is the best option ..any place with a bolt onto the van frame /chassis should do for an earth..
hope this helps..

munsterabu

munsterabu wrote: »

...any place with a bolt onto the van frame /chassis should do for an earth..
hope this helps..

Remember to remove a little paint and clean the contacts for good connectivity.

If you can still purchase the top of the screw then it's not time to give up yet. Remember to be patient. Driliing it out is risky as you may damage the receiving threads unless you are very accurate and use a small bit.

Blowtorching .
you can use a smaller one it just takes longer.

Don't worry about burning up the WD40 as it won't make a significant difference.

Macy0161

Sir Liamalot wrote: »

Don't worry about burning up the WD40 as it won't make a significant difference.

I was more worried about causing damage above it burned off. I gave it a good soaking when I gave up last night, so hopefully it'll have done the job by the time I get a look this evening. I might also see do I have a lead long enough to confirm it's actually the earth that's the issue!

Macy0161

I wouldn't be overly concerned about causing damage to metal with heat, once you have 6 inches cleared of flammables in all directions. You can use the blowtorch from underneath the vehicle if that's more convenient. Suppose that depends on whether you have carpet to worry about.

Vibration is a good tool too. An air-hammer would be ideal, short of this hitting around the screw with a lump hammer and punch may help knock it loose.

Macy0161 wrote: »

. I might also see do I have a lead long enough to confirm it's actually the earth that's the issue!

That'd be a good idea. I'd use jumps leads connected to the negative pole of the battery for convenience.

Just realised this; if you want to drill it out and make sh1te of the threads you can just use a larger bolt with a nut on the far side. (a copper bolt would be best, but you don't see so many of those these days).

If you're installing washers (again copper = better) don't use them between the terminal and the chassis. Directly under the bolt head and nut is fine, putting them between the terminal and body may increase resistance.

Found another video you might like

Macy0161

Thanks for all the advice Liamalot - I'm admitting defeat on this one and calling a pro. My booster cables would reach the chassis from the battery, and it made no difference (assuming I was doing it right), so I'm not sure it is even the ground. Screw still wouldn't budge either. I really haven't the expertise, or time to learn it, at the moment - I'd need a decent run at it.

Fair enough. I've had those days myself too. I sheared my sump nut off once while dealing with a leak in the oil cooler which also sheared as the threads were aluminum on steel (stupid combination). Took me 2 weeks to bleed the system.

The booster cables ought to go from a clean section of the wires attached to the screw you are struggling with to the negative pole of the battery to complete the circuit. Simply attaching them to the chassis will not achieve this when the wires themselves have no connectivity to the chassis. The ground is another word for the negative pole or the wiring of a circuit after a load. Commonly to save on wiring the entire vehicle is used as the negative wire.

Macy0161

Sir Liamalot wrote: »

The booster cables ought to go from a clean section of the wires attached to the screw you are struggling with to the negative pole of the battery to complete the circuit. Simply attaching them to the chassis will not achieve this when the wires themselves have no connectivity to the chassis. The ground is another word for the negative pole or the wiring of a circuit after a load. Commonly to save on wiring the entire vehicle is used as the negative wire.

I was doing it wrong then - I just went to the chassis, not the screw. They wouldn't have reached that far anyway. Someone coming to look tomorrow, so will hopefully have a solution to post, but thanks for the help. Must try and learn a bit more about electrics (add it to my list!).

I'd go for nice clean copper rather than the screw itself. You can clip one booster cable to the other for double the length, the colour is just a convention really. Best of luck getting it sorted in any case.

Aidan_M_M

Any pics of the offensive item? I reckon it's a bad connection on the charger/power station.

Macy0161

It was a fuse - hadn't blown, but had corroded, so wasn't totally not working. I think he said because of that it was overloading the charger.

@14volts

Hope he cleaned the chassis ground up too. Oxidation and battery goop drive the resistance way up. I don't think it was overloading, if anything it was impeding, you'd need a higher voltage to get the same amps where they ought to be. This fits the scenario as while charging @14volts you had some effect, where 12volt was not strong enough. Volts are like the pressure and amps are the volume, if that makes sense.

Might do no harm and have a look around for anymore spots that need a clean. Battery terminals & clamps ok? Two's more than coincidence in this case I suspect. Baking soda and a toothbrush is good for the acid goop, sand paper for the rust/oxidation.
Good to hear you got a suss. :cool:

Macy0161

Sir Liamalot wrote: »

Hope he cleaned the chassis ground up too. Oxidation and battery goop drive the resistance way up. I don't think it was overloading, if anything it was impeding, you'd need a higher voltage to get the same amps where they ought to be.
Might do no harm and have a look around for anymore spots that need a clean. Battery terminals & clamps ok? Two's more than coincidence in this case I suspect. Baking soda and a toothbrush is good for the acid goop, sand paper for the rust/oxidation.
Good to hear you got a suss. :cool:

He checked the ground. Would a fecked battery have put the charger and fuse under pressure? If the one I replaced wasnt goosed, I probably let it get pretty low a bit too frequently over the winter and taken the lazy option of hooking up to charge it, rather than bench charge it.

Not at all the charger should support the battery. If the battery was fecked the charger would be working more to get it to hold a charge but a mains charger should not be stressed at all by producing 12 volt.
It's a fuses job to get put under pressure...you pressure them - they pop...that's the gig. In this case you did not.

The charger should float and maintain the battery at a safe charge level. (13volt range) after an initial bulk charge. Which is good for the battery.

Moisture causes oxidation/corrosion/rust.

Dusty acid on the terminals commonly, is a few things;

Electricity flowing through two dissimilar metals (lead poles and copper clamps for instance).
Condensed gassing resulting in sulphation caused by heat from overcharging (prolonged >14volt range) on an inappropriately vented battery.

Aggressively discharging also plays a part in this as it creates heat and therefore gassing.

I'm not sure if leaving it in a low state of charge causes this, it's certainly bad for inside the battery as it will sulphate in there and diminish your battery's capacity, I'm uncertain about the outside.

In any case external corrosion of the terminals & clamps can be avoided by coating the battery terminals in grease or petroleum jelly.
Internal sulphation can be avoided by staying in the 50%-100% charge range (about 12.2volts or higher)



Does "checked" mean he said something along the lines of "ah sher, it'll be grand" ?:rolleyes:

On a side note if said offending fuse was in the 12volt side of the charger it could have contributed to the feckedness of the battery. I suspect the charging unit measures the voltage of the battery at the charging wires not at the battery terminals. So after taking into account the resistance of the fuse it's possible the charger was getting inaccurate readings from the battery and undercharging the battery.