Leisure battery

corktina · 07-07-2013 6:22pm #1

Help out a novice...should the leisure battery be charged by the alternator when under way? Mine ran nearly flat today with the fridge running.

There is a three position battery condition meter on the dash...do I have to leave this in any particular position to get the battery to charge?

It's on mains now and the battery charger light is on, but there is a "mains " position and the light goes off if I throw the switch to this position.

I really need an elementary lesson in battery power I think...can anyone help me out? (Fridge did work when on battery only before I drove it today)

07-07-2013 7:16pm

What size is your leisure battery (bank)?
What type is the fridge? Do you know the current rating of the fridge?
Can you get or do you have a multimeter?
Can you post photos of both switches?

corktina · 07-07-2013 7:45pm

Been plugged into mains all afternoon, fridge still warm, charger hot. I just switched it to the "mains" position as shown, no light on now....is one position for charging from the alternator perhaps and the "mains" position for charging from the mains?. That would make sense to me

AutostratusEB · 07-07-2013 9:25pm

This is a common problem and there's a good few threads on it on the forum.

When it happened to me, the cause was a break in the connection between the relay on the engine battery side and the leisure battery, which meant that the A) the leisure battery wasn't being charged whilst driving and

the fridge was drawing it's 12v supply whilst underway from the (uncharging) leisure battery.
Re-establishing this connection solved the problem. Finding the bad connection is the hardest part. As it turned out, in my case it was a disconnected lead right at the engine battery.

Hope this helps a bit.

corktina · 07-07-2013 9:38pm

interesting. When I first got it working, I found that the live to the relay controlling the main power to the fridge wasn't live, and I couldn't trace the wire back to the dash or engine bay, so I swapped the live off another socket that did work and that did open the relay and run the fridge. This live came from a fused supply, I must check that fuse hasn't blown.

I will also check the relay under the bonnet and it's connections.

I think an auto-electrician might be quicker!

To pass the DoE, the battery needed to be secured and I wonder if the mechanic has disconnected something he shouldn't have, I did check for stray wires, but I will take out the battery completley in case I missed one. (I checked all the many fuses under the bonnet and all were good.)

My main problem is not knowing what each switch and box actually does and how it should be set up correctly.

07-07-2013 10:05pm

corktina wrote: »

There is a three position battery condition meter on the dash...do I have to leave this in any particular position to get the battery to charge?

I suspect not. It's likely just a meter but if you can check these I may be able to tell you more:

Can you tell me what the meter in the dash reads according to the three positions of the switch?
Can you verify these reading with a DC multimeter with A: the engine battery and B: the leisure battery?
Can you tell me what the meter in the dash reads according to the three positions of the switch again this time with the engine running?

Disconnect your hook up lead before running the engine just in case.

corktina wrote: »

Been plugged into mains all afternoon, fridge still warm, charger hot. I just switched it to the "mains" position as shown, no light on now....is one position for charging from the alternator perhaps and the "mains" position for charging from the mains?.

I'm not familiar with your charger. I suspect it's one position for "mains on" and one position for "mains off"...ie. charging from mains and not charging. Alternator charging may be automatic from a relay or switched elsewhere. I also suspect the switch is installed upside-down....as you say the light comes on in the off position. Disconnect your mains hook up and see if you can pry it out, then check for twisted wires at the back of the switch and rotate it 180° in an unraveling direction. If it won't happily rotate or the wires aren't twisted then show me a photo of the back of it...it may just be that you have to swap two wires and re-install (or the laziest way is to write new labels on a piece of tape).

Chargers often get hot if it's less than about 70°C and ventilated I wouldn't worry about it, it's just working hard.

corktina wrote: »

interesting. When I first got it working, I found that the live to the relay controlling the main power to the fridge wasn't live, and I couldn't trace the wire back to the dash or engine bay, so I swapped the live off another socket that did work and that did open the relay and run the fridge. This live came from a fused supply, I must check that fuse hasn't blown.

Which live to relay? Switched live or battery live? Could it have been a live switched off the ignition?

AutostratusEB · 07-07-2013 10:11pm

Cool. It sounds like you are on the case and are pretty familiar with vehicle electrics. I'd say it's definately a stray connection. Relays do and can go faulty ( relays can be tested if ya google a bit) but check the obvious stuff first. Word is it's trial and and error, but I think you are on the right track. When it happened to me I thought the leisure battery had **** the bed and I replaced it before checking other stuff, so don't panic!
best,
A

07-07-2013 10:27pm

Check the ground continuity too. Good connection from Leisure battery negative to chassis.

07-07-2013 10:35pm

AutostratusEB wrote: »

I'd say it's definately a stray connection. Relays do and can go faulty ( relays can be tested if ya google a bit) but check the obvious stuff first.

Aye most common faults in order;

Blown fuse,
Bad ground
Loose connection

You can check a relay by listening, or by touching the insulated part while they operate. They make a solid electromagnetic tick.

AutostratusEB wrote: »

It sounds like you are on the case and are pretty familiar with vehicle electrics.

..tehehe, nah! Can't read an automotive circuit diagram me, I just hard-wire everything off the cigarette lighter

corktina · 07-07-2013 10:47pm

position one on dash is for vehcle battery (i assume) reads 12v or so
middle position reads zero (OFF?)
position three is for leisure battery (I assume), started off at 12v ish , varies between 9 and 10v now depending if fridge is off or on

relay wire that switches on the relay to power the fridge was dead and appears out of the bodyside...not traced under dash, at ignition switch or under bonnet Adjacent to the fridge switch is an unused socket , with a live feed from a fused source, not controlled from ignition switch. I switched this wire to control the fridge relay, which worked. (Might have needed abigger fuse for the fridge perhaps, haven't checked that yet.(dark)

Seems to me that the leisure battery is not charging from the alternator as I drive, that would point to another relay I guess, there is one next to the battery (see pic)..i'll start there,

I don't have a multi-meter and wouldn't be confident to use one correctly.

07-07-2013 11:16pm

Pos 1 = engine battery
Pos 2 = off
Pos 3 = leisure battery

Don't drop your battery below 12.2 volts you're gonna hurt it.

What do you mean body side? Easier turn the ignition on (not engine start) and see if you get 12v rather than chasing it.
Beware if you have to use a fuse bigger than a 15amp likely you need to use thicker wires too.

Better have a meter than messing with unknowns if you ask me..much safer. Easier diagnose too.

07-07-2013 11:23pm

The common source of charge for the leisure battery is switched from the D+ (often a diode, sometimes a fuse). This can be picked up at the fuse box, behind the battery light in the dash or unlikely at the back of the alternator . Once you find that relay you can check everything there....with a multimeter.

It's quite easy use and safe as long as you don't connect it while turning the engine on.

corktina · 07-07-2013 11:24pm

no the fridge is wired with a relay which is switched by a wire from a fuse to a switch to the relay. Main power to the fridge is a much thicker wire as you'd expect.The wire I have diverted is merely switching the relay on.

Original dead wire appears from a void area and the other end of it I can not trace.

I suspect that the fuse here has blown which would explain the fridge not working (will check tomorrow) but the main issue is the leisure battery is not charging from (or so it seems to me) the alternator

corktina · 07-07-2013 11:27pm

Sir Liamalot wrote: »

The common source of charge for the leisure battery is switched from the D+ (often a diode, sometimes a fuse). This can be picked up at the fuse box, behind the battery light in the dash or unlikely at the back of the alternator . Once you find that relay you can check everything there....with a multimeter.

It's quite easy use and safe as long as you don't connect it while turning the engine on.

there are two wires from the alternator, where I would normally expect one, I imagine one going to each battery, so I check each connection and see what happens.

Does the alternator charge both batteries simultaneously (when it works properly)

07-07-2013 11:37pm

Is the battery not charging on mains? Give the battery a full charge. Then let the battery rest 24hr and try checking position 3 (leisure battery), with A: no load and B: fridge on.
It's also possible the battery has given up the will to live.
A: will tell you how much charge it's losing and B:will tell you how much it has left to give.

corktina · 07-07-2013 11:41pm

not charging fully from the mains, I'm not even sure it is charging at all ...battery could well be ancient although it was at 12v+ when i first got the fridge to work

at present the voltage drops when you switch on the fridge from about 10v to 9v (the lowest reading on the gauge). Recovers a few seconds after switchng off the fridge.

I think I need an auto electrician

07-07-2013 11:54pm

corktina wrote: »

there are two wires from the alternator, where I would normally expect one, I imagine one going to each battery, so I check each connection and see what happens.

No need if your engine battery is charging it's working.

There's usually one or three wires I think. (can anyone else verify

)
They generally go to your starter motor, engine battery via fuseboard and dash light IIRC.

The leisure battery charge will be taken off indirectly as it's non-standard for a factory and would be added further down the production line. If there isn't a relay within eye-shot of the alternator I doubt it's there.

corktina wrote: »

Does the alternator charge both batteries simultaneously (when it works properly)

Simple answer; yes when wired to do so. (Think of it like a set of jump leads...which is what I used for my first camper year :rolleyes:)
Actually what happens is the batteries charge each other until they equalise and the alternator tops them up.

08-07-2013 12:00am

A weak battery will rest at near 12v when unloaded but drops away immediately when you load it (because it can't hold amps).
If it's not taking or holding charge then it's a dud. They usually only last 3-5 years when they're maintained.

08-07-2013 12:41am

corktina wrote: »

but the main issue is the leisure battery is not charging from (or so it seems to me) the alternator

Try turning on your engine and flick the dash switch to position 3, If you are getting more than 13volt here then your connections are good, the alternator is sending charge to the leisure battery but the battery won't accept it.
Leaving the bad battery theory the last one standing.

Aidan_M_M · 08-07-2013 7:47am

If you want I'd have a look at it for you .

corktina · 08-07-2013 9:44am

been thinking about it whilst I sleep

Fridge is OK I assume as the needle drops when you turn it on, so circuit is OK here

second wire from back of alternator is definately not factory (it has a "chocolate block" connector in it!)

battery seems likely to me (How does the fridge NOT draw power from the vehicle battery? That would be the relay I assume, seen in the battery picture above.)

First job today i to check out that wiring from the alternator to the second battery

corktina · 08-07-2013 11:02am

OK, looks like panic over....first thing I found tracing the second alternator wire was a hidden inline fuse, which was blown...replaced and seems to be charging now

Thanks for all your help peeps, hopefully I have solved the mystery!

08-07-2013 11:15am

corktina wrote: »

Thanks for all your help peeps, hopefully I have solved the mystery!

Happy days, automotive electrics is a black art.

corktina wrote: »

How does the fridge NOT draw power from the vehicle battery? That would be the relay I assume, seen in the battery picture above.

If should remain off as long as the switched (signal) live to the relay is not energised.

Sir Liamalot wrote: »

..tehehe, nah! Can't read an automotive circuit diagram me, I just hard-wire everything off the cigarette lighter

tehehe I remembered last night that I never had a cigarette lighter to begin with...that's wired off the hazard lights. ...of course it get's hot it's a cigarette lighter!

corktina · 08-07-2013 12:13pm

Sir Liamalot wrote: »

If should remain off as long as the switched (signal) live to the relay is not energised.

Now you worried me about something, so I checked.
In the pic of the battery there is a blue box which I took to be a relay... both red terminals are live all the time, and the two ends of the circuit are the red terminals of the batteries. The third wire is what I took to be the switching -on wire (to coin a phrase)...this is dead all the time and goes to a third terminal on the alternator along with a couple of other wires from god knows where. (Fourth wire is earth)

I would have expected this thin wire to be dead when the engine is off and be live when you start up and "switch on " the relay connecting the two batteries.

what thinkest thou Oh Noble Knight? seems to me that both batteries are connected together all the time

by now you gather the wiring is a bit of a mess!

08-07-2013 2:16pm

corktina wrote: »

Now you worried me about something, so I checked.
In the pic of the battery there is a blue box which I took to be a relay... both red terminals are live all the time, and the two ends of the circuit are the red terminals of the batteries. The third wire is what I took to be the switching -on wire (to coin a phrase)...this is dead all the time and goes to a third terminal on the alternator along with a couple of other wires from god knows where. (Fourth wire is earth)

Sounds like something is amiss alright, you should have three lives and one ground.
Signal live from switch return (switched on, thin cable), battery live (always on, chunky cable), live to appliance/leisure battery from relay (switched on by relay clicking) and Ground IRCC. The switch energises an electromagnet which makes a connection to the appliance by being pulled forcefully into contact and linking the battery live and appliance/leisure battery live.

Is the fridge always on?

corktina wrote: »

I would have expected this thin wire to be dead when the engine is off and be live when you start up and "switch on " the relay connecting the two batteries.

Should do.

corktina wrote: »

what thinkest thou Oh Noble Knight? seems to me that both batteries are connected together all the time

They're not, if they were the readings on Pos A. & Pos C. in your dash meter would always be the same.
What I've done in mine is I ran the switched live to a sexy missile toggle switch in the dash, fairly idiot proof that way. I didn't bother with the relay I just used 400amp cable on 30A fuses (at both battery positives).
If it's causing you duress sometimes the easiest solution is pull it all out and start again doing it your way.

corktina wrote: »

by now you gather the wiring is a bit of a mess!

I could tell that from the photo

I'm a little confused though as I understand it, you have two relays? One for fridge and on for alternator charge, can you give each a prefix in future?

corktina · 08-07-2013 2:49pm

no fridge isn't always on...theres a switch inside the van which opens a relay to run the fridge.

I was wondering myself whether I could run a live from the ignition switch or some conveniant point to the relayunder the bonnet (via a switch ) to open that one to the battery...that relay seems to me to be banjaxed anyway (I'm still assuming it's a relay....)

It's been on main charge, both needles read about 12 v and I'm trying the fridge now....faidc

08-07-2013 4:12pm

If you're putting a switch on the relay it's easier go straight from the engine battery. The reason people use the dash battery light is because it becomes an automated switch to the appropriate circuit.

If you are just looking for an ignition switched live there's usually one in the radio/hot hair blower/overhead light/electric windows/electric mirrors/seat (belt warning light)/cigarette lighter (depending on vehicle), probably a few more if you look around.

I'd really advise getting a digital multi-meter before you proceed too far, it'll make life much easier and potentially save you from discarding or damaging working kit (last time I mention it, promise).

corktina · 08-07-2013 4:20pm

ah well I do have and am using an old fashion circuit tester so I know what works and what doesn't.

I feel that relay must be faulty if it's live on both sides permanently...I'm going to replace that (have a new one somewhere) and run a lead from live via a switch to the signal terminal. I shall have to check out what the other wire(s) on the back of the alternator do,obviously they don't work either, probably that's where the non-working wire on the other relay ends up.

08-07-2013 4:53pm

corktina wrote: »

ah well I do have and am using an old fashion circuit tester so I know what works and what doesn't.

Fair enough. Just gotta watch out for polarity...the amount of stuff I've blown up...:rolleyes:...plenty-a spares round here.

corktina wrote: »

I feel that relay must be faulty if it's live on both sides permanently

You could try hitting it a few times and shake the be-jaysus outtov it...the return spring for the electromagnet is probably stuck.

corktina wrote: »

...I'm going to replace that (have a new one somewhere) and run a lead from live via a switch to the signal terminal. I shall have to check out what the other wire(s) on the back of the alternator do,obviously they don't work either, probably that's where the non-working wire on the other relay ends up.

Best of luck.

You can by-pass the relay if you're careful. Might spark a bit if you have a load on...that's where the common sense and insulated tools come in handy.

corktina · 08-07-2013 6:02pm

both batteries are chrging but I feel the leisure one is feeding off the vehicle one....new battery needed probably..we'll see once I've sorted relay out.shame they have different terminals, other wise I'd swap em over

08-07-2013 6:59pm

Doesn't really matter when they're charging, as long as you aren't start/stopping every 30mins, one is just taking more amps than the other. They'll never be the same.
Likely your alternator is in the region of 60Ah it'll soon make up the difference.

I'd leave them how they are. At the end of the day it's the engine battery you need the most.

08-07-2013 9:10pm

corktina wrote: »

(I'm still assuming it's a relay....)

Most of the simple (four terminal) relays I've seen in vehicles have the same numbers on the terminals. 85, 86, 87, and 30. According to this diagram.

I only remember the sequence (3 in a row and one odd),. Google seems happy enough to verify the same numbers.

corktina · 09-07-2013 10:59am

here am de news....

tried another relay, couldn't hear or feel that click either (but then again I am officially deaf and my hearing aids might not pick it up)

so I re-did a couple of connections and now have a live signal wire running from the back of the Alternator as original....I'm going to assume that the relay is working and leave well alone. Now plugged into mains with fridge on....battery meter should stay the same , should it not if the charger is working

Thx for the help btw, much appreciated , clarifies the thoughts when you bounce them off someone else

09-07-2013 12:02pm

corktina wrote: »

here am de news....

tried another relay, couldn't hear or feel that click either (but then again I am officially deaf and my hearing aids might not pick it up)

You should be able to feel it working too if you put a finger on the back of it.

corktina wrote: »

so I re-did a couple of connections and now have a live signal wire running from the back of the Alternator as original....I'm going to assume that the relay is working and leave well alone. Now plugged into mains with fridge on....battery meter should stay the same , should it not if the charger is working

If you see the leisure battery voltage rise when the engine is running then it's working. Halfway there then.
Fused every live I hope and both batteries?

Fridge set to mains or 12v? It it's set to 12v the battery won't charge very quickly as the charger will just be powering the fridge really.
On mains charge the voltage should be slowly creeping up from 13.8v to 14.4v/14.7v depending on the charge algorithm as the battery get's topped up. Once it's charged it should drop to a consistent 13.2v/13.6v float voltage.
You'll find alternator charge is significantly more aggressive.
If the battery is weak then it may fluctuate between 12.8v and 13.2v/13.6v on mains float.

I find one of these quite handy for quick reading, they're not highly accurate (+/- 0.3v) but they're cheap and a bit more specific than what you're using at the moment.
If you wire a handy 12v cig. lighter port (with 5v USB port for phones) into the back you can read all the batteries separately and together; engine off dash port = starter battery voltage (if cigarette lighter socket is always on), engine on = linked batteries combined voltage, engine off living quarters port = leisure battery voltage.

dc12v-24v-car-audio-voltmeter-size-same-as-car-cigarette-lighter.jpg

dc12v-24v-car-audio-voltmeter-size-same-as-car-cigarette-lighter.jpg

corktina wrote: »

Thx for the help btw, much appreciated , clarifies the thoughts when you bounce them off someone else

No worries, I'm looking for any excuse to avoid this feckin' tin worm...hate painting I do.

corktina · 09-07-2013 12:18pm

fridge is 12v/gas only...no mains,,,so I'm probalby using more battery power than the chrger is supplying BUT it is working at least now!

Road test called for I think

09-07-2013 1:11pm

It's a 7A fridge and a 15A charger.
Still though I'd advise letting the battery charge up and drop to float before turning on the fridge. If you load the battery that heavily while charging you'll fool the charger into thinking it's not taking charge. So the charge will be suspended at high current near 14v which will boil your battery and destroy it pretty quickly.
Is the battery getting hot/making bubbling noises?

If you've been running the fridge like this a long time it's likely you have gassed off a lot of the electrolyte.
Maybe it might need some topping up of the electrolyte with de-ionised water. There's usually level markers visible once you remove the cell caps (warning; danger acid and all that yadda yadda).

corktina · 09-07-2013 1:37pm

yeah the frideg knocked the voltage back to 9v with the charger supposedly running....fridge off now and I'll be able to tell if the charger is working then...frdige was working initially today

solution is to get the gas going but it's an ancient fridge taht needs work, probably a new 3 way would be the answer, but finding one small enough mighr not be easy

09-07-2013 1:40pm

By the way your fridge manual say's it works on mains with the same element as 12v.

09-07-2013 1:42pm

I still haven't much faith in your leisure battery. It'll only get worse though the longer you leave it below 12.2v.

corktina · 09-07-2013 1:48pm

Sir Liamalot wrote: »

I still haven't much faith in your leisure battery. It'll only get worse though the longer you leave it below 12.2v.

probably right, can't harm it if it's already n it's way out

....i don't understand the significance of the "manual" post...is it a 3 way afterall?

Are you saying the fridge should run when the mains are plugged in? doesn't seem to

i

09-07-2013 2:30pm

Sir Liamalot wrote: »

I still haven't much faith in your leisure battery. It'll only get worse though the longer you leave it below 12.2v.

oops, no it doesn't that manual covers 2 fridges. You have the 12v/gas version. Underlined "manual" is a hyperlink.

corktina · 09-07-2013 2:36pm

ah thought so....now on 12v+, both batteries...i'll leave it charge until this evening and then see if it drops back overnight

09-07-2013 2:36pm

corktina wrote: »

probably right, can't harm it if it's already n it's way out

You can actually. Once they start boiling they release hydrogen which is an explosive gas at somewhere around 7% to air. Once batteries go bad it's best to just recycle them and be rid of them.
As I understand it though I'm not sure you've given it a chance to fully charge and recover so it's hard to tell how bad it is.

09-07-2013 2:37pm

ha snap!...grand so...suppose this exhaust won't paint itself...

09-07-2013 3:08pm

You could make your fridge run on mains with a suitable 12v transformer.

All you need to do is run a mains feed to the transformer and then run the 12vDC output to a splice in the battery fridge input with a two position 6 pole switch (same as your dash meter switch) (Pos. 1 = battery +ive and -ive, Pos 2 = transformer output @12v +ive and -ive).

You could use relays too but it'll get messy I'd recommend just using a good 10amp DC rated switch.

I've got paint on my keyboard now :rolleyes:.

[Edit: I'm having second thoughts on this approach, might be best to establish how well the fridge performs set to 12v before further investment down that track. There's a possibility it's not effective enough to warrant the endeavor.]

corktina · 10-07-2013 11:09am

well, I charged all afternoon and evening on the mains. When I unplugged it both batteries were reading around the 12v mark and were unchanged this morning.

I then went for a 10 mile drive with the fridge on. Leisure battery went down immediately to about 11v, main battery at almost 13v. Checked fridge after 10 miles, warm still, no sign of life. Turned off fridge, leisure battery recovered to about 11.5 or 12v on way home.

Clearly the leisure battery, whilst it may well be weak and old (like me) charged from the mains but was not charging from the alternator, which is most odd. I also think my fridge may be knackered, it's drawing power and producing no cold, you would think when driving, it would be running on the alternator.

I'm going to try the "jump leads" approach, (bypass the relay) see what that does...

corktina · 10-07-2013 1:22pm

actually i replaced the relay which is now working.went for a spin , marked improvement in voltage...not a peep out of frdge though....back on mains charge now

10-07-2013 1:57pm

If you had the fridge off while charging yesterday and your leisure battery meter was showing >13v while on mains charge I can confidently say your leisure battery is dead and probably beyond salvation.

I hear you can get €0.50 per kilo for battery scrap in the right place but I have yet to confirm this myself.

If you are getting a new one I don't recommend any of the sealed ones as they're not designed to take what most alternators throw at them and they're non-serviceable.
I hear Numax/Exide are good value for money, and durable. Personally I'd rather 2 Trojan 6v in series or similar golf cart battery as these
can take some real abuse. If you want the best though it's gotta be forklift batteries.

For a long lasting leisure battery it ought to be a deep cycle semi-traction or mono-block, full traction (mega-bucks). I'd steer clear from AGM/gel types as they're too expensive and easy to destroy.
I'd see what your alternator kicks out accurately (it could be anything between 14.0v < 15.1v) and get a battery that can accept this, see the battery charge requirements on the manufacturers web-site. If the manufacturer doesn't specify bulk, absorption, float and rate of temperature compensation charge levels then I would disregard the company as unprofessional (that's just me though...most people aren't so picky).
It would be a good idea to compare this to the compatibility of your mains charger too. Ideally the max voltage for all charge stages ought to match the battery's acceptance limitation on all generators.

If you want to disregard all that then I hear Varta can cut some mustard too (only sealed versions as far as I've seen).
I can't vouch for Lucas but I get the sense these are good upper middle of the range.

Battery sites;
http://www.batterymegastore.co.uk/
http://www.alpha-batteries.co.uk/
http://www.tayna.co.uk/Leisure-Batteries-C45.html

You can of course choose a cheap and cheerful car starter battery but it won't last as long as a deep cycle as it's designed only for large cranking loads not consistent discharge.

When you are picking a new one it's best to estimate your Ah usage between charges and double it, as to keep a healthy battery you must maintain it above 50% (12.2v). Or >12.4v would be even better.
Depending on how you treat a wet cell battery you can get between 2 and 11 years service life.

10-07-2013 2:06pm

corktina wrote: »

actually i replaced the relay which is now working.

Fridge relay?

Alternator switched battery link relay was fixed yesterday, yes?

corktina wrote: »

went for a spin , marked improvement in voltage

That's probably more to do with a full charge yesterday than anything else.
The alternator outputs the same at idle as it does driving, as long as the engine is running you don't have to drive it.

corktina wrote: »

....back on mains charge now

I'd be cautious that you may have a bad or damaged cells in the leisure battery. Have a listen and see if you can hear it bubbling. You can also take off the cell caps and look for (big) bubbles (with goggles on etc.) if you don't think you'll be able to hear it. If it's boiling below 14.2v don't charge it anymore, get rid of it, it's a liability. If it gets really bad and dangerous it'll smell like bad eggs.

corktina · 10-07-2013 2:18pm

no the relay which links the two batteries when the engine is running.... i worked out it wasn't working after all. Improvement in voltage was only after i had changed relay

The battery may well be a problem but the fridge should work when the engine is running.... after 15 minutes, you should see some change surely?

10-07-2013 2:27pm

corktina wrote: »

no the relay which links the two batteries when the engine is running.... i worked out it wasn't working after all. Improvement in voltage was only after i had changed relay

Ah grand, good news then, I'd say there ought to be an improvement in voltage on Pos. 3
and a reduction (reduction on alternator output...although still higher than standing voltage) on Pos. 1; when you link batteries their voltage will meet in the middle.

corktina wrote: »

The battery may well be a problem but the fridge should work when the engine is running.... after 15 minutes, you should see some change surely?

Kindof, on a working system yes it would.
Specifically when one of the two batteries (now linked with relay active) has 7amps to give it, it will work.

I'd go check that fridge fuse again, the reduction in volts due to low battery condition will raise the amps in the circuit.

Leisure battery

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