Flat battery (1 Viewer)

[JudeC]

Hi, Went to camp in a field (small CL).. poss daft as it was 1st time out, ever, and we were on a huge learning curve Everything seemed to work beautifully, though we didn't try hot water. When we were ready to leave van wouldn't start. Questions.. how do I know if leisure battery is fully charged? Does it automatically use the vehicle battery when it's 'dead' or do you have switch over manually? Do I need a new vehicle battery as we couldn't jump start it from a car? Local farmer brought a power pack down after breakdown still hadn't turned up at 4 hrs waiting. Finally can anyone recommend a power pack? Hope our ignorance gives someone a chuckle. Thanks for any help and advice.

 

[David and Sally]

So many possible answers. Depends on your vehicle and it's wiring plan.

Usually it's only the radio, cab lights, alarm etc that work off the vehicle battery. All habitation uses will work off the leisure battery.

Get a battery place to put a load tester across the battery.

 

[Spriddler]

Do I need a new vehicle battery as we couldn't jump start it from a car?

When you tried to jump start it from a car did the dash lights come on and was there any noise at all from the starter? If not it may be a bad battery/starter/chassis earth.

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[Figaro]

Did you not have electric hook up available ?

 

[Richard n Ann]

If you get a good battery monitor it will tell you the percentage of charge in the leisure battery and also the starter battery voltage, the starter battery voltage tells you it's charge level ie 12.6v = fully charged 11v = empty.
We've got the BM1 monitor, my favourite gadget

More interesting than any TV screen

 

[cmcardle75]

Hi, Went to camp in a field (small CL).. poss daft as it was 1st time out, ever, and we were on a huge learning curve Everything seemed to work beautifully, though we didn't try hot water. When we were ready to leave van wouldn't start. Questions.. how do I know if leisure battery is fully charged? Does it automatically use the vehicle battery when it's 'dead' or do you have switch over manually? Do I need a new vehicle battery as we couldn't jump start it from a car? Local farmer brought a power pack down after breakdown still hadn't turned up at 4 hrs waiting. Finally can anyone recommend a power pack? Hope our ignorance gives someone a chuckle. Thanks for any help and advice.

Normally, habitation equipment should not draw from the starter battery. However, your might not be wired up the normal way. Perhaps get a friend or knowledgable camper to look at what you've got and work out how it all fits together.

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[Off da Grid]

The car might not have had enough oomph to start the van.
Get the Earth strap checked.
connecting a Jump lead from the engine to a bare bit of bodywork should confirm a bad earth.

 

[Landy Andy]

You normally take NO power from the vehicle battery whilst camping in it. So you have a few possibilities

Basics
Did you leave the lights on
Did you use the vehicle radio whilst camping
Did you not shut a door properly so internal light stayed on

Then things get more complicated
Someone may have played with the electrics, or you may have a issue where the systems aren’t separating.
How was your fridge being powered whist you were camping?

What power indication do you have for your habitation battery?

 

[autorouter]

how do I know if leisure battery is fully charged? Does it automatically use the vehicle battery when it's 'dead' or do you have switch over manually

You can tell a lot about a system with just a few voltage readings. Get a multimeter, any old cheap one will be OK for this. Set it to the 20V DC range, if it's not an auto-ranging type.

Measure the voltage across the starter battery terminals and the leisure battery terminals, after the engine has been stopped for at least an hour, and with no loads running off the leisure battery. They should be different, maybe only slightly, but definitely different. That tells you they are not connected together. That's good. Remember the voltage values. Ideally they are between 12.0 and 12.8 volts.

Now start the engine, and measure both the voltages again. If the starter battery voltage is higher than before, that tells you the alternator is charging the starter battery. Ideally about 14 volts.

With the engine still running, if the leisure battery voltage is higher than before, that tells you the alternator is charging the leisure battery too. Again, about 14 volts would be ideal.

Are the starter and leisure battery voltages about the same when the engine is running? That tells you they are connected directly together with a 'split charge relay', which is an electrically controlled switch, that is switched on by the alternator when the engine starts, and off when it stops.

If the starter and leisure battery voltages are not the same as each other when the engine is running, it's likely you have something called a 'Battery-to-Battery charger' (B2B) that is one step better than a split charge relay.

So as I said, you can tell a lot about the system from just a few simple voltage measurements.

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[pappajohn]

Questions.. how do I know if leisure battery is fully charged? Does it automatically use the vehicle battery when it's 'dead' or do you have switch over manually?

Leisure battery voltage...... Use a multimeter directly on the battery terminals. Same applies to engine battery, don't rely on onboard voltage gauges.
The leisure battery doesn't automatically or use a manual switch to use engine battery when dead and visa-versa.
Some old control panels can be switched between the two but usually on vans 20+ years ago

 

[cmcardle75]

Leisure battery voltage...... Use a multimeter directly on the battery terminals. Same applies to engine battery, don't rely on onboard voltage gauges.
The leisure battery doesn't use the engine battery when dead and visa-versa.

Indeed, that is the whole point of having two batteries. You can use the leisure gear without finding you can't start the engine in the morning (although by this point, you've probably trashed your leisure battery, unless it is LiFePO4, which yours isn't, because the previous owner will NOT have neglected to tell you that!)

 

[JudeC]

Thank you everyone for your replies and advice. Hugely appreciated. I will work through all of it over next few days and probably come back with specific questions . Really appreciate it. It's 54 yrs since my physics O level so some of its a bit ...WHHAAT?, but I'll do 'me' best. If one gets it 'all' right, how long would a leisure battery keep you going off grid? The dog in the picture won't travel in the 'van', and is generally vey anxious, hence my wanting to be in a field with no-one else in an attempt to get him used to it.

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[autorouter]

It's 54 yrs since my physics O level so some of its a bit ...WHHAAT?

The volts and amps bit is just as relevant today as back then - the good news is you can forget the Weston Cadmium Standard Cell, and EMF in CGS units. Yes, disappointing, I know.

Motorhomes, like most small vehicles, use 12 volt batteries. The energy stored in a 12 volt battery is referred to as amp-hours. A typical leisure battery has a capacity of about 100 amp-hours (Ah). So for example it could supply 5 amps for 20 hours, or 10 amps for 10 hours, etc.

Power consumption depends very much on lifestyle, but with one 100Ah battery running a few lights, water pump, phone charger etc - quite low usage altogether - I'd expect it to last a weekend. Anything requiring heat - heater, water heater, cooking etc - is best done by gas, although diesel heating is becoming more popular.

 

[pappajohn]

A typical leisure battery has a capacity of about 100 amp-hours (Ah). So for example it could supply 5 amps for 20 hours, or 10 amps for 10 hours, etc.

.
Theoretically correct but.... .... Its recommended and generally accepted the battery should only be discharged to 50% of its total capacity so a 5amp load for 10hours or 10amp load for 5hours.

 

[rosalan]

I see you have an Eldis motorhome, which I would expect to have two batteries. While I am not sure how the system is wired together, may I offer the following thoughts.
If you have a battery specialist nearby, it would be worth having the battery tested 'under load'.
In the future you may like to consider having a battery Master or equivalent if your system does not already have one its equivalent. This connects both the leisure battery and the van battery and controls where any incoming energy goes, This should give priority to the van battery so you should never run out of power to drive away.
N.B. A leisure battery is different to a van battery, although in an emergency it could start the engine.
As you drove the van to the venue where it failed, unless you watched a lot of TV, had lights on all evening while running the heating fan, it should have given some response.
It would be worth blowing the horn or checking headlights working. As already said, the earth wire may not be grounding well.
You could try borrowing a spare battery to eliminate this being the problem.

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[JudeC]

When you tried to jump start it from a car did the dash lights come on and was there any noise at all from the starter? If not it may be a bad battery/starter/chassis earth.

 

[JudeC]

I see you have an Eldis motorhome, which I would expect to have two batteries. While I am not sure how the system is wired together, may I offer the following thoughts......
.

Hi, yes I do have a 16 yr old Elddis , which, as you say, has 2 batteries. Reading the downloaded manual made little sense until it had to when managed to start putting things together. When it was serviced in July the garage said the battery was healthy and it had a habitation check only a few weeks ago. We didn't watch any TV or use heating. Fridge was on gas. I do think that we might have been using the lights and the water pump, directly off the vehicle battery if that is possible.How stupid is that and If so lesson learned the hard way. I'll give it a good run and take it out again overnight very soon making sure switches are "where they should be(?)" and using mainly portable LED lamps. Have also just bought a 'jump starter' pack. I'm not in a rush to go far though do look forward to doing so.

 

[JudeC]

because the previous owner will NOT have neglected to tell you that!)

Unfortunately I think the previous owner neglected to tell me a lot of things, though type of battery isn't one of them as it seems to be standard. Maybe I just didn't ask the right questions. Caveat emptor, definitely applies.

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[ambulancekidd]

NO-CO Boost 40 or upwards for an excellent starter booster.

 

[rosalan]

There are several batteries to be aware of. The most expensive are Gel batteries then the two types of wet acid batteries, standard and leisure, they do different jobs. The heavier the battery is, can indicate a better performance.
As indicated before it is a very good idea to get a load test, often this is free, which will show if there is a problem with the battery.
Good luck. Alan

 

[Mike800966]

An battery shop will be able to test the starter battery. It is designed to give loads of amps for a short time and then be rapidly recharged but its not so easy to test a leisure battery as , as has been said , they are built to give a lower current for a longer period and be recharged slowly. Do watch out for that 50% rule as taking a leisure battery below that state of charge repeatedly will shorten its life.

Not quite sure how long you stayed in the field but if the lights are the older halogen they will take a fair bit out of a leisure battery but usually you can find led equivalents which use hardly anything- the clue is if the bulb gets hot ie wasting energy, other items like pump take a bit but usually only for a short time, the other culprit may be the tv. Whatever you do to the leisure battery should not affect the starter one so have a good look at the connections around it ( after its been tested)

Have fun, its all a learning curve
Mike S

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[Bonkers the Dog]

Batteries again......AGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH run for the hills!

 

[Landy Andy]

I do think that we might have been using the lights and the water pump, directly off the vehicle battery if that is possible

Not unless the system has been fiddled with (bodged)

in reality you should be able to do anything you want in the camping part of the motorhome without it effecting the starting ability. The only things that take power from the van battery whist camping would be the internal door activated light if you keep opening the front cab doors, the cab radio if you use whist parked. Apart from that it is just standard small drains of stereo memory and alarm stuff.
You should not need to limit lights, be carful of water pump, or need to carry a jump starter if the system is properly installed and healthy.

 

[PeteH]

First Suspect would be the condition of the Chassis battery?. A fully charged reading (assuming Lead acid) would only be valid for a hour or so. Test when "rested" for at least 30 min better still longer. Rested voltage should be circa 12.6V or higher. Any Battery over 2 years old is "Suspect". And yes, I do know some have Geriatric batteries that are still working OK, I had 5 year old ones on my R-V. But in general, I suspect anything battery wise over 2years.

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[autorouter]

The problem with failing batteries is that most of them fail by gradually losing capacity. The voltages go up and down just like a perfect battery, but they behave like a battery with half or even a tenth of the storage capacity. So you could leave it on charge all night, and its resting voltage will show it is full. but if you use 10Ah of charge, the voltage falls so it looks like it's empty.

You can't tell if a battery is degraded just from a simple voltage test, you have to see how it holds up when discharging to a load over a period of time.