Leisure battery dead

[GeordieNomad]

Picked the van up from storage tonight for a 2 night off grid & a 2 night with EHU. Leisure battery is completely gone. Tried driving for 30mins but still nothing. If the battery is just flat will 30mins be enough should I drive a bit more?
Of course it may not be the battery it may be the connection. Is there anyway to find out? This is our battery.

 

[HarryML7]

Have you got a multimeter to check the battery, if so check the level with no charge going in, then check with 1. engine running & 2. EHU connected. Report findings.

 

[Kannon Fodda]

If the battery is working you will need to drive for a number of hours to recharge it. This depends on the charger but some may be as pathetic as 10 Amps so for a 100Ah (Amp Hour) you'd need 10 hours.

But why is battery flat? Has the charger failed or a fuse blown? What caused discharge? Is the battery intact and had enough electrolyte? A totally flat battery will probably be fubar and not hold a charge and need replacement.

 

[GeordieNomad]

Have you got a multimeter to check the battery, if so check the level with no charge going in, then check with 1. engine running & 2. EHU connected. Report findings.

No multimeter mate.

 

[GeordieNomad]

If the battery is working you will need to drive for a number of hours to recharge it. This depends on the charger but some may be as pathetic as 10 Amps so for a 100Ah (Amp Hour) you'd need 10 hours.

But why is battery flat? Has the charger failed or a fuse blown? What caused discharge? Is the battery intact and had enough electrolyte? A totally flat battery will probably be fubar and not hold a charge and need replacement.

I am not why the battery is dead. We are newbies to MHing and we’ve done a number of trips since we got the van in June. We normally just put on in storage then pick it up. It’s never be more than a fortnight and the leisure battery has always been ok except for tonight.

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[VXman]

If the battery is working you will need to drive for a number of hours to recharge it. This depends on the charger but some may be as pathetic as 10 Amps so for a 100Ah (Amp Hour) you'd need 10 hours.

Agree with this. When you drive the engine battery is prioritised for charging. It will take a long time for the leisure to charge. Better to plug it into EHU or put an external charger on it.

 

[autorouter]

No multimeter mate.

Measuring a few voltages with a multimeter can give you all kinds of useful information, and can diagnose a lot of faults. Any cheap multimeter will be OK, and you could pick one up from a DIY store for a tenner or so. Measuring voltages is easy and safe.

When a battery is not being charged and is not running any loads, it will have a 'resting voltage' of between about 12.0V (fairly flat) and about 12.7V (full). If anything is charging it, the voltage will rise to over 13V, maybe up to about 14.5V. It should stay there for some time, maybe several hours. When it is full it will drop down to about 13.5V. When charging stops, it will drop back to its resting voltage.

First measure the leisure battery voltage at the terminals. If the voltage is good (12.5V or more) but nothing is working then you have a connection problem. Or maybe a fuse blown.

The voltage of the leisure battery should rise from its resting voltage to about 14.5V when the engine is running, which shows that the alternator is charging it. You could also measure the starter battery voltage to see of the alternator is charging it. With all these voltages you can build up a picture of how well the batteries are doing. It's definitely worth getting a multimeter and learning how to use it. Have you used one before?

Your leisure battery label it says the capacity is 100Ah. If it's very flat it's probably down to about 20Ah, so it would need 80Ah to fill it up. The alternator will probably charge it at 10A to 20A. So that means it would take 8 hours at 10A or 4 hours at 20A to put in 80Ah of charge.

Probably a useful amount of charge is about 20Ah, which would keep you going overnight if you were very careful about what you used. That would need 2 hours at 10A or 1 hour at 20A to put 20Ah of charge into the battery.

 

[GeordieNomad]

Measuring a few voltages with a multimeter can give you all kinds of useful information, and can diagnose a lot of faults. Any cheap multimeter will be OK, and you could pick one up from a DIY store for a tenner or so. Measuring voltages is easy and safe.

When a battery is not being charged and is not running any loads, it will have a 'resting voltage' of between about 12.0V (fairly flat) and about 12.7V (full). If anything is charging it, the voltage will rise to over 13V, maybe up to about 14.5V. It should stay there for some time, maybe several hours. When it is full it will drop down to about 13.5V. When charging stops, it will drop back to its resting voltage.

First measure the leisure battery voltage at the terminals. If the voltage is good (12.5V or more) but nothing is working then you have a connection problem. Or maybe a fuse blown.

The voltage of the leisure battery should rise from its resting voltage to about 14.5V when the engine is running, which shows that the alternator is charging it. You could also measure the starter battery voltage to see of the alternator is charging it. With all these voltages you can build up a picture of how well the batteries are doing. It's definitely worth getting a multimeter and learning how to use it. Have you used one before?

Your leisure battery label it says the capacity is 100Ah. If it's very flat it's probably down to about 20Ah, so it would need 80Ah to fill it up. The alternator will probably charge it at 10A to 20A. So that means it would take 8 hours at 10A or 4 hours at 20A to put in 80Ah of charge.

Probably a useful amount of charge is about 20Ah, which would keep you going overnight if you were very careful about what you used. That would need 2 hours at 10A or 1 hour at 20A to put 20Ah of charge into the battery.

Thanks. Great information. I have changed the battery now as the old one was completely knackered, think it was only showing 1.5v when the lad checked it. I have also booked the van in next week to get a solar panel fitted…

 

[autorouter]

I have changed the battery now as the old one was completely knackered, think it was only showing 1.5v when the lad checked it. I have also booked the van in next week to get a solar panel fitted…

The question is, did the battery just fail or was the failure caused by other things? Are the various charging methods all working as they should? Or maybe you are simply taking out more from the battery than you are putting in, so it gradually discharges.

One thing worth knowing is that a lead-acid battery needs to be taken up to 100% at least every month or so. If you don't, the sulfation gradually accumulates and slowly reduces the capacity of the battery.