Engine charging (1 Viewer)

[Aros More]

Hello, please excuse me if I’m posting a subject which has been well covered previously as I’m new to motorhomes but more familiar with boat charging systems .
While away in our new Elddis 185. Wild camping 1st night all seemed well though leisure battery indicator showed low in morning (I don’t rate these block indicators over a voltage reading) We then drove for 3 hours when I assumed the leisure battery would be charged by engine. 2nd night we used power a fair bit and in morning we had a completely dead van, no lights pumps anything. The engine of course did start so first stop was Halfords for a voltmeter. Leisure battery read 5v, damagingly low I feared! Any after driving for 2 hours I stopped and checked voltage again, 4.5v. I started engine and took another reading, as suspected no increase on 4.5 confirming nothing was coming from alternator. We arrived at a site and with mains charging the battery came back to life as expected. To test alternator again I removed mains power and let the battery settle for 30mins and checked 12.8v Ok. I then started engine and took reading, 14.6v indicating the alternator was indeed charging the battery. At last to my question. Is there some form of diode protection for the alternator that prevents it charging if the leisure battery is too low as after 3 or 4 hours I would have expected at least some charge to have been replaced.
Many thanks in advance.

 

[MikeD]

Hopefully someone who can help will be along shortly

But Hi and welcome to Motorhomefun

 

[Phill D]

it would seem logical that there is some low voltage cutoff device.

i know my bench charger will not instigate a charge if the battery to be charged is below a certain voltage.

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[Figaro]

I`m no techie, but I think if your cab battery is fully charged the alternator will shut down and charge nothing.
A B2B is required, it fools the alternator into providing a permanent charge.
Someone with more technical knowledge will be along soon

 

[TheBig1]

the alternator on your van is putting very little into the leisure battery. Once the cab battery is charged the alternator drops right down on it's output. That is why many of us fit B2B battery to battery chargers and solar panels

 

[TheBig1]

And if the alternator sees no or way too low a voltage fed back, the regulator would shut down

If it's a new van, it likely has a smart alternator, which is even worse on a motorhome

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[Kannon Fodda]

At 10V a standard battery is flat. Do that regularly, and especially if you take it below that, it's not going to be happy with risk of damage so that it can't take or hold a proper charge.

Modern battery charging systems may not like a really flat battery. For your van, as the alternator charging links with both the engine and then habitation, if the engine is saying it's charged, the smart alternator electrickery may not see the really flat leisure so it cuts out. There is a techy video from Sterling that explains what may be happening

 

[andy63]

im thinking what will have happened is that the 12v system will have shut down on very low voltage..
that may well have prevented your split charge system from connecting the leisure battery to the electrical system...hence no charging... thats common enough on some systems
once on mains it will have charged sufficiently to allow normal service to resume..
that would be my best guess
Andy

 

[gus-lopez]

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[Pausim]

If the base vehicle is new and has a smart alternator the constructor should have known that there would be problems charging the leisure battery and done something about it. This is not a new problem.

 

[autorouter]

The split charge relay directly connects the starter battery and the leisure battery. The alternator can't tell that it's two batteries, it thinks it's just one big battery. So if the split charge relay was working, the leisure battery should have been charging, to about the same level as the starter battery.

The split charge relay needs a minimum voltage on the coil to switch the main contacts. It should work from as low as 10V, maybe 8v, but 5V may simply be too low to power the coil so it didn't switch.

If you use a jump lead to momentarily connect the starter battery and leisure battery, that might bump up the voltage to 10V, when it might have started working. There's the risk of dragging the starter battery down so it won't start the engine. If you connected them when the engine was already running, there's much less risk of that.

 

[cmcardle75]

It is likely that either your control panel/split charge relay or your B2B charger detected the low voltage on the leisure battery and decided to disable charging as it couldn't be sure that it would be safe to charge. Once you'd got the battery up to a reasonable voltage, it started working again.

Your battery will almost certainly have been significantly damaged by the low voltage. At a minimum you should run a smart charger on it using a high voltage repair cycle. However, you may find your battery now has significantly reduced capacity.

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[Aros More]

Many thanks for all the replies. It’s a Peugeot vehicle and has a Euro 6 engine which suggests it has a smart alternator. A battery to battery charger sounds like a good solution perhaps they should be fitted as standard.

 

[cmcardle75]

Many thanks for all the replies. It’s a Peugeot vehicle and has a Euro 6 engine which suggests it has a smart alternator. A battery to battery charger sounds like a good solution perhaps they should be fitted as standard.

Your scenario could have played out even if it did have a B2B, if you simply used more electricity than your battery had available and ran it so low that the B2B disabled itself.

However, if you don't already have a B2B, you clearly need one!

 

[Lenny HB]

Many thanks for all the replies. It’s a Peugeot vehicle and has a Euro 6 engine which suggests it has a smart alternator. A battery to battery charger sounds like a good solution perhaps they should be fitted as standard.

It will only be a smart alternator if the engine is Euro 6D your certificate of Conformity should have the info.
Normally if the engine has a smart alternator the converter will fit a B2B charger to overcome the problem.

If you have taken your leisure battery down to 5v it will be and you need a new one.
On a standard set up a flat battery will need 200-300 miles driving to recharge it.

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[Pausim]

It will only be a smart alternator if the engine is Euro 6D your certificate of Conformity should have the info.
Normally if the engine has a smart alternator the converter will fit a B2B charger to overcome the problem.

If you have taken your leisure battery down to 5v it will be and you need a new one.
On a standard set up a flat battery will need 200-300 miles driving to recharge it.

I know Fiat were disabling smart alternators for motorhomes until Euro6D but Mercedes were not. Although Peugeot are basically similar to Fiat there are differences and perhaps they left them working?

 

[eddie]

Many B2B systems won’t try to charge a faulty battery

To a simple B2B 5VDC must be faulty

Everything has done its job

The OP used too much, look at adding a battery, or upgrading to Lithium is the original battery tests faulty

 

[poppycamper]

It will only be a smart alternator if the engine is Euro 6D

Lenny HB. I thought they started fitting smart altenators as early as Euro 5.
Or am I confusing smart altenators with something else????

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[cmcardle75]

Lenny HB. I thought they started fitting smart altenators as early as Euro 5.
Or am I confusing smart altenators with something else????

They've been around since then. However, until Euro 6D, not all motorhomes had them, or had their smart features disabled so converters could save the cost of a B2B charger.

 

[eddie]

I think it’s great that Motorhome converters are finally being forced to fit decent charging systems, as opposed to relying on their customers ignorance on just how crap most ‘split chargers’ really are

 

[Beryl]

We have a 2020 Elddis 115, and it came fitted with the Schaudt B2B - it's a blue box about 6inx4in, if you can find that, you've already got a B2B. Ours is under the nearside couch - not sure where it would be on the bigger Autoquests.

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[Lenny HB]

Lenny HB. I thought they started fitting smart altenators as early as Euro 5.
Or am I confusing smart altenators with something else????

Mercs did but Fiat group didn't fit them on chassis for the Motorhome market until the Euro 6D.

 

[Kannon Fodda]

I think it’s great that Motorhome converters are finally being forced to fit decent charging systems, as opposed to relying on their customers ignorance on just how crap most ‘split chargers’ really are

But that's going to do you out of a job sorting out the inadequacies, that unsuspecting people like me bring to you

 

[eddie]

But that's going to do you out of a job sorting out the inadequacies, that unsuspecting people like me bring to you

Believe it or not we would prefer the industry to do it correctly in the first place

To this day the vast majority of people think that the alternator charges the engine battery and then, when charged concentrates on the leisure battery and that this is somehow efficient. As opposed to a crap relay (in a fancy box or not) and a bit of wire about the thickness of a boot lace !

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[ctc]

To fool the alternator just put you lights on. Smart alternators shut down when the cab battery is at about 80% so any decent load on the battery will keep it on.

 

[Aros More]

I read Beryl’s post and had a check. I do indeed have a B to B charger (see pic) Looks like eddievanbitz may be correct and the extreme low voltage led the charger to believe the battery was damaged.

I’ll monitor the battery and if it needs replaced will consider Lithium for reduced weight and increased capacity.
Many thanks for the replies.

 

[autorouter]

deleted

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[andy63]

To fool the alternator just put you lights on. Smart alternators shut down when the cab battery is at about 80% so any decent load on the battery will keep it on.

Am in right in thinking this 80% capacity limit on the battery is only applicable if you have systems like regenerative braking running in conjunction with smart alternators..
That is not always the case as smart alternators can be fitted and still beneficial without the other these other systems..
Andy

 

[Lenny HB]

I think it’s great that Motorhome converters are finally being forced to fit decent charging systems, as opposed to relying on their customers ignorance on just how crap most ‘split chargers’ really are

The only problem is that the British manufacturers will still wire it up with totally unsuitable undersized wiring.

 

[Pausim]

Am in right in thinking this 80% capacity limit on the battery is only applicable if you have systems like regenerative braking running in conjunction with smart alternators..
That is not always the case as smart alternators can be fitted and still beneficial without the other these other systems..
Andy

The smart alternator regeneration would still need some battery space. As I understand it the alternator load is reduced when the power is needed for driving. However when slowing down or braking the alternator load is increased to produce more current and adds to the braking effect.

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